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PD 2021-0043; HIGHLAND DRIVE 5 LOT SINGLE FAMILY RESIDENCES; PRELIMINARY GEOTECHNICAL EVALUATION; 2021-02-01
PRELIMJJSL4U3Y GEOTECHJ,JLCAL EVALUATION PRoPoD5-LyBDfiiSIoTh TNO.8•-4 CAiLSBA1S N DE COcffrrY A IFORNIA 28!iO OR CROSS REAL ESTATE INVESTORS, LLC do GREG DRAKOS P.O. BOX 231077 CARLSBAD, CALIFORNIA 92023 W.O. 8037-A-SC FEBRUARY 1, 2021 RECn\En NOV 10 2021 LAND :VELOFMENT Geotechnical. Geologic. Coastal • Environmental 5741 Palmer Way • Carlsbad, California 92010 • (760) 438-3155 • FAX (760) 931-0915 • www.geosoilsinc.com February 1, 2021 W.O. 8037-A-SC Cross Real Estate Investors, LLC do Greg Drakos P.O. Box 231077 Encinitas, California 92023 Attention: Mr. Greg Drakos Subject: Preliminary Geotechnical Evaluation, Proposed 5-Lot Subdivision, Tract No. 80-46, Carlsbad, San Diego County, California, Assessor's Parcel Numbers (APNs) 156-200-28, -29, -30, -31, -32. Dear Mr, Drakos: In accordance with your request and authorization, GeoSoils, Inc. (GSl) is pleased to present the results of our preliminary geotechnical evaluation of the subject site. The purpose of our study was to evaluate the site geologic and geotechnical conditions in order to develop preliminary recommendations for earthwork and the design of foundations, walls, and pavements as they relate to the proposed 5-lot residential subdivision at the property. EXECUTIVE SUMMARY Based upon our field exploration, geologic, and geotechnical engineering analysis, the proposed development is feasible from a soils engineering and geologic viewpoint, provided that the recommendations presented in the text of this report are properly incorporated into the design and construction of the project. The most significant elements of our study are summarized below: In general, the site may be characterized as being mantled by relatively thin sections of localized undocumented artificial fill (not encountered) and topsoil/colluvium. These earth materials are in turn underlain by Quaternary-age old paralic deposits. Due to their relatively low density, lack of uniformity, and porous nature, all undocumented fill, topsoil, and any highly weathered old paralic deposits (bedrock) are considered potentially compressible and unsuitable for the support of settlement-sensitive improvements (i.e., residential foundations, concrete slab-on-grade floors, site walls, underground utilities, roadways, exterior hardscape, etc.) and/or engineered fill in their existing state. Based on the available data, the thickness of potentially compressible soils across the site is anticipated to vary between approximately 3 and 6 feet. However, localized thicker sections of unsuitable soils cannot be precluded and should be anticipated. Conversely, the underlying unweathered sedimentary bedrock is considered suitable for the support of settlement-sensitive improvements and engineered fill. Onsite earth materials are typically anticipated to generate good quality fill material within the near surface, and the presence of oversize materials within the native formation is not anticipated. Localized areas of undocumented fill may contain significant amounts of construction debris, or landscaping/organic debris, that may not be suitable for re-use. In order to: facilitate future improvements construction; mitigate the potential for water vapor transmission through floor slabs; and provide for the uniform support of structures; transition (cut/fill) lots, cut lots, lots with relatively thin planned fills, and street areas will need to be undercut (overexcavated), and then brought to grade with suitable fill soil. Undercut recommendations are presented herein. Graded slopes with 2:1 (h:v) gradients and heights below ±10 feet are generally anticipated to be stable, assuming proper construction, maintenance, and normal climatic conditions. When plans are available, GSI will re-examine slope grading stability. It should be noted that the 2019 California Building Code ([2019 CBC], California Building Standards Commission [CBSC], 2019a) indicates that removals of unsuitable soils be performed across all areas to be graded, under the purview of the grading permit, and not just within the influence of the residential structures. Relatively deep removals may also necessitate a special zone of consideration, on perimeter/confining areas. This zone would be approximately equal to the depth of removals, if removals cannot be performed onsite or offsite. In general, any planned improvement located above a 1:1 (horizontal:vertical [h:v]) projection up from the bottom, outboard edge of the remedial grading excavation at the subdivision boundary would be affected by perimeter conditions. On a preliminary basis, any planned settlement-sensitive improvements located within approximately 3 feet to potentially 6 feet from the subdivision boundary would require deepened foundations or additional reinforcement by means of ground improvement or specific structural design. Otherwise these improvements may be subject to distress and experience a reduced serviceable life span. This will require proper disclosure to any owners and all interested/affected parties should this condition exist at the conclusion of grading. Laboratory testing, including expansion index (E.I.) and Atterberg limits, performed on samples of the onsite soils, indicates soil expansion potentials are very low (E.l. range of 0 to 20). As such, site soils (topsoil and highly weathered bedrock) are not considered detrimentally expansive as defined in Section 1803.5.2 of the 2019 CBC, and therefore will not necessitate special foundation considerations. Cross Real Estate Investors, LLC W.O. 8037-A-SC FiIe:e:\wpl2\8000\8037a.pge GeoSoils, Inc. Page Two Corrosion testing performed on a representative sample of the onsite soils indicates site soils are relatively neutral with respect to soil acidity/alkalinity, moderately corrosive to exposed buried metals when saturated, present negligible sulfate exposure to concrete, and are below action levels for chloride exposure. Additional comments may be obtained from a corrosion engineer, depending on the level of protection required, as determined by the project design civil engineer and/or architect. Neither the regional groundwater table nor perched water was encountered during our subsurface studies to the depth explored. As such, regional groundwater is not anticipated to significantly affect the planned improvements. Perched water may occur in the future along zones of contrasting permeability and/or density, or seepage may occur along bedrock joints and fractures. This potential should be disclosed to all interested/affected parties. Our evaluation indicates there are no known active faults crossing the site and the natural slope upon which the site is located has low susceptibility to deep-seated landslides. Owing to the depth to groundwater and the dense nature of the sedimentary bedrock, the potential for the site to be adversely affected by liquefaction/lateral spreading is considered low. Some of the site soils that exist will be generated during grading are considered erosive (low cohesion). Thus, properly designed and maintained site drainage is necessary in reducing erosion damage to the planned improvements. The seismic acceleration values and design parameters provided herein should be considered during the design of the proposed development. The adverse effects of seismic shaking on the structure(s) will likely be wall cracks, some foundation/slab distress, and some seismic settlement. However, it is anticipated that the structure will be repairable in the event of the design seismic event. This potential should be disclosed to any owners and all interested/affected parties. Additional adverse geologic features that would preclude project feasibility were not encountered, based on the available data. The recommendations presented in this report should be incorporated into the design and construction considerations of the project. Cross Real Estate Investors, LLC W.O. 8037-A-SC FiIe:e:\wpl2\8000\8037a.pge GeoSoils, Inc. Page Two The opportunity to be of service is sincerely appreciated. If you should have any questions, please do not hesitate to contact our office. Respectfully submitted, M. 00FESS10%t GeoSoils, Inc. CO CERTIFIED ) Todd R M. Page \\OG4/ * '\EXP..W4L) * ' \ No. RCE 47857 ENGINEERING / , David W. S 4elly 11~~x CIViL Engineering Geologist, CEGBt2." Civil Engineer, R E TM P/J PFID WS/m n Distribution: (3) Addressee - (2) wet signed, (1) email Cross Real Estate Investors, LLC - W.O. 8037-A-SC File:e:\wpl2\8000\8037a.pge GeoSoils, Inc. Page Four TABLE OF CONTENTS SCOPE OF SERVICES . 1 SITE DESCRIPTION AND PROPOSED DEVELOPMENT .........................1 FIELD STUDIES .........................................................3 REGIONAL GEOLOGY ...................................................3 SITE GEOLOGIC UNITS ..................................................4 General..........................................................4 Artificial Fill (Not mapped) ......................................4 Topsoil (Not Mapped) .........................................4 Quaternary-Age Old Paralic Deposits (Map Symbol - Qop24) ..........4 Structural Geology .................................................5 GROUNDWATER........................................................5 GEOLOGIC HAZARDS EVALUATION ........................................5 Mass Wasting/Landslide Susceptibility ..................................5 FAULTING AND REGIONAL SEISMICITY ..................................... Regional Faults ....................................................6 LocalFaulting .....................................................6 Seismicity.........................................................7 SEISMIC DESIGN .......................................................7 General..........................................................7 Seismic Shaking Parameters .........................................8 SECONDARY SEISMIC HAZARDS ....................................... Liquefaction/Lateral Spreading .......................................9 Seismic Densification ..............................................10 Summary........................................................10 Other Geologic/Secondary Seismic Hazards ...........................10 SLOPE STABILITY ......................................................11 LABORATORY TESTING .................................................11 Classification .....................................................11 Moisture-Density Relations .........................................11 Expansion Index ..................................................11 Particle-Size Analysis ..............................................12 Saturated Resistivity, pH, and Soluble Sulfates, and Chlorides .............12 Corrosion Summary .........................................12 R-Value .........................................................13 GeoSoils, Inc. PRELIMINARY CONCLUSIONS AND RECOMMENDATIONS ....................13 EARTHWORK CONSTRUCTION RECOMMENDATIONS .......................15 General.........................................................15 Site Preparation ..................................................16 Removal and Recompaction of Potentially Compressible Earth Materials . . . . 16 Perimeter Conditions ..............................................17 Fill Placement ....................................................17 Overexcavation ...................................................17 OTHER EARTHWORK CRITERIA ..........................................18 Import Soils ......................................................18 Graded Slope Construction .........................................18 Stabilization Fills/Slope Drainage ....................................18 Temporary Slopes ................................................19 Observation ................................................19 Earthwork Balance (Shrinkage/Bulking) ...............................19 PRELIMINARY RECOMMENDATIONS - FOUNDATIONS .......................20 General.........................................................20 Preliminary Foundation Design ......................................20 PRELIMINARY FOUNDATION CONSTRUCTION RECOMMENDATIONS ...........21 Conventional Foundation and Slab-On-Grade Floor Systems ..............21 Foundation Settlement .............................................22 SOIL MOISTURE TRANSMISSION CONSIDERATIONS ........................22 WALL DESIGN PARAMETERS ............................................24 Conventional Retaining Walls .......................................24 Restrained Walls ............................................25 Cantilevered Walls ...........................................25 Seismic Surcharge ................................................26 Retaining Wall Backfill and Drainage ..................................27 Wall/Retaining Wall Footing Transitions ...............................27 TOP-OF-SLOPE WALLS/FENCES/IMPROVEMENTS AND EXPANSIVE SOILS ......31 Exoansive Soils and Slope Creep ....................................31 Top of Slope Walls/Fences .........................................31 DRIVEWAY, FLATWORK, AND OTHER IMPROVEMENTS .......................32 PRELIMINARY ASPHALTIC CONCRETE PAVEMENT DESIGN RECOMMENDATIONS ...........................34 Cross Real Estate Investors, LLC Table of Contents File: e:\wpl2\8000\8037.pge GeoSoils, Inc. Page ii General . 34 PAVEMENT GRADING RECOMMENDATIONS ...............................35 General..........................................................35 Subgrade.......................................................35 AggregateBase ..................................................35 Paving..........................................................35 Drainage........................................................36 PCC Cross Gutters ................................................36 Additional Considerations ..........................................36 STORM WATER TREATMENT AND HYDROMODIFICATION MANAGEMENT .......37 USDAStudy ......................................................37 Infiltration Feasibility ...............................................37 Onsite Infiltration-Runoff Retention Systems .............................38 DEVELOPMENT CRITERIA ...............................................39 Slope Deformation ................................................39 Slope Maintenance and Planting .....................................40 Drainage........................................................40 Toe of Slope Drains/Toe Drains ......................................41 Erosion Control ...................................................42 Landscape Maintenance ...........................................42 Gutters and Downspouts ...........................................42 Subsurface and Surface Water ......................................45 Site Improvements ................................................45 TileFlooring .....................................................45 Additional Grading ................................................45 Footing Trench Excavation .........................................46 Trenching/Temporary Construction Backcuts ..........................46 Utility Trench Backfill ...............................................46 SUMMARY OF RECOMMENDATIONS REGARDING GEOTECHNICAL OBSERVATION AND TESTING .......................47 OTHER DESIGN PROFESSIONALS/CONSULTANTS ..........................48 PLAN REVIEW .........................................................48 LIMITATIONS..........................................................49 FIGURES: Figure 1 - Site Location Map .........................................2 Detail 1 - Typical Retaining Wall Backfill and Drainage Detail ..............28 Detail 2 - Retaining Wall Backfill and Subdrain Detail Geotextile Drain .......29 Cross Real Estate Investors, LLC Table of Contents File: e:\wpl2\8000\8037.pge GeoSoils, Inc. Page iii Detail 3 - Retaining Wall and Subdrain Detail Clean Sand Backfill ...........30 Detail 4 - Schematic Toe Drain Detail .................................43 Detail 5 - Subd rain Along Retaining Wall Detail .........................44 ATTACHMENTS: Appendix A - References ....................................Rear of Text Appendix B - Boring Logs ...................................Rear of Text Appendix C - Seismicity .....................................Rear of Text Appendix D - Laboratory Data ................................Rear of Text Appendix E - Storm Water BMP Checklists/Forms ................Rear of Text Appendix F - General Earthwork and Grading Guidelines ..........Rear of Text Plate 1 - Geotechnical Map ..................................Rear of Text Cross Real Estate Investors, LLC - Table of Contents FiIe:e:\wp12\8000\8037.pge GeoSoils, Inc. Page iv PRELIMINARY GEOTECHNICAL EVALUATION PROPOSED 5-LOT SUBDIVISION, TRACT NO. 80-46 CARLSBAD, SAN DIEGO COUNTY, CALIFORNIA SCOPE OF SERVICES The scope of our services has included the following: Review of readily available published literature, aerial photographs, and maps of the vicinity (see Appendix A), including proprietary in-house geologic/geotechnical reports for other nearby sites. Site reconnaissance mapping and the excavation of five (5) exploratory borings and three (3) percolation/infiltration borings with a truck mounted drill rig to evaluate the soil/bedrock profiles, sample representative earth materials, delineate the horizontal and vertical extent of earth material units, and perform percolation testing (see Appendices B and E). General areal geologic and seismic hazards evaluation (see Appendix C). Appropriate laboratory testing of relatively undisturbed and representative bulk soil samples collected during our geologic mapping and subsurface exploration program (see text and Appendix D). Analysis of field and laboratory data relative to the proposed development. Appropriate engineering and geologic analyses of data collected, and the preparation of this summary report and accompaniments. SITE DESCRIPTION AND PROPOSED DEVELOPMENT The subject site consists of a rectangularly-shaped parcel with gently sloping terrain. The site is located in the City of Carlsbad, San Diego County, California and is currently occupied by two (2) existing single-family residences (see Figure 1). The site appears to be minimally graded natural terrain, located north of Highland Drive and bounded on the remaining sides by existing residential development. Topographically, the site consists of a gently ascending slope to the east and the slope apex is at the approximate location of the end of the driveway. The slope begins to descend to the east, past the driveway end, to the east property line. The slope varies up to approximately 26 feet in height, at gradients on the order of 10:1 (h:v), or flatter. The slope is generally from 160 feet M.S.L. to 186 feet M.S.L. The rear portion of the property descends to approximately 177 feet M.S.L. in elevation at the southeast property corner. So, overall topoghraphic relief is on the order of ±26 feet. GeoSoils, Inc. High Lod Base Map: TOPO! Copyright 2003 National Geographic, USGS Oceanside Quadrangle, California -- San Diego Co., 7.5 Mnute, photo revised 1975. [j:j1 C nH a Ln I Beautiful Saviour Lutheran Sch... ;e Ave Jeff Weber Rare Books II - I) U' CmpVilIage'ew çk Lgur a Di \>Cb .. SCALE . 00t -11, M C 2020 Torfiron. © Openstreetllap 220MicrosoP Base Map Bing Maps, Copyright 2C20 Tom Tom, 2020 OpertStreetMap, 2020 Microsoft This Map is copyrighted by Google 2016. It is ur.lwfiI to copy or reprc duce all or any part thereof, whether foi personal use of resale, without permission. All rights reserved GOSUs • A SITE LOCATION MAP N Scale: See Bar Scales 7 Figure 1 I I I I I I I I I I I I I I I I 1 I I A majority of the site drainage appears to be directed offsite, to the west. A small portion of the upper property, near the eastern boundary, appears to drain to the east. Vegetation onsite consists of scattered trees, shrubs and grasses. We understand that the two (2) existing residences onsite will be razed to make room for five (5) new single-family residences. At this time, site development plans are not available. According to the client, the planned development will generally consist of five (5) new one- or two-story single-family homes, hardscape, landscape improvements, underground utility improvements, and roadway improvements. Cut and fill grading would be required to bring the site to design grade. Since grading plans are being drafted, the actual grading configurations are not known at this time. Sewage disposal is proposed to be accommodated by utilizing the regional municipal system. FIELD STUDIES Site-specific field studies were conducted by GSI on January 7 and 8, 2021, and consisted of reconnaissance geologic mapping, excavating five (5) exploratory borings and three (3) percolation test borings with a truck mounted drill rig, and performing percolation testing onsite. The borings were logged by a representative of this office who collected representative bulk and undisturbed soil samples for appropriate laboratory testing. The logs of the borings are presented in Appendix B. Site geology, and boring locations are presented on the Geotechnical Map (see Plate 1), which uses Google Earth Imagery (2020) as a base. REGIONAL GEOLOGY The subject property lies within the coastal plains physiographic region of the Peninsular Ranges Geomorphic Province of southern California. This region consists of dissected, mesa-like terraces that transition inland to rolling hills. The encompassing Peninsular Ranges Geomorphic Province is characterized as elongated mountain ranges and valleys that generally trend northwesterly. This geomorphic province extends from the base of the east-west aligned Santa Monica - San Gabriel Mountains, and continues south into Baja California. The mountain ranges within this province are underlain by basement rocks consisting of pre-Cretaceous metasedimentary rocks, Jurassic metavolcanic rocks, and Cretaceous plutonic (granitic) rocks. In the Southern California region, deposition occurred during the Cretaceous Period and Cenozoic Era in the continental margin of a forearc basin. Sediments, derived from Cretaceous-age plutonic rocks and Jurassic-age volcanic rocks, were deposited during the Tertiary Period (Eocene-age) into the narrow, steep, coastal plain and continental margin of the basin. These rocks have been uplifted, eroded, and deeply incised. During early Pleistocene time, a broad coastal plain was developed from the deposition of marine terrace Cross Real Estate Investors, LLC W.O. 8037-A-SC Tract 80-46, Carlsbad January 27, 2021 File: e\wp12\800O\8O37pge GeoSoils, Inc. Page 3 deposits (currently termed "paralic deposits"). During mid- to late-Pleistocene time, this plain was uplifted, eroded and incised. Alluvial deposits have since filled the lower valleys, and young marine sediments are currently being deposited/eroded within coastal and beach areas. Regional geologic mapping by Kennedy and Tan (2005) indicate the site is underlain by Pleistocene-age sedimentary bedrock (old paralic deposits). SITE GEOLOGIC UNITS Gp-np-ral The geologic units observed and/or encountered at the subject site consists of artificial fill, topsoil, and Quaternary-age old paralic deposits (bedrock for this site). A general description of each soil type is presented as follows, from youngest to oldest. The general distribution of geologic units across the site is presented on Plate 1. Artificial Fill (Not mapped) Artificial fill soils were not observed and/or encountered at the subject site, however, artificial fill soils may be encountered during development, that were not obvious at the time of this investigation. If encountered, the fill would likely consist reddish brown silty sand, damp to moist, and medium dense to dense. Artificial fill is considered potentially compressible in its existing state. As such, it should not be used for the support of settlement-sensitive improvements and/or new planned fill, unless removed, moisture conditioned, and placed as properly compacted fill. Topsoil (Not Mapped) Variable thicknesses of surficial topsoil deposits occur across a majority of the site as a relatively thin (±0.1 to ±1.1 foot) layer of soil throughout the site. Where encountered, topsoil consists of brown to reddish brown silty sand that is typically damp to moist, loose to medium dense, and porous. The variable thicknesses of topsoil throughout the site is likely due to variable weathering of surficial soils onsite, animal burrowing, and anthropic modification. Topsoil is considered potentially compressible in its existing state. As such, it should not be used for the support of settlement-sensitive improvements and/or new planned fill, unless removed, moisture conditioned, and placed as properly compacted fill. Quaternary-Age Old Paralic Deposits (Map Symbol - 0op2 ) Quaternary-age old paralic deposits underlie the entire site. The old paralic deposits generally consist of 1- to 5-foot thick zone of highly weathered and bioturbated materials consisting of reddish brown silty sand that is typically damp to moist, medium dense, and porous. Below this highly weathered zone, bedrock grades into dark reddish brown silty sand to sand (with some minor sand lenses at depth locally) that is typically dry to moist, Cross Real Estate Investors, LLC W.O. 8037-A-SC Tract 80-46, Carlsbad January 27, 2021 File: e:\wpl2\8000\8037.pge GeoSoils, Inc. Page 4 and dense to very dense. Highly weathered bedrock is considered potentially compressible in its existing state. As such, it should not be used for the support of settlement-sensitive improvements and/or new planned fill, unless removed, moisture conditioned, and placed as properly compacted fill. Structural Geology Bedding within old paralic deposits appears to be generally flat lying. Significant jointing/fractures were not observed. GROUNDWATER GSI did not observe evidence of a regional groundwater table nor perched water within our subsurface explorations. Therefore, regional groundwater is not anticipated to significantly affect proposed site development, provided that the recommendations contained in this report are properly incorporated into final design and construction. These observations reflect site conditions at the time of our investigation and do not preclude future changes in local groundwater conditions from excessive irrigation, precipitation, or that were not obvious, at the time of our investigation. Based on site topography, the regional groundwater table is likely at elevations in excess of 100 feet below the lowest site elevation. Seeps, springs, or other indications of subsurface water were not noted on the subject property during the time of our field investigation. However, perched water seepage may occur locally (as the result of heavy precipitation and/or irrigation, or damaged wet utilities) along zones of contrasting permeabi I ities/densities (fill/bedrock contacts, sandy/clayey fill lifts, etc.) or along geologic discontinuities (contacts, joints/fractures). This potential should be anticipated and disclosed to all interested/affected parties. Due to the potential for post-development perched water to manifest near the surface, owing to as-graded permeability/density contrasts, more onerous slab design is necessary for any new slab-on-grade floor (State of California, 2020). Recommendations for reducing the amount of water and/or water vapor through slab-on-grade floors are provided in the "Soil Moisture Considerations" sections of this report. GEOLOGIC HAZARDS EVALUATION Mass Wasting/Landslide Susceptibility Mass wasting refers to the various processes by which earth materials are moved down slope in response to the force of gravity. Examples of these processes include slope creep, surficial failures, and deep-seated landslides. Creep is the slowest form of mass wasting Cross Real Estate Investors, LLC W.O. 8037-A-SC Tract 80-46, Carlsbad January 27, 2021 File: e:\wpl2'8000\8037.pge GeoSoils, Inc. Page 5 and generally involves the outer 5 to 10 feet of a slope surface. During heavy rains, such as those in El Niño years, creep-affected materials may become saturated, resulting in a more rapid form of downslope movement (i.e., landslides and/or surf icial failures). According to regional landslide susceptibility mapping by Tan and Giffen (1995), the site is located within landslide susceptibility Subarea 3-1 which is characterized as being "generally susceptible" to landsliding. However, geomorphic expressions indicative of past mass wasting events (i.e., scarps and hummocky terrain) were not observed on the property during our field studies nor our review of stereoscopic aerial photographs (United State Department of Agriculture [USDA], 1953). Further, no adverse geologic structures were encountered during our subsurface exploration. Regional geologic maps do not indicate the presence of landslides on the property. The onsite soils are considered erosive when exposed on unprotected slopes. Therefore, slopes comprised of these materials may be subject to rilling, gullying, sloughing, and surficial slope failures depending on rainfall severity and surface drainage practices. Such risks can be minimized through properly designed, and regularly and periodically maintained surface drainage. FAULTING AND REGIONAL SEISMICITY Regional Faults Our review indicates that there are no known active faults crossing the project and the site is not within an Alquist-Priolo Earthquake Fault Zone (Bryant and Hart, 2007). However, the site is situated in a region subject to periodic earthquakes along active faults. The Newport Inglewood fault (offshore), is the closest known active fault to the site (located at a distance of approximately 5.7 miles [9.1 kilometers]) and would have the greatest effect on the site in the form of strong ground shaking, should the design earthquake occur. The location of the The Newport Inglewood (offshore) fault and other major faults relative to the site is shown on the "California Fault Map" in Appendix C. The possibility of ground acceleration, or shaking at the site, may be considered as approximately similar to the Southern California region as a whole. Local Faulting Although active faults lie within a few miles of the site, no active faults were observed to specifically transect the site during the field investigation. Additionally, a review of available regional geologic maps does not indicate the presence of active faults crossing the specific project site. Cross Real Estate Investors, LLC W.O. 8037-A-SC Tract 80-46, Carlsbad January 27, 2021 File: e:\wpl2\8000\8037.pge GeoSoils, Inc. Page 6 Seismicity The acceleration-attenuation relation of Bozorgnia, Campbell, and Niazi (1999) has been incorporated into EQFAULT (Blake, 2000a). EQFAULT is a computer program developed by Thomas F. Blake (2000a), which performs deterministic seismic hazard analyses using digitized California faults as earthquake sources. The program estimates the closest distance between each fault and a given site. If a fault is found to be within a user-selected radius, the program estimates peak horizontal ground acceleration that may occur at the site from an upper bound event (formerly "maximum credible earthquake"), on that fault. Upper bound refers to the maximum expected ground acceleration produced from a given fault. Site acceleration (g) was computed by a user-selected acceleration-attenuation relation that is contained in EQFAULT. Based on the EQFAULT program, a peak horizontal ground acceleration from an upper bound event on the Newport - Inglewood fault (offshore) may be on the order of 0.576g. The computer printouts of pertinent portions of the EQFAULT program are included within Appendix C. Historical site seismicity was evaluated with the acceleration-attenuation relation of Bozorgnia, Campbell, and Niazi (1999), and the computer program EQSEARCH (Blake, 2000b, updated to August 2018). This program performs a search of the historical earthquake records for magnitude 5.0 to 9.0 seismic events within a 100-kilometer radius, between the years 1800 through August 2018. Based on the selected acceleration-attenuation relationship, a peak horizontal ground acceleration is estimated, which may have affected the site during the specific event listed. Based on the available data and the attenuation relationship used, the estimated maximum (peak) site acceleration during the period 1800 through August 2018 was about 0.234 g. A historic earthquake epicenter map and a seismic recurrence curve are also estimated/generated from the historical data. Computer printouts of the EQSEARCH program are presented in Appendix C. SEISMIC DESIGN General It is important to keep in perspective that in the event of an upper bound (maximum probable) or credible earthquake occurring on any of the nearby major faults, strong ground shaking would occur in the subject site's general area. Potential damage to any structure(s) would likely be greatest from the vibrations and impelling force caused by the inertia of a structure's mass rather than from those induced by the hazards listed above. This potential would be no greater than that for other existing structures and improvements in the immediate vicinity. Cross Real Estate Investors, LLC W.O. 8037-A-SC Tract 80-46 Carlsbad January 27, 2021 Fi1e:e:\wp12\8000\8037.pge GeoSoils, Inc. Page 7 Seismic Shakinci Parameters The following table summarizes the reevaluated site-specific design criteria obtained from the 2019 CBC, Chapter 16 Structural Design, Section 1613, Earthquake Loads. The computer program Seismic Design Maps, provided by the California Office of Statewide Health Planning and Development (OSHPD, 2021) has now been utilized to aid in design (https://seismicmaps.org). Details of the seismicity data are included in Appendix C, at the rear of the text. The short spectral response utilizes a period of 0.2 seconds. 2019 CBC SEISMIC DESIGN PARAMETERS PARAMETER 1 VALUE I VALUE PER ASCE 2019 CBC OR REFERENCE 7-16 Risk Category II - Table 1604.5 Site Class D (default) Section 1613.2.2/Chap. 20 - ASCE 7-16 (p. 203-204) Spectral Response -(0.2 sec), S 1.041 g Section 1613.2.1 - Figure 1613.2.1 (1) Spectral Response - (1 sec), 5, 0.378 g - Section 1613.2.1 Figure 1613.2.1(2) Site Coefficient, F 1.2 - Table 1613.2.3(1) Site Coefficient, F null - see Section2.5 11.48 ASCE 7-16 (Section 21.3) Table 1613.2.3(2) Maximum Considered Earthquake Section 1613.2.3 Spectral Response Acceleration 1.249 g - (Eqn 16-36) (0.2 sec), SMS Maximum Considered Earthquake null - see Section Section 1613.2.3 Spectral Response Acceleration 11.48 ASCE 7-16 1.095 (Section 21.4) (Eqn 16-37) (1 sec), 5Mt 5% Damped Design Spectral 0.833 g - Section 1613.2.4 Response Acceleration (0.2 sec), S08 (Eqn 16-38) 5% Damped Design Spectral null - see 0.730 Section 1613.2.4 Response Acceleration (1 sec), S, Section 11.48 ASCE 7-16 (Section 21.4) (Eqn 16-39) PGAM - Probabilistic Vertical Ground Acceleration may be assumed as 0.549 g - ASCE 7-16 (Eqn 11.8.1) about 50% of these values. Seismic Design Category null - see Section 11.48 D Section 1613.2.5/ASCE 7-16 ASCE 7-16 (Section 11.6) (p. 85: Table 11.6-1 or 11.6-2) Ii. FV = 2.5 S1 >0.2 per Section 21.3, [ 2. SM 1 = (1 .5)SD1 =(1.5)(0.73)=1.095 per Section 21.4 3. SD1 L 0.2 => 0.73 2: 0.2 , per Section 11.6 site is in Risk Category 0 Cross Real Estate Investors, LLC W.O. 8037-A-SC Tract 80-46, Carlsbad January 27, 2021 Fi1e:e:\wp12\8000\8037.pge GeoSoils, Inc. Page 8 GENERAL SEISMIC PARAMETERS PARAMETER I VALUE Distance to Seismic Source (B fault)(') 5.7 mi (9.1 km)2 Upper Bound Earthquake (Newport - IngeIwood (Offshore Fault) M = 7.1 " - Cao, et al. (2003) (2) - Blake (2000) Conformance to the criteria above for seismic design does not constitute any kind of guarantee or assurance that significant structural damage or ground failure will not occur in the event of a large earthquake. The primary goal of seismic design is to protect life, not to eliminate all damage, since such design may be economically prohibitive. Cumulative effects of seismic events are not addressed in the 2019 CBC (CBSC, 2019a) and regular maintenance and repair following locally significant seismic events (i.e., M5.5) will likely be necessary, as is the case in all of Southern California. SECONDARY SEISMIC HAZARDS Liquefaction/Lateral Spreading Liquefaction describes a phenomenon in which cyclic stresses, produced by earthquake-induced ground motion, create excess pore pressures in relatively cohesionless soils. These soils may thereby acquire a high degree of mobility, which can lead to vertical deformation, lateral movement, lurching, sliding, and as a result of seismic loading, volumetric strain and manifestation in surface settlement of loose sediments, sand boils and other damaging lateral deformations. This phenomenon occurs only below the water table, but after liquefaction has developed, it can propagate upward into overlying non-saturated soil as excess pore water dissipates. One of the primary factors controlling the potential for liquefaction is depth to groundwater. Typically, liquefaction has a relatively low potential at depths greater than 50 feet and is unlikely and/or will produce vertical strains well below 1 percent for depths below 60 feet when relative densities are 40 to 60 percent and effective overburden pressures are two or more atmospheres (i.e., 4,232 pounds per square foot [Seed, 2005]). The condition of liquefaction has two principal effects. One is the consolidation of loose sediments with resultant settlement of the ground surface. The other effect is lateral sliding. Significant permanent lateral movement generally occurs only when there is significant differential loading, such as fill or natural ground slopes within susceptible materials. No such loading conditions exist at the site. Liquefaction susceptibility is related to numerous factors and the following five conditions should be concurrently present for liquefaction to occur: 1) sediments must be relatively Cross Real Estate Investors, LLC W.O. 8037-A-SC Tract 80-46, Carlsbad January 27, 2021 FiIe:e:\wp12\8000\8037.pge GeoSoils, Inc. Page 9 young in age and not have developed a large amount of cementation; 2) sediments must generally consist of medium- to fine-grained, relatively cohesionless sands; 3) the sediments must have low relative density; 4) free groundwater must be present in the sediment; and 5) the site must experience a seismic event of a sufficient duration and magnitude, to induce straining of soil particles. Only about one of these five necessary, concurrent conditions have the potential to affect the site. Seismic Densification Seismic densification is a phenomenon that typically occurs in low relative density granular soils (i.e., United States Soil Classification System [USCS] soil types SP, SM, and SC) that are above the groundwater table. These unsaturated granular soils are susceptible if left in the original density (unmitigated), and are generally dry of the optimum moisture content (as defined by the ASTM D 1557). During seismic-induced ground shaking, these natural or artificial soils deform under loading and volumetrically strain, potentially resulting in ground surface settlements. Some densification of the adjoining unmitigated properties may influence improvements at the perimeter of the site. Special setbacks and/or foundations may be utilized if significant structures/improvements are placed close to the perimeter of the site. Our evaluation assumed that the current offsite conditions will not be significantly modified by future grading at the time of the design earthquake, which is a reasonably conservative assumption. Summary It is the opinion of GSI that the susceptibility of the site to experience damaging deformations from seismically-induced liquefaction and densification is low owing to the dense nature of the unweathered old paralic deposits that underlies the site in the near-surface and the depth to the regional water table. In addition, the recommendations for remedial earthwork and foundations would further reduce any significant liquefaction/densification potential. Some seismic densification of the adjoining unmitigated site(s) may adversely influence planned improvements at the perimeter of the site. However, given the remedial earthwork and foundation recommendations provided herein, the potential for the planned buildings to be affected by significant seismic densification or liquefaction of offsite soils may be considered low. Other Geologic/Secondary Seismic Hazards The following list includes other geologic/seismic-related hazards that have been considered during our evaluation of the site. The hazards listed are considered negligible and/or mitigated asaresult of site location, soil characteristics, and typical site development procedures: Subsidence Surface Rupture Ground Lurching or Shallow Ground Rupture Cross Real Estate Investors, LLC Tract 80-46, Carlsbad Fi1e:e:\wp12\8000\8037.pge GeoSoils, Inc. W.O. 8037-A-SC January 27, 2021 Page 10 Sieche Tsunami SLOPE STABILITY Assuming proper surface drainage, regular and periodic care and maintenance, normal rainfall, permanent graded slopes, constructed from the onsite materials, as recommended herein, are considered grossly and surficially stable. The tallest natural slope,, located along the western portion of the property from the eastern ridge crest is generally considered grossly stable given the absence of adverse structures and no evidence of historic gross instability. Site earth materials are also considered erosive. As such, positive surface drainage practices and vegetative covering should be maintained throughout the life of the project. Temporary slopes for construction are discussed in subsequent sections of our report. LABORATORY TESTING Laboratory tests were performed on representative samples of site earth materials collected during our subsurface exploration in order to evaluate their physical characteristics. Test procedures used and results obtained are presented below. Classification Soils were visually classified with respectto the Unified Soil Classification System (U.S.C.S.) in general accordance with ASTM D 2487 and D 2488. The soil classifications of the onsite soils are provided on the Boring Logs in Appendix B. Moisture-Density Relations The field moisture contents and dry unit weights were determined for selected samples in the laboratory. Testing was performed in general accordance with ASTM D 2937 and ASTM D2216. The dry unit weight was determined in pounds per cubic foot (pcf), and the field moisture content was determined as a percentage of the dry weight. The results of these tests are shown on the Boring Logs in Appendix B. Expansion Index Representative samples of near-surface site soils were evaluated for expansion potential. Expansion Index (E.I.) testing and expansion potential classification was performed in general accordance with ASTM Standard D 4829, the results of the expansion testing are presented in the following table. Cross Real Estate Investors, LLC Tract 80-46, Carlsbad FiIe:e:\wp128000\8037.pge GeoSoils, Inc. W.O. 8037-A-SC January 27, 2021 Page 11 SAMPLE LOCATION 0 I AND DEPTH (FT) EXPANSION INDEX EXPANSION POTENTIAL B -1 @ 0-5 I !~ 20 1 Very Low Particle-Size Analysis A particle-size evaluation was performed on a representative, soil sample (B - 1 @ 0 - 5') in general accordance with ASTM D 422-63. The testing was utilized to evaluate the soil classification in accordance with the Unified Soil Classification System (USCS). The results of the particle-size evaluation indicate that the tested soil is a silty sand (0.2% gravel, 72% sand, 27.8% fines [USGS Symbol - SM]). Saturated Resistivity, pH, and Soluble Sulfates, and Chlorides GSI conducted sampling of onsite earth materials for general soil corrosivity and soluble sulfates, and chlorides testing. The testing included evaluation of soil pH, soluble sulfates, chlorides, and saturated resistivity. Test results are presented in the following table: SAMPLE LOCATION SATURATED SOLUBLE SOLUBLE AND DEPTH (FT) pH RESISTIVITY SULFATES CHLORIDES (ohm-cm) (% by weight) (PPM) B-1 @ 0-5 7.3 2,800 0.003 1 30 Corrosion Summary Laboratory testing indicates that tested samples of the onsite soils are neutral with respect to soil acidity/alkalinity, are moderately corrosive to exposed, buried metals when saturated, present negligible ("not applicable" [or class SO] per American Concrete Institute [AGI] 318-14) sulfate exposure to concrete, and are below action levels for chloride exposure (per State of California Department of Transportation, 2003). Reinforced concrete mix design for foundations, slab-on-grade floors, and pavements should minimally conform to "Exposure Class Cl" in Table 19.3.2.1 of ACI 318-14, as concrete would likely be exposed to moisture. It should be noted that GSI does not consult in the field of corrosion engineering. The client and project architect should agree on the level of corrosion protection required for the project and seek consultation from a qualified corrosion consultant. Cross Real Estate Investors, LLC Tract 80-4€, Carlsbad FiIe:e:\wp12\8000\8037.pge GeoSoils, Inc. W.O. 8037-A-SC January 27, 2021 Page 12 R-Value Preliminarily, soils were classified with respect to the resistance value in general accordance with CTM 301. The soil classifications of the onsite soils are provided on the R-Value Test Results in Appendix B. PRELIMINARY CONCLUSIONS AND RECOMMENDATIONS Based on our field exploration, laboratory testing, and geotechnical engineering analysis, it is our opinion that the subject site is suitable for the proposed residential development from a geotechnical engineering and geologic viewpoint, provided that the recommendations presented in the following sections are incorporated into the design and construction phases of site development. The primary geotechnical concerns with respect to the proposed development and improvements are: Earth material characteristics and depth to competent bearing material. Potential for construction/landscape debris to be present in some existing fill areas, that may render that fill unsuitable for re-use, if organics content is too high. On-going expansion and corrosion potentials of site soils. Permanent and temporary slope stability. Erosiveness of site earth materials. Potential for perched water during and following site development. Perimeter conditions and planned improvements near the subdivision boundary. Regional seismic activity. The recommendations presented herein consider these as well as other aspects of the site. The engineering analyses performed concerning site preparation and the recommendations presented herein have been completed using the information provided and obtained during our field work. In the event that any significant changes are made to proposed site development, the conclusions and recommendations contained in this report shall not be considered valid unless the changes are reviewed and the recommendations of this report verified or modified in writing by this office. Foundation design parameters are considered preliminary until the foundation design, layout, and structural loads are provided to this office for review. Soil engineering, observation, and testing services should be provided during grading to aid the contractor in removing unsuitable soils and in his effort to compact the fill. 2. Geologic observations should be performed during any grading and foundation construction to verify and/or further evaluate geologic conditions. Although unlikely, if adverse geologic structures are encountered, supplemental recommendations and earthwork may be warranted. Cross Real Estate Investors, LLC Tract 80-46, Carlsbad FiIe:e:\wp12\8000\8037.pge GeoSoils, Inc. W.O. 8037-A-SC January 27, 2021 Page 13 Undocumented fill, topsoil, and any highly weathered paralic deposits are considered unsuitable for the support of the planned settlement-sensitive improvements (i.e., residential structures, walls, underground utilities, and pavements, etc.) and new planned fills. Unsuitable soils within the influence of planned settlement-sensitive improvements and planned fill should be removed to expose suitable bedrock and then be reused as properly engineered fill. Based on the available subsurface data, remedial grading excavations are anticipated to extend to depths of approximately ±3 to ±6 feet. However, locally deeper remedial grading excavations cannot be precluded and should be anticipated. It should be noted that local areas of construction/landscape debris in some existing fill areas may render that fill unsuitable for re-use. Expansion index testing performed on a sample of the onsite soils indicates very low expansive soil conditions (E.l. of 20 or less), for representative site soils. As such, it is possible that soils with higher expansion potentials may be encountered locally. Thus, in general, surficial deposits of topsoil, and highly weathered bedrock do not meet the criteria for detrimentally expansive soils, as defined in Section 1803.5.2 of the 2019 CBC. As such, specialized residential building foundations influenced by expansive soils are not required in accordance with Sections 1808.6.1 or 1808.6.2 of the 2019 CBC. Foundation systems used for the mitigation of expansive soils typically incorporate the Post-Tension Institute (PTI) and Wire Reinforcement Institute (WRI) methodologies can be provided upon request. Preliminary recommendations for the design and construction of conventional foundations are included herein. Final foundation design will be provided at the conclusion of grading, based on the E.I. and P.I. of soils exposed near pad grade. The existing fill soils are likely very low expansion potential, based on visual classification and appearance and are therefore considered not detrimentally expansive, on a preliminary basis. Laboratory testing indicates that site soils are neutral with respect to soil acidity/alkalinity and are moderately corrosive to exposed buried metals when saturated. Testing also indicates that site soils present negligible ("not applicable" or SO per ACI 318-14) sulfate exposure to concrete and are classified as "Cl" for chloride exposure (ACI 318-14). The client and project architect should agree on the level of corrosion protection required for the project and seek consultation from a qualified corrosion consultant as warranted. Earthwork adjacent to property lines will need to consider any perimeter conditions (slopes, walls, adjacent structures, etc.) that may be encountered. On a preliminary basis, perimeter conditions may exist. Site perimeter conditions should be evaluated when the development plan is made available. Should parameter conditions exist, the deepened footings, and structural setbacks may be recommended. This should be evaluated further during the final grading plan review. Site soils are considered erosive. Surface drainage should be designed to eliminate the potential for concentrated flows. Positive surface drainage away from foundations Cross Real Estate Investors, LLC W.O. 8037-A-SC Tract 80-46, Carlsbad January 27, 2021 File: e:\wpl2\8000\8037.pge GeoSods, Inc. Page 14 and tops of slopes is recommended. Temporary erosion control measures should be implemented until vegetative covering is well established. The homeowners and homeowner's association (if any) will need to maintain proper surface drainage over the life of the project. No evidence of a high regional groundwater table nor perched water was observed during our subsurface exploration within the property. However, due to the nature of site earth materials, there is a potential for perched water to occur both during and following site development. This potential should be disclosed to all interested/affected parties. Should perched water conditions be encountered, this office could provide recommendations for mitigation. Typical mitigation includes subdrainage system, cut-off barriers, etc. The removal and recompaction of potentially compressible soils below a 1:1 (h:v) projection down from the bottom outside of planned settlement-sensitive improvements and fill along the perimeter of the site will be limited due to boundary restrictions. As such, any settlement-sensitive improvement located above a 1:1 (h:v) projection from the bottom outboard edge of the remedial grading excavation at the property line would require deepened foundations below this plane, additional reinforcement, or would retain some potential for distress and therefore, a reduced serviceable life. On a preliminary basis, any planned settlement-sensitive improvements located within approximately ±3 to potentially ±6 feet from the subdivision boundary would require deepened foundations or additional reinforcement by means of ground improvement or specific structural design. This should be disclosed to all interested/affected parties. On a preliminary basis, temporary slopes should be constructed in accordance with CAL-OSHA guidelines for Type "B" soils, provided water or seepage is not present. All temporary slopes should be evaluated by the geotechnical consultant, prior to worker entry. Should adverse conditions be identified, the slope may need to be laid back to a flatter gradient or require the use of shoring. The seismicity-acceleration values provided herein should be considered during the design and construction of the proposed development. General Earthwork and Grading Guidelines are provided at the end of this report as Appendix F. Specific recommendations are provided below. EARTHWORK CONSTRUCTION RECOMMENDATIONS General All earthwork should conform to the guidelines presented in the 2019 CBC (CBSC, 2019a), the requirements of the City, County, and the General Earthwork and Grading Guidelines Cross Real Estate Investors, LLC Tract 80-46, Carlsbad File: e:\wpl2\8000\8037.pge GeoSoils, Inc. W.O. 8037-A-SC January 27, 2021 Page 15 presented in Appendix F, except where specifically superceded in the text of this report. Prior to earthwork, a GSI representative should be present at the preconstruction meeting to provide additional earthwork guidelines, if needed, and review the earthwork schedule. This office should be notified in advance of any fill placement, supplemental re-grading of the site, or backfilling underground utility trenches and retaining walls after rough earthwork has been completed. This includes grading for driveway approaches, driveways, and exterior hardscape. During earthwork construction, all site preparation and the general grading procedures of the contractor should be observed and the fill selectively tested by a representative (s) of GSI. If unusual or unexpected conditions are exposed in the field, they should be reviewed by this office and, if warranted, modified and/or additional recommendations will be offered. All applicable requirements of local and national construction and general industry safety orders, the Occupational Safety and Health Act (OSHA), and the Construction Safety Act should be met. It is the onsite general contractor's and individual subcontractors' responsibility to provide a safe working environment for our field staff who are onsite. GSI does not consult in the area of safety engineering. Site Preparation All existing improvements, vegetation and deleterious debris should be removed from the site prior to the start of construction if they are located in areas of proposed earthwork. If an existing pool backfill is present, the backfill shall be removed to suitable formation and properly backfilled. Any remaining cavities should be observed by the geotechnical consultant. Mitigation of cavities would likely include removing any potentially compressible soils to expose suitable bedrock and then backfilling the excavation with a controlled engineered fill or soils that have been moisture conditioned to optimum moisture content and compacted to at least 90 percent of the laboratory standard (ASTM D 1557). Removal and Recompaction of Potentially Compressible Earth Materials Potentially compressible topsoil, and any highly weathered paralic deposits should be removed to expose suitable paralic deposits (bedrock at this site). Following removal, these soils should be cleansed of any vegetation and deleterious debris, moisture conditioned to at least optimum moisture, and then be recompacted to at least 90 percent of the laboratory standard (ASTM D 1557). Based on the available data, excavations necessary to remove unsuitable soils are anticipated to range between approximately 3 and 6 feet across the site. The potential to encounter thicker sections of unsuitable soils that require deeper remedial grading excavations than stated above cannot be precluded and should be anticipated. Potentially compressible soils should be removed below a 1:1 (h:v) projection down from the bottom, outboard edge of any settlement-sensitive improvement or limits of planned fill. Remedial grading excavations should be observed by the geotechnical consultant prior to scarification and fill placement. Once observed and approved, the bottom of the remedial Cross Real Estate Investors, LLC W.O. 8037-A-SC Tract 80-46, Carlsbad January 27, 2021 File: e:\wpl 2\8000\8037.pge GeoSoils, Inc. Page 16 grading excavation should be scarified at least 6 to 8 inches, moisture conditioned to at least the soil's optimum moisture content, and then recompacted to a minimum 90 percent of the laboratory standard (ASTM D 1557). Perimeter Conditions It should be noted that the 2019 CBC (CBSC, 2019a) indicates that the removal of unsuitable soils be performed across all areas to be graded, under the purview of the grading permit, not just within the influence of the residential structures. Relatively deep removals may also necessitate a special zone of consideration, on perimeter/confining areas. This zone would be approximately equal to the depth of removals, if removals cannot be performed onsite or offsite. In general, any planned improvement located above a 1:1 (h:v) projection up from the bottom, outboard edge of the remedial grading excavation at the subdivision boundary would be affected by perimeter conditions. On a preliminary basis, any planned settlement-sensitive improvements located within approximately ±3 to ±6 feet of the subdivision boundary would require deepened foundations or additional reinforcement by means of ground improvement or specific structural design, for perimeter conditions discussed above. Otherwise these improvements maybe subject to distress and a reduced serviceable lifespan. This will also require proper disclosure to any owners and all interested/affected parties should this condition exist at the conclusion of grading. The need for remedial measures for support of settlement-sensitive improvements near the subdivision boundary should be further evaluated at the final grading plan review stage. Fill Placement Following scarification of the bottom of the remedial grading excavation, the reused onsite soils and import (if necessary) should be placed in ±6- to ±8-inch lifts, cleansed of vegetation and debris, moisture conditioned, and compacted to achieve a minimum relative compaction of 90 percent of the laboratory standard (ASTM D 1557). In general, moisture conditioning should be such that site soils are placed to at least optimum moisture content. Overexcavation In orderto provide uniform foundation and slab-on-grade floor support, mitigate water vapor transmission potential, and to facilitate improvements construction, it is recommended that building pads (cut pads and transition pads) are overexcavated (undercut) to a depth of at least 3 feet below pad grade or 2 feet below the lowest bottom of the footing elevation (whichever is greater). When removals do not provide for the minimum fill thickness with a given building pad, the building pad shall be overexcavated as described herein. Overexcavation should be completed across the entire building pad in case the location of the building footprint requires modification after grading. The maximum:minimum fill thickness (subsurface slope) across a lot should not exceed 3:1 (maximum: minimum) and overexcavation is recommended when necessary. The bottom of the overexcavation should be graded such that it slopes away from the residential structure/lot, preferably toward the Cross Real Estate Investors, LLC Tract 80-46, Carlsbad Fi1e:e:\wp12\8000\8037.pge GeoSoils, Inc. W.O. 8037-A-SC January 27, 2021 Page 17 I I street. Prior to fill placement, the bottom of the overexcavation should be scarified at least 6 to 8 inches, moisture conditioned to at least the soil's optimum moisture content, and then recompacted to a minimum 90 percent of the laboratory standard (ASTM D 1557). OTHER EARTHWORK CRITERIA Import Soils If import fill is necessary, a sample of the soil import should be evaluated by this office prior to importing, in order to ensure compatibility with the onsite soils and the recommendations I presented in this report. If non-manufactured materials are used, environmental documentation for the export site should be provided for GSI review. At least three business I days of lead time should be allowed by builders or contractors for proposed import submittals. This lead time will allow for environmental document review, particle size analysis, laboratory standard, expansion testing, and blended import/native characteristics I as deemed necessary. Import soils should be compatible with onsite soils in consideration of soil expansion and corrosion potential. It should be understood that importing higher expansive soils that what is present onsite will result in more onerous foundation design. I Graded Slope Construction I Graded fill slopes should be constructed at gradients no steeper than 2:1 (h:v) to the heights indicated on Plate 1, without further analysis. Fill slopes should be properly keyed and benched if constructed along surfaces steeper than 5:1 (h:v). All fill slopes should be I compacted to at least 90 percent of the laboratory standard (ASTM D 1557) throughout, including the slope face. Graded cut slopes should be constructed at gradients no steeper than 2.1:1 (h:v) to heights up to 10 feet, without further evaluation. Any cut slopes should be mapped by a geologist during construction. Although not anticipated at this time, should intersecting planes of I joints/fractures daylight the cut slope face, or should undocumented fill, topsoil, or highly weathered bedrock be exposed in cut slopes, remedial grading including stabilization fills or inclining the cut slope to a gradient flatter than the adverse structure may be necessary. I The type of remedial grading would be based on the conditions exposed during cut slope construction. I Stabilization Fills/Slope Drainage Stabilization fills are not anticipated at this time. Slope subdrainage maybe accommodated by drainage systems for the planned perimeter, toe of slope walls, on a preliminary basis. I i I Cross Real Estate Investors, LLC Tract 80-46, Carlsbad Fi1e:e:\wp12\8000\8037.pge GeoSoils, Inc. W.O. 8037-A-SC January 27, 2021 Page 18 Temporary Slopes Temporary slopes for excavations greater than 4 feet but less than 20 feet in overall height should conform to CAL-OSHA and/or OSHA requirements for Type "B" soils, provided water or seepage is not present. Temporary slopes, up to a maximum height of ±20 feet, may be excavated at a 1:1 (h:v) gradient, or flatter, provided groundwater and/or running sands are not exposed. Construction materials or soil stockpiles should not be placed within 'H' of any temporary slope where 'H' equals the height of the temporary slope. All temporary slopes should be observed by a licensed engineering geologist and/or geotechnical engineer prior to worker entry into the excavation. Based on the exposed field conditions, inclining temporary slopes to flatter gradients or the use of shoring may be necessary if adverse conditions are observed. If temporary slopes conflict with property boundaries, shoring or alternating slot excavations may be necessary. The need for shoring or alternating slot excavations could be further evaluated during the 40-scale grading plan review stage. Observation It is recommended that all excavations be observed by the Geologist and/or Geotechnical Engineer. Any fill which is placed should be approved, tested, and verified if used for engineered purposes. Should the observation reveal any unforseen hazard, the Geologist or Geotechnical Engineer will recommend treatment. Please inform GSI at least 24 hours prior to any required site observation. Earthwork Balance (Shrinkage/Bulking) The volume change of excavated materials upon compaction as engineered fill is anticipated to vary with material type and location. Based on the available data, the overall earthwork shrinkage and bulking may be approximated by using the following parameters: Artificial Fill/topsoil/highly weathered Bedrock ............5% to 10% shrinkage Bedrock ....................................3% shrinkage to 3% bulking It should be noted that the above factors are estimates only, based on preliminary data. Existing topsoil may achieve higher shrinkage if organics or clay content is higher than anticipated, or if compaction averages more than 92 percent of the laboratory standard (ASTM D 1557). Final earthwork balance factors could vary. In this regard, it is recommended that balance areas be reserved where grades could be adjusted up or down near the completion of grading in order to accommodate any yardage imbalance for the project. Cross Real Estate Investors, LLC Tract 80-46, Carlsbad File:e:\wp12\8000\8037.pge GeoSoils, Inc. W.O. 8037-A-SC January 27, 2021 Page 19 PRELIMINARY RECOMMENDATIONS -FOUNDATIONS General Preliminary recommendations for foundation design and construction are provided in the following sections. These preliminary recommendations have been developed from our understanding of the currently planned site development, site observations, subsurface exploration, laboratory testing, and engineering analyses. Foundation design should be re-evaluated at the conclusion of site grading/remedial earthwork for the as-graded soil conditions. Although not anticipated, revisions to these recommendations may be necessary. In the event that the information concerning the proposed development plan is not correct, or any changes in the design, location or loading conditions of the proposed residential structures are made, the conclusions and recommendations contained in this report shall not be considered valid unless the changes are reviewed and conclusions of this report are modified or approved in writing by this office. The information and recommendations presented in this section are not meant to supercede design by the project structural engineer or civil engineer specializing in structural design. Upon request, GSI could provide additional input/consultation regarding soil parameters, as related to foundation design. In the following sections, GSI provides preliminary design and construction recommendations for foundations underlain by non-detrimentally expansive soil conditions. Foundation systems constructed within the influence of non-detrimentally expansive soils (i.e., E.I. !~ 20 and P1 !~ 15) should be designed in accordance with Sections 1808.6.1 or 1808.6.2 of the 2019 CBC. Preliminary Foundation Design The foundation systems should be designed and constructed in accordance with guidelines presented in the 2019 CBC. An allowable bearing value of 2,000 pounds per square foot (psf) may be used for the design of footings that maintain a minimum width of 12 inches and a minimum depth of 12 inches (below the lowest adjacent grade), and are founded entirely into approved engineered fill. This value may be increased by 20 percent for each additional 12 inches in footing depth to a maximum value of 2,500 psf for footings founded into approved engineered fill. This value may be increased by one-third when considering short duration seismic or wind loads. Isolated pad footings should have a minimum dimension of at least 24 inches square and a minimum embedment of 24 inches below the lowest adjacent grade into approved engineered fill. Foundation embedment depth excludes concrete slabs-on-grade, and/or slab u ndérl aym ent. Cross Real Estate Investors, LLC W.O. 8037-A-SC Tract 80-46, Carlsbad January 27, 2021 File: e:\wpl2\8000\8037.pge GeoSoils, Inc. Page 20 For foundations deriving passive resistance from approved engineered fill, a passive earth pressure may be computed as an equivalent fluid having a density of 250 pcf, with a maximum earth pressure of 2,500 psf. The upper 6 inches of passive pressure should be neglected if not confined by slabs or pavement. For lateral sliding resistance, a 0.35 coefficient of friction may be utilized for a concrete to soil contact when multiplied by the dead load. When combining passive pressure and frictional resistance, the passive pressure component should be reduced by one-third. All footing setbacksfrom slopes should comply with Figure 1808.7.1 of the 2019 CBC. GSI recommends a minimum horizontal setback distance of 7 feet as measured from the bottom, outboard edge of the footing to the slope face. Footings for structures adjacent to retaining walls should be deepened so as to extend below a 1:1 projection up from the heel of the retaining wall. Alternatively, the retaining wall may be designed for the applicable surcharge. PRELIMINARY FOUNDATION CONSTRUCTION RECOMMENDATIONS Conventional Foundation and Slab-On-Grade Floor Systems Thefollowing recommendations are intended to support foundations and slab-on-grade floor systems underlain by at least 7 feet of non-detrimentally expansive soils (i.e., E.I.:!~ 20 and P.1. <15). Exterior and interior footings should be founded into approved engineered fill at a minimum depth of 12 or 18 inches below the lowest adjacent grade for one- or two-story floor loads, respectively. For one- and two-story floor loads, footing widths should be 12 and 15 inches, respectively. Isolated, exterior column and panel pads, or wall footings, should be at least 24 inches square, and founded at a minimum depth of 24 inches into approved engineered fill. All footings should be minimally reinforced with four No. 4 reinforcing bars, two placed near the top and two placed near the bottom of the footing. 2. All interior and exterior column footings, and perimeter wall footings, should be tied together via grade beams in at least two directions. The grade beam should be at least 12 inches square in cross section, and should be provided with a minimum of one No.4 reinforcing bar at the top, and one No.4 reinforcing bar at the bottom of the grade beam. The base of the reinforced grade beam should be at the same elevation as the adjoining footings. Cross Real Estate Investors, LLC W.O. 8037-A-SC Tract 80-46, Carlsbad January 27, 2021 File: e:\wpl2\8000\8037pge GeoSoils, Inc. Page 21 A grade beam, reinforced as previously recommended and at least 12 inches square, should be provided across large (garage) entrances. The base of the reinforced grade beam should be at the same elevation as the adjoining footings. A minimum concrete slab-on-grade thickness of 5 inches is recommended. Concrete slabs should be reinforced with a minimum of No. 3 reinforcement bars placed at 18 inches on center, in two horizontally perpendicular directions (i.e., long axis and short axis). All slab reinforcement should be supported to ensure proper mid-slab height positioning during placement of the concrete. "Hooking" of reinforcement is not an acceptable method of positioning. Slab subgrade pre-soaking is not required for non-detrimentally expansive soil conditions. However, the client should consider pre-wetting the slab subgrade materials to at least the soil's optimum moisture content to a minimum depth of 12 inches, prior to the placement of the underlayment sand and vapor retarder. Soils generated from footing excavations to be used onsite should be compacted to a minimum relative compaction of 90 percent of the laboratory standard (ASTM D 1557), whether the soils are to be placed inside the foundation perimeter or in the yard/right-of-way areas. This material must not alter positive drainage patterns that direct drainage away from the structural areas and toward the street. Reinforced concrete mix design should conform to "Exposure Class Cl" in Table 19.3.2.1 of ACI-318-14 since concrete would likely be exposed to moisture. Foundation Settlement Provided that the earthwork and foundation recommendations in this report are adhered, foundations bearing on approved engineered fill should also be minimally designed to accommodate a total static settlement of 2 inches and a differential static settlement of 1 inch over a 40-foot horizontal span (angular distortion = 1/480), and up to 1/2 inch of seismic differential settlement over a 40-foot horizontal span (seismic angular distortion = 1/960). SOIL MOISTURE TRANSMISSION CONSIDERATIONS GSI has evaluated the potential for vapor or water transmission through the concrete floor slab, in light of typical floor coverings and improvements. Please note that slab moisture emission rates range from about 2 to 27 lbs/24 hours/1,000 square feet from a typical slab (Kanare, 2005), while floor covering manufacturers generally recommend about 3 lbs/24 hours as an upper limit. The recommendations in this section are not intended to preclude the transmission of water or vapor through the foundation or slabs. Cross Real Estate Investors, LLC W.O. 8037-A-SC Tract 80-46, Carlsbad January 27, 2021 Fi1e:e:\wp12\8000\8037.pge GeoSoils, Inc. Page 22 Foundation systems and slabs shall not allow water or water vapor to enter into the structure so as to cause damage to another building component or to limit the installation of the type of flooring materials typically used for the particular application (State of California, 2021). These recommendations may be exceeded or supplemented by a water "proofing" specialist, project architect, or structural consultant. Thus, the client will need to evaluate the following in light of a cost vs. benefit analysis (owner expectations and repairs/replacement), along with disclosure to all interested/affected parties. It should also be noted that vapor transmission will occur in new slab-on-grade floors as a result of chemical reactions taking place within the curing concrete. Vapor transmission through concrete floor slabs as a result of concrete curing has the potential to adversely affect sensitive floor coverings depending on the thickness of the concrete floor slab and the duration of time between the placement of concrete, and the floor covering. It is possible that a slab moisture sealant may be needed prior to the placement of sensitive floor coverings if a thick slab-on-grade floor is used and the time frame between concrete and floor covering placement is relatively short. Considering the E.I. test results presented herein, and known soil conditions in the region, the anticipated typical water vapor transmission rates, floor coverings, and improvements (to be chosen by the Client and/or project architect) that can tolerate vapor transmission rates without significant distress, the following alternatives are provided: Concrete slabs, including garages, should be more than 5 inches thick. Concrete slab underlayment should consist of a 15-mil vapor retarder, or equivalent, with all laps sealed per the 2019 CBC and the manufacturer's recommendation. The vapor retarder should comply with the ASTM E 1745 - Class A criteria, and be installed in accordance with ACI 302.1 R-04 and ASTM E 1643. The 15-mil vapor retarder (ASTM E 1745 - Class A) shall be installed per the recommendations of the manufacturer, including all penetrations (i.e., pipe, ducting, rebar, etc.). Concrete slabs, including the garage areas, shall be underlain by 2 inches of clean, washed sand (SE > 30) above a 15-mil vapor retarder (ASTM E-1 745 - Class A, per Engineering Bulletin 119 [Kanare, 2005]) installed per the recommendations of the manufacturer, including all penetrations (i.e., pipe, ducting, rebar, etc.). The manufacturer shall provide instructions for lap sealing, including minimum width of lap, method of sealing, and either supply or specify suitable products for lap sealing (ASTM E 1745), and per code. ACI 302.1R-04 (2004) states "If a cushion or sand layer is desired between the vapor retarder and the slab, care must be taken to protect the sand layer from taking on additional water from a source such as rain, curing, cutting, or cleaning. Wet cushion or sand layer has been directly linked in the past to significant lengthening of time required for a slab to reach an acceptable level of dryness for floor covering Cross Real Estate Investors, LLC W.O. 8037-A-SC Tract 80-46, Carlsbad January 27, 2021 Fi1e:e:\wp12\8000\8037.pge GeoSoils, Inc. Page 23 applications." Therefore, additional observation and/or testing will be necessary for the cushion or sand layer for moisture content, and relatively uniform thicknesses, prior to the placement of concrete. The vapor retarder should be underlain by at least 2 inches of clean, washed sand (SE > 30). The sand should be placed on the prepared subgrade described above. Concrete should have a maximum water/cement ratio of 0.50. This does not supercede Table 19.3.2.1 of ACI 318-14 (2008) for corrosion or other corrosive requirements. Additional concrete mix design recommendations should be provided by the structural consultant and/or waterproofing specialist. Concrete finishing and workability should be addressed by the structural consultant and a waterproofing specialist. Where slab water/cement ratios are as indicated herein, and/or admixtures used, the structural consultant should also make changes to the concrete in the grade beams and footings in kind, so that the concrete used in the foundation and slabs are designed and/or treated for more uniform moisture protection. The homeowners should be specifically advised which areas are suitable for tile flooring, vinyl flooring, or other types of water/vapor-sensitive flooring and which are not suitable. In all planned floor areas, flooring shall be installed per the manufactures recommendations. Additional recommendations regarding water or vapor transmission should be provided by the architect/structural engineer/slab or foundation designer and should be consistent with the specified floor coverings indicated by the architect. Regardless of the mitigation, some limited moisture/moisture vapor transmission through the slab should be anticipated. Construction crews may require special training for installation of certain product(s), as well as concrete finishing techniques. The use of specialized product(s) should be approved by the slab designer and water-proofing consultant. A technical representative Of the flooring contractor should review the slab and moisture retarder plans and provide comment prior to the construction of the foundations or improvements. The vapor retarder contractor should have representatives onsite during the initial installation. WALL DESIGN PARAMETERS Conventional Retaining Walls The design parameters provided below assume that either very low expansive soils (typically Class 2 permeable filter material or Class 3 aggregate base) or native onsite materials with an expansion index up to 20 are used to backfill any retaining wall (this latter case would Cross Real Estate Investors, LLC W.O. 8037-A-SC Tract 80-46, Carlsbad January 27, 2021 FiIe:e:\wp12\8000\8037.pge GeoSoils, Inc. Page 24 require significant compliance testing). The type of backfill (i.e., select or native), should be specified by the wall designer, and clearly shown on the plans. Building walls, below grade, should be water-proofed. The foundation system for the proposed retaining walls should be designed in accordance with the recommendations presented in this and preceding sections of this report, as appropriate. Retaining wall footings should be embedded a minimum of 18 inches belowthe lowest adjacent grade (excluding landscape layer, 6 inches [i.e., 24 inches total]) and should be at least 24 inches in width. There should be no increase in bearing for footing width. Planned retaining wall footings near the perimeter of the site will likely need to be deepened into suitable bedrockfor adequate vertical and lateral bearing support. Recommendations for the design of specialty walls (i.e., crib, earthstone, geogrid, etc.) can be provided upon request. Restrained Walls Any retaining walls that will be restrained prior to placing and compacting backfill material or that have re-entrant or male corners, should be designed for an at-rest equivalent fluid pressure (EFP) of 55 pcf and 65 pcf for select and very low to low expansive native backfill, respectively. The design should include any applicable surcharge loading. For areas of male or re-entrant corners, the restrained wall design should extend a minimum distance of twice the height of the wall (2H) laterally from the corner. Cantilevered Walls The recommendations presented below are for cantilevered retaining walls up to 10 feet high. Design parameters for walls less than 3 feet in height may be superceded by San Diego Regional Standard design. Active earth pressure may be used for retaining wall design, provided the top of the wall is not restrained from minor deflections. An equivalent fluid pressure approach may be used to compute the horizontal pressure against the wall. Appropriate fluid unit weights are given below for specific slope gradients of the retained material. These do not include other superimposed loading conditions due to traffic, structures, seismic events or adverse geologic conditions. When wall configurations are finalized, the appropriate loading conditions for superimposed loads can be provided upon request. For preliminary planning purposes, the structural consultant should incorporate the surcharge of traffic on the back of retaining walls. The traffic surcharge may be taken as 100 psf/ft in the upper 5 feet of backfill for light truck and car traffic within "H" feet from the back of the wall, where "H" equals the wall height. This does not include the surcharge of parked vehicles which should be evaluated at a higher surcharge to account for the effects of seismic loading. Cross Real Estate Investors, LLC - W.O. 8037-A-SC Tract 80-46, Carlsbad January 27, 2021 Fi1e:e:\wp12\8000\8037.pge GeoSoils, Inc. Page 25 SURFACE SLOPE OF RETAINED MATERIAL (HORIZONTAL:VERTICAL) EQUIVALENT FLUID WEIGHT P.C.F. (SELECT BACKFILL)2 EQUIVALENT FLUID WEIGHT P.C.F. (APPROVED NATIVE BACKFILL)3 Level(') 38 1 50 2tol 55 65 Level backfill behind a retaining wall is defined as compacted earth materials, properly drained, without a slope for a distance of 2H behind the wall, where H is the height of the wall. SE > 30, P.1. < 15, E.I. < 21, and < 10% passing No. 200 sieve. E.I. = 0 to 20, SE >25, P.1. < 15, and < 15% passing No. 200 sieve; confirmation testing required, and soils will need to be selectively mined for this purpose. Seismic Surcharge For engineered retaining walls that may pose ingress or egress constraints within 6 feet of a structure, GSI recommends that such walls be evaluated for a seismic surcharge (in general accordance with 2019 CBC requirements). The site walls in this category should maintain an overturning Factor-of-Safety (FOS) of approximately 1.25 when the seismic surcharge (increment), is applied. For restrained walls, the seismic surcharge should be applied as a uniform surcharge load from the bottom of the footing (excluding shear keys) to the top of the backfill at the heel of the wall footing. This seismic surcharge pressure (seismic increment) may be taken as 15H where "H" for retained walls is the dimension previously noted as the height of the backfill to the bottom of the footing. The resultant force should be applied at a distance 0.6 H up from the bottom of the footing. For the evaluation of the seismic surcharge, the bearing pressure may exceed the static value by one-third, considering the transient nature of this surcharge. For cantilevered walls the pressure should bean inverted triangular distribution using 15H. Reference for the seismic surcharge is Section 1802.2 of the 2019 CBC. Please note this is for local wall stability only. The 15H is derived from a Mononobe-Okabe solution for both restrained cantilever walls. This accounts for the increased lateral pressure due to shakedown or movement of the sand fill soil in the zone of influence from the wall or roughly a 45° - 0/2 plane away from the back of the wall. The 15H seismic surcharge is derived from the formula: Ph =3/8 • a• yH Where: Ph = Seismic increment ah = Probabilistic horizontal site acceleration with a percentage of "g" = total unit weight (120 to 130 pcf for site soils @ 90% relative compaction). H = Height of the wall from the bottom of the footing or point of pile fixity. Cross Real Estate Investors, LLC W.O. 8037-A-SC Tract 80-46 Carlsbad January 27, 2021 FiIe:e:\wpl2\8000\8037.pge GeoSoils, Inc. Page 26 Retaining Wall Backfill and Drainage Positive drainage must be provided behind all retaining walls in the form of gravel wrapped in geofabric and outlets. A backdrain system is considered necessary for retaining walls that are 2 feet or greater in height. Details 1, 2, and 3, present the backdrainage options discussed below. Backd rains should consist of a 4-inch diameter perforated PVC or ABS pipe encased in either Class 2 permeable filter material or 3/4-IflCh to 1 1/2-inch gravel wrapped in approved filter fabric (Mirafi 140N or equivalent). The drain should flow via gravity to an approved drainage facility. For select backfill, the filter material should extend a minimum of 1 horizontal foot behind the base of the walls and upward at least 1 foot. For native backfill that has up to E.I. = 20, continuous Class 2 permeable drain materials should be used behind the wall. This material should be continuous (i.e., full height) behind the wall, and it should be constructed in accordance with the enclosed Detail 1 (Typical Retaining Wall Backfill and Drainage Detail). For limited access and confined areas, (panel) drainage behind the wall may be constructed in accordance with Detail 2 (Retaining Wall Backfill and Subdrain Detail Geotexti le Drain). Materials with an expansion index (E.l.) potential of greater than 20 should not be used as backfill for retaining walls. For more onerous expansive situations, backfill and drainage behind the retaining wall should conform with Detail 3 (Retaining Wall And Subdrain Detail Clean Sand Backfill). Retaining wall backfill should be moisture conditioned to 1.1 times the soil's optimum moisture content, placed in relatively thin lifts, and compacted to at least 90 percent of the laboratory standard (ASTM D 1557). Outlets should consist of a 4-inch diameter solid PVC or ABS pipe spaced no greater than ± 100 feet apart, with a minimum of two outlets, one on each end. The use of weep holes, only, in walls higher than 2 feet, is not recommended. The surface of the backfill should be sealed by pavement or the top 18 inches compacted with native soil (E.l. !~ 50). Proper surface drainage should also be provided. For additional mitigation, consideration should be given to applying a water-proof membrane to the back of all retaining structures. The use of a waterstop should be considered for all concrete and masonry joints. Wall/Retaining Wall Footing Transitions Site walls are anticipated to be founded on footings designed in accordance with the recommendations in this report. Should wall footings transition from cut to fill, the civil designer may specify either: A minimum of a 2-foot overexcavation and recompaction of cut materials for a distance of 2H, from the point of transition. Increase of the amount of reinforcing steel and wall detailing (i.e., expansion joints or crack control joints) such that a angular distortion of 1/360 for a distance of 2H on either side of the transition may be accommodated. Expansion joints should be Cross Real Estate Investors, LLC W.O. 8037-A-SC Tract 80-46, Carlsbad January 27, 2021 Fi1e:e:\wp12\8000\8037.pge GeoSoils, Inc. Page 27 Structural footing or settlement-sensitive improvement (1) Waterproofing membrane CMU or reinforced-concrete wall ±12 inches Proposed grade sloped to drain per precise civil drawings (5) Weep hole Footing and wall design by others - Provide surface drainage via an / engineered V-ditch (see civil plans / for details) / 2:1 NO slope ope..or level. 12:inche4 .:. .. :. ... . •• (3) Filter fabri-- Native backfill : 1:1 NO or flatter ... backcut to be properly benched (6) Footing Waterproofing membrane. Gravel: Clean, crushed, /4 to 1Y2 inch. Filter fabric: Mirafi 140N or approved equivalent. Pipe: 4-inch-diameter perforated PVC, Schedule 40, or approved alternative with minimum of 1 percent gradient sloped to suitable, approved outlet point (perforations down). Weep hole: Minimum 2-inch diameter placed at 20-foot centers along the wall and placed 3 inches above finished surface. Design civil engineer to provide drainage at toe of wall. No weep holes for below-grade walls. Footing: If bench is created behind the footing greater than the footing width, use level fill or cut natural earth materials. An additional "heel" drain will likely be required by geotechnical consultant. I G4 jic. I RETAINING WALL DETAIL - ALTERNATIVE A Detail 1 Structural footing or (1) Waterproofing settlement-sensitive improvement - membrane (optional) 1 Provide surface drainage via engineered V-ditch (see civil plan details) CMU or 21 NO slope reinforced-concrete wall 6 inches IComposite.: drain (5) Weep hole- - Proposed grade ••. . '. .. •...: Native backfill —F --- / sloped to drain / per precise civil drawings (4) Pipe 11 NO or flatter backcut to be Footing and wall properly benched design by others — . (6) 1 cubic foot of 3/4-inch crushed rock (7) Footing (1) Waterproofing membrane (optional): Liquid boot or approved mastic equivalent. 4 -I Drain: Miradrain 6000 or J-drain 200 or equivalent for non-waterproofed walls; Miradrain 6200 or J-drain 200 or equivalent for waterproofed walls (all perforations down). Filter fabric: Mirafi 140N or approved equivalent; place fabric flap behind core. Pipe: 4-inch-diameter perforated PVC, Schedule 40, or approved alternative with minimum of 1 percent gradient to proper outlet point (perforations down). Weep hole: Minimum 2-inch diameter placed at 20-foot centers along the wall and placed 3 inches above finished surface. Design civil engineer to provide drainage at toe of wall. No weep holes for below-grade walls. Gravel: Clean, crushed, 3/4 to iY2 inch. Footing: If bench is created behind the footing greater than the footing width, use level fill or cut natural earth materials. An additional "heel" drain will likely be required by geotechnical consultant. I G4 #4)2e- J RETAINING WALL DETAIL - ALTERNATIVE B I Detail 2 (1) Waterproofing membrane CMU or reinforced-concrete wall -------L ±12 inches (5) Weep hole H r Proposed grade / sloped to drain per precise civil drawings Footing and wall Structural footing or settlement-sensitive improvement Provide surface drainage 2:1 (h:v) slope $lope or level ..H12 .• .• .. .., :..... - - minimum • .. . . ..... 1:: .. . .... .. (8) Native backfill (6) Clean ......... :.':.: . . sand backfill - 1:1 NO or flatter backcut to be (3) Filter fabric properly benched (2) Gravel Heel quo I IJ}' UU II 0 wIdth Pipe (7) Footing Waterproofing membrane: Liquid boot or approved masticequivalent. Gravel: Clean, crushed, 3/4 to 13 inch. Filter fabric: Mirafi 140N or approved equivalent. Pipe: 4-inch-diameter perforated PVC, Schedule 40, or approved alternative with minimum of 1 percent gradient to proper outlet point (perforations down). Weep hole: Minimum 2-inch diameter placed at 20-foot centers along the wall and placed 3 inches above finished surface. Design civil engineer to provide drainage at toe of wall. No weep holes for below-grade walls. Clean sand backfill: Must have sand equivalent value (SE.) of 35 or greater; can be densitied by water jetting upon approval by geotechnical engineer. Footing: If bench is created behind the footing greater than the footing width, use level fill or cut natural earth materials. An additional "heel" drain will likely be required by geotechnical consultant. Native backfill: If E.I. (21 and S.E. )35 then all sand requirements also may not be required and will be reviewed by the geotechnical consultant. G4Jw. RETAINING WALL DETAIL - ALTERNATIVE C Detail 3 placed no greater than 20 feet on-center, in accordance with the structural engineer's/wall designer's recommendations, regardless of whether or not transition conditions exist. Expansion joints should be sealed with a flexible, non-shrink grout. c) Embed the footings entirely into native formational material (i.e., deepened footings). If transitions from cut to fill transect the wall footing alignment at an angle of less than 45 degrees (plan view), then the designer should follow recommendation "a" (above) and until such transition is between 45 and 90 degrees to the wall alignment. TOP-OF-SLOPE WALLS/FENCES/IMPROVEMENTS AND EXPANSIVE SOILS Expansive Soils and Slope Creep Some of the soils at the site may possibly be expansive and therefore, become desiccated when allowed to dry. Such soils are susceptible to surficial slope creep, especially with seasonal changes in moisture content. Typically in southern California, during the hot and dry summer period, these soils become desiccated and shrink, thereby developing surface cracks. The extent and depth of these shrinkage cracks depend on many factors such as the nature and expansivity of the soils, temperature and humidity, and extraction of moisture from surface soils by plants and roots. When seasonal rains occur, water percolates into the cracks and fissures, causing slope surfaces to expand, with a corresponding loss in soil density and shear strength near the slope surface. With the passage of time and several moisture cycles, the outer 3 to 5 feet of slope materials experience a very slow, but progressive, outward and downward movement, known as slope creep. For slope heights greaterthan 7 feet, this creep related soil movement will typically impact all rear yard flatwork and other secondary improvements that are located within about 15 feet from the top of slopes, such as swimming pools, concrete flatwork, etc., and in particular top of slope fences/walls. This influence is normally in the form of detrimental settlement, and tilting of the proposed improvements. The dessication/swelling and creep discussed above continues over the life of the improvements, and generally becomes progressively worse. Accordingly, the developer should provide this information to all interested/affected parties. Top of Slope Walls/Fences Due to the potential for slope creep for slopes higher than about 7 feet, some settlement and tilting of the walls/fence with the corresponding distresses, should be expected. To mitigate the tilting of top of slope walls/fences, we recommend that the walls/fences be constructed on a combination of grade beam and caisson foundations. The grade beam should be at a minimum of 12 inches by 12 inches in cross section, supported by drilled caissons, 12 inches minimum in diameter, placed at a maximum spacing of 6 feet on center, and with a minimum embedment length of 7 feet below the bottom of the grade beam. The strength of the concrete and grout should be evaluated by the structural engineer of record. The Cross Real Estate Investors, LLC W.O. 8037-A-SC Tract 80-46, Carlsbad January 27, 2021 File: e:\wpl2\8000\8037.pge GeoSoils, Inc. Page 31 proper ASTM tests for the concrete and mortar should be provided along with the slump quantities. The concrete used should be appropriate to mitigate site corrosion, as warranted. The design of the grade beam and caissons should be in accordance with the recommendations of the project structural engineer, and include the utilization of the following geotechnical parameters: Creep Zone: 5-foot vertical zone below the slope face and projected upward parallel to the slope face. Creep Load: The creep load projected on the area of the grade beam should be taken as an equivalent fluid approach, having a density of 60 pcf. For the caisson, it should be taken as a uniform 900 pounds per linear foot of caisson's depth, located above the creep zone. Point of Fixity: Located a distance of 1.5 times the caisson's diameter, below the creep zone. Passive Resistance: Passive earth pressure of 300 psf per foot of depth per foot of caisson diameter, to a maximum value of 4,500 psf may be used to determine caisson depth and spacing, provided that they meet or exceed the minimum requirements stated above. To determine the total lateral resistance, the contribution of the creep prone zone above the point of fixity, to passive resistance, should be disregarded. Allowable Axial Capacity: Shaft capacity: 350 psf applied below the point of fixity over the surface area of the shaft. Tip capacity: 4,500 psf. DRIVEWAY, FLATWORK, AND OTHER IMPROVEMENTS The effects of expansive soils are cumulative, and typically occur over the lifetime of any improvements. On relatively level areas, when the soils are allowed to dry, the dessication and swelling process tends to cause heaving and distress to flatwork and other improvements. The resulting potential for distress to improvements may be reduced, but not totally eliminated. To that end, it is recommended that the developer should notify all interested/affected parties of this long-term potential for distress. To reduce the likelihood of distress, the following recommendations are presented for all exterior flatwork: Cross Real Estate Investors, LLC W.O. 8037-A-SC Tract 80-46, Carlsbad January 27, 2021 FiIe:e:\wp12\8000\8037.pge GeoSoils, Inc. Page 32 The subgrade area for concrete slabs should be compacted to achieve a minimum 90 percent relative compaction, and then be presoaked to 1 to 2 percentage points above (or 110 percent of) the soils' optimum moisture content, to a depth of 18 inches below subgrade elevation. If very low expansive soils are present, only optimum moisture content, or greater, is required and specific presoaking is not warranted. The moisture content of the subgrade should be proof tested within 72 hours prior to concrete placement. Exterior concrete slabs should be cast over a non-yielding surface, consisting of a 4- inch layer of Class 3 base, crushed rock, gravel, or clean sand (or City of Carlsbad minimum, whichever is greater), that should be compacted and level prior to placement of concrete. If very low expansive soils are present, the base, rock, gravel, or sand may be deleted. The layer or subgrade should be wet-down completely prior to placement of concrete, to minimize loss of concrete moisture to the surrounding earth materials. Exterior slabs should be a minimum of 4 inches thick. Driveway slabs and approaches should additionally have a thickened edge (12 inches) adjacent to all landscape areas, to help impede infiltration of landscape water under the slab. The use of transverse and longitudinal control joints are recommended to help control slab cracking due to concrete shrinkage or expansion. Two ways to mitigate such cracking are: a) add a sufficient amount of reinforcing steel, increasing tensile strength of the slab; and, b) provide an adequate amount of control and/or expansion joints to accommodate anticipated concrete shrinkage and expansion. In order to reduce the potential for unsightly cracks, slabs should be reinforced at mid-height with a minimum of No. 3 bars placed at 18 inches on center, in each direction. The exterior slabs should be scored or saw cut, 1/2 to 3/8 inches deep, often enough so that no section is greater than 10 feet by 10 feet. For sidewalks or narrow slabs, control joints should be provided at intervals of every 6 feet. The slabs should be separated from the foundations and sidewalks with expansion joint filler material. No traffic should be allowed upon the newly poured concrete slabs until they have been properly cured to within 75 percent of design strength. Concrete compression strength should be a minimum of 2,500 psi. Driveways, sidewalks, and patio slabs adjacent to the house should be separated from the house with thick expansion joint filler material. In areas directly adjacent to a continuous source of moisture (i.e., irrigation, planters, etc.), all joints should be additionally sealed with flexible mastic. Planters and walls should not be tied to the house. I I Cross Real Estate Investors, LLC Tract 80-46, Carlsbad File: e:\wpl2\8000\8037.pge GeoSoils, Inc. W.O. 8037-A-SC January 27, 2021 Page 33 I I I I I I I I I I Overhang structures should be supported on the slabs, or structurally designed with continuous footings tied in at least two directions. Any masonry landscape walls that are to be constructed throughout the property should be grouted and articulated in segments no more than 20 feet long. These segments should be keyed or doweled together. Utilities should be enclosed within a closed utilidor (vault) or designed with flexible connections to accommodate differential settlement and expansive soil conditions. Positive site drainage should be maintained at all times. Finish grade on the lots should provide a minimum of 1 to 2 percent fall to the street, as indicated herein. It should be kept in mind that drainage reversals could occur, including post-construction settlement,, if relatively flat yard drainage gradients are not periodically maintained by the homeowner or homeowners association. Due to expansive soils, air conditioning (A/C) units should be supported by slabs that are incorporated into the building foundation or constructed on a rigid slab with flexible couplings for plumbing and electrical lines. A/C waste water lines should be drained to a suitable non-erosive outlet. Shrinkage cracks could become excessive if proper finishing and curing practices are not followed. Finishing and curing practices should be performed per the Portland Cement Association Guidelines. Mix design should incorporate rate of curing for climate and time of year, sulfate content of soils, corrosion potential of soils, and fertilizers used on site. PRELIMINARY ASPHALTIC CONCRETE PAVEMENT DESIGN RECOMMENDATIONS General The City of Carlsbad may retain the authority to approve the final structural design sections after subgrade elevations and actual resistance values (R-values) have been obtained at the conclusion of earthwork. On a preliminary basis, and for estimation and bidding purposes, the asphaltic concrete pavement section for the planned cul-de-sac street may consist of 3 inches of asphaltic concrete over 8 inches of aggregate base (Caltrans Class II, or equivalent). Final pavement sections should be based on actual R-value testing performed following the backfill of underground utilities in the street right-of-way. The preliminary pavement section provided is intended as a minimum guideline. If thinner or highly variable pavement sections are constructed, increased maintenance and repair could be expected. If the ADT (average daily traffic) or ADIT (average daily truck traffic) Cross Real Estate Investors, LLC W.O. 8037-A-SC Tract 80-46, Carlsbad January 27, 2021 File: e:\wp12\8000\8037pge GeoSoils, Inc. Page 34 increases beyond that intended, as reflected by the T.I. used for design, increased maintenance and repair could be required for the pavement section. Consideration should be given to the increased potential for distress from overuse of paved street areas by heavy equipment and/or construction related heavy traffic (e.g., concrete trucks, loaded supply trucks, etc.), particularly when the final section is not in place (i.e., topcoat). Best management construction practices should be followed at all times, especially during inclement weather. PAVEMENT GRADING RECOMMENDATIONS General All section changes should be properly transitioned. If adverse conditions are encountered during the preparation of subgrade materials, special construction methods may need to be employed. A GSI representative should be present for the preparation of subgrade, aggregate base, and asphaltic concrete. Subgrade Within street and parking areas, all surficial deposits of loose soil material should be removed and recompacted as recommended. After the loose soils are removed, the bottom is to be scarified to a depth of at least 6 inches, moisture conditioned as necessary and - compacted to 95 percent of the maximum laboratory density, as determined by ASTM D 1557. Deleterious material, excessively wet or dry pockets, concentrated zones of oversized rock fragments, and any other unsuitable materials encountered during grading should be removed. The compacted fill material should then be brought to the elevation of the proposed subgrade for the pavement. The subgrade should be proof-rolled in order to promote a uniform firm and unyielding surface. All grading and fill placement should be observed by the project geotechnical consultant. Aggregate Base Compaction tests are required for the recommended aggregate base section. Minimum relative compaction required will be 95 percent of the laboratory maximum density as determined by ASTM D 1557. Base aggregate should be in accordance to the "Greenbook" crushed aggregate base rock (minimum R-value=78). Paving Prime coat may be omitted if all of the following conditions are met: Cross Real Estate Investors, LLC W.O. 8037-A-SC Tract 80-46, Carlsbad January 27, 2021 File: e:\wpl 2\8000\8037. pge GeoSoils, Inc. Page 35 The asphalt pavement layer is placed within two weeks of completion of aggregate base and/or subbase course. Traffic is not routed over completed base before paving Construction is completed during the dry season of May through October. The aggregate base is kept free of debris prior to placement of asphaltic concrete. If construction is performed during the wet season of November through April, prime coat may be omitted if no rain occurs between completion of the aggregate base course and paving and the time between completion of aggregate base and paving is reduced to three days, provided the aggregate base is free of loose soil or debris. Where prime coat has been omitted and rain occurs, traffic is routed over the aggregate base course, or paving is delayed, measures shall be taken to restore the aggregate base course, and subgrade to conditions that will meet specifications as directed by the geotechnical consultant. Drainage Positive drainage should be provided for all surface water to drain towards the area swale, curb and gutter, or to an approved drainage channel. Positive site drainage should be maintained at all times. Water should not be allowed to pond or seep into the ground, such as from behind unprotected curbs, both during and after grading. If planters or landscaping are adjacent to paved areas, measures should be taken to minimize the potential for water to enter the pavement section, such as thickened edges, enclosed planters, etc. Also, best management construction practices should be strictly adhered to at all times to minimize the potential for distress during construction and roadway improvements. PCC Cross Gutters PCC cross gutters should be designed in accordance with San Diego Regional Standard Drawing (SDRSD) G-12. Additional Considerations To mitigate perched groundwater, consideration should be given to installation of subgrade separators (cut-offs) between pavement subgrade and landscape areas, although this is not a requirement from a geotechnical standpoint. Cut-offs, if used, should be 6 inches wide and at least 12 inches below the pavement subgrade contact or 12 inches below the crushed aggregate base rock, if utilized. Cross Real Estate Investors, LLC W.O. 8037-A-SC Tract 80-46, Carlsbad January 27, 2021 File: e:\wpl2\8000\8037.pge GeoSoils, Inc. Page 36 STORM WATER TREATMENT AND HYDROMODIFICATION MANAGEMENT USDA Study A review of the United States Department of Agriculture database ([USDA]; 1973, 2020) indicates that site soils located within the upper and lower elevations of the western two- thirds of the site are classified as Marina loamy coarse sand (2-30 percent slopes). The USDA study further indicates that the Marina series is classified as belonging to Hydrologic Soil Group "B." A review of USDA (1973 and 2019) indicates that the capacity of the most limiting layer to transmit water (Ksat) within the Marina loamy coarse sand is moderately high to high (0.57 toOl .98 inches per hour [in/hr]). Some soils identified as Marina loamy coarse sand may be removed and recompacted as engineered fill during grading operations. Infiltration Feasibility Per our onsite infiltration test results, an infiltration rate at the location tested onsite ranged between 1.74 inches per hour to 2.82 inches per hour (See Table below). Test holes lB-i and IB-2 are generally above the recommended feasibility threshold of 0.52 inches per hour per the EPA (Clar, et al., 2004), and 0.50 inches per hour per the County (2019) for full infiltration. With a factor of safety of 2, and utilizing the most conservative design infiltration rate for lB-1, the design rate is 0.87 inches/hour. The permeability of the underlying soil/bedrock can be expected to decrease with depth, as the soil/bedrock becomes less weathered, thereby promoting the lateral migration of water in soil. Test data sheets are presented in Appendix E. Boring locations (lB-1, lB-2 and I13-3), are shown on Plate 1. I INFILTRATION I TEST HOLE OBSERVED FIELD INFILTRATION RATE (INCHES PER HOUR) SOIL UNIT PER USDA (1973) lB-i 1.74 Marina Loamy Coarse Sand I13-2 2.82 Marina Loamy CoarseSand Proposed or existing fill, and/or moisture-sensitive improvements, such as pavements, and utility trench backfill, foundations, retaining walls, and below grade building walls, would likely be adversely affected by excessive soil moisture, including existing offsite improvements, causing settlement and distress. Bio-basins can adversely affect the performance of the onsite and offsite structures, foundation systems by: 1) increasing soil moisture transmission rates through concrete flooring, 2) reducing the stability of slopes, and 3) increasing the potential for a loss in bearing strength of soil. Onsite mitigative grading of compressible near-surface soils for the support of structures generally involves removal and recompaction. This is anticipated to create the potential for permeability contrast, and the potential for the development of a shallow "perched" and mounded water table, which can reasonably be anticipated to migrate laterally, beneath the structure(s), or offsite onto adjacent property, causing settlement and associated distress. Based on City (2016), the Cross Real Estate Investors, LLC W.O. 8037-A-SC - Tract 80-46, Carlsbad January 27, 2021 FiIe:e:\wp12\8000\8037.pge GeoSoils, Inc. Page 37 calculated infiltration rate with safety factor added yields a rate of 0.87 inches per hour, which is above the minimum acceptable rate of 0.025 inches per hour; however, "no infiltration" is recommended, owing to the potential to cause distress to existing and proposed improvements, both onsite and offsite. In addition, infiltrating into site soils within 10 feet of any settlement sensitive structure/improvement is considered poor engineering judgement. In addition, "no infiltration" is recommended within 10 feet of any planned settlement/expansion sensitive improvement. Based on our review and engineering analysis, the site belongs to HSG "B" and we recommend " no infiltration" BMP design. In addition, due to the potential for associated settlement, distress, and perched groundwater for any BMP structure within close proximity (i.e., potentially within 10 feet) of any planned basin to building foundations, retaining walls, slopes, and other settlement-sensitive improvement, a "no infiltration" BMP design is warranted. Furthermore, any basin constructed entirely of compacted fill is considered as belonging to HSG D, and a "no infiltration" BMP design is also warranted (Clar, et al., 2004). Form I-B and Form 1-9 (City of Carlsbad, 2016) are presented in Appendix E. Onsite Infiltration-Runoff Retention Systems General design criteria regarding the use of onsite infiltration-runoff retention systems (OIRRS) are presented below. Should onsite infiltration-runoff retention systems (OIRRS) be planned for Best Management Practices (BMPs) or Low Impact Development (LID) principles for the project, some guidelines should be followed in the planning, design, and construction of such systems. Such facilities, if improperly designed or implemented without consideration of the geotechnical aspects of site conditions, can contribute to flooding, saturation of bearing materials beneath site improvements, slope instability, and possible concentration and contribution of pollutants into the groundwater or storm drain and/or utility trench systems. A key factor in these systems is the infiltration rate (sometimes referred to as the percolation rate) which can be ascribed to, or determined for, the earth materials within which these systems are installed. Additionally, the infiltration rate of the designed system (which may include gravel, sand, mulch/topsoil, or other amendments, etc.) will need to be considered. The project infiltration testing is very site specific, any changes to the location of the proposed OIRRS and/or estimated size of the OIRRS, may require additional infiltration testing. Locally, relatively impermeable residual soils include the underlying bedrock, which is anticipated to have a very low vertical infiltration rate. The following geotechnical guidelines should be considered when designing onsite infiltration-runoff retention systems: It is not good engineering practice to allow water to saturate soils, especially near slopes or improvements; however, the controlling agency/authority may now require this. Cross Real Estate Investors, LLC W.O. 8037-A-SC Tract 80-46, Carlsbad January 27, 2021 File: e:\wpl2\8000\8037pge GeoSoils, Inc. Page 38 Areas adjacent to, or within, the OIRRS that are subject to inundation should be properly protected against scouring, undermining, and erosion, in accordance with the recommendations of the design engineer. Where infiltration systems are located near slopes or improvements, impermeable liners and subdrains should be used along the bottom of bioretention swales/basins located within the influence of such slopes and structures. Impermeable liners used in conjunction with bioretention basins should consist of a 30-mil polyvinyl chloride (PVC) membrane that is covered by a minimum of 12 inches of clean soil, free from rocks and debris, with a maximum 4:1 (h:v) slope inclination, or flatter, and meets the following minimum specifications: Solid Soils Specific Gravity (ASTM D792): 1.2 (g/cc, mm.); Tensile (ASTM D882):73 (lb/in-width, mm); Elongation at Break (ASTM D882):380 (%, mm); Modulus (ASTM D882): 32 (lb/in-width, mm.); and Tear Strength (ASTM D1004): 8 (lb/in, mm); Seam Shear Strength (ASTM D882) 58.4 (lb/in, mm); Seam Peel Strength (ASTM D882) 15 (lb/in, mm). Subdrains should consist of at least 4-inch diameter Schedule 40 or SDR 35 drain pipe with perforations oriented down. The drain pipe should be sleeved with a filter sock. Storm drain, standpipes, and utilities that cross BMPs should be slurried with a 2-sack mix, to 5 feet outside the structure. Final project plans (grading, precise grading, foundation, retaining wall, landscaping, etc.), should be reviewed by this office prior to construction, so that construction is in accordance with the conclusions and recommendations of this report. Based on our review, supplemental recommendations and/or further geotechnical studies may be warranted. It should be noted that structural and landscape plans were not available for review at this time. DEVELOPMENT CRITERIA Slope Deformation Compacted fill slopes designed using customary factors of safety for gross or surficial stability and constructed in general accordance with the design specifications should be expected to undergo some differential vertical heave or settlement in combination with differential lateral movement in the out-of-slope direction, after grading. This post-construction movement occurs in two forms: slope creep, and lateral fill extension (LEE). Slope creep is caused by alternate wetting and drying of the fill soils which results in slow downslope movement. This type of movement is expected to occur throughout the Cross Real Estate Investors, LLC W.O. 8037-A-SC Tract 80-46, Carlsbad January 27, 2021 File: e:\wpl2\8000\8037.pge GeoSoils, Inc. Page 39 life of the slope, and is anticipated to potentially affect improvements or structures (e.g., separations and/or cracking), placed near the top-of-slope, up to a maximum distance of approximately l5 feet from the top-of-slope, depending on the slope height. This movement generally results in rotation and differential settlement of improvements located within the creep zone. LIFE occurs due to deep wetting from irrigation and rainfall on slopes comprised of expansive materials. Although some movement should be expected, long-term movement from this source may be minimized, but not eliminated, by placing the fill throughout the slope region, wet of the fill's optimum moisture content. It is generally not practical to attempt to eliminate the effects of either slope creep or LFE. Suitable mitigative measures to reduce the potential of lateral deformation typically include: setback of improvements from the slope faces (per the adopted California Building Code), positive structural separations (i.e., joints) between improvements, and stiffening and deepening of foundations. Expansion joints in walls should be placed no greater than 20 feet on-center, and in accordance with the structural engineer's recommendations. All of these measures are recommended for design of structures and improvements. The ramifications of the above conditions, and recommendations for mitigation, should be provided to each homeowner and/or any homeowners association. Slope Maintenance and Planting Water has been shown to weaken the inherent strength of all earth materials. Slope stability is significantly reduced by overly wet conditions. Positive surface drainage away from slopes should be maintained and only the amount of irrigation necessary to sustain plant life should be provided for planted slopes. Over-watering should be avoided as it adversely affects site improvements, and causes perched groundwater conditions. Graded slopes constructed utilizing onsite materials would be erosive. Eroded debris may be minimized and surficial slope stability enhanced by establishing and maintaining a suitable vegetation cover soon after construction. Compaction to the face of fill slopes would tend to minimize short-term erosion until vegetation is established. Plants selected for landscaping should be light weight, deep rooted types that require little water and are capable of surviving the prevailing climate. Jute-type matting or other fibrous covers may aid in allowing the establishment of a sparse plant cover. Utilizing plants other than those recommended above will increase the potential for perched water, staining, mold, etc., to develop. A rodent control program to prevent burrowing should be implemented. Irrigation of natural (ungraded) slope areas is generally not recommended. These recommendations regarding plant type, irrigation practices, and rodent control should be provided to each homeowner. Over-steepening of slopes should be avoided during building construction activities and landscaping. Drainage Adequate surface drainage is a very important factor in reducing the likelihood of adverse performance of foundations, hardscape, and slopes. Surface drainage should be sufficient to mitigate ponding of water anywhere on the property, and especially near structures and tops of slopes. Surface drainage should be carefully taken into consideration during fine Cross Real Estate Investors, LLC W.O. 8037-A-SC Tract 80-46, Carlsbad January 27, 2021 FiIe:e:\wp12\8000\8037.pge GeoSoils, Inc. Page 40 grading, landscaping, and building construction. Therefore, care should betaken that future landscaping or construction activities do not create adverse drainage conditions. Positive site drainage within the property should be provided and maintained at all times. Drainage should not flow uncontrolled down any descending slope. Water should be directed away from foundations and tops of slopes, and not allowed to pond and/or seep into the ground. In general, site drainage should conform to Section 1804.3 of the 2019 CBC. Consideration should be given to avoiding construction of planters adjacent to structures (buildings, pools, spas, etc.). Building pad drainage should be directed toward the street or other approved area(s). Although not a geotechnical requirement, roof gutters, down spouts, or other appropriate means may be utilized to control roof drainage. Down spouts, or drainage devices should outlet a minimum of 5 feet from structures or into a subsurface drainage system. Areas of seepage may develop due to irrigation or heavy rainfall, and should be anticipated. Minimizing irrigation will lessen this potential. If areas of seepage develop, recommendations for minimizing this effect could be provided upon request. Toe of Slope Drains/Toe Drains Where significant slopes intersect pad areas, surface drainage down the slope allows for some seepage into the subsurface materials, sometimes creating conditions causing or contributing to perched and/or ponded water. Toe of slope/toe drains may be beneficial in the mitigation of this condition due to surface drainage. The general criteria to be utilized by the design engineer for evaluating the need for this type of drain is as follows: Is there a source of irrigation above or on the slope that could contribute to saturation of soil at the base of the slope? Are the slopes hard rock and/or impermeable, or relatively permeable, or; do the slopes already have or are they proposed to have subdrains (i.e., stabilization fills, etc.)? Are there cut-fill transitions (i.e., fill over bedrock), within the slope? Was the lot at the base of the slope overexcavated or is it proposed to be overexcavated? Overexcavated lots located at the base of a slope could accumulate subsurface water along the base of the fill cap. Are the slopes north facing? North facing slopes tend to receive less sunlight (less evaporation) relative to south facing slopes and are more exposed to the currently prevailing seasonal storm tracks. What is the slope height? It has been our experience that slopes with heights in excess of approximately 10 feet tend to have more problems due to storm runoff and irrigation than slopes of a lesser height. Cross Real Estate Investors, LLC - W.O. 8037-A-SC Tract 80-46, Carlsbad January 27, 2021 File: e:\wpl2\8000\8037.pge GeoSoils, Inc. Page 41 Do the slopes "toe out" into a residential lot or a lot where perched or ponded water may adversely impact its proposed use? Based on these general criteria, the construction of toe drains may be considered by the design engineer along the toe of slopes, or at retaining walls in slopes, descending to the rear of such lots. Following are Detail 4 (Schematic Toe Drain Detail) and Detail 5 (Subdrain Along Retaining Wall Detail). Other drains may be warranted due to unforeseen conditions, homeowner irrigation, or other circumstances. Where drains are constructed during grading, including subdrains, the locations/elevations of such drains should be surveyed, and recorded on the final as-built grading plans by the design engineer. It is recommended that the above be disclosed to all interested parties, including homeowners and any homeowners association. Erosion Control Onsite earth materials have a moderate to high erosion potential. Consideration should be given to providing hay bales and silt fences for the temporary control of surface water, from a geotechnical viewpoint. Landscape Maintenance Only the amount of irrigation necessary to sustain plant life should be provided. Over-watering the landscape areas will adversely affect proposed site improvements. We would recommend that any proposed open-bottom planters adjacent to proposed structures be eliminated for a minimum distance of 10 feet. As an alternative, closed-bottom type planters could be utilized. An outlet placed in the bottom of the planter, could be installed to direct drainage away from structures or any exterior concrete flatwork. If planters are constructed adjacent to structures, the sides and bottom of the planter should be provided with a moisture barrier to prevent penetration of irrigation water into the subgrade. Provisions should be made to drain the excess irrigation water from the planters without saturating the subgrade below or adjacent to the planters. Graded slope areas should be planted with drought resistant vegetation. Consideration should be given to the type of vegetation chosen and their potential effect upon surface improvements (i.e., some trees will have an effect on concrete flatwork with their extensive root systems). From a geotechnical standpoint leaching is not recommended for establishing landscaping. If the surface soils are processed for the purpose of adding amendments, they should be recompacted to 90 percent minimum relative compaction. Gutters and Downspouts As previously discussed in the drainage section, the installation of gutters and downspouts should be considered to collect roof water that may otherwise infiltrate the soils adjacent to the structures. If utilized, the downspouts should be drained into PVC collector pipes or other non-erosive devices (e.g., paved swales or ditches; below grade, solid tight-lined PVC Cross Real Estate Investors, LLC W.O. 8037-A-SC Tract 80-46, Carlsbad January 27, 2021 FUe:e:\wp12\8000\8037.pge GeoSoils, Inc. Page 42 Pad grade Y Drain may be constructed into, or at, the toe-of-slope Native soil 12-inch cap minimum I Drain pipe Soil cap compacted to 90 percent relative compaction. Permeable material may be gravel wrapped in filter fabric (Mirafi 140N or equivalent). 4-inch-diameter, perforated pipe (SDR-35 or equivalent) with perforations down. Pipe to maintain a minimum 1 percent fall. Concrete cut-oft wall to be provided at transition to solid outlet pipe. Solid outlet pipe to drain to approved area. Cleanouts are recommended at each property line. I G4ic. I SCHEMATIC TOE DRAIN DETAIL Detail 4 2:1 (H:V) slope (typical) Backfill with compacted native soils Top of wall \ Retaining wall .• 12 ches - Finish grade --_ - - Mirati 140 fitter \ - fabric or equivalent 3/a-inch crushed gravel Wall footing 4-inch drain 24 inches L 1/2 to 1 •] - 12 inches NOTES: Soil cap compacted to 90 percent relative compaction. Permeable material may be gravel wrapped in filter fabric (Mirafi 140N or equivalent). 4-inch-diameter, perforated pipe (SDR-35 or equivalent) with perforations down. Pipe to maintain a minimum 1 percent fall. Concrete cut-off wall to be provided at transition to solid outlet pipe. Solid outlet pipe to drain to approved area. Cleanouts are recommended at each property line. Effort to compact should be applied to drain rock. [G4*:-Z~~vc. SUBDRAIN ALONG RETAINING WALL DETAIL Detail 5 pipes; etc.), that will carry the water away from the house, to an appropriate outlet, in accordance with the recommendations of the design civil engineer. Downspouts and gutters are not a requirement; however, from a geotechnical viewpoint, provided that positive drainage is incorporated into project design (as discussed previously). Subsurface and Surface Water Subsurface and surface water are not anticipated to affect site development, provided that the recommendations contained in this report are incorporated into final design and construction and that prudent surface and subsurface drainage practices are incorporated into the construction plans. Perched groundwater conditions along zones of contrasting permeabilities may not be precluded from occurring in the future due to site irrigation, poor drainage conditions, or damaged utilities, and should be anticipated. Should perched groundwater conditions develop, this office could assess the affected area(s) and provide the appropriate recommendations to mitigate the observed groundwater conditions. Groundwater conditions may change with the introduction of irrigation, rainfall, or other factors. Site Improvements If in the future, any additional improvements (e.g., pools, spas, etc.) are planned for the site, recommendations concerning the geological or geotechnical aspects of design and construction of said improvements could be provided upon request. Pools and/or spas should not be constructed without specific design and construction recommendations from GSl, and this construction recommendation should be provided to all interested/affected parties. Rock fills may not be suitable for supporting pools/spa. This office should be notified in advance of any fill placement, grading of the site, or trench backfilling after rough grading has been completed. This includes any grading, utility trench and retaining wall backfills, flatwork, etc. Tile Flooring Tile flooring can crack, reflecting cracks in the concrete slab below the tile, although small cracks in a conventional slab may not be significant. Therefore, the designer should consider additional steel reinforcement for concrete slabs-on-grade where tile will be placed. The tile installer should consider installation methods that reduce possible cracking of the tile such as slipsheets. Slipsheets or a vinyl crack isolation membrane (approved by the Tile Council of America/Ceramic Tile Institute) are recommended between tile and concrete slabs on grade. Additional Grading This office should be notified in advance of any fill placement, supplemental regrading of the site, ortrench backfilling after rough grading has been completed. This includes completion Cross Real Estate Investors, LLC - W.O. 8037-A-SC Tract 80-46, Carlsbad January 27, 2021 File: e:\wpl2\8000\8037.pge GeoSoils, Inc. Page 45 of grading in the street, driveway approaches, driveways, parking areas, and utility trench and retaining wall backfills. Footing Trench Excavation All footing excavations should be observed by a representative of this firm subsequent to trenching and prior to concrete form and reinforcement placement. The purpose of the observations is to evaluate that the excavations have been made into the recommended bearing material and to the minimum widths and depths recommended for construction. If loose or compressible materials are exposed within the footing excavation, a deeper footing or removal and recompaction of the subgrade materials would be recommended at that time. Footing trench spoil and any excess soils generated from utility trench excavations should be compacted to a minimum relative compaction of 90 percent, if not removed from the site. Trenching/Temporary Construction Backcuts Considering the nature of the onsite earth materials, it should be anticipated that caving or sloughing could be a factor in subsurface excavations and trenching. Shoring or excavating the trench walls/backcuts at the angle of repose (typically 25 to 45 degrees [except as specifically superceded within the text of this report]), should be anticipated. All excavations should be observed by an engineering geologist or soil engineer from GSI, prior to workers entering the excavation or trench, and minimally conform to CAL-OSHA, state, and local safety codes. Should adverse conditions exist, appropriate recommendations would be offered at that time. The above recommendations should be provided to any contractors and/or subcontractors, or homeowners, etc., that may perform such work. Utility Trench Backfill All interior utility trench backfill should be brought to at least 2 percent above optimum moisture content and then compacted to obtain a minimum relative compaction of 90 percent of the laboratory standard. As an alternative for shallow (12-inch to 18-inch) under-slab trenches, sand having a sand equivalent value of 30 or greater may be utiized and jetted or flooded into place. Observation, probing and testing should be provided to evaluate the desired results. Exterior trenches adjacent to, and within areas extending below a 1:1 plane projected from the outside bottom edge of the footing, and all trenches beneath hardscape features and in slopes, should be compacted to at least 90 percent of the laboratory standard. Sand backfill, unless excavated from the trench, should not be used in these backfill areas. Compaction testing and observations, along with probing, should be accomplished to evaluate the desired results. All trench excavations should conform to CAL-OSHA, state, and local safety codes. Cross Real Estate Investors, LLC W.O. 8037-A-SC Tract 80-46, Carlsbad January 27, 2021 File: e:\wpl2\8000\8037.pge GeoSoils, Inc. Page 46 4. Utilities crossing grade beams, perimeter beams, or footings should either pass below the footing or grade beam utilizing a hardened collar or foam spacer, or pass through the footing or grade beam in accordance with the recommendations of the structural engineer. SUMMARY OF RECOMMENDATIONS REGARDING GEOTECHNICAL OBSERVATION AND TESTING We recommend that observation and/or testing be performed byGSl at each of the following construction stages: During grading/recertification. During excavation. During placement of subdrains or other subdrainage devices, prior to placing fill and/or backfill. After excavation of building footings, retaining wall footings, and free standing walls footings, prior to the placement of reinforcing steel or concrete. Prior to pouring any slabs or flatwork, after presoaking/presaturation of building pads and other flatwork subgrade, before the placement of concrete, reinforcing steel, capillary break (i.e., sand, pea-gravel, etc.), or vapor retarders (i.e., visqueen, etc.). During retaining wall subdrain installation, prior to backfill placement. During placement of backfill for area drain, interior plumbing, utility line trenches, and retaining wall backfill. During slope construction/repair. When any unusual soil conditions are encountered during any construction operations, subsequent to the issuance of this report. When any homeowner improvements, such as flatwork, spas, pools, walls, etc., are constructed, prior to construction. A report of geotechnical observation and testing should be provided at the conclusion of each of the above stages, in order to provide concise and clear documentation of site work, and/or to comply with code requirements. Cross Real Estate Investors, LLC Tract 80-46, Carlsbad FiIe:e:\wp12\8000\8037.pge GeoSoils, Inc. W.O. 8037-A-SC January 27, 2021 Page 47 OTHER DESIGN PROFESSIONALS/CONSULTANTS The design civil engineer, structural engineer, post-tension designer, architect, landscape architect, wall designer, etc., should review the recommendations provided herein, incorporate those recommendations into all their respective plans, and by explicit reference, make this report part of their project plans. This report presents minimum design criteria for the design of slabs, foundations and other elements possibly applicable to the project. These criteria should not be considered as substitutes for actual designs by the structural engineer/designer. Please note that the recommendations contained herein are not intended to preclude the transmission of water or vapor through the slab or foundation. The structural engineer/foundation and/or slab designer should provide recommendations to not allow water or vapor to enter into the structure so as to cause damage to another building component, or so as to limit the installation of the type of flooring materials typically used for the particular application. The structural engineer/designer should analyze actual soil-structure interaction and consider, as needed, bearing, expansive soil influence, and strength, stiffness and deflections in the various slab, foundation, and other elements in order to develop appropriate, design-specific details. As conditions dictate, it is possible that other influences will also have to be considered. The structural engineer/designer should consider all applicable codes and authoritative sources where needed. If analyses by the structural engineer/designer result in less critical details than are provided herein as minimums, the minimums presented herein should be adopted. It is considered likely that some, more restrictive details will be required. If the structural engineer/designer has any questions or requires further assistance, they should not hesitate to call or otherwise transmit their requests to GSI. In order to mitigate potential distress, the foundation and/or improvement's designer should confirm to GSI and the governing agency, in writing, that the proposed foundations and/or improvements can tolerate the amount of differential settlement and/or expansion characteristics and other design criteria specified herein. PLAN REVIEW Final project plans (architecture, grading, precise grading, foundation, retaining wall, landscaping, etc.), should be reviewed by this office prior to construction, so that construction is in accordance with the conclusions and recommendations of this report. Based on our review, supplemental recommendations and/or further geotechnical studies may be warranted. Cross Real Estate Investors, LLC W.O. 8037-A-SC Tract 80-46, Carlsbad January 27, 2021 File: e:\wpl2\8000\8037.pge GeoSoils, Inc. Page 48 LIMITATIONS The materials encountered on the project site and utilized for our analysis are believed representative of the area; however, soil and bedrock materials vary in character between excavations and natural outcrops or conditions exposed during mass grading. Site conditions may vary due to seasonal changes or other factors. Inasmuch as our study is based upon our review and engineering analyses and laboratory data, the conclusions and recommendations are professional opinions. These opinions have been derived in accordance with current standards of practice, and no warranty, either express or implied, is given. Standards of practice are subject to change with time. GSI assumes no responsibility or liability for work or testing performed by others, or their inaction; or work performed when GSl is not requested to be onsite, to evaluate if our recommendations have been properly implemented. Use of this report constitutes an agreement and consent by the user to all the limitations outlined above, notwithstanding any other agreements that may be in place. In addition, this report may be subject to review by the controlling authorities. Thus, this report brings to completion our scope of services for this portion of the project. All samples will be disposed of after 30 days, unless specifically requested by the client, in writing. Cross Real Estate Investors, LLC W.O. 8037-A-SC Tract 80-46, Carlsbad January 27, 2021 Fi1e:e:\wp12\8000\8037.pge GeoSoils, Inc. Page 49 APPENDIX A REFERENCES GeoSoils, Inc. APPENDIX A REFERENCES American Concrete Institute, 2014a, Building code requirements for structural concrete (ACI 318-14), and commentary (ACI 318R-14): reported by ACI Committee 318, dated September. 2014b, Building code requirements for concrete thin shells (ACI 318.2-14), and commentary (ACI 318.213-14), dated September. 2008, Building code requirements for structural concrete (AC1318-08) and commentary, dated January. 2004, Guide for concrete floor and slab construction: reported byACI Committee 302; Designation ACI 302.1 R-04, dated March 23. Allen, V., Connerton, A., and Carlson, C., 2011, Introduction to Infiltration Best Management Practices (BMP), Contech Construction Products, Inc., Professional Development Series, dated December. American Society for Testing and Materials (ASTM), 2003, Standard test method for infiltration rate of soils in field using double-ring infiltrometer, Designation D 3385-03, dated August. ,1998, Standard practice for installation of water vapor retarder used in contact with earth or granular fill under concrete slabs, Designation: E 1643-98 (Reapproved 2005). 1997, Standard specification for plastic water vapor retarders used in contact with soil or granular fill under concrete slabs, Designation: E 1745-97 (Reapproved 2004). American Society of Civil Engineers, 2010, Minimum design loads for buildings and other structures, ASCE Standard ASCE/SEI 7-10. Blake, Thomas F., 2000a, EQFAULT, A computer program for the estimation of peak horizontal acceleration from 3-D fault sources; Windows 95/98 version. 2000b, EQSEARCH, A computer program for the estimation of peak horizontal acceleration from California historical earthquake catalogs; Updated to December 2011, Windows 95/98 version. Bozorgnia, Y., Campbell K.W., and Niazi, M., 1999, Vertical ground motion: Characteristics, relationship with horizontal component, and building-code implications; Proceedings of the SM1P99 seminar on utilization of strong-motion data, September 15, Oakland, pp. 23-49. GeoSoils, Inc. Bryant, WA., and Hart, E.W., 2007, Fault-rupture hazard zones in California, Alquist-Priolo earthquake fault zoning act with index to earthquake fault zones maps; California Geological Survey, Special Publication 42, interim revision. Building Industry News, 2012, Greenbook, standard specifications for public works construction, Section 306-1.3., California Building Standards Commission, 2019a, California Building Code, California Code of Regulations, Title 24, Part 2, Volume 2 of 2, based on the 2018 International Building Code, effective January 1, 2020. 2019b, California Building Code, California Code of Regulations, Title 24, Part 2, Volume 1 of 2, Based on the 2018 International Building Code, effective January 1, 2020. California Department of Water Resources, 1993, Division of Safety of Dams, Guidelines for the design and construction of small embankments dams, reprinted January. California Office of Statewide Health Planning and Development (OSHPD), 2021, Seismic design maps, https://seismicmaps.org/. California Stormwater Quality Association (CASQA), 2003, Stormwater best management practice handbook, new development and redevelopment, dated January. City of Carlsbad, 2016, BMP design manual, Apendices, Effective date February 16. County of San Diego, Department of Planning and Land Use, 2007, Low impact development (LID) handbook, stormwater management strategies, dated December 31. Hydrologic Solutions, StormChamberTM installation brochure, pgs. 1 through 8, undated. Jennings, C.W., 1994, Fault activity map of California and adjacent areas: California Division of Mines and Geology, Map Sheet No. 6, scale 1:750,000. Kanare, H.M., 2005, Concrete floors and moisture, Engineering Bulletin 119, Portland Cement Association. Kennedy, M.P., and Tan, SS., 2005, Geologic map of the Oceanside 30' by 60' quadrangle, California, regional map series, scale 1:100,000, California Geologic Survey and United States Geological Survey, www.conservation.ca.gov/ cgs/rghm/rgm/preliminary geologic maps.html Romanoff, M., 1957, Underground corrosion, originally issued April 1. Cross Real Estate Investors, LLC. Appendix A File: e:\wpl2\8000\8037a.pge GeoSoils, Inc. Page 2 Seed, 2005, Evaluation and mitigation of soil liquefaction hazard "evaluation of field data and procedures for evaluating the risk of triggering (or inception) of liquefaction", in Geotechnical earthquake engineering; short course, San Diego, California, April 8-9. Sowers and Sowers, 1979, Unified soil classification system (After U. S. Waterways Experiment Station and ASTM 02487-667) in Introductory Soil Mechanics, New York. State of California, 2021, Civil Code, Sections 895 et seq. State of California Department of Transportation, Division of Engineering Services, Materials Engineering, and Testing Services, Corrosion Technology Branch, 2003, Corrosion Guidelines, Version 1.0, dated September. Tan, S.S., and Giffen, D.G., 1995, Landslide hazards in the northern part of the San Diego Metropolitan area, San Diego County, California, Landslide hazard identification map no. 35, Plate 35A, Department of Conservation, Division of Mines and Geology, DMG Open File Report 95-04. Cross Real Estate Investors, LLC. Appendix A File: e:\wpl2\8000\8037a.pge GeoSoils, Inc. Page 3 APPENDIX B BORING LOGS GeoSoils, Inc. UNIFIED SOIL CLASSIFICATION SYSTEM CONSISTENCY OR RELATIVE DENSITY Major Divisions Group Typical Names CRITERIA Symbols Well-graded gravels and gravel- GW sand mixtures, little or no fines Standard Penetration Test > a) Poorly graded gravels and .2 a) o Penetration > U)8 t5 a GP gravel-sand mixtures, little or no Resistance N Relative in 0) E Z fines (blows/ft) Density 8 c,,J o a)- GM Silty gravels gravel-sand-silt 0 - 4 Very loose z mixtures D0 16 Co.— 4-10 Loose GC Clayey gravels, gravel-sand-clay C mixtures 10-30 Medium SW Well-graded sands and gravelly a 0 a 30 -50 Dense 00 sands, little or no fines 0 LO ., a 2 . a0 2 _____ _______________ > 50 Very dense -C — a co 0 Poorly graded sands and a gravelly sands, little or no fines o a)Z SM Silty sands, sand-silt mixtures Ca W E a a a D 0) _____ _______________ U- Clayey sands, sand-clay (/) Sc mixtures Inorganic silts, very fine sands, Standard Penetration Test ML rock flour, silty or clayey fine sands 0) CD 0 2 Unconfined Penetration Compressive Inorganic clays of low to o CL medium plasticity, gravelly clays, Resistance N Strength 0 sandy clays, silty clays, lean (blows/ft) Consistency (tons/ft) Nclays Organic silts and organic silty °) Z U) <2 Very Soft <0.25 0)0) U) OL clays of low plasticity FU U) 2 - 4 Soft 0.25 -050 .050 Inorganic silts, micaceous or . 0 a 0 MH diatomaceous fine sands or silts, 4 - 8 Medium 0.50 -1.00 elastic silts E 8 -15 Stiff 1.00 -2.00 Inorganic clays of high plasticity, 0 a 0 - U' CH fat clays 15 -30 Very Stiff 2.00 -4.00 Organic clays of medium to high CO >30 Hard >4.00 OH plasticity Highly Organic Soils PT Peat, mucic, and other highly organic soils 3" 3/4 #4 #10 #40 #200 U.S. Standard Sieve Gravel I Sand ______________________________________________________________________ Silt or Clay 1 E Unified Soil Classification Cobbles III coarse fine coarse medium fine MOISTURE CONDITIONS MATERIAL QUANTITY OTHER SYMBOLS Dry Absence of moisture: dusty, dry to the touch trace 0 -5% C Core Sample Slightly Moist Below optimum moisture content for compaction few 5-10% S SPT Sample Moist Near optimum moisture content little 10-25% B Bulk Sample Very Moist Above optimum moisture content some 25 -45% Groundwater Wet Visible free water; below water table Op Pocket Penetrometer BASIC LOG FORMAT: Group name, Group symbol, (grain size), color, moisture, consistency or relative density. Additional comments: odor, presence of roots, mica, gypsum, coarse grained particles, etc. EXAMPLE: Sand (SP), fine to medium grained, brown, moist, loose, trace silt, little fine gravel, few cobbles up to 4 in size, some hair roots and rootlets. File:Mgr: c;\SoilClassif.wpd PLATE B-i GeoSoils, Inc. BORING LOG PROJECT: CROSS REAL ESTATE INVESTORS 2908 Highland Dr., Carlsbad W.O. 8037A5C BORING B1 SHEET _L... OF DATE EXCA VA TED 1-7-21 LOGGED BY: TMP APPROX. ELEV.: 180 MSL SAMPLE METHOD: Cal Sampler & 140 lb Hammer 30-in Drop Sample 0 Material Description I : CL 0 PrOPSOIL: \@ 0' SILTY SAND, brown, damp, loose. PARALIC DEPOSITS: 47/ 139.2 7.8 32.9@ 0.1' SILTY SAND, light brown, damp, very dense; Clean, fine to _.L 50-5" medium grained. 37 168.7 11.8 © 5' As per 0.1'; dense, light reddish brown. - 10 58 150.9 7.7 @ 10' As per 5; very dense. @ 13' Slight Color Change to dark gray reddish brown. 15- 64 169.5 6.3 @ 15' SILTY SAND, red brown, damp, very dense. 41 SP 193.7 4.1 @ 18' SAND, olive gray, dry, loose; Cohesionless fine to medium sands. 20- Total Depth - 19.5 No Groundwater or Caving Encountered BaCkfilled 1-7-21 25- 30- A Standard Penetra'ionTest Groundwater I Undisturbed, Ring Sample 9 Seepage GeoSoils, Inc. PLATE B-2 GeoSoils, Inc. BORING LOG PROJECT: CROSS REAL ESTATE INVESTORS 2908 HigHand Dr., Carlsbad WO. 8037A5C BORING B-2 SHEET _L. OF -L. DATE EXCAVATED 1-7-21 LOGGED BY: TMP APPROX. ELEV.: 183 MSL SAMPLE METHOD: Cal Sampler & 140 lb Hammer @ 30-in Drop Sample C) 5 . - Material Description (I) CL '1) . S . . o . . 12 Fn D 0 co 0 - SM OPSOlL: \ 0' SILTY SAND, brown, damp, medium dense. PARALIC DEPOSITS: @ 0.1' SILTY SAND, reddish brown, damp, dense. 18 169.4 6.6 31.5 10- 50-51A 154.0 8.3 37...© 10' As per 0.1'; very dense. 15- 50-51A 128.6 8.5 37.3 @ 15' As per 10'. Total Depth = 16' No Groundwater or Caving Encountered Backfilled 1-7-21 20- 25- 30- Standard Penetration Test Groundwater I Undisturbed, Ring Sample 2 Seepage GeoSoils, Inc. PLATE B-3 GeoSoils, Inc. BORING LOG PROJECT: CROSS REAL ESTATE INVESTORS 2908 Highland Dr., Carlsbad WO. 8037A5C BORING 8-3 SHEET OF ._L. - DATE EXCA VA TED 1-7-21 LOGGED BY.- TMP APPROXELEV.: 178 MSL SAMPLE METHOD: Cal Sampler & 140 lb Hammer 30-in Drop Sample U Material Description CL : • 12 0 - SM TOPSOIL: @ 0 SILTY SAND, dark reddish brown, moist dense; numerous roots and \rootlets to ' diameter. PARALIC DEPOSITS: @ 1 SILTY SAND, reddish light brown, damp, dense; Clean. 21 @ 10 As per 1'; very dense. 10-45 15 - 49 - @16'As per 10. Total Depth = 16 No Groundwater or Caving Encountered Backfilled 1-7-21 20- 25- 30- I Standard Penetration Test ' Groundwater I Undisturbed, Ring Sample ? Seepage GeoSoils, Inc. PLATE B-4 GeoSoils, Inc. BORING LOG PROJECT: CROSS REAL ESTATE INVESTORS 2908 Highland Dr., Carlsbad WO. 8037ASC BORING B-4 SHEET _i_. OF -L.. DATE EXCAVATED 1-7-21 LOGGED BY: TMP APPROX. ELEV.: 174 MSL SAMPLE METHOD: Cal Sampler & 140 lb Hammer & 30-in Drop Sample C) Material Description LI- U) . . c 2 U) 0 Co . . o L a 0 L: V:0TI LTY SAND, brown, damp, medium dense. PARALIC DEPOSITS: 29 @ 0.1' SILTY SAND, light reddish brown, damp, medium dense; abundant gopher holes, fine to medium sands. 24 @ 5' As per 0, dense, reddish brown, moist, dense; fine to coarse sands. 10 10' As per 5'; very dense. Total Depth = 11' No Groundwater or Caving Encountered Backfilled 1-7-21 15 - 20- 25- 30- Standard Penetration Test Groundwater I Undisturbed, Ring Sample 9 Seepage GeoSoils, Inc. PLATE B-5 GeoSoils, Inc. BORING LOG PROJECT: CROSS REAL ESTATE INVESTORS 2908 Highland Dr., Carlsbad W.O. 8037ASC BORING B5 SHEET _L... OF ._.L DATE EXCAVATED 1-7-21 LOGGED BY: TMP APPROX. ELEV.: 168 MSL SAMPLE METHOD: Cal Sampler & 140 lb Hammer @ 30-in Drop Sample C., . Material Description I I I i 0 SM TOPSOIL: @ 0' SILTY SAND, dark reddish brown, moist, medium dense. PARALIC DEPOSITS: @ 1.1 SILTY SAND, light reddish brown, damp, medium dense; fine to coarse sands. 126 10- 54 @ 10'As per 1.1; very dense. Total Depth = 11.5' No Groundwater or Caving Encountered Backfilled 1-7-21 15- 20- 25- 30- IJ Penetration Test Groundwater I Undisturbed, Ring Sample 9 Seepage GeoSoils, Inc. PLATE B-6 GeoSoils, Inc. BORING LOG PROJECT: CROSS REAL ESTATE INVESTORS 2908 Highland Dr., Carlsbad W.O. 8037A5C BORING I131 SHEET _L OF -_L. DATE EXCAVATED 1-7-21 LOGGED BY: TMP APPROX. ELEV.: 163 MSL SAMPLE METHOD: Sample U Material Description IE I i 0 SM TOPSOIL: '\O' SILTY SAND, reddish brown, damp, medium dense; fine to medium \sands. PARALIC DEPOSITS: @ 0.8' SILTY SAND, reddish light brown, damp, dense; fine sands. Total Depth = 5' No Groundwater or Caving Encountered Backfilled 1-8-21 10- 15- 20- 25- 30- I Standard Penetration Test Groundwater I Undisturbed, Ring Sample 9 Seepage GeoSoils, Inc. PLATE B-7 GeoSoils, Inc. BORING LOG PROJECT: CROSS REAL ESTATE INVESTORS 2908 Highland Dr., Carlsbad WO. 8037-A-SC BORING I132 SHEET _L. OF _i_ DATE EXCA VA TED 1-7-21 LOGGED BY: TMP APPROX. ELEV.: 163 MSL SAMPLE METHOD: Sample C-, Material Description CL Q 75 i : 0 00 0 SM TOPSOIL: \ 0' SILTY SAND, reddish brown, damp, medium dense; fine to medium \sands. PARALIC DEPOSITS: @ 0.8' SILTY SAND, reddish light brown, damp, dense. Total Depth = 5' No Groundwater or Caving Encountered 1-8-21 10- 15- 20- 25- 30- II Standard Penetration Test Groundwater I Undisturbed, Ring Sample 9 Seepage GeoSoils, Inc. PLATE B-8 GeoSoils, Inc. BORING LOG PROJECT: CROSS REAL ESTATE INVESTORS 2908 Highland Dr., Carlsbad W.O. 8037A5C BORING I133 SHEET _L_ OF _L DATE EXCAVATED 1-7-21 LOGGED BY: TMP APPROX. ELEV.: 162 MSL SAMPLE METHOD: Sample 0 6 Material Description , . .2 CL 0 (J) C) a 16 ' . 0 - co D M D 0 C') 0 SM TOPSOIL: O 0' SILTY SAND, reddish brown, damp, medium dense. PARALIC DEPOSITS: @ 0.8 SILTY SAND, reddish light brown, damp, medium dense to very ws dense with depth; fine sands. @ 5 Becomes reddish brown; fine to medium sands. 10- 15- - - - ____ - - Total Depth = 15' No Groundwater or Caving Encountered Backfilled 1-8-21 20- 25- 30- Standard Penetration Test Groundwater I Undisturbed, Ring Sample 9 Seepage GeoSoils, Inc. PLATE B-9 APPENDIX C SEISMICITY DATA GeoSoils, Inc. * * * * * * * * * * * * * * * * * * * * * * * * * * E Q F A U L T * * * * Version 3.00 * * ******************* DETERMINISTIC ESTIMATION OF PEAK ACCELERATION FROM DIGITIZED FAULTS JOB NUMBER: 8037-A-SC DATE: 12-22-2020 JOB NAME: Cross Real Estate Investors LLC CALCULATION, NAME: Test Run Analysis FAULT-DATA-FILE NAME: C:\Program Files\EQFAULT1\CGSFLTE.DAT SITE COORDINATES: SITE LATITUDE: 33.1673 SITE LONGITUDE: 117.3382 SEARCH RADIUS: 62.2 mi ATTENUATION RELATION: 11) Bozorgnia Campbell Niazi (1999) Hor.-Pleist. Soil-Cor. UNCERTAINTY (M=Median, S=Sigma): S Number of Sigmas: 1.0 DISTANCE MEASURE: cdist SCOND: 0 Basement Depth: 5.00 km Campbell SSR: 0 Campbell SHR: C COMPUTE PEAK HORIZONTAL ACCELERATION FAULT-DATA FILE USED: C:\Program Files\EQFAULT1\CGSFLTE.DAT MINIMUM DEPTH VALUE (km): 3.0 Page 1 W.O. 8037-A-SC PLATE C-i --------------- EQFAULT SUMMARY --------------- ----------------------------- DETERMINISTIC SITE PARAMETERS ----------------------------- Page 1 ------------------------------------------------------------------------------- ESTIMATED MAX. EARTHQUAKE EVENT APPROXIMATE ABBREVIATED DISTANCE MAXIMUM I PEAK JEST. SITE FAULT NAME I mi (km) JEARTHQUAKE1 SITE JINTENSITY MAG.(Mw) I ACCEL. g JMOD.MERC. NEWPORT-INGLEWOOD (Offshore) 1 5.7( 9.1)1 7.1 1 0.576 1 X ROSE CANYON 1 6.1( 9.8)1 7.2 1 0.574 1 X CORONADO BANK 1 21.7( 35.0)1 7.6 1 0.265 1 IX ELSINORE (TEMECULA) 1 23.5( 37.9)1 6.8 1 0.144 1 VIII ELSINORE (JULIAN) 1 23.8( 38.3)1 7.1 1 0.174 1 VIII ELSINORE (GLEN IVY) 1 32.9( 53.0)1 6.8 1 0.101 1 VII SAN JOAQUIN HILLS 1 34.9( 56.1)1 6.6 1 0.119 1 VII PALOS VERDES 1 35.7( 57.5)1 7.3 1 0.132 1 VIII EARTHQUAKE VALLEY 1 43.8( 70.5)1 6.5 1 0.062 1 VI NEWPORT-INGLEWOOD (L.A.Basin) 1 45.5( 73.3)1 7.1 1 0.089 1 VII SAN JACINTO-ANZA 1 46.0( 74.1)1 7.2 1 0.094 1 VII SAN JACINTO-SAN JACINTO VALLEY 1 46.5( 74.8)1 6.9 1 0.076 1 VII CHINO-CENTRAL AVE. (Elsinore) 1 47.0( 75.7)1 6.7 1 0.092 1 VII WHITTIER 1 50.9( 81.9)1 6.8 1 0.064 1 VI SAN JACINTO-COYOTE CREEK 1 52.1( 83.8)1 6.6 1 0.055 1 VI ELSINORE (COYOTE MOUNTAIN) 1 58.2( 93.7)1 6.8 1 0.056 1 VI SAN JACINTO-SAN BERNARDINO 1 59.0( 95.0)1 6.7 1 0.051 1 VI PUENTE HILLS BLIND THRUST 60.8( 97.9) 7.1 0.093 VII * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * -END OF SEARCH- 18 FAULTS FOUND WITHIN THE SPECIFIED SEARCH RADIUS. THE NEWPORT-INGLEWOOD (offshore) FAULT IS CLOSEST TO THE SITE. IT IS ABOUT 5.7 MILES (9.1 km) AWAY. LARGEST MAXIMUM-EARTHQUAKE SITE ACCELERATION: 0.5760 g Page 2 W.O. 8037-A-SC PLATE C-2 I I I I I I I I I I I I I I I I I I I 1100 1000 400 900 800 700 600 500 300 200 100 0 CALIFORNIA FAULT MAP Cross Real Estate Investors LLC 0 100 200 300 400 500 600 W.O. 8037-A-SC PLATE C-3 -100 -400 -300 -200 -100 I .1 EI .01 .001 I I STRIKE-SLIP FAULTS 11) Bozorgnia Campbell Niazi (1999) Hor.-Pleist. Soil-Cor. M=5 M=6 M=7 M=8 1 10 100 Distance [adist] (km) W.O. 8037-A-SC PLATE C-4 I 1 I I I 1 I I I I I I I I .2 C.) C.) El .01 MAXIMUM EARTHQUAKES I Cross Real Estate Investors LLC .1 1 10 Distance (mi) W.O. 8037-A-SC PLATE C-5 Wel 7.5 7.4 7.3 7.2 6.7 6.6 6.5 EARTHQUAKE MAGNITUDES & DISTANCES Cross Real Estate Investors LLC .1 1 10 Distance (mi) W.O. 8037-A-SC PLATE C-6 ** ** * * * * * * * * * E Q S E A R C H * Version 3.00 * * * * * * * * * * * * * * * * * * * * * * * * * * * * ESTIMATION OF PEAK ACCELERATION FROM CALIFORNIA EARTHQUAKE CATALOGS JOB NUMBER: 8037-A-SC DATE: 12-22-2020 JOB NAME: Cross Real Estate Investors, LLC EARTHQUAKE-CATALOG-FILE NAME: ALLQUAKE.DAT SITE COORDINATES: SITE LATITUDE: 33.1673 SITE LONGITUDE: 117.3382 SEARCH DATES: START DATE: 1800 END DATE: 2015 SEARCH RADIUS: 62.2 mi 100.1 km ATTENUATION RELATION: 11) Bozorgnia Campbell Niazi (1999) Hor.-Pleist. Soil-Cor. UNCERTAINTY (M=Median, S=Sigma): S Number of Sigmas: 1.0 ASSUMED SOURCE TYPE: SS [SS=strike-slip, DS=Reverse-slip, BT=Blind-thrust] SCOND: 1 Depth Source: A Basement Depth: 5.00 km Campbell SSR: 0 Campbell SHR: 0 COMPUTE PEAK HORIZONTAL ACCELERATION MINIMUM DEPTH VALUE (km): 3.0 Page 1 W.O. 8037-A-SC PLATE C-7 ------------------------- EARTHQUAKE SEARCH RESULTS ------------------------- Page 1 I I I I TIME I I I SITE ISITEl APPROX. FILEI LAT. I LONG. I DATE I (uTC) IDEPTHIQUAKEI ACC. I MM I DISTANCE CODEI NORTH I WEST I I H M Secl (km)I MAG.I g IINT.I ml [km] ---+--------+----------+--------+-----+-----+-------+----+------------ 0MG 133.00001117.3000111/22/180012130 0.01 0.01 6.501 0.234 I IX I 11.8( 18.9) MGI I33.00001117.0000109/21/18561 730 0.01 0.01 5.001 0.048 I VI I 22.7( 36.6) MGI I32.80001117.1000105/25/18031 0 0 0.01 0.01 5.001 0.038 I V I 28.9( 46.5) DMG I32.70001117.2000105/2711862120 0 0.01 0.01 5.901 0.056 I VI I 33.2( 53.5) PAS I32.97101117.8700107/13/198611347 8.21 6.01 5.301 0.038 I V I 33.6( 54.1) T-A I32.67001117.1700112/O0/18561 0 0 0.01 0.01 5.001 0.030 I V I 35.7( 57.4) T-A I32.67001117.1700110/21/18621 0 0 0.01 0.01 5.001 0.030 I V I 35.7( 57.4) T-A I32.67001117.1700105/24/18651 0 0 0.01 0.01 5.001 0.030 I V I 35.7( 57.4) DMG I33.20001116.7000101/01/19201 235 0.01 0.01 5.001 0.029 I V I 36.9( 59.5) DMG I33.70001117.4000105/13/19101 620 0.01 0.01 5.001 0.029 I v I 36.9( 59.5) DMG I33.70001117.4000105/15/191011547 0.01 0.01 6.001 0.053 I VI I 36.9( 59.5) DMG I33.70001117.4000104/11/19101 757 0.01 0.01 5.001 0.029 I V I 36.9( 59.5) DMG I33.69901117.5110105/31/19381 83455.41 10.01 5.501 0.038 I V I 38.0( 61.2) DMG 132.80001116.8000110/23/1894123 3 0.01 0.01 5.701 0.040 I V I 40.2( 64.7) MGI I33.20001116.6000110/12/192011748 0.01 0.01 5.301 0.030 I V I 42.7( 68.7) DMG I33.71001116.9250109/23/19631144152.61 16.51 5.001 0.024 I V I 44.4( 71.4) DMG I33.75001117.0000104/21/19181223225.OI 0.01 6.801 0.074 I VIII 44.7( 71.9) DMG I33.75001117.0000106/06/191812232 0.01 0.01 5.001 0.024 I V I 44.7( 71.9) MGI I33.80001117.6000104/22/191812115 0.01 0.01 5.001 0.023 I IV I 46.2( 74.4) DMG I33.57501117.9830103/11/19331 518 4.01 0.01 5.201 0.026 I V I 46.6( 75.0) DMG I33.61701117.9670103/11/19331 154 7.81 0.01 6.301 0.049 I VI I 47.7( 76.8) DMG I33.80001117.0000112/25/189911225 0.01 0.01 6.401 0.052 I VI I 47.8( 77.0) DMG I33.61701118.0170103/14/1933119 150.01 0.01 5.101 0.023 I IV I 49.9( 80.4) GSP I33.52901116.5720106/12/20051154146.51 14.01 5.201 0.023 I IV I 50.8( 81.7) DMG I33.90001117.2000112/19/18801 0 0 0.01 0.01 6.001 0.038 I V I 51.2( 82.4) GSG I33.42001116.4890107/07/20101235333.51 14.01 5.501 0.027 I V I 52.0( 83.7) PAS I33.50101116.5130102/25/19801104738.51 13.61 5.501 0.027 I V I 52.9( 85.1) GSP I33.50801116.5140110/31/20011075616.61 15.01 5.101 0.021 I IV I 53.0( 85.4) DMG I33.50001116.5000109/30/19161 211 0.01 0.01 5.001 0.020 I IV I 53.5( 86.1) DMG I33.00001116.4330106/04/194011035 8.31 0.01 5.101 0.021 I IV I 53.6( 86.3) DMG I33.68301118.0500103/11/19331 658 3.01 0.01 5.501 0.026 I V I 54.3( 87.4) DMG I33.70001118.0670103/11/19331 51022.01 0.01 5.101 0.020 I IV I 55.8( 89.8) DMG I33.70001118.0670103/11/19331 85457.01 0.01 5.101 0.020 I IV I 55.8( 89.8) DMG I34.00001117.2500107/23/19231 73026.01 0.01 6.251 0.039 I V I 57.7( 92.9) MGI I34.00001117.5000112/16/1858110 0 0.01 0.01 7.001 0.064 I VI I 58.2( 93.7) DMG I33.34301116.3460104/28/19691232042.91 20.01 5.801 0.029 I V I 58.6( 94.2) DMG I33.75001118.0830103/11/19331 230 0.01 0.01 5.101 0.019 I IV I 58.8( 94.6) DMG I33.75001118.0830103/11/19331 323 0.01 0.01 5.001 0.018 I IV I 58.8( 94.6) DMG I33.75001118.0830103/11/19331 910 0.01 0.01 5.101 0.019 I IV I 58.8( 94.6) DMG I33.75001118.0830103/13/19331131828.OI 0.01 5.301 0.021 I IV I 58.8( 94.6) DMG I33.75001118.0830103/11/19331 2 9 0.01 0.01 5.001 0.018 I IV I 58.8( 94.6) GSG I33.95301117.7610107/29/20081184215.71 14.01 5.301 0.021 I IV I 59.4( 95.7) DMG I33.95001116.8500109/28/19461 719 9.01 0.01 5.001 0.017 I IV I 60.9( 98.0) DMG I33.40001116.3000102/09/1890112 6 0.01 0.01 6.301 0.037 I V I 62.0( 99.8) * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * Page 2 W.O. 8037-A-SC PLATE C-8 -END OF SEARCH- 44 EARTHQUAKES FOUND WITHIN THE SPECIFIED SEARCH AREA. TIME PERIOD OF SEARCH: 1800 TO 2015 LENGTH OF SEARCH TIME: 216 years THE EARTHQUAKE CLOSEST TO THE SITE IS ABOUT 11.8 MILES (18.9 km) AWAY. LARGEST EARTHQUAKE MAGNITUDE FOUND IN THE SEARCH RADIUS: 7.0 LARGEST EARTHQUAKE SITE ACCELERATION FROM THIS SEARCH: 0.234 g COEFFICIENTS FOR GUTENBERG & RICHTER RECURRENCE RELATION: a-value= 0.901 b-value= 0.364 beta-value= 0.837 ------------------------------------ TABLE OF MAGNITUDES AND EXCEEDANCES: ------------------------------------ Earthquake I Number of Times I Cumulative Magnitude I Exceeded I No. / Year +-----------------+------------ 4.0 I 44 I 0.20465 4.5 I 44 I 0.20465 5.0 I 44 I 0.20465 5.5 I 16 I 0.07442 6.0 9 I 0.04186 6.5 I 3 I 0.01395 7.0 I 1 I 0.00465 Page 3 W.O. 8037-A-SC PLATE C-9 I I I I I I I I I I I I 1 I I I I I I EARTHQUAKE EPICENTER MAP Cross Real Estate Investors, LLC 1100 1000 900 800 700 600 500 400 300 200 100 0 -100 -400 -300 -200 -100 0 100 200 300 400 500 600 W.O. 8037-A-SC PLATE C-ic) I I STRIKE-SLIP FAULTS 11) Bozorgnia Campbell Niazi (1999) Hor.-Pleist. Soil-Cor. M=5 M=6 M=7 M=8 ii .1 21 .01 .001 1 10 100 Distance [adist] (km) W.O. 8037-A-SC PLATE C-il I 1 I I I I I I I I I I I I I I 1 EARTHQUAKE RECURRENCE CURVE Cross Real Estate Investors, LLC 100 i I I I I I I 10 I- a) >- z > w 0 I a) - E z 0) > .01 E E C-) .001 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0 7.5 8.0 8.5 9.0 Magnitude (M) W.O. 8037-A-SC PLATE C-12 Number of Earthquakes (N) Above Magnitude (M) Cross Real Estate Investors, LLC - 40 20 U, 10 w 9- 0 I- .D - E 6 z > .! 4 E C.) I 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0 7.5 8.0 8.5 9.0 Magnitude (M) W.O. 8037-A-SC PLATE C-13 APPENDIX D LABORATORY DATA GeoSoils, Inc. GRAIN SIZE - %+3" % Gravel I % Sand I Coarse Fine I Coarse Medium I 0.0 0.0 0.2 0.0 24.2 % Fines Fine Silt 47.8 27.8 I I I I I I I I I I I I $ I I I I I I Particle Size Distribution Report 0 0 0 100 90 80 70 LU 60 Z U- I.— z 50 LU 0 of LU 40 CL 30 20 10 SIEVE SIZE PERCENT FINER SPEC.* PERCENT PASS? (X=NO) .5 100.0 .375 99.8 #4 99.8 #10 99.8 #20 96.2 #40 75.6 #60 52.6 #100 38.2 #200 27.8 (no specification provided) Source of Sample: B-i Depth: 0-5 Sample Number: B-i q i-0 Tested By: ii I\I n Soil Description Reddish Brown Silty Sand Atterbera Limits PL= LL= P1= Coefficients D90= 0.6415 D85= 0.5451 060= 0.2989 D50= 0.2325 D30= 0.0896 015= D10= C= C= Classification USCS= SM AASHTO= Remarks Date: 1-18-21 Client: Cross Real Estate Investors Project: 2908 Highland Dr. Prolect No: 8037-A-SC Checked By: 0.001 TEST SPECIMEN A B C D Compactor air pressure PSI 350 350 350 Water added % 1.9 2.6 3.7 Moisture at compaction % 9.1 9.8 10.9 Height of sample IN 2.52 2.52 2.53 Dry density PCF 128.3 127.9 126.3 R-Value by exudation 79 68 41 R-Value by exudation, corrected 79 68 41 Exudation pressure PSI 602 300 189 Stability thickness FT 0.27 0.41 0.76 Expansion pressure thickness FT 0.10 0.00 0.00 DESIGN CALCULATION DATA SAMPLE INFORMATION Traffic index, assumed 5.0 Gravel equivalent factor, assumed 1.25 Expansion, stability equilibrium 0 R-Value by expansion NA R-Value by exudation 68 R-Value at equilibrium 68 Expansion, Stability Equilibrium 2.00 liii, 1.50 Sample Location: B-4, 0-5ft Sample Description: Reddish Brown Silty Sand Notes: - 0% Retained on 3/4 inch sieve Test Method: Cal-Trans Test 301 R-Value By Exudation 100 90 80 70 60 50 40 30 20 10 0.00 i"1 111! III II 1 II II I 0.00 0.50 1.00 1.50 2.00 Cover Thickness by Expansion Pressure (ft) 1I70I0I0I010I0[sI.!811!AsI.1.Iil Exudation Pressure (psi) GeoSoils, Inc. R - VALUE TEST RESULTS 5741 Palmer Way Project: Cross Real Estate Investors Carlsbad, CA 92008 Telephone: (760) 438-3155 Number: 8037-A-SC Fax: (760) 931-0915 Date: January 2021 Plate: D-2 B S0 811cor CORROSION & THERMAL SCIENCES 42184 Remington Ave, Temecula CA 92590 ph (951) 795-3135 • fx (951) 894-2683 Work Order No.: 21A3141 Client: GeoSoils, Inc. Project No.: 8037-A-SC Project Name: Cross Real Estate Investors Report Date: January 21, 2021 Laboratory Test(s) Results Summary The subject soil sample was processed with the U.S. Standard No. 10 Sieve and tested for pH (ASTM G 51-95 2012), Soil Resistivity (ASTM G 57-06 2012), Sulfate Ion Content (ASTM D 516-16) and Chloride Ion Content (ASTM D 512-12B). The test results follow: H As Rec'd Saturated Sulfate Chloride Sample Identification Resistivity Resistivity Content Content / (ohm-cm) (ohm-cm) (mg/L) (mg/L) B-1 @ 0-5ft 7.3 190,000 2,800 30 30 *NDNo Detection We appreciate the opportunity to serve you. Please do not hesitate to contact us with any questions or clarifications regarding these results or procedures. Ahmet K. Kaya, Laboratory Manager Form No. 1-PR Rev. 08/2019 www.soilcor.com W.O. 8037. A-SC Plate D-3 APPENDIX E STORM WATER BMP CHECKLISTS/FORMS GeoSoils, Inc. Appendix I: Forms and Checklists _____ ~Categorization of InfiltrationI1Condition Part 1 - Full Infiltration Feasibility Screening Criteria Would infiltration of the full design volume be feasible from a physical perspective without any undesirable consequences that cannot be reasonably mitigated? Criteria Screening Question Yes No Is the estimated reliable infiltration rate below proposed facility locations greater 1 than 0.5 inches per hour? The response to this Screening Question shall be based on X a comprehensive evaluation of the factors presented in Appendix C.2 and Appendix D. Provide basis: Yes. Testing demonstrates that the estimated reliable infiltration rate is 0.87 in/hr, which is greater than 0.5 in/hr Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/data source applicability. Can infiltration greater than 0.5 inches per hour be allowed without increasing risk of geotechnical hazards (slope stability, groundwater mounding, utilities, or 2 other factors) that cannot be mitigated to an acceptable level? The response to this No Screening Question shall be based on a comprehensive evaluation of the factors presented in Appendix C.2. Provide basis: No. This is a 5-lot project. Given the nature of the bedrock, there is a high potential for mounding, nad lateral migration of groundwater, onsite and offsite, to adversely affect existing and proposed improvements, causing distress. Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/data source applicability. Storm Water Standards February 2016 Edition Appendices: BMP Design Manual '-3 r • Criteria Screening Question Yes No Can infiltration greater than 0.5 inches per hour be allowed without increasing risk of groundwater contamination (shallow water table, storm water pollutants 3 or other factors) that cannot be mitigated to an acceptable level? The response to this Screening Question shall be based on a comprehensible evaluation of the factors presented in Appendix C.3. Provide basis: No response required. See Criteria No. 2. Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/data source applicability. Can infiltration greater than 0.5 inches per hour be allowed without causing potential water balance issues such as a change of seasonality of ephemeral streams 4 or increased discharge of contaminated groundwater to surface waters? The response to this Screening Question shall be based on a comprehensive evaluation of the factors presented in Appendix C.3. Provide basis: No response required. See Criteria No. 2. Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/data source applicability. Part I In the answers to rows 1-4 are "Yes" a full infiltration design is potentially feasible. The feasibility Proceed Result* screening category is Full Infiltration to Part 2 If any answer from row 1-4 is "No", infiltration maybe possible to some extent but would not gene-ally be feasible or desirable to achieve a "full infiltration" design. Proceed to Part 2 * To be completed using gathered site information and best professional judgement considering the definition of MEP in the MS4 Permit. Additional testing and/or studies may be required by [City Engineer] to substantiate findings. Storm Water Standards February 2016 Edition Appendices: BMP Design Manual 1-4 Part 2 - Partial Infiltration vs. No Infiltration Feasibility Screening Criteria Would infiltration of water in an appreciable amount be physically feasible without any negative consequences that cannot be reasonably mitigated? Criteria Screening Question Yes No Do soil and geologic conditions allow for infiltration in any appreciable rate or volume? The response to this Screening Question shall be based on a comprehensive evaluation of the factors presented in Appendix C.2 and Appendix D. Provide basis: Testing and analyses show the near-surface earth materials have an estimated reliable infiltration rate of roughly 0.87 in/hr in the general vicinity of the proposed BMP. Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/data source applicability. Can infiltration in any appreciable quantity be allowed without increasing risk of geotechnical hazards (slope stability, groundwater 6 mounding, utilities, or other factors) that cannot be mitigated to an X acceptable level? The response to this Screening Question shall be based on a comprehensive evaluation of the factors presented in Appendix C.2. Provide basis: If storm water infiltration into the onsite soils were to occur, there would be an increased potential for shallow perched groundwater conditions (i.e., groundwater mounding) to develop, owing to the collection of water upon the indurated and less permeable unweathered old paralic deposits, which occur at depths ranging between approximately 2 feet and 3 feet below the existing grades, within the project area. Perched groundwater conditions which would adversely affect the performance of the existing and proposed improvements, onsite and offsite, as well as the public right-of-way, and cuase distress, has a high potential to occur. Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/data source applicability. Storm Wa:er Standards February 2016 Edition Appendices: BMP Design Manual Criteria Screening Question Yes No Can Infiltration in any appreciable quantity be allowed without posing significant risk for groundwater related concerns (shallow water table, 7 storm water pollutants or other factors)? The response to this Screening Question shall be based on a comprehensive evaluation of the factors presented in Appendix C.3. Provide basis: See criteria No. 6 Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussior of study/data source applicability. Can infiltration be allowed without violating downstream water rights? 8 The response to this Screening Question shall be based on a comprehensive evaluation of the factors presented in Appendix C.3. Provide basis: Downstream water rights are a legal matter that do not fall under the purview of geotechnical engineering. However, there are no water courses traversing the subject site. See criteria No. 6 Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/data source applicability. Part 2 If all answers from row 5-8 are yes then partial infiltration design is potentially feasible. The Result* feasibility screening category is Partial Infiltration. No If any answer from row 5-8 is no, then infiltration of any volume is considered to be Infiltration infeasible within the drainage area. The feasibility screening category is No Infiltration. * To be completed using gathered site information and best professional judgement considering the definition of MEP in the MS4 Permit. Additional testing and/or studies may be required by Agency/Jurisdictions to substantiate findings. Storm Water Standards February 2016 Edition Appendices: BMP Design Manual 1-6 Appendix I: Factor of Safety and Design Infiltration Rate Worksheet ctor Infiltration Rate Worksheet Factor Criteria Factor Description Assigned Weight (w) Form I-, Factor Product (j) Value (v) p = w x v A Suitability Soil assessment methods 0.25 1 0.25 Predominant soil texture 0.25 1 0.25 Assessment Site soil variability 0.25 1 0.25 Depth to groundwater/impervious layer 0.25 1 0.25 Suitability Assessment Safety Factor, SA = EP Min = 2.0 B Design Level of pretreatment/expected sediment loads 0.5 Redundancy/resiliency 0.25 Compaction during construction 0.25 Design Safety Factor, SB = 1p Combined Safety Factor, s= S, x SB 2.0 mm Observed Infiltration Rate, inch/hr, KOb,,V,d (corrected for test-specific bias) 1.74 in/hr Design Infiltration Rate, in/hr, KdCSBfl = KOh erVCd / Stotai 0.87 in/hr Supporting Data Briefly describe infiltration test and provide reference to test forms: See Appendix E of Geotechnical Report by GeoSoils, Inc. (2021). I I Li I I D-19 February 26, 2016 I I I I I I 1 I 1 I I APPENDIX F GENERAL EARTHWORK, GRADING GUIDELINES AND PRELIMINARY CRITERIA GeoSoils, Inc. GENERAL EARTHWORK AND GRADING GUIDELINES General These guidelines present general procedures and requirements for earthwork and grading as shown on the approved grading plans, including preparation of areas to be filled, placement of fill, installation of subdrains, excavations, and appurtenant structures or flatwork. The recommendations contained in the geotechnical report are part of these earthwork and grading guidelines and would supercede the provisions contained hereafter in the case of conflict. Evaluations performed by the consultant during the course of grading may result in new or revised recommendations which could supercede these guidelines or the recommendations contained in the geotechnical report. Generalized details follow this text. The contractor is responsible for the satisfactory completion of all earthwork in accordance with provisions of the project plans and specifications and latest adopted code. In the case of conflict, the most onerous provisions shall prevail. The project geotechnical engineer and engineering geologist (geotechnical consultant), and/or their representatives, should provide observation and testing services, and geotechnical consultation during the duration of the project. EARTHWORK OBSERVATIONS AND TESTING Geotechnical Consultant Prior to the commencement of grading, a qualified geotechnical consultant (soil engineer and engineering geologist) should be employed for the purpose of observing earthwork procedures and testing the fills for general conformance with the recommendations of the geotechnical report(s), the approved grading plans, and applicable grading codes and ordinances. The geotechnical consultant should provide testing and observation so that an evaluation maybe made that the work is being accomplished as specified. It is the responsibility of the contractor to assist the consultants and keep them apprised of anticipated work schedules and changes, so that they may schedule their personnel accordingly. All remedial removals, clean-outs, prepared ground to receive fill, key excavations, and subdrain installation should be observed and documented by the geotechnical consultant prior to placing any fill. It is the contractor's responsibility to notify the geotechnical consultant when such areas are ready for observation. Laboratory and Field Tests Maximum dry density tests to determine the degree of compaction should be performed in accordance with American Standard Testing Materials test method ASTM designation D-1557. Random or representative field compaction tests should be performed in GeoSoils, Inc. accordance with test methods ASTM designation D-1556, D-2937 or D-2922, and D-3017, at intervals of approximately ±2 feet of fill height or approximately every 1,000 cubic yards placed. These criteria would vary depending on the soil conditions and the size of the project. The location and frequency of testing would be at the discretion of the geotechnical consultant. Contractor's Responsibility All clearing, site preparation, and earthwork performed on the project should be conducted by the contractor, with observation by a geotechnical consultant, and staged approval by the governing agencies, as applicable. It is the contractor's responsibility to prepare the ground surface to receive the fill, to the satisfaction of the geotechnical consultant, and to place, spread, moisture condition, mix, and compact the fill in accordance with the recommendations of the geotechnical consultant. The contractor should also remove all non-earth material considered unsatisfactory by the geotechnical consultant. Notwithstanding the services provided by the geotechnical consultant, it is the sole responsibility of the contractor to provide adequate equipment and methods to accomplish the earthwork in strict accordance with applicable grading guidelines, latest adopted codes or agency ordinances, geotechnical report(s), and approved grading plans. Sufficient watering apparatus and compaction equipment should be provided by the contractor with due consideration for the fill material, rate of placement, and climatic conditions. If, in the opinion of the geotechnical consultant, unsatisfactory conditions such as questionable weather, excessive oversized rock or deleterious material, insufficient support equipment, etc., are resulting in a quality of work that is not acceptable, the consultant will inform the contractor, and the contractor is expected to rectify the conditions, and if necessary, stop work until conditions are satisfactory. During construction, the contractor shall properly grade all surfaces to maintain good drainage and prevent ponding of water. The contractor shall take remedial measures to control surface water and to prevent erosion of graded areas until such time as permanent drainage and erosion control measures have been installed. SITE PREPARATION All major vegetation, including brush, trees, thick grasses, organic debris, and other deleterious material, should be removed and disposed of off-site. These removals must be concluded prior to placing fill. In-place existing fill, soil, alluvium, topsoil, or rock materials, as evaluated by the geotechnical consultant as being unsuitable, should be removed prior to any fill placement. Depending upon the soil conditions, these materials may be reused as compacted fills. Any materials incorporated as part of the compacted fills should be approved by the geotechnical consultant. Any underground structures such as cesspools, cisterns, mining shafts, tunnels, septic tanks, wells, pipelines, or other structures not located prior to grading, are to be removed Cross Real Estate Investors, LLC Appendix F Fi1e:e:\wp1218000\8037a.pge GeoSods, Inc. Page 2 or treated in a manner recommended by the geotechnical consultant. Soft, dry, spongy, highly fractured, or otherwise unsuitable ground, extending to such a depth that surface processing cannot adequately improve the condition, should be overexcavated down to firm ground and approved by the geotechnical consultant before compaction and filling operations continue. Overexcavated and processed soils, which have been properly mixed and moisture conditioned, should be re-compacted to the minimum relative compaction as specified in these guidelines. Existing ground, which is determined to be satisfactory for support of the fills, should be scarified (ripped) to a minimum depth of 6 to 8 inches, or as directed by the geotechnical consultant. After the scarified ground is brought to optimum moisture content, or greater and mixed, the materials should be compacted as specified herein. If the scarified zone is greater than 6 to 8 inches in depth, it may be necessary to remove the excess and place the material in lifts restricted to about 6 to 8 inches in compacted thickness. Existing ground which is not satisfactory to support compacted fill should be overexcavated as required in the geotechnical report, or by the on-site geotechnical consultant. Scarification, disc harrowing, or other acceptable forms of mixing should continue until the soils are broken down and free of large lumps or clods, until the working surface is reasonably uniform and free from ruts, hollows, hummocks, mounds, or other uneven features, which would inhibit compaction as described previously. Where fills are to be placed on ground with slopes steeper than 5:1 (horizontal to vertical [h:v]), the ground should be stepped or benched. The lowest bench, which will act as a key, should be a minimum of 15 feet wide and should be at least 2 feet deep into firm material, and approved by the geotechnical consultant. In fill-over-cut slope conditions, the recommended minimum width of the lowest bench or key is also 15 feet, with the key founded on firm material, as designated by the geotechnical consultant. As a general rule, unless specifically recommended otherwise by the geotechnical consultant, the minimum width of fill keys should be equal to 1/2 the height of the slope. Standard benching is generally 4 feet (minimum) vertically, exposing firm, acceptable material. Benching may be used to remove unsuitable materials, although it is understood that the vertical height of the bench may exceed 4 feet. Pre-stripping may be considered for unsuitable materials in excess of 4 feet in thickness. All areas to receive fill, including processed areas, removal areas, and the toes of fill benches, should be observed and approved by the geotechnical consultant prior to placement of fill. Fills may then be properly placed and compacted until design grades (elevations) are attained. COMPACTED FILLS Any earth materials imported or excavated on the property may be utilized in the fill provided that each material has been evaluated to be suitable by the geotechnical consultant. These materials should be free of roots, tree branches, other organic matter, or other deleterious Cross Real Estate Investors, LLC Appendix F Fi1e:e:\wp12\8000\8037apge GeoSoils, Inc. Page 3 materials. All unsuitable materials should be removed from the fill as directed by the geotechnical consultant. Soils of poor gradation, undesirable expansion potential, or substandard strength characteristics may be designated bythe consultant as unsuitable and may require blending with other soils to serve as a satisfactory fill material. Fill materials derived from benching operations should be dispersed throughout the fill area and blended with other approved material. Benching operations should not result in the benched material being placed only within a single equipment width away from the fill/bedrock contact. Oversized materials defined as rock, or other irreducible materials, with a maximum dimension greater than 12 inches, should not be buried or placed in fills unless the location of materials and disposal methods are specifically approved by the geotechnical consultant. Oversized material should be taken offsite, or placed in accordance with recommendations of the geotechnical consultant in areas designated as suitable for rock disposal. GSI anticipates that soils to be utilized as fill material for the subject project may contain some rock. Appropriately, the need for rock disposal may be necessary during grading operations on the site. From a geotechnical standpoint, the depth of any rocks, rock fills, or rock blankets, should be a sufficient distance from finish grade. This depth is generally the same as any overexcavation due to cut-fill transitions in hard rock areas, and generally facilitates the excavation of structural footings and substructures. Should deeper excavations be proposed (i.e., deepened footings, utility trenching, swimming pools, spas, etc.), the developer may consider increasing the hold-down depth of any rocky fills to be placed, as appropriate. In addition, some agencies/jurisdictions mandate a specific hold-down depth for oversize materials placed in fills. The hold-down depth, and potential to encounter oversize rock, both within fills, and occurring in cut or natural areas, would need to be disclosed to all interested/affected parties. Once approved by the governing agency, the hold-down depth for oversized rock (i.e., greater than 12 inches) in fills on this project is provided as 10 feet, unless specified differently in the text of this report. The governing agency may require that these materials need to be deeper, crushed, or reduced to less than 12 inches in maximum dimension, at their discretion. To facilitate future trenching, rock (or oversized material), should not be placed within the hold-down depth feet from finish grade, the range of foundation excavations, future utilities, or underground construction unless specifically approved by the governing agency, the geotechnical consultant, and/or the developer's representative. If import material is required for grading, representative samples of the materials to be utilized as compacted fill should be analyzed in the laboratory by the geotechnical consultant to evaluate it's physical properties and suitability for use onsite. Such testing should be performed three (3) days prior to importation. If any material other than that previously tested is encountered during grading, an appropriate analysis of this material should be conducted by the geotechnical consultant as soon as possible. Approved fill material should be placed in areas prepared to receive fill in near horizontal layers, that when compacted, should not exceed about 6 to 8 inches in thickness. The Cross Real Estate Investors, LLC Appendix F File: e:\wpl 2\8000\8037a.pge GeoSoils, Inc. Page 4 geotechnical consultant may approve thick lifts if testing indicates the grading procedures are such that adequate compaction is being achieved with lifts of greater thickness. Each layer should be spread evenly and blended to attain uniformity of material and moisture suitable for compaction. Fill layers at a moisture content less than optimum should be watered and mixed, and wet fill layers should be aerated by scarification, or should be blended with drier material. Moisture conditioning, blending, and mixing of the fill layer should continue until the fill materials have a uniform moisture content at, or above, optimum moisture. After each layer has been evenly spread, moisture conditioned, and mixed, it should be uniformly compacted to a minimum of 90 percent of the maximum density as evaluated by ASTM test designation D-1557, or as otherwise recommended by the geotechnical consultant. Compaction equipment should be adequately sized and should be specifically designed for soil compaction, or of proven reliability to efficiently achieve the specified degree of compaction. Where tests indicate that the density of any layer of fill, or portion thereof, is below the required relative compaction, or improper moisture is in evidence, the particular layer or portion shall be re-worked until the required density and/or moisture content has been attained. No additional fill shall be placed in an area until the last placed lift of fill has been tested and found to meet the density and moisture requirements, and is approved by the geotechnical consultant. In general, per the latest adopted version of the California Building Code (CBC), fill slopes should be designed and constructed at a gradient of 2:1 (h:v), or flatter. Compaction of slopes should be accomplished by over-building a minimum of 3 feet horizontally, and subsequently trimming back to the design slope configuration. Testing shall be performed as the fill is elevated to evaluate compaction as the fill core is being developed. Special efforts maybe necessary to attain the specified compaction in the fill slope zone. Final slope shaping should be performed by trimming and removing loose materials with appropriate equipment. A final evaluation of fill slope compaction should be based on observation and/or testing of the finished slope face. Where compacted fill slopes are designed steeper than 2:1 (h:v), prior approval from the governing agency, specific material types, a higher minimum relative compaction, special reinforcement, and special grading procedures will be recommended. If an alternative to over-building and cutting back the compacted fill slopes is selected, then special effort should be made to achieve the required compaction in the outer 10 feet of each lift of fill by undertaking the following: An extra piece of equipment consisting of a heavy, short-shanked sheepsfoot should be used to roll (horizontal) parallel to the slopes continuously as fill is placed. The sheepsfoot roller should also be used to roll perpendicular to the slopes, and extend out over the slope to provide adequate compaction to the face of the slope. Cross Real Estate Investors, LLC Appendix F Fi1e:e:\wp12'8000\8037apge GeoSoils, Inc. Page 5 2. Loose fill should not be spilled out over the face of the slope as each lift is compacted. Any loose fill spilled over a previously completed slope face should be trimmed off or be subject to re-rolling. 2. Field compaction tests will be made in the outer (horizontal) ±2 to ±8 feet of the slope at appropriate vertical intervals, subsequent to compaction operations. After completion of the slope, the slope face should be shaped with a small tractor and then re-rolled with a sheepsfoot to achieve compaction to near the slope face. Subsequent to testing to evaluate compaction, the slopes should be grid-rolled to achieve compaction to the slope face. Final testing should be used to evaluate compaction after grid rolling. Where testing indicates less than adequate compaction, the contractor will be responsible to rip, water, mix, and recompact the slope material as necessary to achieve compaction. Additional testing should be performed to evaluate compaction. SUBDRAIN INSTALLATION Subdrains should be installed in approved ground in accordance with the approximate alignment and details indicated by the geotechnical consultant. Subdrain locations or materials should not be changed or modified without approval of the geotechnical consultant. The geotechnical consultant may recommend and direct changes in subdrain line, grade, and drain material in the field, pending exposed conditions. The location of constructed subdrains, especially the outlets, should be recorded/surveyed by the project civil engineer. Drainage at the subdrain outlets should be provided by the project civil engineer. EXCAVATIONS Excavations and cut slopes should be examined during grading by the geotechnical consultant. If directed by the geotechnical consultant, further excavations or overexcavation and refilling of cut areas should be performed, and/or remedial grading of cut slopes should be performed. When fill-over-cut slopes are to be graded, unless otherwise approved, the cut portion of the slope should be observed by the geotechnical consultant prior to placement of materials for construction of the fill portion of the slope. The geotechnical consultant should observe all cut slopes, and should be notified by the contractor when excavation of cut slopes commence. If, during the course of grading, unforeseen adverse or potentially adverse geologic conditions are encountered, the geotechnical consultant should investigate, evaluate, and make appropriate recommendations for mitigation of these conditions. The need for cut slope buttressing or stabilizing should be based on in-grading evaluation by the geotechnical consultant, whether anticipated or not. Cross Real Estate Investors, LLC Appendix F File: e:\wpl2\8000\8037a.pge GeoSoils, Inc. Page 6 Unless otherwise specified in geotechnical and geological report(s), no cut slopes should be excavated higher or steeper than that allowed by the ordinances of controlling governmental agencies. Additionally, short-term stability of temporary cut slopes is the contractor's responsibility. Erosion control and drainage devices should be designed by the project civil engineer and should be constructed in compliance with the ordinances of the controlling governmental agencies, and/or in accordance with the recommendations of the geotechnical consultant. COMPLETION Observation, testing, and consultation by the geotechnical consultant should be conducted during the grading operations in order to state an opinion that all cut and fill areas are graded in accordance with the approved project specifications. After completion of grading, and after the geotechnical consultant has finished observations of the work, final reports should be submitted, and may be subject to review by the controlling governmental agencies. No further excavation or filling should be undertaken without prior notification of the geotechnical consultant or approved plans. All finished cut and fill slopes should be protected from erosion and/or be planted in accordance with the project specifications and/or as recommended by a landscape architect. Such protection and/or planning should be undertaken as soon as practical after completion of grading. PRELIMINARY OUTDOOR POOL/SPA DESIGN RECOMMENDATIONS The following preliminary recommendations are provided for consideration in pool/spa design and planning. Actual recommendations should be provided by a qualified geotechnical consultant, based on site specific geotechnical conditions, including a subsurface investigation, differential settlement potential, expansive and corrosive soil potential, proximity of the proposed pool/spa to any slopes with regard to slope creep and lateral fill extension, as well as slope setbacks per Code, and geometry of the proposed improvements. Recommendations for pools/spas and/or deck flatwork underlain by expansive soils, or for areas with differential settlement greater than ¼-inch over 40 feet horizontally, will be more onerous than the preliminary recommendations presented below. The 1:1 (h:v) influence zone of any nearby retaining wall site structures should be delineated on the project civil drawings with the pool/spa. This 1:1 (h:v) zone is defined as a plane up from the lower-most heel of the retaining structure, to the daylight grade of the nearby building pad or slope. If pools/spas or associated pool/spa improvements are constructed within this zone, they should be re-positioned (horizontally or vertically) so that they are supported by earth materials that are outside or below this 1:1 plane. If this is not possible given the area of the building pad, the owner should consider eliminating these improvements or allow for increased potential for lateral/vertical deformations and associated Cross Real Estate Investors, LLC Appendix F Fi1e:e:\wp12\8000\8037a.pge GeoSoils, Inc. Page 7 ko distress that may render these improvements unusable in the future, unless they are periodically repaired and maintained. The conditions and recommendations presented herein should be disclosed to all homeowners and any interested/affected parties. General The equivalent fluid pressure to be used for the pool/spa design should be 60 pounds per cubic foot (pcf) for pool/spa walls with level backfill, and 75 pcf for a 2:1 sloped backfill condition. In addition, backdrains should be provided behind pool/spa walls subjacent to slopes. Passive earth pressure may be computed as an equivalent fluid having a density of 150 pcf, to a maximum lateral earth pressure of 1,000 pounds per square foot (psf). An allowable coefficient of friction between soil and concrete of 0.30 may be used with the dead load forces. When combining passive pressure and frictional resistance, the passive pressure component should be reduced by one-third. Where pools/spas are planned near structures, appropriate surcharge loads need to be incorporated into design and construction by the pool/spa designer. This includes, but is not limited to landscape berms, decorative walls, footings, built-in barbeques, utility poles, etc. All pool/spa walls should be designed as "free standing" and be capable of supporting the water in the pool/spa without soil support. The shape of pool/spa in cross section and plan view may affect the performance of the pool, from a geotechnical standpoint. Pools and spas should also be designed in accordance with the latest adopted Code. Minimally, the bottoms of the pools/spas, should maintain a distance H/3, where H is the height of the slope (in feet), from the slope face. This distance should not be less than 7 feet, nor need not be greater than 40 feet. The soil beneath the pool/spa bottom should be uniformly moist with the same stiffness throughout. If a fill/cut transition occurs beneath the pool/spa bottom, the cut portion should be overexcavated to a minimum depth of 48 inches, and replaced with compacted fill, such that there is a uniform blanket that is a minimum of 48 inches below the pool/spa shell. If very low expansive soil is used for fill, the fill should be placed at a minimum of 95 percent relative compaction, at optimum moisture conditions. This requirement should be 90 percent relative compaction at over optimum moisture if the pool/spa is constructed within or near expansive soils. The potential for grading and/or re-grading of the pool/spa bottom, and attendant potential for shoring and/or slot excavation, needs to be considered during all aspects of pool/spa planning, design, and construction. Cross Real Estate Investors, LLC Appendix F File: e:\wpl 2\8000\8037a. pge GeoSoils, Inc. Page 8 If the pool/spa is founded entirely in compacted fill placed during rough grading, the deepest portion of the pool/spa should correspond with the thickest fill on the lot. Hydrostatic pressure relief valves should be incorporated into the pool and spa designs. A pool/spa under-drain system is also recommended, with an appropriate outlet for discharge. All fittings and pipe joints, particularly fittings in the side of the pool or spa, should be properly sealed to prevent water from leaking into the adjacent soils materials, and be fitted with slip or expandible joints between connections transecting varying soil conditions. An elastic expansion joint (flexible waterproof sealant) should be installed to prevent water from seeping into the soil at all deck joints. A reinforced grade beam should be placed around skimmer inlets to provide support and mitigate cracking around the skimmer face. In order to reduce unsightly cracking, deck slabs should minimally be 4 inches thick, and reinforced with No. 3 reinforcing bars at 18 inches on-center. All slab reinforcement should be supported to ensure proper mid-slab positioning during the placement of concrete. Wire mesh reinforcing is specifically not recommended. Deck slabs should not be tied to the pool/spa structure. Pre-moistening and/or pre-soaking of the slab subgrade is recommended, to a depth of 12 inches (optimum moisture content), or 18 inches (120 percent of the soil's optimum moisture content, or 3 percent over optimum moisture content, whichever is greater), for very low to low, and medium expansive soils, respectively. This moisture content should be maintained in the subgrade soils during concrete placement to promote uniform curing of the concrete and minimize the development of unsightly shrinkage cracks. Slab underlayment should consist of a 1- to 2-inch leveling course of sand (S.E. >30) and a minimum of 4 to 6 inches of Class 2 base compacted to 90 percent. Deck slabs within the H/3 zone, where H is the height of the slope (in feet), will have an increased potential for distress relative to other areas outside of the H/3 zone. If distress is undesirable, improvements, deck slabs or flatwork should not be constructed closer than H/3 or 7 feet (whichever is greater) from the slope face, in order to reduce, but not eliminate, this potential. Pool/spa bottom or deck slabs should be founded entirely on competent bedrock, or properly compacted fill. Fill should be compacted to achieve a minimum 90 percent relative compaction, as discussed above. Prior to pouring concrete, subgrade soils below the pool/spa decking should be throughly watered to achieve a moisture content that is at least 2 percent above optimum moisture content, to a depth of at least 18 inches below the bottom of slabs. This moisture content should be maintained in the subgrade soils during concrete placement to promote uniform curing of the concrete and minimize the development of unsightly shrinkage cracks. Cross Real Estate Investors, L.LC Appendix F Fi1e:e:\wp12\8000\8037a.pge GeoSoils, Inc. Page 9 In order to reduce unsightly cracking, the outer edges of pool/spa decking to be bordered by landscaping, and the edges immediately adjacent to the pool/spa, should be underlain by an 8-inch wide concrete cutoff shoulder (thickened edge) extending to a depth of at least 12 inches below the bottoms of the slabs to mitigate excessive infiltration of water under the pool/spa deck. These thickened edges should be reinforced with two No.4 bars, one at the top and one at the bottom. Deck slabs may be minimally reinforced with No. 3 reinforcing bars placed at 18 inches on-center, in both directions. All slab reinforcement should be supported on chairs to ensure proper mid-slab positioning during the placement of concrete. Surface and shrinkage cracking of the finish slab may be reduced if a low slump and water-cement ratio are maintained during concrete placement. Concrete utilized should have a minimum compressive strength of 4,000 psi. Excessive water added to concrete prior to placement is likely to cause shrinkage cracking, and should be avoided. Some concrete shrinkage cracking, however, is unavoidable. Joint and sawcut locations for the pool/spa deck should be determined by the design engineer and/or contractor. However, spacings should not exceed 6 feet on center. Considering the nature of the onsite earth materials, it should be anticipated that caving or sloughing could be a factor in subsurface excavations and trenching. Shoring or excavating the trench walls/backcuts at the angle of repose (typically 25 to 45 degrees), should be anticipated. All excavations should be observed by a representative of the geotechnical consultant, including the project geologist and/or geotechnical engineer, prior to workers entering the excavation or trench, and minimally conform to Cal/OSHA ("Type C" soils may be assumed), state, and local safety codes. Should adverse conditions exist, appropriate recommendations should be offered at that time by the geotechnical consultant. GSI does not consult in the area of safety engineering and the safety of the construction crew is the responsibility of the pool/spa builder. It is imperative that adequate provisions for surface drainage are incorporated by the homeowners into their overall improvement scheme. Ponding water, ground saturation and flow over slope faces, are all situations which must be avoided to enhance long-term performance of the pool/spa and associated improvements, and reduce the likelihood of distress. Regardless of the methods employed, once the pool/spa is filled with water, should it be emptied, there exists some potential that if emptied, significant distress may occur. Accordingly, once filled, the pool/spa should not be emptied unless evaluated by the geotechnical consultant and the pool/spa builder. For pools/spas built within (all or part) of the Code setback and/or geotechnical setback, as indicated in the site geotechnical documents, special foundations are recommended to mitigate the affects of creep, lateral fill extension, expansive soils Cross Real Estate Investors, LLC Appendix F File: e:\wpl2\8000\8037a.pge GeoSoils, Inc. Page 10 and settlement on the proposed pool/spa. Most municipalities or County reviewers do not consider these effects in pool/spa plan approvals. As such, where pools/spas are proposed on 20 feet or more of fill, medium or highly expansive soils, or rock fill with limited "cap soils" and built within Code setbacks, or within the influence of the creep zone, or lateral fill extension, the following should be considered during design and construction: OPTION A: Shallow foundations with or without overexcavation of the pool/spa "shell," such that the pool/spa is surrounded by 5 feet of very low to low expansive soils (without irreducible particles greater that 6 inches), and the pool/spa walls closer to the slope(s) are designed to be free standing. GSI recommends a pool/spa under-drain or blanket system (see attached Typical Pool/Spa Detail). The pool/spa builders and owner in this optional construction technique should be generally satisfied with pool/spa performance under this scenario; however, some settlement, tilting, cracking, and leakage of the pool/spa is likely over the life of the project. OPTION B: Pier supported pool/spa foundations with or without overexcavation of the pool/spa shell such that the pool/spa is surrounded by 5 feet of very low to low expansive soils (without irreducible particles greater than 6 inches), and the pool/spa walls closer to the slope(s) are designed to be free standing. The need for a pool/spa under-drain system may be installed for leak detection purposes. Piers that support the pool/spa should - be a minimum of 12 inches in diameter and at a spacing to provide vertical and lateral support of the pool/spa, in accordance with the pool/spa designers recommendations current applicable Codes. The pool/spa builder and owner in this second scenario construction technique should be more satisfied with pool/spa performance. This construction will reduce settlement and creep effects on the pool/spa; however, it will not eliminate these potentials, nor make the pool/spa "leak-free." The temperature of the water lines for spas and pools may affect the corrosion properties of site soils, thus, a corrosion specialist should be retained to review all spa and pool plans, and provide mitigative recommendations, as warranted. Concrete mix design should be reviewed by a qualified corrosion consultant and materials engineer. All pool/spa utility trenches should be compacted to 90 percent of the laboratory standard, under the full-time observation and testing of a qualified geotechnical consultant. Utility trench bottoms should be sloped away from the primary structure on the property (typically the residence). Pool and spa utility lines should not cross the primary structure's utility lines (i.e., not stacked, or sharing of trenches, etc.). Cross Real Estate Investors, LLC Appendix F File: e:\wpl2\8000\8037a.pge GeoSoils, Inc. Page 11 The pool/spa or associated utilities should not intercept, interrupt, or otherwise adversely impact any area drain, roof drain, or other drainage conveyances. If it is necessary to modify, move, or disrupt existing area drains, subdrains, or tightlines, then the design civil engineer should be consulted, and mitigative measures provided. Such measures should be further reviewed and approved by the geotechnical consultant, prior to proceeding with any further construction. The geotechnical consultant should review and approve all aspects of pool/spa and flatwork design prior to construction. A design civil engineer should review all aspects of such design, including drainage and setback conditions. Prior to acceptance of the pool/spa construction, the project builder, geotechnical consultant and civil designer should evaluate the performance of the area drains and other site drainage pipes, following pool/spa construction. All aspects of construction should be reviewed and approved by the geotechnical consultant, including during excavation, prior to the placement of any additional fill, prior to the placement of any reinforcement or pouring of any concrete. Any changes in design or location of the pool/spa should be reviewed and approved by the geotechnical and design civil engineer prior to construction. Field adjustments should not be allowed until written approval of the proposed field changes are obtained from the geotechnical and design civil engineer. Disclosure should be made to homeowners and builders, contractors, and any interested/affected parties, that pools/spas built within about 15 feet of the top of a slope, and/or H/3, where H is the height of the slope (in feet), will experience some movement or tilting. While the pool/spa shell or coping may not necessarily crack, the levelness of the pool/spa will likely tilt toward the slope, and may not be esthetically pleasing. The same is true with decking, flatwork and other improvements in this zone. Failure to adhere to the above recommendations will significantly increase the potential for distress to the pool/spa, flatwork, etc. Local seismicity and/or the design earthquake will cause some distress to the pool/spa and decking or flatwork, possibly including total functional and economic loss. The information and recommendations discussed above should be provided to any contractors and/or subcontractors, or homeowners, interested/affected parties, etc., that may perform or may be affected by such work. Cross Real Estate Investors, LLC Appendix F FiIe:e:\wp12\8000\8037a.pge GeoSoils, Inc. Page 12 JOB SAFETY General At GSI, getting the job done safely is of primary concern. The following is the company's safety considerations for use by all employees on multi-employer construction sites. On-ground personnel are at highest risk of injury, and possible fatality, on grading and construction projects. GSI recognizes that construction activities will vary on each site, and that site safety is the prime responsibility of the contractor; however, everyone must be safety conscious and responsible at all times. To achieve our goal of avoiding accidents, cooperation between the client, the contractor, and GSI personnel must be maintained. In an effort to minimize risks associated with geotechnical testing and observation, the following precautions are to be implemented for the safety of field personnel on grading and construction projects: Safety Meetings: GSI field personnel are directed to attend contractor's regularly scheduled and documented safety meetings. Safety Vests: Safety vests are provided for, and are to be worn by GSI personnel, at all times, when they are working in the field. Safety Flags: Two safety flags are provided to GSI field technicians; one is to be affixed to the vehicle when on site, the other is to be placed atop the spoil pile on all test pits. Flashing Lights: All vehicles stationary in the grading area shall use rotating or flashing amber beacons, or strobe lights, on the vehicle during all field testing. While operating a vehicle in the grading area, the emergency flasher on the vehicle shall be activated. In the event that the contractor's representative observes any of our personnel not following the above, we request that it be brought to the attention of our office. Test Pits Location, Orientation, and Clearance The technician is responsible for selecting test pit locations. A primary concern should be the technician's safety. Efforts will be made to coordinate locations with the grading contractor's authorized representative, and to select locations following or behind the established traffic pattern, preferably outside of current traffic. The contractor's authorized representative (supervisor, grade checker, dump man, operator, etc.) should direct excavation of the pit and safety during the test period. Of paramount concern should be the soil technician's safety, and obtaining enough tests to represent the fill. Test pits should be excavated so that the spoil pile is placed away from oncoming traffic, whenever possible. The technician's vehicle is to be placed next to the test pat, opposite the Cross Real Estate Investors, LLC Appendix F FiIe:e:\wp12\3000\8037apge GeoSoils, Inc. Page 13 spoil pile. This necessitates the fill be maintained in a driveable condition. Alternatively, the contractor may wish to park a piece of equipment in front of the test holes, particularly in small fill areas or those with limited access. A zone of non-encroachment should be established for all test pits. No grading equipment should enter this zone during the testing procedure. The zone should extend approximately 50 feet outward from the center of the test pit. This zone is established for safety and to avoid excessive ground vibration, which typically decreases test results. When taking slope tests, the technician should park the vehicle directly above or below the test location. If this is not possible, a prominent flag should be placed at the top of the slope. The contractor's representative should effectively keep all equipment at a safe operational distance (e.g., 50 feet) away from the slope during this testing. The technician is directed to withdraw from the active portion of the fill as soon as possible following testing. The technician's vehicle should be parked at the perimeter of the fill in a highly visible location, well away from the equipment traffic pattern. The contractor should inform our personnel of all changes to haul roads, cut and fill areas or other factors that may affect site access and site safety. In the event that the technician's safety is jeopardized or compromised as a result of the contractor's failure to comply with any of the above, the technician is required, by company policy, to immediately withdraw and notify his/her supervisor. The grading contractor's representative will be contacted in an effort to affect a solution. However, in the interim, no further testing will be performed until the situation is rectified. Any fill placed can be considered unacceptable and subject to reprocessing, recompaction, or removal. In the event that the soil technician does not comply with the above or other established safety guidelines, we request that the contractor bring this to the technician's attention and notify this office. Effective communication and coordination between the contractor's representative and the soil technician is strongly encouraged in order to implement the above safety plan. Trench and Vertical Excavation It is the contractor's responsibility to provide safe access into trenches where compaction testing is needed. Our personnel are directed not to enter any excavation or vertical cut which: 1) is 5 feet or deeper unless shored or laid back; 2) displays any evidence of instability, has any loose rock or other debris which could fall into the trench; or 3) displays any other evidence of any unsafe conditions regardless of depth. All trench excavations or vertical cuts in excess of 5 feet deep, which any person enters, should be shored or laid back. Trench access should be provided in accordance with Cal/OSHA and/or state and local standards. Our personnel are directed not to enter any trench by being lowered or "riding down" on the equipment. Cross Real Estate Investors, LLC Appendix F Fi1e:e:\wp12\.3000\8037a.pge GeoSoils, Inc. Page 14 If the contractor fails to provide safe access to trenches for compaction testing, our company policy requires that the soil technician withdraw and notify his/her supervisor. The contractor's representative will be contacted in an effort to affect a solution. All backfill not tested due to safety concerns or other reasons could be subject to reprocessing and/or removal. If GSI personnel become aware of anyone working beneath an unsafe trench wall or vertical excavation, we have a legal obligation to put the contractor and owner/det'eloper on notice to immediately correct the situation. If corrective steps are not taken, GSI then has an obligation to notify Cal/OSHA and/or the proper controlling authorities. Cross Real Estate Investors, LLC Appendix F File: e:\wpl2\8000\8037a.pge GeoSoils, Inc. Page 15 TYPE A Natural :e;: — Colluvium and alluvium (remove) -\ -\ - Typical benching Bedrock or approved native material See Alternate Details TYPE V Natural grade "— Proposed grade .• . Colluvium and alluvium (rer Typical benching Bedrock or approved native material See Alternate Details Selection of alternate subdrain details, location, and extent of subdrains should be evaluated by the geotechnical consultant during grading. G44 ic. CANYON SUBDRAIN DETAIL Plate F—i 6-inch minimum 6-inch [_12-inch minimum I I -"---6-inch minimum 6-inch mmum -T R-.(miniw,. r A-i B-i Filter material: Minimum volume of 9 cubic feet per lineal foot of pipe.FILTER MATERIAL Sieve Size Percent Passing Perforated pipe: 6-inch-diameter ABS or PVC pipe or 1 inch 100 approved substitute with minimum 8 perforations 3/4 inch 90-100 (Y4-inch diameter) per lineal foot in 3/ inch 40-100 bottom half of pipe (ASTM D-2751, SDR-35, or No. 4 25-40 ASTM D-1527, Schd. 40). No. 8 18-33 No. 30 5-15 For continuous run in excess of 500 feet, use No. 50 0-7 8-inch-diameter pipe (ASTM D-3034, SDR-35, or No. 200 0-3 ASTM D-1785, Schd. 40). ALTERNATE 1: PERFORATED PIPE AND ALTER MATERIAL \ \_— 6-inch minimum minimum — — — 6-inch minimum 6 inch minimum Filter fabric 6-inch minimum j 6-inch minimum B-2 Gravel Material: 9 cubic feet per lineal foot. Perforated Pipe: See Alternate 1 Gravel: Clean 3/4-inch rock or approved substitute. Filter Fabric: Mirafi 140 or approved substitute. ALTERNATE 2: PERFORATED PIPE, GRAVEL, AND ALTER FABRIC [G4*A2e. I CANYON SUBDRAIN ALTERNATE DETAILS Plate F-2 no 11 — M : ;am — — :_ — — .0 — an — — — an — — Toe of slope as shown on grading plan Original ground surface to be restored with compacted fill 2D - del / I \___Original ground surface D - Anticipated removai of unsuitable material (depth per geotechnical engineer) / '- Provide a 1:1 (H:V) minimum projection from toe of Back-cut varies. For deep removals, slope as shown on grading plan to the recommended backcut should be made no steeper removal depth. Slope height, site conditions, and/or than 1:1 (H:V), or flatter as necessary local conditions could dictate flatter projections. for safety considerations. 1 Qq*A2e. FILL SLOPE TOEING OUT ON FLAT ALLUVIATED CANYON DETAIL Plate F-3 no M. - — — — — — — — — — — — — — - — — Previously placed, temporary Proposed grade - compacted fill for drainage only Bedrock or approved native material To be removed before placing additional compacted fill J G44@Ave. I REMOVAL ADJACENT TO EXISTING FILL ADJOINING CANYON FILL DETAIL Plate F-4 Drainage per design civil engineer Blanket fill (if recommended by the geotechnical consultant) Design finish minimum T ii is foot 10-foot minimum 7 25-foot maximum — — 7 I 15-foot minimum - or H/2 where H is the I elope height Buttress or stabilization fill Typical benching (4-foot minimum) '— Bedrock or approved native material Subdrain as recommended by geotechnical consultant Typical benching 4-inch-diameter non-perforated outlet pipe and backdrain (see detail Plate F-6). Outlets to be spaced at 100-foot maximum intervals and shall extend 2 feet beyond the face of slope at time of rough grading completion. At the completion of rough grading. the design civil engineer should provide recommendations to convey any outlet's discharge to a suitable conveyance, utilizing a non-erosive device. 1 t 2 foot] 2-foot minimum key depth 15-foot typical/ drain spacin i_ Toe 2-Percent Gradient Heel I G4~0*Avc. I TYPICAL STABILIZATION / BUTTRESS FILL DETAIL Plate F-5 2-foot I I 2-loot I minimum minimum 2-foot n*dmum T 4-inch minimu~ cLi 1+ _io 2-inch J pipe minimum Filter Material: Minimum of 5 cubic feet per lineal foot of pipe or 4 cubic feet per lineal feet of pipe when placed in square cut trench. Alternative in Lieu of Filter Material: Gravel may be encased in approved filter fabric. Filter fabric shall be Mirafi 140 or equivalent. Filter fabric shall be lapped a minimum of 12 inches in all joints. Minimum 4-Inch-Diameter Pipe: ABS-ASTM D-2751, SDR 35; or ASTM D-1527 Schedule 40, PVC-ASTM D-3034, SDR 35; or ASTM D-1785 Schedule 40 with a crushing strength of 1,000 pounds minimum, and a minimum of 8 uniformly-spaced perforations per foot of pipe. Must be installed with perforations down at bottom of pipe. Provide cap at upstream end of pipe. Slope at 2 percent to outlet pipe. Outlet pipe to be connected to subdrarn pipe with tee or elbow. Notes: 1. Trench for outlet pipes to be backfilled and compacted with onsite soil. 2. Backdrains and lateral drains shall be located at elevation of every bench drain. First drain located at elevation just above lower lot grade. Additional drains may be required at the discretion of the geotechnical consultant. Filter Material shall be of the following Gravel shall be of the following specification or an approved equivalent, specification or an approved equivalent. Sieve Size Percent Passing Sieve Size Percent Passing 1 inch 100 iY2 inch 100 3/4 inch 90-100 No. 4 50 % inch 40-100 No. 200 8 No. 4 25-40 No. 8 18-33 No. 30 5-15 No. 50 0-7 No. 200 0-3 IG44)Ic.I TYPICAL BUTTRESS SUBDRAIN DETAIL Plate F-6 Proposed grade _ Toe of slope as shown on grading plan Natural slope to Compacted fill be restored with compacted fill - Backcut varies 2-foot minimum .. in bedrock or :. approved .. . ..' earth material qe ---- Jtay vary -- Bedrock or 3-foot minimum L* approved 2-Percent Gradient___ native material - - 15-foot minimum or - 11/2 where H is- Subdrain as recommended by the slope height geotechnical consultant NOTES: Where the natural slope approaches or exceeds the design slope ratio, special recommendations would be provided by the geotechnical consultant. The need for and disposition of drains should be evaluated by the geotechnical consultant, based upon exposed conditions. I G4)2c. I FILL OVER NATURAL (SIDEHILL FILL) DETAIL Plate F-7 H - height of slope Original (existing) grade Cut slope - Proposed grade Maintain Compacted fill ,minimum 15-toot Till section from I backcut to face of finish slope or 4-foot minimum ------1 e. < Bench width ["(4-loot minimum) I 2graent may vary - \\ A minimum I 15-foot minimum or key depth L..._ H/2 where H Subdrain as recommended by the slope helght1 geotechnical consultant Cut/fill contact as shown on grading plan Cut/fill contact as shown on as-built plan Bedrock or approved native material NOTE: The cut portion of the slope should be excavated and evaluated by the geotechnical consultant prior to construction of the fill portion. G4*0~ie. I FILL OVER CUT DETAIL Plate F-8 .•..• Typical benching (4-foot minimum) A Compacted stablization fill - - 1-loot minimum tilt back Bedrock or other approved native material If recommended by the geotechnical consultant, the remaining cut portion of dt 2 Percent Gradient the slope may require removal and k — - - - - \— replacement with compacted fill. w Subdrain as recommended by geotechnical consultant NOTES: 1. Subdrains may be required as specified by the geotechnical consultant. 2 W shall be equipment width (15 feet) for slope heights less than 25 feet. For slopes greater than 25 feet, W shall be evaluated by the geotechnical consultant. At no time, shall W be less than H/2, where H is the height of the slope. I G4#10Ave. STABLIZATION FILL FOR UNSTABLE MATERIAL EXPOSED IN CUT SLOPE DETAIL Plate F-9 Proposed finish grade Natural grade ------------- 3-foot minimum :.:.:;• got minimum see Note 1) Typical benching (4-foot minimum) Bedrock or approved native material 2-Percent Gradient, 2-foot minimum key depth low 15-foot minimum k orH/2ifH)30 Subdrain as recommended by geotechnical consultant I NOTES: 1. 15-foot minimum to be maintained from proposed finish slope face to backcut. The need and disposition of drains will be evaluated by the geotechnical consultant based on field conditions. Pad overexcavation and recompaction should be performed if evaluated to be necessary by the geotechnical consultant. j Gq*~ie. I SKIN FILL OF NATURAL GROUND DETAIL Plate F-10 Reconstruct compacted fill slope at 2:1 or flatter Natural grade . (may increase or decrease pad area) .. . ::. Overexcavate and recompact replacement fill Remove Proposed unsiiitable aterial .: I Back-cut varies / finish grade 3-toot minimum fill blanket Avoid and/or clean up . • ....... / .. '. :. : spillage of materials on - the natural slope •.:• \) N___ IVY Bedrock or approved 2-foot minimum •. ••. .• \—\\\A\\ native material i7e y width Typical benching - - - .. -.- ---. •- aef,ent (4-foot minimum) F \\ Subdrain as recommended by geotechnical consultant NOTES: 1. Subdrain and key width requirements will be evaluated based on exposed subsurface conditions and thickness of overburden. 2. Pad overexcavation and recompaction should be performed if evaluated necessary by the geotechnical consultant. Gq#A2e. DAYLIGHT CUT LOT DETAIL Plate F-i 1 I I I I I I I I I I I I I I I I I I I Natural grade Proposed pad grade 3- to 7-foot minimum* overexcavete and recompact Bedrock or per text of report approved native Typical benching material CUT LOT OR MATERIAL-TYPE TRANSITION Subgrade at 2 percent gradient, drainirg toward street 3- to 7-foot minimum* per text of report Deeper overexcavation may be Bedrock or recommended by the geotechnical consultant in steep cut-fill transition approved native areas, such that the underlying Typical benching material topography is no steeper than 3:1 (H-.V) 7_177- (4-foot minimum) 71 CUT-FILL LOT (DAYLIGHT TRANSITION) [Gq*)~nc. I TRANSITION LOT DETAILS Plate F-12 VIEW NORMAL TO SLOPE FACE Proposed finish grade (E) (E) Hold-down depth (B) CC (A) (D) dD------15-foot - _____ cZXD - minimum native material VIEW PARALLEL TO SLOPE FACE Proposed finish grade (B) (E) Hold-down depth ioo-toot_.. I I maximum ccxcx2c yr) __ 15-foot minimum -H H- 3-toot minimum xXXD 25-foot minimum from wall wa yon - - (C) J5-foot minimum Bedrock or approved native material NOTES: One equipment width or a minimum of 15 feet between rows (or windrows). Height and width may vary depending on rock size and type of equipment. Length of windrow shall be no greater than 100 feet. If approved by the geotechnical consultant, windrows may be placed direcity on competent material or bedrock, provided adequate space is available for compaction. Orientation of windrows may vary but should be as recommended by the geotechnical engineer and/or engineering geologist. Staggering of windrows is not necessary unless recommended. Clear area for utility trenches, foundations, and swimming pools; Hold-down depth as specified in text of report, subject to governing agency approval. All fill over and around rock windrow shall be compacted to at least 90 percent relative compaction or as recommended. After fill between windrows is placed and compacted, with the lift of fill covering windrow, windrow should be proof rolled with a D-9 dozer or equivalent. VIEWS ARE DIAGRAMMATIC ONLY AND MAY BE SUPERSEDED BY REPORT RECOMMENDATIONS OR CODE ROCK SHOULD NOT TOUCH AND VOIDS SHOULD BE COMPLETELY FILLED IG4J)2c. I OVERSIZE ROCK DISPOSAL DETAIL Plate F-13 Layer one rock high Proposed finish grade Hold-down depth - PRORLE ALONG LAYER ROCK DISPOSAL PITS Fill lifts compacted over / rock after embedment Granular material Large Rock Size of excavation to I I be commensurate I I Compacted Fill with rock size ROCK DISPOSAL LAYERS Granular soil to fill voids, den8itied by flooding r Compacted fill Hold-down depth Compacted fill - 3-foot rimum / IL : XDC 1Fill Slope I. Clear zone TOP VIEW -T Layer one rock high Hold-down depth or below lowest utility as specified in text of report, subject to governing agency approval. . Clear zone for utility trenches, foundations, and swimming pools, as specified in text of report: VIEWS ARE DIAGRAMMATIC ONLY AND MAY BE SUPERSEDED BY REPORT RECOMMENDA11ONS OR CODE ROCK SHOULD NOT TOUCH AND VOIDS SHOULD BE COMPLETELY FILLED IN G40)~C. I ROCK DISPOSAL DETAIL Plate F-14 5-foot-high impact/debris wall METHOD 1 ____ _j Pad grade — Existing grade 5-toot-high impact/debris wall METHOD 2 Pad grade -- le catchment area -foot-high METHOD 3 pact/debris all — Pad grade Existing grade 2:1 NO slope Fence / 2:1 NO slope METHOD 4 Pad grade NOT TO SCALE I Gq*Aic. I DEBRIS DEVICE CONTROL METHODS DETAIL Plate F-15 Rock-filled gabion basket Existing grade -r 5-foot mininun or as recommended by geotechnical consultant Proposed grade Filter fabric Drain rock Compacted fill Gabion impact or diversion wall should be constructed at the base of the ascending slope subject to rock fall. Walls need to be constructed with high segments that sustain impact and mitigate potential for overtopping, and low segment that provides channelization of sediments and debris to desired depositional area for subsequent clean-out. Additional subdrain may be recommended by geotechnical consultant. From GSA, 1987 G4*zne. ROCK FALL MITIGATION DETAIL Plate F-16 MAP VIEW NOT TO SCALE Concrete cut-oft wall SEE NOTES BI Top of slope Gravity-flow, -" nonpert orated subdrain pipe (transverse) Toe of slope 4-inch perforated subdrain pipe (longitudinal) A i i Coping i -5 4-inch perforated subdrain pipe (transverse) Pool _ B' Direction of drainage --> CROSS SEC11ON VIEW -1 NOT TO SCALE I SEE NOTES Coping ............................................ ........................................... ............................................ 2-inch-thick sand layer Pool encapsulated in 5-foot thickness of sand Vapor retarder \__ 6-inch-thick gravel layer 4-inch perforated subdrain pipe I-, Coping_ II r— 5 feet -- Outlet per .-i•;;-: civil engineer- Zone of Pool aye T I gravel 2-inch-thick sandi layer Gravity-flow subdrain pipe cut-off - Vapor retarder Perforated subdrain pipe NOTES: 6-inch-thick, dean gravel (3/4 to 1Y2 inch) sub-base encapsulated in Mirafi 140N or equivalent, underlain by a 15-mil vapor retarder, with 4-inch-diameter perforated pipe longitudinal connected to 4-inch-diameter perforated pipe transverse. Connect transverse pipe to 4-inch-diameter nonperf orated pipe at low point and outlet or to sump pump area. Pools on fills thicker than 20 feet should be constructed on deep foundations; otherwise, distress (tilting, cracking, etc.) should be expected. a Design does not apply to infinity-edge pools/spas. Gq*)~C. I TYPICAL POOL/SPA DETAIL Plate F-17 2-foot x 2-foot x Y4-inch steel plate 3tandard %-inch pipe nipple velded to top of plate 1-inch x 5-foot galvanized pipe, andard pipe threads top and bottom; Ktensions threaded on both ends and ded in 5-foot increments 3-inch schedule 40 PVC pipe sleeve, add n 5-foot increments with glue joints rroposea tinism grade ---r I I I I I 51eet 5feet I I I I I I 51eet , , r2 feet / . . .. ....... . - .7 . I. I .•• -. / Bottom of cleanout 1foot:.:.:..:.:.:.:.::.:.:.:.:. I::::::::::::::j Provide a minimum 1-foot bedding of compacted sand NOTES: Locations of settlement plates should be clearly marked and readily visible (red flagged) to equipment operators. Contractor should maintain clearance of a 5-foot radius of plate base and withiin 5 feet (vertical) for heavy equipment. Fill within clearance area should be hand compacted to project specifications or compacted by alternative approved method by the geotechnical consultant (in writing, prior to construction). After 5 feet (vertical) of fill is in place, contractor should maintain a 5-foot radius equipment clearance from riser. Place and mechanically hand compact initial 2 feet of fill prior to establishing the initial reading. In the event of damage to the settlement plate or extension resulting from equipment operating within the specified clearance area, contractor should immediately notify the geotechnical consultant and should be responsible for restoring the settlement plates to working order. An alternate design and method of installation may be provided at the discretion of the geotechnical consultant. Gq**c. I SETTLEMENT PLATE AND RISER DETAIL Plate F-18 Finish grade 3/8-inch-diameter X 6-inch-long carriage bolt or equivalent I< 6-inch diameter X 3 to 6 feet 4 J 3Y2-inch-long hole I - Concrete backfill J Q(~O*Xie. I TYPICAL SURFACE SETTLEMENT MONUMENT Plate F-19 SIDE VIEW poil pile Test pit TOP VIEW Flag Flag Spoil pile Test pit Light Vehicle -50 feet 50feet lOOfeet G442c. TEST PIT SAFETY DIAGRAM Plate F-20 I GSI LEGEND Quaternary-age Old Paralic I Deposits (Bedrock), Circled - _I where Buried