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CT 2021-0005; CHINQUAPIN COASTAL HOMES; PRELIMINARY GEOTECHNICAL INVESTIGATION; 2021-10-28
.. 111111 .. ---• -.. ... .. .. .. ... .. .. .. .. ... .. ... .. .. .. .. .. .. ... ,. ... ... ... REPORT OF PRELIMINARY GEOTECHNICAL INVESTIGATION Proposed Chinquapin Coast Homes 330 Chinquapin Avenue Carlsbad, California C...T 2o2.l-l'.)C-05' JOB NO. 21-13506 28 October 2021 Prepared for: RINCON CAPITAL GROUP, LLC RE,CEiVED JUL 12 2022 LANO DEVFLOPiViENT Cl\;{-:;:·:,\ r= r= L 1 I. f lG l_l •• ,:• ·, • · .. .. .. .. .. ... ... .. ... .. ... .. ... .. Geotechnical Exploration, Inc . SOIL AND FOUNDATION ENGINEERING • GROUNDWATER • ENGINEERING GEOLOGY 28 October 2021 RINCON CAPITAL GROUP, LLC 5315 Avenida Encinas, Suite 200 Carlsbad, CA 92008 Attn: Mr. Kevin Dunn lob No. 21-13506 Subject: Report of Preliminary Geotechnical Investigation Proposed Chinquapin Coastal Homes 330 Chinquapin Avenue Carlsbad, California Dear Mr. Dunn: ,,,. ... In accordance with your request, and our proposal of August 23, 2021, Geotechnical Exploration, Inc. has performed a preliminary geotechnical investigation for the ,.. proposed residential project in Carlsbad, California. The field work was performed 111111 on October 5, 2021. ,.. If the conclusions and recommendations presented in this report are incorporated ... into the design and construction of the proposed nine (9) three-story, single family residences with ground-floor garages and associated improvements, it is our opinion ?"' that the site is suitable for the proposed project. This opportunity to be of service is sincerely appreciated. Should you have any ... questions concerning the following report, please do not hesitate to contact us. ~ Reference to our Job No. 21-13506 will expedite a response to your inquiries. ... Respectfully submitted, ... _,. ... .. ... ... ... ; ... GEOTECHNICAL EXPLORATION, INC. Senior Geotechnical Engineer R.C.E. 34422/G.E. 2007 ~' President C.E.G. 999/P.G. 3391 ,-7420 TRADE STREET• SAN DIEGO, CA. 92121 • (858) 549-7222 • FAX: (858) 549-1604 • EMAIL: geotech@gei-sd.com I.. .. .. .. -.. .. .. ... ,,. .. ... ... .. .. ... .. .. ... ... ... ... ,. .. ... ... ... .. ... ,. ... ,. ... ,,. ... TABLE OF CONTENTS I. PROJECT SUMMARY .................................................................................. 1 II. SCOPE OF WORK ..................................................................................... 1 III. SITE DESCRIPTION ................................................................................ 2 IV. FIELD INVESTIGATION ............................................................................ 3 V. LABORATORY TESTING & SOIL INFORMATION ............................................. 4 VI. REGIONAL GEOLOGIC DESCRIPTION ......................................................... 7 VII. SITE-SPECIFIC SOIL & GEOLOGIC DESCRIPTION ..................................... 12 VIII. GEOLOGIC HAZARDS .......................................................................... 13 A. Local and Regional Faults ............................................................ 13 B. Other Geologic Hazards .............................................................. 19 IX. GROUNDWATER ................................................................................... 22 X. CONCLUSIONS & RECOMMENDATIONS ..................................................... 24 A. Preparation of Soils for Site Development ...................................... 25 B. Seismic Design Criteria ............................................................... 34 C. Foundation Recommendations ..................................................... 35 D. Retaining Wall Design ................................................................. 37 E. Concrete Slab On-Grade Criteria .................................................. 39 F. Pavements ................................................................................ 43 G. Site Drainage Considerations ....................................................... 44 H. General Recommendations .......................................................... 45 XI. GRADING NOTES .................................................................................. 47 XII. LIMITATIONS ...................................................................................... 47 REFERENCES FIGURES I. Vicinity Map II. Plot Plan and Site-Specific Geologic Map IIIa-m. Exploratory Excavation Logs and Laboratory Results IV. Laboratory Test Results V. Geologic Map Excerpt and Legend APPENDICES A. B . C. D. Unified Soil Classification System Storm Water Infiltration Testing --Group Delta Laboratory Tests --Group Delta ASCE Seismic Summary Report 111 -.. .. ... .. .... .. ... ... ... ... ... ... -,... -... .. .. ... ... .. .. -... .. ... ... REPORT OF PRELIMINARY GEOTECHNICAL INVESTIGATION Proposed Chinquapin Coast Homes 330 Chinquapin Avenue Carlsbad, California JOB NO. 21-13506 The following report presents the findings and recommendations of Geotechnical Exploration, Inc. for the subject project . I. PROJECT SUMMARY It is our understanding, based on our review of the available conceptual site plan prepared by Kirk Moeller Architects, Inc., that the existing residential structure and associated improvements are to be entirely demolished and replaced with nine (9) three-story residential structures with ground-level garages, a shared driveway, parking areas and associated improvements. The new structures are to be constructed of standard-type building materials utilizing conventional foundations with concrete slab on-grade. Foundation loads are expected to be typical for this type of relatively light construction. When final plans are completed, they should be made available for our review. Additional or modified recommendations will be provided at that time if warranted . Based on the available information at this stage, it is our opinion that the proposed site development would not destabilize neighboring properties or induce the settlement of adjacent structures or improvements if designed and constructed in accordance with our recommendations . II. SCOPE OF WORK The scope of work performed for this investigation included a site reconnaissance and subsurface exploration program under the direction of our geologist with placement, Iii -.. ... ... -... - ,,,. ... ... ... 11111" ... ... .. .. .. ... ... ... ... ... .. ... ... ... ... Chinquapin Coast Homes Carlsbad, California Job No. 21-13506 Page 2 logging and sampling of thirteen (13) exploratory handpit excavations, review of available published information pertaining to the site geology, laboratory testing, geotechnical engineering analysis of the field and laboratory data, and the preparation of this report. The data obtained and the analyses performed were for the purpose of providing design and construction criteria for the project earthwork, building foundations, slab on-grade floors and associated improvements . In addition, we were provided and reviewed a previously prepared geotechnical report for a prior proposed development at the site titled "Report of Geotechnical Investigation, 330 Chinquapin Avenue, Carlsbad, California" dated November 30, 2018, by Group Delta Consultants, Inc. (their Project No. SD589). Storm Water Infiltration Testing was performed by Group Delta in 2018 and has been included as Appendix B in this report. III. SITE DESCRIPTION The lot is known as Assessor's Parcel No. 206-020-11-00, the northeastern half of Lot 3 of Palisades No. 2 in Block S, according to Recorded Map No. 1803, with a current address of 330 Chinquapin Avenue, in the City of Carlsbad, County of San Diego, State of California. Refer to Figure No. I, Vicinity Map, for the site location . The rectangular-shaped property is located on the north side of Chinquapin Avenue and is bordered on the north, east and west by multi-family residential developments . Refer to the Plot Plan, Figure No. II. The existing property is currently developed with a single-story, single-family residential structure, an asphalt-paved driveway, walkways, and associated improvements. Vegetation on the site primarily consists of decorative shrubbery and mature trees. The large rear yard is covered with grasses and weeds . .. ... .. .. .. ... --... .. ,,. -.. -... .. ... - .... ... .. --... .. ... .. .. ,. 1111111 ... ... .. ... Chinquapin Coast Homes Carlsbad, California Job No. 21-13506 Page 3 The property is relatively level with elevations on the property ranging from 50 feet above mean sea level (MSL) at the front (south) of the property adjacent to Chinquapin Avenue to an approximate elevation of 54 feet above mean sea level (MSL) across most of the property. Survey information concerning elevations across the site was obtained from topographic elevations provided on the Conceptual Site Plan prepared by Kirk Moeller Architects, Inc., dated August 18, 2021. IV. FIELD INVESTIGATION A. Subsurface Soils Investigation The field investigation was conducted on October 5, 2021, and consisted of surface reconnaissance and a subsurface exploration program utilizing hand tools to investigate and sample the subsurface soils. Thirteen (13) exploratory handpit excavations (HP-1 through HP-13) were excavated to depths ranging from 1 foot to 2.5 feet in the areas of the proposed construction and associated improvements. Excavation locations were limited to accessible areas. The handpits were continuously logged in the field by our geologist and described in accordance with the Unified Soil Classification System (refer to Appendix A). The approximate locations of the exploratory handpit excavations are shown on the Plot Plan, Figure No. II. In addition to our handpit excavations we reviewed five boring logs contained within the "Report of Geotechnical Investigation, 330 Chinquapin Avenue, Carlsbad, California" dated November 30, 2018, by Group Delta Consultants, Inc. (their Project No. SD589). The small-diameter borings were placed to depths ranging from 4.9 to 21.5 feet . Representative samples were obtained from the exploratory excavations at selected depths appropriate to the investigation. Relatively undisturbed drive samples and disturbed bulk samples were collected from the exploratory handpits to aid in 81 - ... ... ... -... ... ... ... ,.. ... .... ,.. --.... -... ... ... ... ,,,. ... .. .. ... .. ... .. ... Chinquapin Coast Homes Carlsbad, California Job No. 21-13506 Page 4 classification and for appropriate laboratory testing. The samples were returned to our laboratory for evaluation and testing. Exploratory excavation logs have been prepared on the basis of our observations and laboratory test results, and are attached as Figure Nos. IIIa-m . The exploratory excavation logs and related information depict subsurface conditions only at the specific locations shown on the plot plan and on the particular date designated on the logs. Subsurface conditions at other locations may differ from conditions occurring at the locations. Also, the passage of time may result in changes in subsurface conditions due to environmental changes . B. Storm Water Infiltration Testing Infiltration testing was previously performed at the site by Group Delta in 2018. We have included in Appendix B the results of the Infiltration testing and the Worksheet 1-8: Categorization of Infiltration Feasibility Condition prepared by Group Delta. V. LABORATORY TESTING & SOIL INFORMATION Laboratory tests were performed on retrieved soil samples in order to evaluate their physical and mechanical properties. The test results are presented on Figure Nos . IIIa-e and IVa-c. The following tests were conducted on representative soil samples: ;el -.... ... .. ... -.. .. ... ,,,. ... - ... ,.. -.. .. .... -... ... ... ... ,,,. --.. .. ... ... .. Chinquapin Coast Homes Carlsbad, California Job No. 21-13506 Page 5 1. 2. 3 . 4. 5 . 6 . 7. 8. Moisture Content (ASTM 02216-19) Density Measurements (ASTM D2937-17e2) Laboratory Compaction Characteristics (ASTM D1557-12e1) Determination of Percentage of Particles Smaller than #200 Sieve (ASTM 01140-17) Standard Test Method for Expansion Index of Soils (ASTM 4829-11) Resistivity and pH Analysis (Department of Transportation California Test 643) Water Soluble Sulfate (Department of Transportation California Test 417) Water Soluble Chloride (Department of Transportation California Test 422) Moisture content and density measurements were performed by ASTM methods D2216-19 and D2937-17e2 respectively, in conjunction with D1188-07 to establish the in-situ moisture and density of samples retrieved from the exploratory excavations. The test results are presented on the handpit logs at the appropriate sample depths and laboratory test results. Laboratory compaction values (ASTM D1557-12el) establish the optimum moisture content and the laboratory maximum dry density of the tested soils. The relationship between the moisture and density of remolded soil samples helps to establish the relative compaction of the existing site soils and the soil compaction conditions to be anticipated during any future grading operation. The test results are presented on the handpit logs at the appropriate sample depths and laboratory test results . The particle size smaller than a No. 200 sieve analysis (ASTM D1140-17) aids in classifying the tested soils in accordance with the Unified Soil Classification System and provides qualitative information related to engineering characteristics such as expansion potential, permeability, and shear strength. The test results are presented on the handpit logs at the appropriate sample depths and laboratory test results . 111 -... ... .. .. ... ... ... -... ,. .. -... .. ... ,,. .. ... .. .. .. .. ... .. ... ,,. ... ... ... ,.. ... Chinquapin Coast Homes Carlsbad, California Job No. 21-13506 Page 6 The expansion potential of soils is determined, when necessary, utilizing the Standard Test Method for Expansion Index of Soils (ASTM D4829-19). In accordance with the Standard (Table 5.3), potentially expansive soils are classified as follows: EXPANSION INDEX POTENTIAL EXPANSION Oto 20 Very low 21 to 50 Low 51 to 90 Medium 91 to 130 High Above 130 Very hiqh Expansion index testing of a representative sample of the sandy onsite natural soil resulted in an expansion index of 0 (Sample retrieved at the location of excavation HP-6). In addition, expansion index testing of two representative samples of the sandy onsite fill and natural soils by Group Delta in 2018 also resulted in expansion indices of 0 for both samples (refer to Appendix C for Group Delta laboratory test results). Based on our visual classification, our Expansion Index and particle-size test results, and our experience with similar soils, it is our opinion that the existing silty sand fill and the formational materials of the Old Paralic Deposits, Units 6-7, encountered in the excavations possess a negligible to very low potential for expansion (EI less than 20). Therefore, we have assigned a maximum expansion index of less than 20 to these soils . The primary cause of deterioration of concrete in foundations and other below ground structures is the corrosive attack by soluble sulfates present in the soil and groundwater. Soil with a chloride concentration greater than or equal to 500 ppm (0.05 percent) or more is considered corrosive to ferrous metals. The results of water-soluble sulfate testing performed on a representative sample of the near surface soils by Group Delta in 2018 in the general area of the proposed structures, yielded a soluble 111 -.. -.. ---... -... ,,,. ... - .... .... ... - .. .... ,,. .... .. .. .. .. ... ,.. -.. .. ... Chinquapin Coast Homes Carlsbad, California Job No. 21-13506 Page 7 sulfate content of 0.01 percent, indicating that the proposed cement-concrete structures that are in contact with the underlying soils are anticipated to not be affected by negligible sulfate exposure. As such, there is no restriction on selection of cement type (refer to Appendix C for Group Delta laboratory test results). It should be noted that Geotechnical Exploration Inc., does not practice corrosion engineering and our assessment here should be construed as an aid to the owner or owner's representative. A corrosion specialist should be consulted for any specific design requirement . Based on the field and laboratory test data, our observations of the primary soil types, and our previous experience with laboratory testing of similar soils, our Geotechnical Engineer has assigned values for friction angle, coefficient of friction, and cohesion for those soils that will have significant lateral support or load bearing functions on the project. The assumed soil strength values have been utilized in determining the recommended bearing value as well as active and passive earth pressure design criteria for foundations, retaining walls and shoring . VI. REGIONAL GEOLOGIC DESCRIPTION San Diego County has been divided into three major geomorphic provinces: The Coastal Plain, the Peninsular Ranges and the Salton Trough. The Coastal Plain exists west of the Peninsular Ranges. The Salton Trough is east of the Peninsular Ranges . These divisions are the result of the basic geologic distinctions between the areas. Mesozoic metavolcanic, metasedimentary and plutonic rocks predominate in the Peninsular Ranges with primarily Cenozoic sedimentary rocks to the west and east of this central mountain range (Demere, 1997). ---.. -.. ... -... --- ... -... ---... - ... ... -,.. .. .. ... ,.. ... Chinquapin Coast Homes Carlsbad, California Job No. 21-13506 Page 8 In the Coastal Plain region, where the subject property is located, the "basement" consists of Mesozoic crystalline rocks. Basement rocks are also exposed as high relief areas (e.g., Black Mountain northeast of the subject property and Cowles Mountain near the San Carlos area of San Diego). Younger Cretaceous and Tertiary sediments lap up against these older features. These sediments form a "layer cake" sequence of marine and non-marine sedimentary rock units, with some formations up to 140 million years old. Faulting related to the La Nacion and Rose Canyon Fault zones has broken up this sequence into a number of distinct fault blocks in the southwestern part of the county. Northwestern portions of the county are relatively undeformed by faulting (Demere, 1997). The Peninsular Range form the granitic spine of San Diego County. These rocks are primarily plutonic, forming at depth beneath the earth's crust 140 to 90 million years ago as the result of the subduction of an oceanic crustal plate beneath the North American continent. These rocks formed the much larger Southern California batholith. Metamorphism associated with the intrusion of these great granitic masses affected the much older sediments that existed near the surface over that period of time. These metasedimentary rocks remain as roof pendants of marble, schist, slate, quartzite and gneiss throughout the Peninsular Ranges. Locally, Miocene-age volcanic rocks and flows have also accumulated within these mountains (e.g., Jacumba Valley). Regional tectonic forces and erosion over time have uplifted and unroofed these granitic rocks to expose them at the surface (Demere, 1997) . The Salton Trough is the northerly extension of the Gulf of California. This zone is undergoing active deformation related to faulting along the Elsinore and San Jacinto Fault Zones, which are part of the major regional tectonic feature in the southwestern portion of California, the San Andreas Fault Zone. Translational movement along these fault zones has resulted in crustal rifting and subsidence. The Salton Trough, also referred to as the Colorado Desert, has been filled with sediments to depth of ;JI -----.. -.. .. -,. ----- -- --... ... -,,. - ,. .. ... ... ... ... Chinquapin Coast Homes Carlsbad, California Job No. 21-13506 Page 9 approximately 5 miles since the movement began in the early Miocene, 24 million years ago. The source of these sediments has been the local mountains as well as the ancestral and modern Colorado River (Demere, 1997) . As indicated previously, the San Diego area is part of a seismically active region of California. It is on the eastern boundary of the Southern California Continental Borderland, part of the Peninsular Ranges Geomorphic Province. This region is part of a broad tectonic boundary between the North American and Pacific Plates. The actual plate boundary is characterized by a complex system of active, major, right- lateral strike-slip faults, trending northwest/southeast. This fault system extends eastward to the San Andreas Fault (approximately 70 miles from San Diego) and westward to the San Clemente Fault (approximately 50 miles off-shore from San Diego) (Berger and Schug, 1991). In California, major earthquakes can generally be correlated with movement on active faults. As defined by the California Division of Mines and Geology, now the California Geological Survey, an "active" fault is one that has had ground surface displacement within Holocene time, about the last 11,000 years (Hart and Bryant, 1997). Additionally, faults along which major historical earthquakes have occurred (about the last 210 years in California) are also considered to be active (Association of Engineering Geologist, 1973). The California Division of Mines and Geology defines a "potentially active" fault as one that has had ground surface displacement during Quaternary time, that is, between 11,000 and 1.6 million years (Hart and Bryant, 1997). During recent history, prior to April 2010, the San Diego County area has been relatively quiet seismically. No fault ruptures or major earthquakes had been experienced in historic time within the greater San Diego area. Since earthquakes have been recorded by instruments (since the 1930s), the San Diego area has --.. .. -... ... .. ... .. -... ... ... - ... .. ... ... ... ... ... -.. .. ,. ... .. .. ,.. Chinquapin Coast Homes Carlsbad, California Job No. 21-13506 Page 10 experienced scattered seismic events with Richter magnitudes generally less than M4.0. During June 1985, a series of small earthquakes occurred beneath San Diego Bay, three of which were recorded at M4.0 to M4.2. In addition, the Oceanside earthquake of July 13, 1986, located approximately 26 miles offshore of the City of Oceanside, had a magnitude of M5.3 (Hauksson and Jones, 1988) . On June 15, 2004, a M5.3 earthquake occurred approximately 45 miles southwest of downtown San Diego (26 miles west of Rosarito, Mexico). Although this earthquake was widely felt, no significant damage was reported. Another widely felt earthquake on a distant southern California fault was a M5.4 event that took place on July 29, 2008, west-southwest of the Chino Hills area of Riverside County. Several earthquakes ranging from M5.0 to M6.0 occurred in northern Baja California, centered in the Gulf of California on August 3, 2009. These were felt in San Diego but no injuries or damage was reported. A M5.8 earthquake followed by a M4.9 aftershock occurred on December 30, 2009, centered about 20 miles south of the Mexican border city of Mexicali. These were also felt in San Diego, swaying high-rise buildings, but again no significant damage or injuries were reported . On April 4, 2010, a large earthquake occurred in Baja California, Mexico. It was widely felt throughout the southwest including Phoenix, Arizona and San Diego in California. This M7 .2 event, the Sierra El Mayor earthquake, occurred in northern Baja California, approximately 40 miles south of the Mexico-USA border at shallow depth along the principal plate boundary between the North American and Pacific plates. According to the U. S. Geological Survey this is an area with a high level of historical seismicity, and it has recently also been seismically active, although this is the largest event to strike in this area since 1892. The April 4, 2010, earthquake appears to have been larger than the M6.9 earthquake in 1940 or any of the early 20th century events (e.g., 1915 and 1934) in this region of northern Baja California . ta ---... - -... - ... -.. ... -... .. .. -... .. ... ... .. ... .. .. .. ... ... ,,. ... Chinquapin Coast Homes Carlsbad, California Job No. 21-13506 Page 11 The event caused widespread damage to structures, closure of businesses, government offices and schools, power outages, displacement of people from their homes and injuries in the nearby major metropolitan areas of Mexicali in Mexico and Calexico in Southern California. This event's aftershock zone extends significantly to the northwest, overlapping with the portion of the fault system that is thought to have ruptured in 1892. Some structures in the San Diego area experienced minor damage and there were some injuries. Ground motions for the April 4, 2010, main event, recorded at stations in San Diego and reported by the California Strong Motion Instrumentation Program (CSMIP), ranged up to 0.058g . On July 7, 2010, a M5.4 earthquake occurred in Southern California at 4:53 pm (Pacific Time) about 30 miles south of Palm Springs, 25 miles southwest of Indio, and 13 miles north-northwest of Borrego Springs. The earthquake occurred near the Coyote Creek segment of the San Jacinto Fault. The earthquake exhibited right lateral slip to the northwest, consistent with the direction of movement on the San Jacinto Fault. The earthquake was felt throughout Southern California, with strong shaking near the epicenter. It was followed by more than 60 aftershocks of Ml.3 and greater during the first hour . In the last 50 years, there have been four other earthquakes in the magnitude M5.0 range within 20 kilometers of the Coyote Creek segment: M5.8 in 1968, M5.3 on 2/25/1980, M5.0 on 10/31/2001, and M5.2 on 6/12/2005. The biggest earthquake near this location was the M6.0 Buck Ridge earthquake on 3/25/1937 . Bi -.. -- .. ... ... .. -... .. ... .. ... .. ,,,. ... -.... ... -.... ... ... .. ,,,. ... .. ,.. ... ,,,. ... Chinquapin Coast Homes Carlsbad, California Job No. 21-13506 Page 12 VII. SITE-SPECIFIC SOIL & GEOLOGIC DESCRIPTION Our field investigation, reconnaissance and review of the geologic map by Kennedy and Tan, 2007, "Geologic Map of the Oceanside 30'x60' Quadrangle, California" indicate that the site is underlain by late to middle Pleistocene-Aged Old Paralic Deposits, Units 6-7 (QOP6-7) formational materials. An excerpt of the geological map is included as Figure No. V. Our exploratory excavations indicate the formational materials are overlain across the site by shallow-depth topsoil/fill soils (Qaf). Site- specific geology is shown on the Plot Plan, Figure No. II . Topsoil/Fill Soil (Oaf): Our site investigation indicates that the lot is overlain by approximately 1 foot of topsoil/fill soil. The encountered surficial soil is generally in a loose condition and consists of moist, brown, fine-to medium-grained silty sand (SM) with some roots. In our opinion, the surficial soils are not considered suitable in their current condition to support loads from structures or additional fill. Refer to Figure Nos. IIIa-m for details. Old Paralic Deposits, Unit 6-7 (OoD6-1l: The encountered formational materials are described in the literature as Quaternary (late to middle Pleistocene) Old Paralic Deposits, Units 6-7. These formational materials were encountered in all exploratory excavations underlying the topsoil/fill soil at variable depths of 1 foot or less. The formational materials are generally medium dense below the pad elevation, becoming dense at depth. The formational soils are damp, light brown, fine-to medium-grained silty sand (SM). In our opinion, the medium dense to dense nature of the Old Paralic Deposits, Units 6-7, below a depth of 3 feet makes it suitable in its current condition to support loads from structures or additional fill. Refer to Figure Nos. IIIa-m for details . ill ---... - -.. ... -- ... ... ... ... ,,. -... ... .. --.. ... ,,. ... ... .. ... ... ,. ... Chinquapin Coast Homes Carlsbad, California Job No. 21-13506 Page 13 Based on our review of the geologic map by Kennedy and Tan, 2007, "Geologic Map of the Oceanside 30'x60' Quadrangle, California" the Old Paralic Deposits, Units 6-7, formational materials underlie the entire site at depth. The aforementioned Old Paralic Deposit Units are described as "Poorly sorted, moderately permeable, reddish- brown, interfingered strandline, beach, estuarine and colluvial deposits composed of siltstone, sandstone and conglomerate." According to the map, there are no faults known to pass through the site (refer to Figure No. V, Geologic Map Excerpt and Legend). VIII. GEOLOGIC HAZARDS The following is a discussion of the geologic conditions and hazards common to this area of Carlsbad, as well as project-specific geologic information relating to development of the subject property. A. Local and Regional Faults Reference to the Geologic Map and Legend, Figure No. V (Kennedy and Tan, 2007), indicates that no faults are shown to cross the site. Furthermore, our site reconnaissance presented no indications of faulting crossing the site. In our professional opinion, neither an active fault nor a potentially active fault underlies the site. A brief description of the nearby active faults including distances from the mapped fault to the subject site at the closest point (based on the USGS Earthquake Hazards- Interactive Fault Map), is presented below: Newport-Inglewood-Rose Canyon Fault Zone System: The Rose Canyon portion of the Newport-Inglewood-Rose Canyon Fault Zone is mapped approximately 4.8 miles west-southwest of the site and the offshore portion of the Newport-Inglewood portion 81 -.. -.. -... ... ... ... ... ,.. -.. ... -.. --... ... .... -... ... .. .. ... ... ... ... ... ... -... Chinquapin Coast Homes Carlsbad, California Job No. 21-13506 Page 14 is mapped approximately 5.4 miles west-northwest of the site. The offshore portion of the Newport-Inglewood Fault Zone is described as a right-lateral; local reverse slip associated with fault steps (SCEDC, 2020); the reported length is 46.2 miles extending in a northwest-southeast direction. Surface trace is discontinuous in the Los Angeles Basin, but the fault zone can easily be noted there by the existence of a chain of low hills extending from Culver City to Signal Hill. South of Signal Hill, it roughly parallels the coastline until just south of Newport Bay, where it heads offshore, and becomes the Newport-Inglewood -Rose Canyon Fault Zone. A significant earthquake (M6.4) occurred along this fault on March 10, 1933. Since then, no additional significant events have occurred. The fault is believed to have a slip rate of approximately 0.6-mm/yr with an unknown recurrence interval. This fault is believed capable of producing an earthquake of M6.0 to M7.4 (Grant Ludwig and Shearer, 2004) . Rose Canyon Fault Zone: The Rose Canyon Fault Zone is the southern section of the Newport-Inglewood-Rose Canyon Fault Zone system mapped in the San Diego County area as trending north-northwest to south-southeast from Oceanside to La Jolla and generally north-south into San Diego Bay, through Coronado and offshore downtown San Diego, from where it appears to head southward. The Rose Canyon Fault Zone system is considered to be a complex zone of onshore and offshore, en echelon right lateral, strike slip, oblique reverse, and oblique normal faults. This fault is considered to be capable of generating an M6.9 earthquake (EERI, 2020) and is considered microseismically active, although no significant recent earthquakes since 1862 {Legg and Agnew, 1979) are known to have occurred on the fault . Investigative work on faults that are part of the Rose Canyon Fault Zone at the Police Administration and Technical Center in downtown San Diego, at the SDG&E facility in Rose Canyon, and within San Diego Bay and elsewhere within downtown San Diego, has encountered offsets in Holocene (geologically recent) sediments (Singleton et al., iii --.. ---... --.... --... -... -... ... -- ... -.. .... ... --.... -... .. ... -... Chinquapin Coast Homes Carlsbad, California Job No. 21-13506 Page 15 2019). These findings confirm Holocene displacement on the Rose Canyon Fault, which was designated an "active" fault in November 1991 (Hart and Bryant, 1997) . Rockwell (2010) has suggested that the Rose CFZ underwent a cluster of activity including 5 major earthquakes in the early Holocene, with a long period of inactivity following, suggesting major earthquakes on the RCFZ behaves in a cluster-mode, where earthquake recurrence is clustered in time rather than in a consistent recurrence interval. With the most recent earthquake (MRE) nearly 160 years ago, it is suggested that a period of earthquake activity on the RCFZ may have begun. Rockwell (2010) and a compilation of the latest research implies a long-term slip rate of approximately 1 to 2 mm/year . Coronado Bank Fault: The Coronado Bank Fault is located approximately 20.7 miles southwest of the site. Evidence for this fault is based upon geophysical data (acoustic profiles) and the general alignment of epicenters of recorded seismic activity (Greene et al., 1979). The Oceanside earthquake of M5.3 recorded July 13, 1986, is known to have been centered on the fault or within the Coronado Bank Fault Zone. Although this fault is considered active, due to the seismicity within the fault zone, it is significantly less active seismically than the Elsinore Fault (Hileman et al., 1973). It is postulated that the Coronado Bank Fault is capable of generating a M7 .6 earthquake and is of great interest due to its close proximity to the greater San Diego metropolitan area . San Diego Trough Fault Zone: The San Diego Through Fault Zone is mapped at approximately 30 miles to the west-southwest of the site at its closest point. This fault is described as a right-lateral type fault with a length of at least 93.2 miles and a slip rate of roughly 1.5 mm/yr. The most recent surface rupture is of Holocene age (SCEDC, 2020) . ta --.. .. -... -.. .. .. ... .. ... ... ... .. ... .. .. ... ... ... ... ... ... -.. ... ... .. Chinquapin Coast Homes Carlsbad, California Job No. 21-13506 Page 16 San Clemente Fault Zone: The San Clemente Fault Zone is mapped at approximately 50 miles to the southwest of the site at its closest point. This fault is described as a right-lateral an<:t vertical offsets type fault with a length of at least 130.5 miles described as essentially continuous with the San Isidro fault zone, off the coast of Mexico and a slip rate of roughly 1.5 mm/yr. The most recent surface rupture is of Holocene age (SCEDC, 2020) . Elsinore Fault: The Temecula and Julian sections of the Elsinore Fault Zone are located approximately 25 miles northeast and east of the site respectively. The Elsinore Fault Zone extends approximately 125 miles from the Mexican border to the northern end of the Santa Ana Mountains. The Elsinore Fault zone is a 1-to 4-mile- wide, northwest-southeast-trending zone of discontinuous and en echelon faults extending through portions of Orange, Riverside, San Diego, and Imperial Counties. Individual faults within the Elsinore Fault Zone range from less than 1 mile to 16 miles in length. The trend, length and geomorphic expression of the Elsinore Fault Zone identify it as being a part of the highly active San Andreas Fault system . Like the other faults in the San Andreas system, the Elsinore Fault is a transverse fault showing predominantly right-lateral movement. According to Hart et al. (1979), this movement averages less than 1 centimeter per year. Along most of its length, the Elsinore Fault Zone is marked by a bold topographic expression consisting of linearly aligned ridges, swales and hallows. Faulted Holocene alluvial deposits (believed to be less than 11,000 years old) found along several segments of the fault zone suggest that at least part of the zone is currently active . Although the Elsinore Fault Zone belongs to the San Andreas set of active, northwest- trending, right-slip faults in the southern California area (Crowell, 1962), it has not been the site of a major earthquake in historic time, other than a M6.0 earthquake near the town of Elsinore in 1910 (Richter, 1958; Toppozada and Parke, 1982) . Yi -----... -... -.... --.. ... -.. -... -.. ... .. ... --... -... ... ... -... -.. .. Chinquapin Coast Homes Carlsbad, California Job No. 21-13506 Page 17 However, based on length and evidence of late-Pleistocene or Holocene displacement, Greensfelder (1974) has estimated that the Elsinore Fault Zone is reasonably capable of generating an earthquake with a magnitude as large as M7.5. Study and logging of exposures in trenches placed in Glen Ivy M_arsh across the Glen Ivy North Fault (a strand of the Elsinore Fault Zone between Corona and Lake Elsinore), suggest a maximum earthquake recurrence interval of 300 years, and when combined with previous estimates of the long-term horizontal slip rate of 0.8 to 7 .0 mm/year, suggest typical earthquake magnitudes of M6.0 to M7.0 (Rockwell et al., 1985). The Working Group on California Earthquake Probabilities (2008) has estimated that there is a 11 percent probability that an earthquake of M6. 7 or greater will occur within 30 years on this fault . San Jacinto Fault: The San Jacinto Fault is located approximately 47 to 65 miles northeast of the site. The San Jacinto Fault Zone consists of a series of closely spaced faults, including the Coyote Creek Fault, that form the western margin of the San Jacinto Mountains. The fault zone extends from its junction with the San Andreas Fault in San Bernardino, southeasterly toward the Brawley area, where it continues south of the international border as the Imperial Transform Fault (Rockwell et al., 2014) . The San Jacinto Fault zone has a high level of historical seismic activity, with at least 10 damaging earthquakes (M6.0 to M7.0) having occurred on this fault zone between 1890 and 1986. Earthquakes on the San Jacinto Fault in 1899 and 1918 caused fatalities in the Riverside County area. Offset across this fault is predominantly right- lateral, similar to the San Andreas Fault, although some investigators have suggested that dip-slip motion contributes up to 10% of the net slip (Ross et al., 2017) . The segments of the San Jacinto Fault that are of most concern to major metropolitan areas are the San Bernardino, San Jacinto Valley and Anza segments. Fault slip rates 111 -- - ... -... ... ... ... .. .. ... --.. .. .. ... ... -- ... ... ... 111111 -... ... .. ... .. - Chinquapin Coast Homes Carlsbad, California Job No. 21-13506 Page 18 on the various segments of the San Jacinto are less well constrained than for the San Andreas Fault, but the available data suggest slip rates of 12 ±6 mm/yr for the northern segments of the fault, and slip rates of 4 ±2 mm/yr for the southern segments. For large ground-rupturing earthquakes on the San Jacinto fault, various investigators have suggested a recurrence interval of 150 to 300 years. The Working Group on California Earthquake Probabilities (2008) has estimated that there is a 31 percent probability that an earthquake of M6. 7 or greater will occur within 30 years on this fault. Maximum credible earthquakes of M6.7, M6.9 and M7.2 are expected on the San Bernardino, San Jacinto Valley and Anza segments, respectively, capable of generating peak horizontal ground accelerations of 0.48g to 0.53g in the County of Riverside. A M5.4 earthquake occurred on the San Jacinto Fault on July 7, 2010 . The United States Geological Survey has issued the following statements with respect to the recent seismic activity on southern California faults: The San Jacinto fault, along with the Elsinore, San Andreas, and other faults, is part of the plate boundary that accommodates about 2 inches/year of motion as the Pacific plate moves northwest relative to the North American plate. The largest recent earthquake on the San Jacinto fault, near this location, the M6.5 1968 Borrego Mountain earthquake April 8, 1968, occurred about 25 miles southeast of the July 7, 2010, M5.4 earthquake. This M5.4 earthquake follows the 4th of April 2010, Easter Sunday, M7 .2 earthquake, located about 125 miles to the south, well south of the US Mexico international border. A M4.9 earthquake occurred in the same area on June 12th at 8:08 pm (Pacific Time). Thus, this section of the San Jacinto fault remains active . Seismologists are watching two major earthquake faults in southern California. The San Jacinto fault, the most active earthquake fault in southern California, extends for more than 100 miles from the international border into San Bernardino and Riverside, a major metropolitan area often called the Inland Empire. The Elsinore fault is more than 110 miles long, and extends into the Orange County and Los Angeles area as the Whittier fault. The Elsinore fault is capable of a major earthquake that would significantly affect the large metropolitan SP --.. ... .. -... -... .. --.. ... .. ... .. .. .. --... -... .. -.. --.. -.. - -... - Chinquapin Coast Homes Carlsbad, California Job No. 21-13506 Page 19 B . areas of southern California. The Elsinore fault has not hosted a major earthquake in more than 100 years. The occurrence of these earthquakes along the San Jacinto fault and continued aftershocks demonstrates that the earthquake activity in the region remains at an elevated level. The San Jacinto fault is known as the most active earthquake fault in southern California. Caltech and USGS seismologist continue to monitor the ongoing earthquake activity using the Caltech/USGS Southern California Seismic Network and a GPS network of more than 100 stations. Other Geologic Hazards Ground Rupture: Ground rupture is characterized by bedrock slippage along an established fault and may result in displacement of the ground surface. For ground rupture to occur along a fault, an earthquake usually exceeds MS.0. If a MS.0 earthquake were to take place on a local fault, an estimated surface-rupture length 1 mile long could be expected (Greensfelder, 1974). Our investigation indicates that the subject site is not directly on a known active fault trace and, therefore, the risk of ground rupture is remote. Ground Shaking: Structural damage caused by seismically induced ground shaking is a detrimental effect directly related to faulting and earthquake activity. Ground shaking is considered to be the greatest seismic hazard in San Diego County. The intensity of ground shaking is dependent on the magnitude of the earthquake, the distance from the earthquake, and the seismic response characteristics of underlying soils and geologic units. Earthquakes of MS.O or greater are generally associated with significant damage. It is our opinion that the most serious damage to the site would be caused by a large earthquake originating on a nearby strand of the Rose Canyon, Coronado Bank or Newport-Inglewood Faults. Although the chance of such an event is remote, it could occur within the useful life of the structure. .. -.. .. ... .... - -.. -... --... .. -.. -.. .. .. -.. -.. - ... ... .. ... .. ... .. Chinquapin Coast Homes Carlsbad, California Job No. 21-13506 Page 20 Landslides: Our investigation indicates that the subject site is not directly on a known recent or ancient landslide. Review of the "Geologic Map of the Oceanside 30'x60' Quadrangle, California" by Kennedy and Tan (2007) and the USGS Landslide Hazard Program Site (US Landslide Inventory), indicate that there are no known or suspected ancient landslides located on the site. Slope Stability: Our site reconnaissance indicates that the site is relatively level and underlain by relatively stable and medium dense Old Paralic Deposits, Unit 6-7 formational materials at depths of approximately 1 to 5 feet. In our opinion, there is not a topographic slope stability issue with the site. Liquefaction: The liquefaction of saturated sands during earthquakes can be a major ' ' cause of damage to buildings. Liquefaction is the process by which soils are transformed into a viscous fluid that will flow as a liquid when unconfined. It occurs primarily in loose, cohesionless saturated silt, sand, and fine-grained gravel deposits of Holocene to late Pleistocene age and in areas where the groundwater is shallower than about 50 feet (DMG Special Publication 117) when they are sufficiently shaken by an earthquake. On this site, the risk of liquefaction of formational materials due to seismic shaking does not exist due to the dense to very dense nature of the underlying formational materials and the lack of shallow static groundwater. The site does not have a potential for soil strength loss to occur due to a seismic event . Tsunamis and Seiches: A tsunami is a series of long waves generated in the ocean by a sudden displacement of a large volume of water. Underwater earthquakes, landslides, volcanic eruptions, meteor impacts, or onshore slope failures can cause this displacement. Tsunami waves can travel at speeds averaging 450 to 600 miles per hour. As a tsunami nears the coastline, its speed diminishes, its wave length decreases, and its height increases greatly. After a major earthquake or other tsunami-inducing activity occurs, a tsunami could reach the shore within a few -.. .. ... .. ... -.. ... -... -... .. .. -... .... ... .... ... ... ... .... .. -.. .. ... -... - 11111 ... .. .. Chinquapin Coast Homes Carlsbad, California Job No. 21-13506 Page 21 minutes. One coastal community may experience no damaging waves while another may experience very destructive waves. Some low-lying areas could experience severe inland inundation of water and deposition of debris more than 3,000 feet inland . The site is located less than 0.25-mile from the exposed coastline and at an elevation of approximately 50 feet above MSL. Review of the Tsunami Inundation Map for Emergency Planning, Encinitas Quadrangle, the site is located outside the inundation area. There is minimal risk of tsunami inundation at the site . A seiche is a run-up of water within a lake or embayment triggered by fault-or landslide-induced ground displacement. The site is located near a coastal lagoon, that is not considered capable of producing a seiche and inundating the subject site . Flood Hazard: Review of the FEMA flood maps number 06073C0764H, effective on 12/20/2019, the project site is located within the Special Flood Hazard Area (SFHA) X. Zone X is described as minimal flood hazard. The civil engineer should verify this statement with the City of Carlsbad and County of San Diego (FEMA, 2019) . Geologic Hazards Summary: It is our opinion, based upon a review of the available maps, our research and our site investigation, that the site is underlain at shallow depth by stable Old Paralic Deposits formational materials and is suited for the proposed residential structures and associated improvements provided the recommendations herein are implemented. Furthermore, based on the available information at this stage, it appears the proposed site development will not destabilize or result in settlement of adjacent property or improvements if the recommendations presented in this report are implemented . ... -... ... ... .... ... -... -... -... ... -.... ... ... .. ... .. 11111 ... ... ... ... -... -... ... ... -... --- Chinquapin Coast Homes Carlsbad, California · Job No. 21-13506 Page 22 No significant geologic hazards are known to exist on the site that would prohibit the construction of the proposed residential structures, retaining walls and associated improvements. Ground shaking from earthquakes on active southern California faults and active faults in northwestern Mexico is the greatest geologic hazard at the property. Design of building structures in accordance with the current building codes would reduce the potential for injury or loss of human life. Buildings constructed in accordance with current building codes may suffer significant damage but should not undergo total collapse . In our explicit professional opinion, no active or potentially active faults underlie the project site . IX. GROUNDWATER Free groundwater was not encountered in our shallow exploratory excavations nor was it encountered in prior borings placed on the site by Group Delta in 2018 to maximum depths of approximately 21.5 feet. It is likely that groundwater depth on the site is at or slightly above the mean sea level of approximately 5 feet. It should be recognized that minor groundwater seepage problems might occur after development of a site even where none were present before development. These are usually minor phenomena and are often the result of an alteration in drainage patterns and/or an increase in irrigation water. Based on the permeability characteristics of the soil and the anticipated usage and development, it is our opinion that any seepage problems, which may occur, will be minor in extent. It is further our opinion that these problems can be most effectively corrected on an individual basis if and when they occur . SP -... .. ... .. - -... -... - ... ... .. .. .. .. .... --.. -... ... .. ... Chinquapin Coast Homes Carlsbad, California Job No. 21-13506 Page 23 We do not anticipate significant groundwater problems to develop in the future, if the property is developed as proposed and proper drainage is implemented and maintained. It should be kept in mind that any required construction operations will change surface drainage patterns and/or reduce permeabilities due to the densification of compacted soils. Such changes of surface and subsurface hydrologic conditions, plus irrigation of landscaping or significant increases in rainfall, may result in the appearance of surface or near-surface water at locations where none existed previously. The damage from such water is expected to be localized and cosmetic in nature, if good positive drainage is implemented, as recommended in this report, during and at the completion of construction . On properties such as the subject site where dense, low permeability soils exist at shallow depths, even normal landscape irrigation practices on the property or neighboring properties, or periods of extended rainfall, can result in shallow "perched" water conditions. The perching (shallow depth) accumulation of water on a low permeability surface can result in areas of persistent wetting and drowning of lawns, plants and trees. Resolution of such conditions, should they occur, may require site-specific design and construction of subdrain and shallow "wick" drain dewatering systems . It must be understood that unless discovered during site exploration or encountered during site construction operations, it is extremely difficult to predict if or where perched or true groundwater conditions may appear in the future. When site fill or formational soils are fine-grained and of low permeability, water problems may not become apparent for extended periods of time. r, ... .... .. ... .... .. .. .. .. --.. ... .. .. .. .... .. .. ... ... ... .... ... ... ,.. ... Chinquapin Coast Homes Carlsbad, California Job No. 21-13506 Page 24 Water conditions, where suspected or encountered during construction, should be evaluated and remedied by the project civil and geotechnical consultants. The project developer and property owner, however, must realize that post-construction appearances of groundwater may have to be dealt with on a site-specific basis . Proper functional surface drainage should be implemented and maintained at the property. X. CONCLUSIONS & RECOMMENDATIONS The following recommendations are based upon the practical field investigations conducted by our firm, and resulting laboratory tests, in conjunction with our knowledge and experience with similar soils in the Carlsbad area .. The opinions, conclusions, and recommendations presented in this report are contingent upon Geotechnical Exploration, Inc. being retained to review the final plans and specifications as they are developed and to observe the site earthwork and installation of foundations. Accordingly, we recommend that the following paragraph be included on the grading and foundation plans for the project . If the geotechnical consultant of record is changed for the project, the work shall be stopped until the replacement has agreed in writing to accept responsibility within their area of technical competence for approval upon completion of the work. It shall be the responsibility of the permittee to notify the governing agency in writing of such change prior to the recommencement of grading and/or foundation installation work and comply with the governing agency's requirements for a change to the Geotechnical Consultant of Record for the project. From a geotechnical engineering standpoint, it is our opinion that the site is suitable for construction of the proposed residences and associated improvements provided the conclusions and recommendations presented in this report are incorporated into its design and construction . ti& .. .. .. .. ... .. -.. ... .. ... ... .. .... ... ... ... .... -.. .. .. .. .. 1111 .. ... Chinquapin Coast Homes Carlsbad, California Job No. 21-13506 Page 25 A . 1. 2. Preparation of Soils for Site Development General: Grading should conform to the guidelines presented in the 2019 California Building Code (CBC, 2019), as well as the requirements of the City of Carlsbad . During earthwork construction, removals and reprocessing of fill materials, as well as general grading procedures of the contractor, should be observed, and the fill placed selectively tested, by representatives of the geotechnical engineer, Geotechnical Exploration Inc. If any unusual or unexpected conditions are exposed in the field, they should be reviewed by the geotechnical engineer and if warranted, modified and/or additional remedial recommendations will be offered. Specific guidelines and comments pertinent to the planned development are provided herein. The recommendations presented herein have been completed using the information provided to us regarding site development. If information concerning the proposed development is revised, or any changes are made in the design and location of the proposed property, they must be modified or approved in writing by this office. Clearing and Stripping: Complete demolition of the existing residential structures and associated improvements should be undertaken. This is to include the complete removal of all subsurface footings, utility lines and miscellaneous debris. After clearing the entire ground surface, the site should be stripped of existing vegetation within the areas of proposed new construction. This includes any roots from existing trees and shrubbery. Holes resulting from the removal of root systems or other buried obstructions that extend below the planned grades should be cleared and backfilled with suitable 111 .. -.. -.. .... ... ... .. .. .. ... --... .. .. -.. ... ... .. ... ... -.. .. ,. ... Chinquapin Coast Homes Carlsbad, California Job No. 21-13506 Page 26 3 . 5. compacted material compacted to the requirements provided under Recommendation Nos. 4, 5 and 6 below. Prior to any filling operations, the cleared and stripped vegetation and debris should be disposed of off-site . Excavation: After the entire site has been cleared and stripped, the existing surficial topsoils/fill soils and the upper 2 feet of weathered terrace deposits should be removed and recompacted. It is anticipated that the depth of removals will be approximately 3 feet below existing grade and should include removal of existing foundations, utility lines, etc. Based on the results of our exploratory excavations, as well as our experience with similar materials in the project area, it is our opinion that the existing surficial soils and formational materials can be excavated utilizing ordinary light to heavy weight earthmoving equipment. Contractors should not, however, be relieved of making their own independent evaluation of excavating the on-site materials prior to submitting their bids. Contractors should also review this report along with the excavation logs to understand the scope and quantity of grading required for this project . The areal extent required to remove the surficial soils should be confirmed by our representatives during the excavation work based on their examination of the soils being exposed. The lateral extent of the excavation and recompaction should be at least 5 feet beyond the edge of the perimeter ground level foundations of the new residential structures and any areas to receive exterior improvements, where feasible, or to the depth of excavation or planned fill at that location, whichever is greater . Temporary Slopes: Temporary slopes required for removal and recompaction grading operations may be cut at 1.0: 1.0 (horizontal to vertical) to heights of fa -.. -- ... - t/11111 ... ... .. "' -... p ... ... ... .. ,,,. ' .... .. ... .. .. .. -,.. 11111 Chinquapin Coast Homes Carlsbad, California Job No. 21-13506 Page 27 6. 7. 5 feet. If moderately cemented materials are encountered at depth, the lower 2 feet of the temporary slope may be cut vertical. Subgrade Preparation: After the site has been cleared, stripped, and the required excavations made, the exposed subgrade soils in areas to receive new fill and/or slab-on-grade building improvements should be scarified to a depth of 6 inches, moisture conditioned, and compacted to the requirements for structural fill. While not anticipated, in the event that planned cuts expose any medium to highly expansive formational materials in the building areas, they should be scarified and moisture conditioned to at least 3 percent over optimum moisture for medium expansive soils and 5 percent for highly expansive soils (if encountered). Material for Fill: Existing on-site low-expansion potential (Expansion Index of 50 or less per ASTM D4829-19) soils with an organic content of less than 3 percent by volume are, in general, suitable for use as fill. Imported fill material, where required, should have a low-expansion potential. In addition, both imported and existing on-site materials for use as fill should not contain rocks or lumps more than 6 inches in greatest dimension if the fill soils are compacted with heavy compaction equipment (or 3 inches in greatest dimension if compacted with lightweight equipment). All materials for use as fill should be approved by our representative prior to importing to the site. If encountered at the site, medium to highly expansive soils should not be used as structural fill at a depth of less than 5 feet from footing bearing surface elevation or behind retaining walls. Backfill material to be placed behind retaining walls should be low expansive (E.I. less than 50), with rocks no larger than 3 inches in diameter . ta ,.. ... ... - ... -.. -.. .. .. -,.. ,. ... .. -.. ... .. ... ,. ,. .. Chinquapin Coast Homes Carlsbad, California Job No. 21-13506 Page 28 8. Structural Fill Compaction: All structural fill, and areas to receive any associated improvements, should be compacted to a minimum degree of compaction of 90 percent based upon ASTM D1557-12el. Fill material should be spread and compacted in uniform horizontal lifts not exceeding 8 inches in uncompacted thickness. Before compaction begins, the fill should be brought to a water content that will permit proper compaction by either: (1) aerating and drying the fill if it is too wet, or (2) watering the fill if it is too dry. Each lift should be thoroughly mixed before compaction to ensure a uniform distribution of moisture. For low expansive soils, the moisture content should be within 2 percent of optimum. Though we do not anticipate any medium to high expansive soils to be exposed during grading operations, if encountered, the compaction moisture content should be at least 3 percent over optimum for medium expansive soils and 5 percent over optimum for highly expansive soils . Any rigid improvements founded on the existing surficial soils can be expected to undergo movement and possible damage. Geotechnical Exploration, Inc. takes no responsibility for the performance of any improvements built on loose natural soils or inadequately compacted fills. Subgrade soils in any exterior area receiving concrete improvements should be verified for compaction and moisture by a representative of our firm within 48 hours prior to concrete placement. No uncontrolled fill soils should remain after completion of the site work. In the event that temporary ramps or pads are constructed of uncontrolled fill soils, the loose fill soils should be removed and/or recompacted prior to completion of the grading operation . ta .. ... - ... .. - -.. .. .. ... ,.. -.. - .. .. ... .. .. ... Chinquapin Coast Homes Carlsbad, California Job No. 21-13506 Page 29 9. Based on the results of laboratory testing (see Section V above), the water- soluble sulfate content of the tested soils at the site yielded a negligible sulfate exposure. As such, based on table 1904.3 of the building code, there are no restrictions for cement type if on-site soils are used. If imported soils are medium to highly expansive they should be tested for soluble sulfate content and the pertinent recommendations should apply. It is recommended that after grading is completed, and if imported soils are used, a sample be obtained of the surficial soils to be in contact with the proposed concrete foundations to test for water-soluble sulfate content, and determine cement type recommended by the current edition of the California Building Code (2019). If soluble sulfate testing does not take place, and imported soils are used, it is recommended that the concrete for the footings and slabs on-grade be Type V. The structural plans should indicate that soil soluble sulfate tests be performed at rough grading completion if Type II cement is to be specified for the concrete . Trench and Retaining Wall Backfill: All utility trenches and retaining walls should be backfilled with properly compacted fill. Backfill material should be placed in lift thicknesses appropriate to the type of compaction equipment utilized and compacted to a minimum degree of compaction of 90 percent based upon ASTM D1557-12el by mechanical means. Any portion of the trench backfill in public street areas within pavement sections should conform to the material and compaction requirements of the adjacent pavement section. Backfill soils placed behind retaining walls should be installed as early as the retaining walls are capable of supporting lateral loads. Backfill soils behind .. .. ... - ... ... .. .. -- ... .. .. ... .... ,.. ... ... - ... 1111 Chinquapin Coast Homes Carlsbad, California Job No. 21-13506 Page 30 retaining walls should be low expansive (Expansion Index less than SO per ASTM D4829-19). Our experience has shown that even shallow, narrow trenches (such as for irrigation and electrical lines) that are not properly compacted can result in problems, particularly with respect to shallow groundwater accumulation and migration . 10. Observations and Testing: As stated in CBC 2019, Section 1705.6 Soils: "Special inspections and tests of existing site soil conditions, fi/1 placement and load-bearing requirements shall be performed in accordance with this section and Table 1705.6 (see below). The approved geotechnical report and the construction documents prepared by the registered design professionals shall be used to determine compliance. During fi/1 placement, the special inspector shall verify that proper materials and procedures are used in accordance with the provisions of the approved geotechnical report" . A summary of Table 1705.6 "REQUIRED SPECIAL INSPECTIONS AND TESTS OF SOILS" is presented below: a) Verify materials below shallow foundations are adequate to achieve the design bearing capacity; b) Verify excavations are extended to proper depth and have reached proper material; c) Perform classification and testing of compacted fill materials; d) Verify use of proper materials, densities and thicknesses during placement and compaction of compacted fill prior to placement of compacted fill, inspect subgrade and verify that site has been prepared properly -.. ... ... ... ... - .. ... .... .. ... - ,. .... ... ... - ... - ... ... 11111 .. Chinquapin Coast Homes Carlsbad, California Job No. 21-13506 Page 31 Section 1705.6 "Soils" statement and Table 1705.6 indicate that it is mandatory that a representative of this firm (responsible engineering firm), perform observations and fill compaction testing during excavation operations to verify that the remedial operations are consistent with the recommendations presented in this report. All grading excavations resulting from the removal of soils should be observed and evaluated by a representative of our firm before they are backfilled. Quality control grading observation and field density testing for the purpose of documenting that adequate compaction has been achieved and acceptable soils have been utilized to properly support a project applies not only to fill soils supporting primary structures; unless supported by deep foundations or caissons, but all site improvements such as stairways, patios, pools and pool decking, sidewalks, driveways and retaining walls etc. Observation and testing of utility line trench backfill also reduces the potential for localized settlement of all of the above including all improvements outside of the footprint of primary structures. Often after primary building pad grading, it is not uncommon for the geotechnical engineer of record to not be notified of grading performed outside the footprint of the project primary structures. As a result, settlement damage of site improvements such as patios, pool and pool decks, exterior landscape walls and walks, and structure access stairways can occur. It is therefore strongly recommended that the project general contractor, grading contractor, and others tasked with completing a project with workmanship that reduces the potential for damage to the project from soil settlement, or expansive soil uplift, to be advised and acknowledge the importance of adequate and comprehensive observation and testing of soils intended to support the project 81 -.. .. ... ... -.. .. ... -.. ... JIii ... ... ,.. ... ,,. .... .. -.. -... -• .. ... ... -... Chinquapin Coast Homes Carlsbad, California Job No. 21-13506 Page 32 they are working on. The project geotechnical engineers of record must be contacted and requested to provide these services. Failure to comply with this recommendation can result in several costly and time-consuming requirements from the governing municipality or county engineering and planning departments. For example, the geotechnical and/or civil engineer of record may be required to: • • • • • Clarify if observation and testing services were performed for all grading shown on the Grading Plans. If not, indicate the areas NOT observed or tested on the As-Graded Geological Map . A construction change must be processed to indicate the revised grading recommendations by the geotechnical engineer of work on the plans. The geotechnical engineer must submit on addendum letter addressing the change to the grading plan specifications for the earthwork presented on the grading plans. The geotechnical consultant must evaluate the existing unobserved/undocumented fill as an uncontrolled embankment and provide a statement indicating the uncontrolled embankment will not endanger the public health, safety and welfare. In order to make this statement the geotechnical engineer would have to clearly define the potential problems such as damage to project improvements that could result from construction on undocumented fill soils. The geotechnical consultant must indicate if the unobserved fill placed during earthwork within the limits of work is suitable for the intended 11A ... .. ... ... ... 1111111 ... .. ... .. .. - ,,.. ... -... ,,.. ... ... ... ... - ,.. .. ... ,,,. Chinquapin Coast Homes Carlsbad, California Job No. 21-13506 Page 33 • • • • • • use. To render such an opinion the geotechnical consultant would have to place a sufficient number of test excavations and conduct enough testing to warrant such an opinion. If the geotechnical consultant cannot render an opinion that the unobserved fill is suitable for the purpose intended, "They must indicate if additional fill remedial grading is recommended." The limits of the "Unobserved fill/uncontrolled embankment must be shown on revised grading plans along with the "Uncontrolled Embankment Maintenance Agreement Approval Number." The owner must execute an "Uncontrolled Embankment Agreement: for the portion of the undocumented fill to remain. This must be coordinated with the LOR Drainage and Grading reviewer. The title and date of the requested addendum letter or geotechnical investigation report must be added under note no. 1 of the "Grading and Geotechnical Specification" Certification as construction change "A". These changes must be made on a redline copy, and submitted as a "Construction Change A" for review and approval by the geology section and Drainage and Grades Section . All approved changes will then be transferred to the mylars for approval and signatures by the Deputy City Engineer. The Geotechnical Engineer of Record, in this case Geotechnical Exploration, Inc., cannot be held responsible for the costs and time delays associated with ta - ... .. ... ... 111111 ... ... -... .... -... ,.. -.... ,.. -... --... -... ... - Chinquapin Coast Homes Carlsbad, California Job No. 21-13506 Page 34 B. the lack of contact and requests for testing services by the client, general contractor, grading contractor or any of the project design team responsible for requesting the required geotechnical services. Requests for services are to be made through our office telephone number (858) 549-7222 and the telephone number of the G.E.I. personnel assigned to the project . Seismic Design Criteria 11. Seismic Data Bases: The estimation of the peak ground acceleration and the repeatable high ground acceleration (RHGA) likely to occur at the site is based on the known significant local and regional faults within 100 miles of the site . 12. Seismic Design Criteria: The proposed structure should be designed in accordance with the 2019 CBC, which incorporates by reference the ASCE 7- 16 for seismic design. We have determined the mapped spectral acceleration values for the site based on a latitude of 33.1480 degrees and a longitude of - 117.3416 degrees, utilizing a program titled "Seismic Design Map Tool" and provided by the USGS through SEAOC, which provides a solution for ASCE 7- 16 utilizing digitized files for the Spectral Acceleration maps. See Appendix D. 13. Structure and Foundation Design: The design of the new structures and foundations should be based on Seismic Design Category D, Risk Category II for stiff soils, Class D. 14. Spectral Acceleration and Design Values: The structural seismic design, when applicable, should be based on the following values, which are based on the site location, soil characteristics, and seismic maps by USGS, as required by the 2019 CBC. The summarized seismic soil parameters are presented in Table ... ,. ... ... ... ... ... ... --... ... -... ,,. ... -... --... ... ,. .. ... ... .... ,.,. ... Chinquapin Coast Homes Carlsbad, California Job No. 21-13506 Page 35 C. I below, have been calculated with the SEAOC Seismic Design Map Tool. The complete values are included in Appendix D. The values for this property are: TABLE I Mapped Spectral Acceleration Values and Design Parameters Ss 51 5Ms SM1 Sos 501 Fa Fv PGA PGAM SDC 1.092 0.394 1.161 0.751 0.774 0.501 1.063 1.906 0.483 0.539 D Foundation Recommendations 15. Footings: Footing configuration and reinforcement should be designed by the Project Structural Engineer.· The following are provided as design minimums. We recommend that the proposed structures be supported on conventional, individual-spread and/or continuous footing foundations bearing on undisturbed medium dense to dense formational materials or on properly compacted fill soils over formational soils. No footings should be underlain by undocumented fill soils. All building footings should be built on formational soils or properly compacted fill prepared as recommended in this report. The footings should be founded at least 24 inches below the lowest adjacent finished grade when founded into properly compacted fill or medium dense to dense formational soils . Footings located adjacent to utility trenches should have their bearing surfaces situated below an imaginary 1.0: 1.0 plane projected upward from the bottom edge of the adjacent utility trench. Otherwise, the utility trenches should be excavated farther from the footing locations. ;Ji ,,.. ... ... ... --,,. ... -.. ,,.. ... ,.. ,,. .... ... ... -... ... -..., .. -... ,,. .. Chinquapin Coast Homes Carlsbad, California Job No. 21-13506 Page 36 Footings located adjacent to the tops of slopes should be extended sufficiently deep so as to provide at least 8 feet of horizontal cover between the slope face and outside edge of the footing at the footing bearing level. 16. Bearing Values: At the recommended depths, footings on formational or properly compacted fill soils may be designed for allowable bearing pressures of 2,500 psf for combined dead and live loads and 3,325 psf for all loads, including wind or seismic. The footings should, however, have a minimum width of 15 inches. An increase in soil allowable static bearing can be used as follows: 800 psf for each additional foot over 1.5 feet in depth and 400 psf for each additional foot in width to a total not exceeding 4,000 psf. The static soil bearing value may be increased one-third for seismic and wind load analysis. As previously indicated, all of the foundations for the structure should be built on medium dense to dense formational soils or properly compacted fill soils . 17. Footing Reinforcement: All footings should be reinforced as specified by the structural engineer. However, based on our field investigation findings and laboratory testing, we provide the following minimum recommendations. All continuous footings should contain top and bottom reinforcement to provide structural continuity and to permit spanning of local irregularities. We recommend that a minimum of two No. 5 top and two No. 5 bottom reinforcing bars be provided in the footings. All footings should be reinforced as specified by the structural engineer. A minimum clearance of 3 inches should be maintained between steel reinforcement and the bottom or sides of the footing . Isolated square footings should contain, as a minimum, a grid of three No. 4 steel bars on 12-inch centers, both ways. In order for us to offer an opinion as to whether the footings are founded on soils of sufficient load bearing capacity, it is essential that our representative inspect the footing excavations prior to the placement of reinforcing steel or forms . at .... .... 1111111 ... .. ... .. .. -... ---.. ,,.. ... ... - ,,. --... ... .... ... ... .. .. ,.. ,. .. Chinquapin Coast Homes Carlsbad, California Job No. 21-13506 Page 37 18. NOTE: The project Civil/Structural Engineer should review all reinforcing schedules. The reinforcing minimums recommended herein are not to be construed as structural designs, but merely as minimum reinforcement to reduce the potential for cracking and separations . Lateral Loads: Lateral load resistance for the structure supported on footing foundations may be developed in friction between the foundation bottoms and the supporting subgrade. An allowable friction coefficient of 0.40 is considered applicable. An additional allowable passive resistance equal to an equivalent fluid weight of 275 pounds per cubic foot (pcf) acting against the foundations may be used in design provided the footings are poured neat against the medium dense to dense formational or properly compacted fill materials. These lateral resistance value assume a level surface in front of the footing for a minimum distance of three times the embedment depth of the footing and any shear keys, but not less than 8 feet from a slope face, measured from effective top of foundation. Retaining walls supporting surcharge loads or affected by upper foundations should consider the effect of those upper loads. 19. Settlement: Settlements under structural design loads are expected to be within tolerable limits for the proposed structures. For footings designed in accordance with the recommendations presented in the preceding paragraphs, we anticipate that the total and differential static settlement for the proposed improvements should be on the order of approximately 1-inch and post- construction differential settlement angular rotation should be less than 1/240 . D. Retaining Wall Design 20. Retaining Wall Design: Any required retaining walls must be designed to resist lateral earth pressures and any additional lateral pressures caused by ill .. ... ,,,,. -,,,. ... ... ... ... ---.. - ... -.. .. -,,. ... -... - -,.. ... ... - ,. ... Chinquapin Coast Homes Carlsbad, California Job No. 21-13506 Page 38 surcharge loads on the adjoining retained surface. We recommend that unrestrained (cantilever) walls with level backfill be designed for an equivalent fluid pressure of 38 pcf. We recommend that restrained walls (i.e., walls with angle points or that are curvilinear that restrain them from rotation) with level backfill be designed for an equivalent fluid pressure of 38 pcf plus an additional uniform lateral pressure of SH pounds per square foot, where H is equal to the height of backfill above the top of the wall footing in feet. 21. For seismic design of unrestrained walls if required, we recommend that the seismic pressure increment be taken as a fluid pressure distribution utilizing an equivalent fluid weight of 14 pcf . 22. The preceding design pressures assume that the walls are backfilled with low expansion potential materials (Expansion Index less than 50) and that there is sufficient drainage behind the walls to prevent the build-up of hydrostatic pressures from surface water infiltration. We recommend that drainage be provided by a composite drainage material such as J-Drain 200/220 and J- Drain SWD, or equivalent. No perforated pipes or gravel are utilized with the J-Drain system. The drain material should terminate 12 inches below the finish surface where the surface is covered by slabs or 18 inches below the finish surface in landscape areas. 23. Backfill placed behind the walls should be compacted to a minimum degree of compaction of 90 percent using light compaction equipment. If heavy equipment is used, the walls should be appropriately temporarily braced. The structural plans should indicate when the retaining wall backfill may be placed. fa .. ,,,. ... ... .. .. ... ,.. ... -... ... .... .... ... ,,,. ... ,.. ... .... ... .. -.... .. ... .. .. .... ... Chinquapin Coast Homes Carlsbad, California Job No. 21-13506 Page 39 E . Concrete Slab On-Grade Criteria Slabs on-grade may only be used on new, properly compacted fill or when bearing on dense formational soils . 24. Minimum Floor Slab Thickness and Reinforcement: Based on our experience, we have found that, for various reasons, floor slabs occasionally crack . Therefore, we recommend that all slabs on-grade contain at least a minimum amount of reinforcing steel to reduce the separation of cracks, should they occur. Slab subgrade soil should be verified by a Geotechnical Exploration, Inc. representative to have the proper moisture content within 48 hours prior to placement of the vapor barrier and pouring of concrete . All slabs should be reinforced as specified by the structural engineer. However, based on our field investigation findings and laboratory testing, we provide the following minimum recommendations. New interior floor slabs should be a minimum of 4-inches actual thickness and be reinforced with No. 4 bars on 18-,5!!!!!!!!-- inch centers, both ways, placed at mid-height in the slab. Soil moisture content should be kept above the optimum prior to waterproofing placement under the new concrete slab . Shrinkage control joints should be specified by the project structural engineer. In addition, we note that shrinkage cracking can result in reflective cracking in brittle flooring surfaces such as stone and tiles. It is imperative that if movement intolerant flooring materials are to be utilized, the flooring contractor and/or architect should provide specifications for the use of high- quality isolation membrane products installed between slab and floor materials . a& -... ,,. ... ,,,,. .. ,,. .. - -- ,,,. .. .... ... ,,.. ,,,. .... ,,. ... .. ... ... ... .. ii.- .. .. .. ,. ... Chinquapin Coast Homes Carlsbad, California Job No. 21-13506 Page 40 25. Slab Moisture Emission: Although it is not the responsibility of geotechnical engineering firms to provide moisture protection recommendations, as a service to our clients we provide the following discussion and suggested minimum protection criteria. Actual recommendations should be provided by the project architect and waterproofing consultants or product manufacturer. It is recommended to contact the vapor barrier manufacturer to schedule a pre-construction meeting and to coordinate a review, in-person or digital, of the vapor barrier installation. Soil moisture vapor can result in damage to moisture-sensitive floors, some floor sealers, or sensitive equipment in direct contact with the floor, in addition to mold and staining on slabs, walls and carpets. The common practice in Southern California is to place vapor retarders made of PVC, or of polyethylene . PVC retarders are made in thickness ranging from 10-to 60-mil. Polyethylene retarders, called visqueen, range from 5-to 10-mil in thickness. These products are ~ longer considered adequate for moisture protection and can actually deteriorate over time . Specialty vapor retarding and barrier products possess higher tensile strength and are more specifically designed for and intended to retard moisture transmission into and through concrete slabs. The use of such products is highly recommended for reduction of floor slab moisture emission . The following American Society for Testing and Materials (ASTM) and American Concrete Institute (ACI) sections address the issue of moisture transmission into and through concrete slabs: ASTM E1745-17 Standard Specification for Plastic Water Vapor Retarders Used in Contact Concrete Slabs; ASTM E1643- 18a Standard Practice for Selection, Design, Installation, and Inspection of Water Vapor Retarders Used in Contact with Earth or Granular Fill Under ta -... ,,. -,,. ,,. ... ... ----,,. ... ... ... ... ... ... .. ... ... -... ,,. ... Chinquapin Coast Homes Carlsbad, California Job No. 21-13506 Page 41 Concrete Slabs; ACI 302.2R-06 Guide for Concrete Slabs that Receive Moisture-Sensitive Flooring Materials; and ACI 302.lR-15 Guide to Concrete Floor and Slab Construction . 25.1 Based on the above, we recommend that the vapor barrier consist of a minimum 15-mil extruded polyolefin plastic (no recycled content or woven materials permitted). Permeance as tested before and after mandatory conditioning (ASTM E1745 Section 7.1 and subparagraphs 7.1.1-7.1.5) should be less than 0.01 perms (grains/square foot/hour/per inch of Mercury) and comply with the ASTM E1745-17 Class A requirements. Installation of vapor barriers should be in accordance with ASTM E1643-18a. The basis of design is 15-mil Stego Wrap vapor barrier placed per the manufacturer's guidelines. Reef Industries Vapor Guard membrane has also been shown to achieve a permeance of less than 0.01 perms. We recommend that the slab be poured directly on the vapor barrier, which is placed directly on the prepared properly compacted smooth subgrade soil surface . 25.2 Common to all acceptable products, vapor retarder/barrier joints must be lapped at least 6 inches. Seam joints and permanent utility penetrations should be sealed with the manufacturer's recommended tape or mastic. Edges of the vapor retarder should be extended to terminate at a location in accordance with ASTM E1643-18a or to an alternate location that is acceptable to the project's structural engineer. All terminated edges of the vapor retarder should be sealed to the building foundation (grade beam, wall, or slab) using the manufacturer's recommended accessory for sealing the vapor retarder to pre-existing or freshly placed concrete. Additionally, in actual practice, stakes are often driven through the retarder material, equipment is dragged or =- --,.. ... ,.. .. ... ... ... ... ... --,,. ... ... ... ,,. .. .... JIii' ... .... ... ... -... ... ... 1111111 ... ... ... ,,. Chinquapin Coast Homes Carlsbad, California Job No. 21-13506 Page 42 rolled across the retarder, overlapping or jointing is not properly implemented, etc. All these construction deficiencies reduce the retarder's effectiveness. In no case should retarder/barrier products be punctured or gaps be allowed to form prior to or during concrete placement. Vapor barrier-safe screeding and forming systems should be used that will not leave puncture holes in the vapor barrier, such as Beast Foot (by Stego Industries) or equivalent . 25.3 Vapor retarders/barriers do not provide full waterproofing for structures constructed below free water surfaces. They are intended to help reduce or prevent vapor transmission and/or capillary migration through the soil and through the concrete slabs. Waterproofing systems must be designed and properly constructed if full waterproofing is desired. The owner and project designers should be consulted to determine the specific level of protection required . 25.4 Following placement of any concrete floor slabs, sufficient drying time must be allowed prior to placement of floor coverings. Premature placement of floor coverings may result in degradation of adhesive materials and loosening of the finish floor materials . 26. Exterior Slab Thickness and Reinforcement: As a minimum for protection of on-site improvements, we recommend that all exterior pedestrian concrete slabs be 4 inches thick and be founded on properly compacted and tested fill, with No. 3 bars at 15-inch centers, both ways, at the center of the slab, and contain adequate isolation and control joints. The performance of on-site improvements can be greatly affected by soil base preparation and the quality of construction. It is therefore important that all improvements are properly designed and constructed for the existing soil conditions. The improvements .. ... ,,. .... ... .... ... ... .. ... ... - ... ... ... .. ... ... ... .. .... ... ... ... - .... .. ... -.. Chinquapin Coast Homes Carlsbad, California Job No. 21-13506 Page 43 F. should not be built on loose soils or fills placed without our observation and testing . For exterior slabs with the minimum shrinkage reinforcement, control joints should be placed at spaces no farther than 15 feet apart or the width of the slab, whichever is less, and also at re-entrant corners. Control joints in exterior slabs should be sealed with elastomeric joint sealant. The sealant should be inspected every 6 months and be properly maintained . Pavements 27. Concrete Pavement: We recommend that driveways subject only to automobile and light truck traffic be 5.5 inches thick and be supported directly on properly prepared/compacted on-site subgrade soils. The upper 6 inches of the subgrade below the slab should be compacted to a minimum degree of compaction of 95 percent just prior to paving. The concrete should conform to Section 201 of The Standard Specifications for Public Works Construction, 2018 Edition, for Class 560-C-3250 . In order to control shrinkage cracking, we recommend that saw-cut, weakened-plane joints be provided at about 12-foot centers both ways and at reentrant corners. The pavement slabs should be saw-cut as soon as practical but no more than 24 hours after the placement of the concrete. The depth of the joint should be one-quarter of the slab thickness and its width should not exceed 0.02-foot. Reinforcing steel is not necessary unless it is desired to increase the joint spacing recommended above. Pavement joints should be sealed with an approved pavement joint sealer. 1!31 .. ... ,. ,,. ... ... ... .... ... ... -... ,,,. ... ,,. .. ... ... .. ,.. ... -.... ... Chinquapin Coast Homes Carlsbad, California Job No. 21-13506 Page 44 28. Interlocking Permeable Pavers: If desired, we recommend that permeable pavement pavers for the driveway, subject only to automobile and light truck traffic, be supported on a 1.5 inches of bedding sand No. 8 Sand, on 6-inch thickness of Crushed Miscellaneous Base conforming to Section 200-2 of the Standard Specifications for Public Works Construction, 2018 Edition; or 6 inches of No.57 crushed rock gravel per ASTM D448 gradation. The upper 6 inches of the pavement subgrade soil as well as the aggregate base layer should be compacted to a minimum degree of compaction of 95 percent. Preparation of the subgrade and placement of the base materials should be performed under the observation of our representative. G. Site Drainage Considerations 29. Erosion Control: Appropriate erosion control measures should be taken at all times during and after construction to prevent surface runoff waters from entering footing excavations or ponding on finished building pad areas . 30. Surface Drainage: Adequate measures should be taken to properly finish- grade the lot after the residential structures and other improvements are in place. Drainage waters from this site and adjacent properties should be . .__ __ _....,,... ~ .. , ............ ,--, . ._,.,,. ,,. ,_ --....... ~.-·--~·--. ' . directed away from the footings, floor slabs, and slopes, onto the natural , • ·-... ~.,.~-•-•>-••• ~ ,-,,, __ ,. -• -~,,- drainage direction for this area or into properly designed and approved ---• ... ~ ,,, "'"'"'• ... -'l<t-.. ~--,.,--__ ,. _____ ,.,, . .,."0 • .,.,...,,.,.., ....... ~~--~·-···-~·-· " ,_,. - drainage facilitie~ovided by the project civil engineer. Roof gutters and ........__ .,...... __ ,.,...,....,,,,._,~,._,O',_H,~•••~•M"-"'..--.... "-""'~•-•"""•·'~""·•~•·,··.,._.. '"'•••~••~.,,,·,,••• • downspouts should be installed on the residences, with the runoff directed away from the foundations via closed drainage lines. Proper subsurface and -~--~ "•• .. •""' 0 ~ •L, • surface drainage will help minimize the potential for waters to seek the level .,, ........ ,.,-~ ........ ,.---. .. ..,., •• _,., _____ '<•> .. '··~••< ·••·• < ,,.... •. • •· •• ,,,,.,,_, .. , ...... ~,,...--._., _____ ....,.,., ... ,~..., •• ,, .. ,.,,,,_,,~• of the bearing soils under the footings and floor slabs. ,, . •, •. , ,, .•. ,.~-,. ,,.J_.,;,r.~, , .... ,, ........ ~,...,;:, ....... .-,;.,. ,,,.,.,... •• _.,..,.i,--,--~ iii ... ... ,,. ... ,.. ... ... ... ,,. ... -... ,.. -... ,.. ... ... ... ... ,,. ... ,,. ... - -- .... ... .... ,,. ... Chinquapin Coast Homes Carlsbad, California Job No. 21-13506 Page 45 Failure to observe this recommendation could result in undermining and possible differential settlement of the structure or other improvements on the site or cause other moisture-related problems. Currently, the CBC requires a minimum 1-percent surface gradient for proper drainage of building pads unless waived by the building official. Concrete pavement may have a minimum gradient of 0.5-percent. 31. Planter Drainage: Planter areas, flower beds and planter boxes should be sloped to drain away from the footings and floor slabs at a gradient of at least 5 percent within 5 feet from the perimeter walls. Any planter areas adjacent to the residence or surrounded by concrete improvements should be provided with sufficient area drains to help with rapid runoff disposal. No water should be allowed to pond adjacent to the residence or other improvements or anywhere on the site. 32. Drainage Quality Control: It must be understood that it is not within the scope of our services to provide quality control oversight for surface or subsurface drainage construction or retaining wall sealing and base of wall drain construction. It is the responsibility of the contractor to verify proper wall sealing, geofabric installation, protection board (if needed), drain depth below interior floor or yard surface, pipe percent slope to the outlet, etc . H. General Recommendations 33. Pro;ect Start Up Notification: In order to reduce work delays during site development, this firm should be contacted 48 hours prior to any need for observation of footing excavations or field density testing of compacted fill soils. If possible, placement of formwork and steel reinforcement in footing excavations should not occur prior to observing the excavations; in the event YI ... ... ,,. ... ... ... ... ... ... ... ... -... .. - .. .. -... ... .. -... ... ... ---.. .. .... ... .... Chinquapin Coast Homes Carlsbad, California Job No. 21-13506 Page 46 that our observations reveal the need for deepening or re-designing foundation structures at any locations, any formwork or steel reinforcement in the affected footing excavation areas would have to be removed prior to correction of the observed problem (i.e., deepening the footing excavation, recompacting soil in the bottom of the excavation, etc.) . 34. Cal-OSHA: Where not superseded by specific recommendations presented in this report, trenches, excavations, and temporary slopes at the subject site should be constructed in accordance with Title 8, Construction Safety Orders, issued by Cal-OSHA . 35. Erosion Control: Appropriate erosion control measures should be taken at all times during and after construction to prevent surface runoff waters from entering footing excavations or ponding on finished building pad areas . 36. Construction Best Management Practices (BMPs): Construction BMPs must be implemented in accordance with the requirements of the controlling jurisdiction. Sufficient BMPs must be installed to prevent silt, mud or other construction debris from being tracked into the adjacent street(s) or storm water conveyance systems due to construction vehicles or any other construction activity. The contractor is responsible for cleaning any such debris that may be in the street at the end of each work day or after a storm event that causes breach in the installed construction BMPs . All stockpiles of uncompacted soil and/or building materials that are intended to be left unprotected for a period greater than 7 days are to be provided with erosion and sediment controls. Such soil must be protected each day when the probability of rain is 40% or greater. A concrete washout should be provided on all projects that propose the construction of any concrete -... ... - ... .... ... ... ... -.. ... --... -... ... ... -.... ... --... ... ---.. ... .. ... Chinquapin Coast Homes Carlsbad, California Job No. 21-13506 Page 47 improvements that are to be poured in place. All erosion/sediment control devices should be maintained in working order at all times. All slopes that are created or disturbed by construction activity must be protected against erosion and sediment transport at all times. The storage of all construction materials and equipment must be protected against any potential release of pollutants into the environment . XI. GRADING NOTES Geotechnical Exploration, Inc. recommends that we be retained to verify the actual soil conditions revealed during site grading work and footing excavation to be as anticipated in this "Report of Preliminary Geotechnical Investigation" for the project. In addition, the placement and compaction of any fill or backfill soils during site grading work must be observed and tested by the soil engineer. It is the responsibility of the grading contractor and general contractor to comply with the requirements on the grading plans as well as the local grading ordinance. All retaining wall and trench backfill should be properly compacted. Geotechnical Exploration, Inc. will assume no liability for damage occurring due to improperly or uncompacted backfill placed without our observations and testing . XII. LIMITATIONS Our conclusions and recommendations have been based on available data obtained from our field investigation and laboratory analysis, as well as our experience with similar soils and formational materials located in this area of Carlsbad. Of necessity, we must assume a certain degree of continuity between exploratory excavations and/or natural exposures. It is, therefore, necessary that all observations, conclusions, and recommendations be verified at the time grading operations begin ta -... ... ... ... .. ... ... .. -... ... ... -... .. -... ... ... .. ... ... ... - ... 111,o ... ... Chinquapin Coast Homes Carlsbad, California Job No. 21-13506 Page 48 or when footing excavations are placed. In the event discrepancies are noted, additional recommendations may be issued, if required . The work performed and recommendations presented herein are the result of an investigation and analysis that meet the contemporary standard of care in our profession within the County of San Diego. No warranty is provided . As stated previously, it is not within the scope of our services to provide quality control oversight for surface or subsurface drainage construction or retaining wall sealing and base of wall drain construction. It is the responsibility of the contractor to verify proper wall sealing, geofabric installation, protection board installation (if needed), drain depth below interior floor or yard surfaces; pipe percent slope to the outlet, etc . This report should be considered valid for a period of two (2) years, and is subject to review by our firm following that time. If significant modifications are made to the building plans, especially with respect to the height and location of any proposed structures, this report must be presented to us for immediate review and possible revision. It is the responsibility of the owner and/or developer to ensure that the recommendations summarized in this report are carried out in the field operations and that our recommendations for design of this project are incorporated in the project plans. We should be retained to review the project plans once they are available, to verify that our recommendations are adequately incorporated in the plans. Additional or modified recommendations may be issued if warranted after plan review . -... ... ... ... ... ... ... ... .. ... -... ... ... -... ... Chinquapin Coast Homes Carlsbad, California Job No. 21-13506 Page 49 This firm does not practice or consult in the field of safety engineering. We do not direct the contractor's operations, and we cannot be responsible for the safety of personnel other than our own on the site; the safety of others is the responsibility of the contractor. The contractor should notify the owner if any of the recommended actions presented herein are considered to be unsafe . The firm of Geotechnical Exploration, Inc. shall not be held responsible for changes to the physical condition of the property, such as addition of fill soils or changing drainage patterns, which occur subsequent to issuance of this report and the changes are made without our observations, testing, and approval. Once again, should any questions arise concerning this report, please feel free to contact the undersigned. Reference to our lob No. 21-13506 will expedite a reply to your inquiries . .., Respectfully submitted, -.. ---.. ... ... --... ... ... ... . erros, .. R.C.E. 34422/G.E. 2007 ceotechnical En,_g-in_e_e_r ____ ___ Cathy K. an , Project Coordinator Senior Project Geologist Leslie D. Reed, President C.E.G. 999/P.G. 3391 Ii ... .... ... ... ... .. ... .... .... ... ... ... ... ... -... ... -... ... ... ... ... .. ... ... ... --... .. ... ... - REFERENCES JOB NO. 21-13506 October 2021 2007 Working Group on California Earthquake Probabilities, 2008, The Uniform California Earthquake Rupture Forecast, Version 2 (UCERF 2), U.S Geological Survey Open-file Report 2007-1437 and California Geological Survey Special Report 203 . Association of Engineering Geologists, 1973, Geology and Earthquake Hazards, Planners Guide to the Seismic Safety Element, Association of Engineering Geologists, Southern California Section . Berger, V. and Schug, D.L., 1991, Probabilistic Evaluation of Seismic Hazard in the San Diego-Tijuana Metropolitan Region, Environmental Perils, San Diego Region, Geological Society of America by the San Diego Association of Geologists, October 20, 1991, p. 89-99 . Crowell, J.C., 1962, Displacement Along the San Andreas, Fault, California, Geological Society of America, Special Papers, no. 71. Demere, T.A. 1997, Geology of San Diego County, California, San Diego Natural History Museum, http://archive.sdnhm.org/research/paleontology/sdgeol.html, accessed July 30, 2020 . Earthquake Engineering Research Institute (EERI), 2020, San Diego Planning Scenario, Magnitude 6.9 on the Rose Canyon Fault. Google Earth, 2021, historic aerial images of area . Grant Ludwig, L.B. and Shearer, P.M., 2004, Activity of the Offshore Newport-Inglewood Rose Canyon Fault Zone, Coastal Southern California, from Relocated Microseismicity. Bulletin of the Seismological Society of America, 94(2), 747-752 . Greene, H.G., Bailey, K.A., Clarke, S.H., Ziony, J.I. and Kennedy, M.P., 1979, Implications of fault patterns of the inner California continental borderland between San Pedro and San Diego, in Abbott, P.L., and Elliot, W.J., eds., Earthquakes and other perils, San Diego region: San Diego Association of Geologists, Geological Society of America field trip, November, 1979, p. 21-28 . Greensfelder, R.W., 1974, Maximum Credible Rock Accelerations from Earthquakes in California, California Division of Mines and Geology . Hart E.W. and Bryant, W.A., 1997, Fault-Rupture Hazard Zones in California, California Division of Mines and Geology, Special Publication 42 . Hart, E.W., Smith, D.P. and Saul, R.B., 1979, Summary Report: Fault Evaluation Program, 1978 Area (Peninsular Ranges-Salton Trough Region), California Division of Mines and Geology, Open-file Report 79-10 SF, 10 . Hauksson, E. and Jones, L.M., 1988, The July 1986 Oceanside (ML=5.3) Earthquake Sequence in the Continental Borderland, Southern California Bulletin of the Seismological Society of America, v. 78, p. 1885-1906. Hileman, J.A., Allen, C.R. and Nordquist, J.M., 1973, Seismicity of the Southern California Region, January 1, 1932 to December 31, 1972; Seismological Laboratory, Cal-Tech, Pasadena, California. Hi .. -.. .... ... .. -.. -.. .... .. .... ... .. .. .. ... -... .. .. ... .. ... ... ... ... ... ... ... ... .. REFERENCES/Page 2 Jennings, C.W., and Bryant, W.A., 2010, Fault Activity Map of California, California Geological Survey Geologic Data Map No. 6 Kennedy, M.P. and Tan, S.S., 2007, Geologic Map of the Oceanside 30'x60' Quadrangle, California, California Geological Survey, Department of Conservation . Legg, M., and Agnew, D., 1979, The 1862 Earthquake in San Diego, in Earthquakes and Other Perils: San Diego Region (Abbott, P.L., Elliott, W.J., eds.), San Diego Association of Geologists, San Diego, CA 139-141. Richter, C.F., 1958, Elementary Seismology, W.H. Freeman and Company, San Francisco, California. Rockwell, T.K., 2010, The Rose Canyon Fault Zone in San Diego, Proceedings of the Fifth International Conference on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics. Paper No. 7.06C. Rockwell, T.K., Dawson, T.E., Young Ben-Horin, J. and Seitz, G., 2014, A 21-Event, 4,000-Year History of Surface Ruptures in the Anza Seismic Gap, San Jacinto Fault, and Implications for Long-term Earthquake Production on a Major Plate Boundary Fault. Pure and Applied Geophysics, v. 172, 1143- 1165 (2015). Rockwell, T.K., Millman, D.E., MCEiwain, R.S. and Lamar, D.L., 1985, Study of Seismic Activity by Trenching Along the Glen Ivy North Fault, Elsinore Fault Zone, Southern California: Lamar-Merifield Technical Report 85-1, U.S.G.S. Contract 14-08-0001-21376, 19 p . Ross, Z.E., Hauksson E. and Ben-Zion Y., 2017, Abundant Off-fault Seismicity and Orthogonal Structures in the San Jacinto Fault Zone, Science Advances, 2017; 3(3): e1601946. Published 2017 Mar 15. Singleton, D.M., Rockwell, T.K., Murbach, D., Murbach, M., Maloney, J., Freeman, T., Levy, Y., 2019, Late-Holocene Rupture History of the Rose Canyon Fault in Old Town, San Diego: Implications of Cascading Earthquakes on the Newport-Inglewood-Rose Canyon Fault System, Bulletin of the Seismological Society of America 109, 855-874. Tan, S.S. and Giffen, D.G., 1995, Landslide Hazards in the Northern Part of San Diego Metropolitan Area, San Diego County, California, Landslide Hazard Identification Map No. 35, California Division of Mines and Geology, Open-file Report 95-04, Map Sheet 35H . Toppozada, T.R. and Parke, D.L., 1982, Areas Damaged by California Earthquakes, 1900-1949, California Division of Mines and Geology, Open-file Report. 82-17 . VICINITY MAP Carlsb s Bea Thomas Bros Guide San Diego County pg 1106-F6 Chinquapin Coast Homes 330 Chinquapin Avenue Carlsbad , CA. Figure No. I Job No. 21-13506 •P.-= 'ieotechnical ~,.-, Exploration, Inc. ~ A 1.1 SITE PlAN I 'I' I I I I . !lu CHINQUAPIN COAST HOMES 330 CHINQUAPIN AVE. CARLSBAD, CA ~ _ _. .. __ ______ .. --.. -.. ·---- REFERENCE: This Plot Plan was prepared from and existing CONCEPTUAL SITE PLAN by KIRK MOELLER ARCHITECTS, INC. dated 8-18-21 and from on-site field reconnaissance with subsurface investigation performed by GEi. REFERENCE: This Plot Plan is not to be used for legal purposes. Locations and dimensions are approximate. Actual property dimensions and locations of utilities may be obtained from the Approved Building Plans I 1 I I I I I 1 I I I I I li'L EJ0ST"NG TWO ST1Jl'I AU1l811W.MDING ___.J ElCJS!ll;GlWOSTOR'f '81lEHT\OlMDING EJQS11IG TWO STaff -- or the "As-Built" Grading Plans. :; j I I I --------------------------~--------l......:..::::::::::.i--c:-;-::==-,==-v=="T"-·-~ ---------=--=-~---;=. ~ ------------= ~ ,-r-•--------------------·----=-=---- I .:_:-------------:rH~ ;-~~-_----------r------o-p -_-_-_-_-r-.-.... -_-_-_-+1-_-_-_-_-_-_-_-_-_-_-_---l-~-~~-H-----_--_-_-_-...::~::-:.:~::;::::,,~~:::-::-:::_-_-_-_-_-_-_-_-i:f.:::l_-=~--=--=---=--~--•--_--;----=_;_~-i-1-=_-=_-,ttf---="""lJ~;;.~=--=;_--r--r\l I 21-13506-p.ai I /~ !, 1 I rl ' ~ I r--- 1 I I I amr, 20 0 ~I __ I ~ HP-10 r , , I ' \ I \ I -\---....~ -JI LL I I HP-11 I i EJQS11IG ONE STORY AD1l91TW.MDING 10 20 I_I GRAPHIC SCALE ( 1" = 20') ' I ~ ---~ 7 ~ n1 ---FIIEHOltl'W.LINGllt•l•H'-HP-5 HP-4 a::] -- I I I I I I ~· 30 I LEGEND ~ Approximate Location HP-13 of Exploratory Handpit GEOLOGIC LEGEND Qop 7 Quaternary Old Paralic Deposits (unit 7) r,r 11 , ~ OOR'f I amr, • " , I I I I t I ~ , --I ' I, I I' ' ' CONCEPTUAL SITE PLAN 5' 10' amr, (") I HP -' , - EX!$TINGTWOSTORI' AESllEH!W.IUUIJIG 20' ~ ~ r I -11 I II J. " . L r " I 1 , r , r I t ~ ~ -.. t zr-cr'M ~ i i v- e ....,,,.,..,. PLOT PLAN Chinquapin Coast Homes 330 Chinquapin Avenue Carlsbad, CA. Figure No. II Job No. 21-13506 Geotechnical Exploration, Inc. October 2021 w ::::> z w <C z -0. c( ::::> 0 z -J: 0 ;St Geotechnical Exploration, Inc. EQUIPMENT: Hand Tools ~ DIMENSION & TYPE OF EXCAVATION: 2.0'x2.0'x2.0' DATE LOGGED: October 5, 2021 LOGGED BY: HE SURFACE ELEVATION: ±49' Above Mean Sea Level REVIEWED BY: GROUNDWATER/SEEPAGE DEPTH: Not Encountered 0 ~ ~ .... 0 &'5' N FIELD DESCRIPTION AND CLASSIFICATION ::R. &'S ::R. 0 ~ ~ e.... e.... ::R. i~ z o.e, 0 a. e.... 0 l!) ---w ::E~ ::E ~ w a:: t'3jS iS ~ +~ -z ...J w Vl DESCRIPTION AND REMARKS l/l ~~ ~~ :::i iS ~...J l/l tii I 0 ...J 3: = u zO zx ~w f-:;:;-[Xl 0.. 0 >D (Grain Size, Density, Moisture, Color) '.:i Vl ~ Vl Vl 0 <( Vl <( w Eb al ::E ::E ui o..-0.. z ~-~ r5 r5 0 0.. z a.. Cl 0.. (ij ~ ...J •o 'w o..O 1:i'l8 Xz 0~ (j:j [Xl :::i ~::E ~o O::E ::EO O::E w -~ ti:; SILTY SAND, fi ne to medium grained, medium dense, SM -moist, brown, some roots, porous. - -Toosoil/ Artificial Fill (Oafl 1 SIL TY SANDSTONE, fine to medium grained, medium dense SM -to dense, damp, light brown to light red-brown, some roots. - - 2 Formation (Ooo .. ) - -Bottom of Excavation at 2.0 ft. - 3 -No Groundwater, No Caving, Backfilled with Cuttings - - - 4 - - - - 5 - - - - 6 - - - - 7 - - - - 8 - - - - 9 - - - - 10- - - * DISTURBED BLOWCOUNT JOB NUMBER: 21-13506 PERCHED WATER TABLE BULK BAG SAMPLE JOB NAME: Chinquapin Coast Homes LOG NO. HP-1 IN-PLACE SAMPLE MODIFIED CALIFORNIA SAMPLE IN-PLACE HAND-DRIVE SAMPLE STANDARD PENETRATION TEST SITE LOCATION: 330 Chinquapin Ave Carlsbad, CA FIGURE No. Illa ~ ci ci w ...J 0.. ::E <( Vl ,,.. ~ Geotechnical Exploration, Inc. EQUIPMENT: Hand Tools ~ DIMENSION & TYPE OF EXCAVATION: 2.0'x2.0'xl.0' DATE LOGGED: October 5, 2021 LOGGED BY: HE SURFACE ELEVATION: ±49' Above Mean Sea Level REVIEWED BY: GROUNDWATER/SEEPAGE DEPTH: Not Encountered 0 ~ ~ .... 0 ~'6' N FIELD DESCRIPTION AND CLASSIFICATION ,R ~'6' ,R 0 ~ ~ e., e., ,R i~ z UJ o_e, :d~ 0 0. e., 0 l!) --UJ a:: l'.j~ ::E~ +~ vi z ....J UJ V) DESCRIPTION AND REMARKS l/) ~~ ~~ ::::, ~ ~~ ~....J vi I ~ ....J 3: = u :'.5 V) ! V) zO zx ~ UJ f-Z' Q. 0 \D (Grain Size, Density, Moisture, Color) V) 0 <( V) ~ w Q. QJ ::E ::E vi Q. -Q. z ~-~m mo Q. z c.. Cl Q. c;j UJ~ l7i ....J •o ' UJ Q. 0 xO Xz 1';; CD :::j ~ ::E ~o ,R -o~ O::E ::EO O::E UJ u w ...... 0 V) SILTY SAND, fine to medium grained, medium dense, SM -moist, brown, some roots. -lllilill I\ Toosoil/ Artificial Fill COafl ) SM 1 SIL TY SANDSTONE, fine to medium grained, medium dense to dense, damp, light brown to light red-brown, some roots - -\ in the upper 6-inches. I Formation (Ooo~ '\ - 2 -Bottom of Excavation at 1.0 ft. -No Groundwater, No Caving, Backfilled with Cuttings - - 3 - - - - 4 - - - - 5 - - - - 6 - - - - 7 - - - - 8- - - - 9 - - - - 10- - - * DISTURBED BLOWCOUNT JOB NUMBER: 21-13506 PERCHED WATER TABLE BULK BAG SAMPLE JOB NAME: Chinquapin Coast Homes LOG NO. HP-2 IN-PLACE SAMPLE MODIFIED CALIFORNIA SAMPLE IN-PLACE HAND-DRIVE SAMPLE STANDARD PENETRATION TEST SITE LOCATION: 330 Chinquapin Ave Carlsbad, CA FIGURE NO. IIIb '2 v ci 0 UJ ....J Q. ::E <( V) ~ Geotechnical Exploration, Inc. ~ EQUIPMENT: Hand Tools 1---------------------------1DIMENSION & TYPE OF EXCAVATION: 2.0'x2.0'x2.0' DATE LOGGED: October 5, 2021 LOGGED BY: HE REVIEWED BY: ---....J lJ.J Vl J: 0 ....J ~= f-~ Ill 0.. 0 "' 0.. 'Qj ::;: ::;: LJ.J~ l7i ....J o~ r';; Ill - - - 1 - -: -1 -- 2 - - - 3 - - - - 4- - - - 5 - - - - 6- - - - 7- - - - 8 - - - - 9 - - - - 10- - - SURFACE ELEVATION: ±49' Above Mean Sea Level GROUNDWATER/SEEPAGE DEPTH: Not Encountered FIELD DESCRIPTION AND CLASSIFICATION DESCRIPTION AND REMARKS l/l (Grain Size, Density, Moisture, Color) u ui :::i SILTY SAND, fine to medium grained, medium dense, SM moist, brown, some roots, porous. Topsoil/ Artificial Fill (Qaf) SILTY SANDSTONE, fine to medium grained, medium dense SM to dense, damp, light brown to light red-brown, some roots. Formation (Qoo .. ) Bottom of Excavation at 2.0 ft. No Groundwater, No Caving, Backfilled with Cuttings ~ ~ &£ ~ C) ,3: lJ.J lJ.J a:: t'.j~ ~~ ~ Vl 0.. ,_, 0.. z '0 ' lJ.J ~::;: ~ C) 2.2 112.9 * DISTURBED BLOWCOUNT JOB NUMBER: 21-13506 ~ &£ ~ ~ C) C. ::;:~ ::;:~ ~ ~ :::,~ ~ Vl I= ,_, ~ as o..0 o::;: ::;: C) "-0 ~~ z ~ :Ro' 0 ~ +~ -~~ ~....J l/l zO zx ct Vl <t w z C) 0.. z a.. Cl lJ.J C) xO Xz C) ::;: LJ.JU w ...... 0 0 N ~ (.!) z vi ~LJ.J 0.. (ij ~ tn PERCHED WATER TABLE BULK BAG SAMPLE JOB NAME: Chinquapin Coast Homes LOG NO. HP-3 IN-PLACE SAMPLE MODIFIED CALIFORNIA SAMPLE IN-PLACE HAND-DRIVE SAMPLE STANDARD PENETRATION TEST SITE LOCATION: 330 Chinquapin Ave Carlsbad, CA FIGURE No. Ille '2 v ci ci lJ.J ....J 0.. ::;: l7i ~ Geotechnical Exploration, Inc. EQUIPMENT: Hand Tools ~ DIMENSION & TYPE OF EXCAVATION: 2.0'x2.0'x2.5' DATE LOGGED: October 5, 2021 LOGGED BY: HE SURFACE ELEVATION: ±49' Above Mean Sea Level REVIEWED BY: GROUNDWATER/SEEPAGE DEPTH: Not Encountered 0 ~ ~ ..... 0 ~£ N FIELD DESCRIPTION AND CLASSIFICATION ~ ~£ ~ a ~ '11' (:; (:; ~ i~ z o,e 0 a. 0 l!) --w ::;: ~ ::;:~ (:; w 0:: tJ t t~ +~ -z ...J w V) DESCRIPTION AND REMARKS Vl ~~ ~~ ::J t ~...J Vl vi ~z-g ...J 3: = u zO zx ~w C. o"' (Grain Size, Density, Moisture, Color) :5 Vl ~ V) Vl Cl <t Vl <( w fr; al ::;: ::;: vi C. ..... C. z 5: 0 ~a:i C. z a.. 0 C. [ij l7i ...J •o 'w a:i Cl xO Xz 0 ~ ?n co =i iS ::;: iS Cl O::E: ::;: Cl Cl ::;: ~ ti, WU w - SILTY SAND, fine to medium grained, medium dense, SM -moist, brown, some roots, porous. - -Topsoil/ Artificial Fill (Oaf) 1 SIL TY SANDSTONE, fine to medium grained, medium dense SM - -f---to dense, damp, light brown to light red-brown, some roots. 1 1.7 109.5 -· f--- 2- -Formation ( Qop7) - 3-Bottom of Excavation at 2.5 ft. -No Groundwater, No Caving, Back,filled with Cuttings - - 4 - - - - 5- - - - 6- - - - 7 - - - - 8- - - - 9- - - - 10- - - * DISTURBED BLOWCOUNT JOB NUMBER: 21-13506 PERCHED WATER TABLE BULK BAG SAMPLE JOB NAME: Chinquapin Coast Homes LOG NO. HP-4 IN-PLACE SAMPLE MODIFIED CALIFORNIA SAMPLE IN-PLACE HAND-DRIVE SAMPLE STANDARD PENETRATION TEST SITE LOCATION: 330 Chinquapin Ave Carlsbad, CA FIGURE NO. IIId "2 ::=, ci 0 w ...J C. ::;: <( Vl ~ D Geotechnical Exploration, Inc. EQUIPMENT: Hand Tools ~ DIMENSION & TYPE OF EXCAVATION: 2.0'x2.0'xl.5' DATE LOGGED: October 5, 2021 LOGGED BY: HE SURFACE ELEVATION: ±50' Above Mean Sea Level REVIEWED BY: GROUNDWATER/SEEPAGE DEPTH: Not Encountered 0 0 ~ ~ .... ~<6" N FIELD DESCRIPTION AND CLASSIFICATION ~ ~<6" ~ 0 ~';; 'Ile ~ ~ ~ z o.e Cl a. ~ ~<3' 0 l? ---UJ UJ ::;:~ 0 ' z UJ a'. ~ t ::;: a'. +~ vi ....J UJ Vl DESCRIPTION AND REMARKS l/J ~~ ~ ~ ::::, t t~ ~....J vi ~~ 0 ....J ;;::= 0 '.) Vl ! Vl zO zx ¼I UJ co c.. 0 U) (Grain Size, Density, Moisture, Color) Vl Cl <( Vl <( w ::;: ::;: vi c..-c..z ~a ~ a'i c..Z 0.. 0 c.. a'.; UJ QJ <( ....J •o ' UJ a'j Cl xO Xz o:t:-~ Vl co ::::> ~::;: ~ Cl O::E ::E Cl Cl ::E UJ u w ...... ~ V) SIL TY SAND, fine to medium grained, medium dense, SM -moist, brown, some roots, porous. - -Topsoil/ Artificial Fill fOaf) 1 lillil' -I fl 1 SIL TY SANDSTONE, fine to medium grained, medium dense SM 1.9 112.6 to dense, damp, light brown to light red-brown, some roots. -\ Formation (Qop7) ) 2 - - -Bottom of Excavation at 1.5 ft. - 3-No Groundwater, No Caving, Backfilled with Cuttings - - - 4- - - - 5- - - - 6 - - - - 7- - - - 8- - - - 9- - - - 10- - - * DISTURBED BLOWCOUNT JOB NUMBER: 21-13506 PERCHED WATER TABLE BULK BAG SAMPLE JOB NAME: Chinquapin Coast Homes LOG NO. HP-5 IN-PLACE SAMPLE MODIFIED CALIFORNIA SAMPLE IN-PLACE HAND-DRIVE SAMPLE STANDARD PENETRATION TEST SITE LOCATION: 330 Chinquapin Ave carlsbad, CA FIGURE No. Ille '2 ;::;, ci ci UJ ....J c.. ::;: <( Vl fli-4~ Geotechnical Exploration, Inc. EQUIPMENT: Hand Tools I~-DIMENSION & TYPE OF EXCAVATION: 2.0'x2.0'x2.5' DATE LOGGED: October 5, 2021 ,, LOGGED BY: HE SURFACE ELEVATION: ±51' Above Mean Sea Level REVIEWED BY: GROUNDWATER/SEEPAGE DEPTH: Not Encountered 0 ~ ~ .... 0 &'5' N FIELD DESCRIPTION AND CLASSIFICATION ~ &'S ~ 0 ~'; ~ e., e., 0 a. ~ ~'cF-z o,e e., 0 (.!) --w ::E ~ ::E~ 0 ...!.. z WO:: t'.j t t~ 3-...J .... ...J w Vl DESCRIPTION AND REMARKS l/l ~~ ~~ =>t l/l vi ~Z' g ...J 3:: = u ~ Vl ~ Vl zO ~riS ~w C. o"' (Grain Size, Density, Moisture, Color) Vl 0 <t Vl C. Q) ::E ::E vj a. -C. z 5: 0 ~ to to 0 C. z C. 0 C. c]j w~ :>-~ ...J •o 'w ?i'l8 Xz co :::, :'S ::E :'S 0 O::E ::E 0 0 ::E ~-0 ~ Vl w .... o Vl SILTY SAND, fine to medium grained, medium dense, SM -moist, brown, some roots, porous. - -TODSOil/ Artificial Fill (Oaf) 1 SIL TY SANDSTONE, fine to medium grained, medium dense SM -to dense, damp, light brown to light red-brown, some roots. -- -~ 2-2.2 103.9 8.0 125.0 0.0 18.0 -1.8 109.5 Formation ( Ooo..,) - 3 - Bottom of Excavation at 2.5 ft. -No Groundwater, No Caving, Backfilled with Cuttings - - 4 - - - - 5 - - - - 6 - - - - 7 - - - - 8 - - - - 9 - - - - 10- - - * DISTURBED BLOWCOUNT JOB NUMBER: 21-13506 PERCHED WATER TABLE BULK BAG SAMPLE JOB NAME: Chinquapin Coast Homes LOG NO. HP-6 IN-PLACE SAMPLE MODIFIED CALIFORNIA SAMPLE IN-PLACE HAND-DRIVE SAMPLE STANDARD PENETRATION TEST SITE LOCATION: 330 Chinquapin Ave Carlsbad, CA FIGURE NO. lllf ~ ci ci w ...J C. ::E <t Vl ~ Geotechnical Exploration, Inc. EQUIPMENT: Hand Tools ~ ,__ _____________________ __,DIMENSION & TYPE OF EXCAVATION: 2.0'x2.0'xl.5' DATE LOGGED: October 5, 2021 LOGGED BY: HE SURFACE ELEVATION: ±50' Above Mean Sea Level REVIEWED BY: GROUNDWATER/SEEPAGE DEPTH: Not Encountered -' w ~~ 0 -' co c.. c.. ~ ::E ::E ~g ct i'i; Vl --Vl 3: = 0 \!) -' co FIELD DESCRIPTION AND CLASSIFICATION DESCRIPTION AND REMARKS (Grain Size, Density, Moisture, Color) SM SILTY SAND, fine to medium grained, medium dense, moist, brown, some roots. -----mm:t--+-~i\ Topsoil/ Artificial Fill (Qaf) J SM ~------------~-~---~ SILTY SANDSTONE, fine to medium grained, medium dense 1 ~ to dense, damp, light brown to light red-brown, some roots. 1.8 105.1 - 2 - - - - 4- - - 5 - - 6 - - 7 - - - 8 - - 9 - - 10- i\'---____ ___;F....;;o;.;;..r.;.;.m;;..;;;a;..;;.ti;;..;;;o..;.;n...,l(~Q,oLL,jo .. ,)r....._ ____ __J/ Bottom of Excavation at 1.5 ft. No Groundwater, No Caving, Backfilled with Cuttings PERCHED WATER TABLE BULK BAG SAMPLE IN-PLACE SAMPLE * DISTURBED BLOWCOUNT MODIFIED CALIFORNIA SAMPLE IN-PLACE HAND-DRIVE SAMPLE STANDARD PENETRATION TEST JOB NUMBER: 21-13506 JOB NAME: Chinquapin Coast Homes SITE LOCATION: 330 Chinquapin Ave Carlsbad, CA LOG NO. HP-7 FIGURE NO. Illg ~ Geotechnical Exploration, Inc. EQUIPMENT: Hand Tools ~ t----------------------------iDIMENSION & TYPE OF EXCAVATION: 2.0'x2.0'x2.5' DATE LOGGED: October 5, 2021 LOGGED BY: HE SURFACE ELEVATION: ±50' Above Mean Sea Level REVIEWED BY: GROUNDWATER/SEEPAGE DEPTH: Not Encountered ~ ~ ~'6' FIELD DESCRIPTION AND CLASSIFICATION l ~~ t 0 0. UJ 0~ ~ ~ ~~ UJ IX ~ i'.: DESCRIPTION AND REMARKS l/l ~~ ~~ :::) i'.: (Grain Size, Density, Moisture, Color) u :'.5 Vl ~ Vl vi c..-c..z I= -~ r5 '0 I UJ c..O ::i ~~ ~ 0 0~ ~o SILTY SAND, fine to medium grained, medium dense, SM ---moist, brown, some roots, porous. -Topsoil/ Artificial Fill (Oaf) 1 --t,r.m;rt--;------1--------------------"""'."""'----~-------.......... -----+---,----,---+---+------t--+-+--+--+----t SIL TY SANDSTONE, fine to medium grained, medium dense SM -: to dense, damp, light brown to light red-brown, some roots in the upper 6-inches. - 2 -fl'Jltl'l-----l -H Formation (Qoo7) 2.0 101.6 3- Bottom of Excavation at 2.5 ft. No Groundwater, No caving, Backfilled with Cuttings - 4- - 5 - - - 6 - - 7- - - 8- - 9 - - - 10- PERCHED WATER TABLE BULK BAG SAMPLE IN-PLACE SAMPLE * DISTURBED BLOWCOUNT MODIFIED CALIFORNIA SAMPLE IN-PLACE HAND-DRIVE SAMPLE STANDARD PENETRATION TEST JOB NUMBER: 21-13506 JOB NAME: Chinquapin Coast Homes SITE LOCATION: 330 Chinquapin Ave Carlsbad, CA LOG NO. HP-8 FIGURE NO. lllh ~ Geotechnical Exploration, Inc. EQUIPMENT: Hand Tools ~ DIMENSION & TYPE OF EXCAVATION: 2.0'x2.0'xl.5' DATE LOGGED: October 5, 2021 LOGGED BY: HE SURFACE ELEVATION: ±50' Above Mean Sea Level REVIEWED BY: GROUNDWATER/SEEPAGE DEPTH: Not Encountered 0 ~ ~ ~ 0 &£ N FIELD DESCRIPTION AND CLASSIFICATION ,J?. &£ ,J?. 0 ~ ~ e.., e.., ,J?. ~~ z UJ o,e ::E~ 0 Cl. e.., 0 l9 --::,:~ 0 0 z UJ o,'. t'.j t t ~...J vi ...J UJ V) DESCRIPTION AND REMARKS l/l ~~ ~~ :::, t vi I ~ ...J ~= u :'.5 V) ~ V) zO zx ~ UJ I-z-Q. 0"' (Grain Size, Density, Moisture, Color) vis <( Vl <( LU Q. Q) ::E ::E vi Q. ..... Q. z ~ ..... ~ rE rjj 0 Q. z a.. Cl Q. clj UJ .l!! <( ...J '0 ' UJ Q. 0 1:58 Xz o~ 1'ii V) CD :::i ~::E ~o O::E ::E 0 0 ::E LU ,_. ~ V) SIL TY SAND, fine to medium grained, medium dense, SM -moist, brown, some roots, porous. - -Topsoil/ Artificial Fill (Oaf) 1 :111111 1 SIL TY SANDSTONE, fine to medium grained, medium dense SM 1.9 112.6 -:(::: 11 / to dense, damp, light brown to light red-brown, some roots in the upper 6-inches. -\ Formation (Qop7) I 2 - - -Bottom of Excavation at 1.5 ft. - 3-No Groundwater, No caving, Backfilled with Cuttings - ._ - 4 - - - - 5 - - - - 6 - - - - 7 - - - - 8 - - - - 9- - - - 10- - - * DISTURBED BLOWCOUNT JOB NUMBER: 21-13506 PERCHED WATER TABLE BULK BAG SAMPLE JOB NAME: Chinquapin Coast Homes LOG NO. HP-9 IN-PLACE SAMPLE MODIFIED CALIFORNIA SAMPLE IN-PLACE HAND-DRIVE SAMPLE STANDARD PENETRATION TEST SITE LOCATION: 330 Chinquapin Ave Carlsbad, CA FIGURE NO. llli ~ ~ ci 0 UJ ...J Q. ::E l7i EQUIPMENT: Hand Tools D Geotechnical Exploration, Inc. ~ t----------------------------iDIMENSION & TYPE OF EXCAVATION: 2.0'x2.0'x2.0' DATE LOGGED: October 5, 2021 LOGGED BY: HE REVIEWED BY: - SURFACE ELEVATION: ±51' Above Mean Sea Level GROUNDWATER/SEEPAGE DEPTH: Not Encountered FIELD DESCRIPTION AND CLASSIFICATION DESCRIPTION AND REMARKS (Grain Size, Density, Moisture, Color) Topsoil/ Artificial Fill (Qaf): SIL TY SAND, fine to medium grained, medium dense, moist, brown, abundant roots, porous. l/l u l/) ::::i SM ~ ~'6' e., 0,9, UJ UJ Ct'. t'.j t ~~ '.:i V) o..-0.. z '0 ' UJ = ::E =o ,-... .... ~'6' ,I? 0 e., ,I? i~ z 0 C. 0 ::E 15! ::.:~ e., +~ tii ~~ ::it t ~....J ~ V) zO zx vi a ~ V) <(W ~a ~ f5 0.. z Cl. 0 f5 0 xO Xz O::E ::E 0 0 ::E UJ u w ...... 0 ,-... 0 C N C, '<le ci (.'.) z ci vi UJ ~ UJ ....J 0.. 0.. (i'j ::E ~ ~ vi Topsoil/ Artificial Fill (Oaf) 1 ---!,,r,rn+-+--+------.c...L..;;_;;_....L.._c..._...;;....;.;;..;...;....;.;.;.....,_;a.=------+-+--+---+---+---+--+--+---+---+------f -SIL TY SANDSTONE, fine to medium grained, medium dense SM to dense, damp, light brown to light red-brown, some roots. 2 -----F"+---+--~-----....;F....;o;;..;;.r..;.;m..;.;a;;..;;t..;.;io;;..;;.n;;...(:i...;'. Qlil,;,o;;.Jl10;;.t .. ,.,,__ ) _____ ---1----4----1-------~---+--' +-----1---+---+-----4-~ - 3 - - 4- - - 5- - 6- - 7- - 8- - 9- - 10- - Bottom of Excavation at 2.0 ft. No Groundwater, No Caving, Backfilled with Cuttings PERCHED WATER TABLE BULK BAG SAMPLE IN-PLACE SAMPLE * DISTURBED BLOWCOUNT MODIFIED CALIFORNIA SAMPLE IN-PLACE HAND-DRIVE SAMPLE STANDARD PENETRATION TEST JOB NUMBER: 21-13506 JOB NAME: Chinquapin Coast Homes SITE LOCATION: 330 Chinquapin Ave Carlsbad, CA LOG NO. HP-10 FIGURE NO. lllj ~ Geotechnical Exploration, Inc. ~ ------------------------DIMENSION & TYPE OF EXCAVATION: 2.0'x2.0'x2.5' EQUIPMENT: Hand Tools DATE LOGGED: October 5, 2021 LOGGED BY: HE SURFACE ELEVATION: ±51' Above Mean Sea Level REVIEWED BY: GROUNDWATER/SEEPAGE DEPTH: Not Encountered ~ ~ ~'t FIELD DESCRIPTION AND CLASSIFICATION :R ~'t t ~ lJ.J o,e ::;: ~ Cl a. UJ IX lj t; ::;:~ DESCRIPTION AND REMARKS l/) ~~ ~~ ::i t; (Grain Size, Density, Moisture, Color) u ::i l/l ~ l/l vi "--<l. z ~ -~ilj ::i '0 ' lJ.J <1.0 ~::;: ~ Cl O::E ::E Cl 0 ~ ..... 0 C: 0 N v ~ 'It :R i~ z l? 0 ~ 0 ci +~ vi z §~ ~-' vi lJ.J zO zx ~UJ -' <( l/l <( w <l. Z Cl <l. z o.. Cl <l. [ij ::;: UJ Cl ?.S8 Xz <( Cl ::E w ...... ~ tn l/l SILTY SAND, fine to medium grained, medium dense, SM moist, brown, some roots, porous. - -TODSOil/ Artificial Fill (Oaf) 1 -t=r+-+--+-----....;...;;;.,;..;;..;;.;;.;..,..._;;.._..;_;'--'~;..o.;:,,.;;.;.;"'-------+-+--+----+----+---+--+--~-~-~---1 SIL TY SANDSTONE, fine to medium grained, medium dense SM -to dense, damp, light brown to light red-brown, some roots. - 2 -,__ - 3 - 4- - 5- - 6- - 7- - 8- - - 9- - 10- - H Formation (Ooo .. ) 2.2 105.1 Bottom of Excavation at 2.5 ft. No Groundwater, No Caving, Backfilled with Cuttings PERCHED WATER TABLE BULK BAG SAMPLE IN-PLACE SAMPLE * DISTURBED BLOWCOUNT MODIFIED CALIFORNIA SAMPLE IN-PLACE HAND-DRIVE SAMPLE STANDARD PENETRATION TEST JOB NUMBER: 21-13506 JOB NAME: Chinquapin Coast Homes SITE LOCATION: 330 Chinquapin Ave Carlsbad, CA LOG NO. HP-11 FIGURE NO. IIIk •lr4H Geotechnlcal Exploration, Inc. EQUIPMENT: Hand Tools ~ DIMENSION & TYPE OF EXCAVATION: 2.0'x2.0'x2.0' DATE LOGGED: October 5, 2021 LOGGED BY: HE SURFACE ELEVATION: ±51' Above Mean Sea Level REVIEWED BY: GROUNDWATER/SEEPAGE DEPTH: Not Encountered c;5 0 ~ ~ ..... Cl 0 ~~ ~ N FIELD DESCRIPTION AND CLASSIFICATION :ii? ~~ :ii? 0 ~~ 'l;, e.., e.., Cl E, Cl c. :ii? ~ cF z L? --UJ UJ ::;:~ ~ 0 -'.., 0 z UJ ~ t'.j t ::;:~ ~ .... ...J UJ Vl DESCRIPTION AND REMARKS (/) 5~ ~~ :::, t t vi vi ~ Z' g ...J :s: = u :s Vl ~ Vl zO z ~ UJ c.. 01.0 (Grain Size, Density, Moisture, Color) <ll5" ct Vl ct fu gj ::;: ::;: vi c.. ..... c..z I= ..... ~ as as Cl c.. z c.. c.. [ij ct ...J •o ' UJ c..O CJ58 c;5 o:t::.. ~ Vl cc :::i ~::;: ~ Cl O::E ::;: Cl Cl ::;: ~ ti, SILTY -SAND, fine to medium grained, medium dense, SM moist, brown, some roots, porous. - -Topsoil/ Artificial Fill (Oaf) 1-SILTY SANDSTONE, fine to medium grained, medium dense SM -to dense, damp, light brown to light red-brown, some roots. -- -1 Formation (Oop7) 1.6 108.0 18.0 2 - - Bottom of Excavation at 2.0 ft. - 3-No Groundwater, No Caving, Backfilled with Cuttings - -'-- - 4- - - - 5- - - - 6- - - - 7- - - - 8- - - - 9- - - - 10- - - * DISTURBED BLOWCOUNT JOB NUMBER: 21-13506 PERCHED WATER TABLE BULK BAG SAMPLE JOB NAME: Chinquapin Coast Homes LOG NO. HP-12 IN-PLACE SAMPLE MODIFIED CALIFORNIA SAMPLE IN-PLACE HAND-DRIVE SAMPLE STANDARD PENETRATION TEST SITE LOCATION: 330 Chinquapin Ave Carlsbad, CA FIGURE NO. 1111 '2 v ci ci UJ ...J c.. ::;: ~ ~ Geotechnical Exploration, Inc. EQUIPMENT: Hand Tools ~ DIMENSION & TYPE OF EXCAVATION: 2.0'x2.0'x2.0' DATE LOGGED: October 5, 2021 LOGGED BY: HE SURFACE ELEVATION: ±51' Above Mean Sea Level REVIEWED BY: GROUNDWATER/SEEPAGE DEPTH: Not Encountered 0 0 ,....., ,....., ..... ~cs N FIELD DESCRIPTION AND CLASSIFICATION ~ ~cs ~ 0 ,....., 'ii, ~ ~ ~ ~~ z o,e 0 0. 0 (.!) ---w :E ~ :E~ ~ +~ z w er:: tj t vi --' w Vl DESCRIPTION AND REMARKS Vl ~~ ~ ~ :::it t~ ~--' vi t ~ 0 --' ~: u ~ Vl ~Vl zO zx ~w cc c.. 0 \0 (Grain Size, Density, Moisture, Color) Vl 0 <( Vl ~w :E :E vi c.. ..... c.. z 5: 0 ~H:i c.. z c.. 0 c.. (ij W.J!! <( --' '0 'w d:i 0 (j58 Xz o ~ i';; Vl cc => ~ :E ~o 0 :E :E 0 0 :E w ...... ~ V) SIL TY SAND, fine to medium grained, medium dense, SM -moist, brown, some roots, porous. - -Topsoil/ Artificial Fill (Oaf) 1 111!111 1 SIL TY SANDSTONE, fine to medium grained, medium dense SM -to dense, damp, light brown to light red-brown, some roots. -ll!lilli Formation (Oop7) 2 - - Bottom of Excavation at 2.0 ft. - 3 -No Groundwater, No caving, Backfilled with Cuttings - -'- - 4 - - - - 5 - - - - 6 - - - - 7 - - - - 8 - - - - 9 - - - - 10- - - * DISTURBED BLOWCOUNT JOB NUMBER: 21-13506 PERCHED WATER TABLE BULK BAG SAMPLE JOB NAME: Chinquapin Coast Homes LOG NO. HP-13 IN-PLACE SAMPLE MODIFIED CALIFORNIA SAMPLE IN-PLACE HAND-DRIVE SAMPLE STANDARD PENETRATION TEST SITE LOCATION: 330 Chinquapin Ave Carlsbad, CA FIGURE No. Illm ,....., C: -::, ci ci w --' c.. :E ~ ti C, ~ a, UJ u._ w C, --, c.. C, z a: <( :J 0 z :i: (.) <O 0 "' M 13 5 13 0 12 5 12 0 11 5 110 't3 a. ~ en ~ 105 0 >-0::: 0 100 95 90 85 80 75 0 \ .I ' ~' ., 5 \ ' \ \ \ ' \ ~ \ I\ \ \ \ \ \ \ \ \ \ \ \ , \ \ " \ \ I. \ \ i\ \ 1\ \ \ \ 10 15 Source of Material HP-6@1.5' Description of Material SIL TY SANDSTONE {SM}1 Brown Test Method ASTM D1557 Method A \ \ ,1 \ TEST RES UL TS \ \ ' \ \ Maximum Dry Density 125.0 PCF \ Optimum Water Content 8.0 % \ \ \ \ 1 \ f\ \ Expansion Index (El) 0 \ \ \ \ \ I\ \ I. \ \ \ \. \ \ ' \ \ \ \ ~ Curves of 100% Saturation \ I\ \ '\ I\ r\ for Specific Gravity Equal to: ~ \ " 2.80 I\ \ \ \ I\. 2.70 \ \ \. \ "' '\ 2.60 \ \ \ "' I\. [\ \ ~ I\. "' '\ " "' "' \ I\. "-"' ' ' ~ '\ '-" " \. '\.. " 'i... " '\.. '"' I\ "" ""' I\ "' '~ i"\ "' ~ l'"s. "' " '\. "" 20 25 30 35 40 45 PACIFIC OCEAN --~~!~~ ftydrogr;aof'ry .,., tt~JfT'OlftUSGS IIOlalllM~tDLOJ d-. S....~,0 ,-fl(t~~ s,.,., ~bae~USGS 09'.al~~ tDEM•I Ohtlore Doi~ oonlOUrl ana 11\aOed ~ lrom NOAA tonp, #10 ~ 6-. Protecmn • UlM Zani!' 11 ~ NMflCan Ollum 1127 musGs -----........ - Thl5mapwHtUftCMd~per1b<J'INIUS ~ ------·--S1ATEIMP 4....-cs no ~9 Prep;att,d., ~~ ... us GectoQcal ~ s.,,,,,,,,,c-... __ _ ~I OZOOI by IN ~ ~ C.-~ ~ngr,g,...,..,.., li(lpa,t1ol--~m.ybe~ ~~conMntdtl'le e..Mor"'9~~ Tri. ~Of~,,._ no..,.,,...a1-to1r1a ~ ol ._ P'OO'JCt ban; ~ ~ chinquapin-OC-gea.ai Chinquapin Coast Homes 330 Chinquapin Avenue Carlsbad, CA. 70 EXCERPT FROM GEOLOGIC MAP OF THE OCEANSIDE 30' x 60' QUADRANGLE , CALIFORNIA Compiled by Michael P. Kennedy1 and Siang S. Tan 1 2007 Digital preparation by Kelly R. Bovard2, Rachel M. Alvarez2, Michael J. Watson2, and Carlos I. Guti1 !rrez1 ' -oleor-...oo. ~-S<,wy 2 USGoologafs.,voy""-"'-ole---o/C-....,__ ONSHORE MAP SYMBOLS DESCRIPTION OF MAP UNITS ·-ContaC1 • ContaC1 between geologic units; dotted where concealed _L_u _ ........... . Fault -Solid where accurately located, dashed where approximately located; dotted where concealed. U = upthrown block. D = downthrown block. Arrow and number indicate direC11on and angle of dip of fault plane aop I D . ~-- 60 ..Q.. Anticline -Solid where accurately located: dashed where approximately located: dotted where concealed. Arrow indicates d1reC1Jon of axial plunge Syncline -Solid where ac:curately located; dotted where concealed. Arrow 1nd1cates d1rect1on of a.,al plunge Landslide -Arrows indicate principal direction of movement Quened where existence 1s quesbonable. Strike and dip of beds Inclined Strike and dip of igneous JOtntS Inclined Ven,cal Stnke and dip of metamorphic foliation Inclined 6-7 Quartenary Old Paralic Deposits (unit 6-7) Figure No. V Job No. 21-13506 Geotechnical Exploration, Inc. October 2021 ----------... -----... - ------- ... -... --- ... --... APPENDIX A UNIFIED SOIL CLASSIFICATION CHART SOIL DESCRIPTION Coarse-grained (More than half of material is larger than a No. 200 sieve) GRAVELS, CLEAN GRAVELS (More than half of coarse fraction is larger than No. 4 sieve size, but smaller than 3") GRAVELS WITH FINES (Appreciable amount) SANDS, CLEAN SANDS (More than half of coarse fraction is smaller than a No. 4 sieve) SANDS WITH FINES (Appreciable amount) GW GP GC SW SP SM Well-graded gravels, gravel and sand mixtures, little or no fines. Poorly graded gravels, gravel and sand mixtures, little or no fines . Clay gravels, poorly graded gravel-sand-silt mixtures Well-graded sand, gravelly sands, little or no fines Poorly graded sands, gravelly sands, little or no fines. Silty sands, poorly graded sand and silty mixtures. SC Clayey sands, poorly graded sand and clay mixtures . Fine-grained (More than half of material is smaller than a No. 200 sieve) SILTS AND CLAYS Liquid Limit Less than 50 Liquid Limit Greater than 50 HIGHLY ORGANIC SOILS ML CL OL MH CH OH PT Inorganic silts and very fine sands, rock flour, sandy silt and clayey-silt sand mixtures with a slight plasticity Inorganic clays of low to medium plasticity, gravelly clays, silty clays, clean clays. Organic silts and organic silty clays of low plasticity. Inorganic silts, micaceous or diatomaceous fine sandy or silty soils, elastic silts. Inorganic clays of high plasticity, fat clays. Organic clays of medium to high plasticity. Peat and other highly organic soils BJ -- ------- ---.. ------------.. ------... -... APPENDIX B STORM WATER INFILTRATION TESTING- GROUP DELTA (2018) -- -.... .... ... ---.. - - -... .... -- ... --... .. ... .... -- ... ... -.. Report of Geotechnical Investigation 330 Chinquapin Avenue Mr. Jeff Galizia 6.3.6 Surface Drainage GDC Project No. SD589 November 30, 2018 Page 10 Slope, foundation, and slab performance depends greatly on how well surface runoff drains from the site. This is true both during construction and over the entire life of the structure. The ground surface should be graded so that water flows rapidly away from the structures and slope tops without ponding. The surface gradient needed to achieve this may depend on the prevailing landscaping. Planters should be built so that water will not seep into the foundation, slab, or pavement areas. If roof drains are used, the drainage should be channeled by pipe to storm drains, or discharge at least ten feet from buildings. Irrigation should be limited to the minimum needed to sustain landscaping. Excessive irrigation, surface water, water line breaks, or rainfall may cause perched groundwater to develop within the underlying soil. 6.3.7 Temporary Excavations Temporary excavations are anticipated for the construction of the proposed utilities. All excavations should conform to Cal-OSHA guidelines. Temporary slopes should be inclined no steeper than 1:1 for heights up to ten feet. Higher temporary slopes, or any excavations which encounter seepage, should be evaluated by the geotechnical consultant on a case-by-case basis. 6.4 Storm Water Infiltration Our investigation included a feasibility study of storm water management in accordance with the Design Manual. The evaluation consisted oftest borings, laboratory testing, infiltration testing, and an evaluation of feasibility for on-site storm water infiltration. Group Delta advanced six borings (B-1 through B-5 and 1-1) to a maximum depth of 21½ feet to evaluate soil characteristics and the depth of groundwater across the site. Figures 2A and 2B show the locations of these borings. Based on observations and sampling blow counts, the density of the soils varied from loose to very dense. Groundwater was not encountered in our investigation. A descriptive log for each boring is shown in Appendix A. A disturbed soil sample was obtained from the infiltration test boring for particle size distribution testing to evaluate the physical characteristics of the soils. The soils tested were classified as silty sand (SM) per ASTM D2487. The test results are presented in Appendix A and B . Group Delta performed field testing using the Borehole Percolation Test referenced in the Design Manual. We completed a field test (1-1) that is discussed in detail in Appendix C, and the results are shown in Figures C-1.1 and C-1.2 . The site and subsurface conditions, including our field testing, were reviewed relative to the criteria stated in Worksheet l-8: Categorization of Infiltration Feasibility Condition. The soils tested appeared to be relatively permeable. The granular nature of the on-site soils are believed to be associated with the relatively high infiltration rate we measured at the site . A GROUP DELTA --,.. - ... ... ... -- - .... ... -... .... .... - Report of Geotechnical Investigation 330 Chinquapin Avenue Mr. Jeff Galizio GDC Project No. SD589 November 30, 2018 Page 11 Based on the preliminary test results, infiltration at the test location would be feasible. A: detailen study of the BMP location with respect to existing and planned utilities, walls, and other improvements should be considered during the design development stage. In addition, storm water contaminants and water balance issues should be considered in the BMP design. Due to / variability of the soil at the project site, design of the BMP's should consider the location and / results of the preliminary infiltration test. ,,-i The conclusion and recommendations for storm water infiltration are based on the assumption that soil and groundwater conditions do not deviate appreciably from those locally observed by Group Delta. If remedial grading results in different soil conditions in proposed infiltration zones, further testing may be warranted. The results should only be considered valid for the design assumptions used for testing, including the location and elevation of the soils tested, and the amount of pressure head in the test. These results may not be applicable if significant changes to the design occur. A detailed account of the test method, including the assumptions made, is presented in Appendix C. 6.5 Foundation Recommendations The foundations for the new buildings should be designed by the project structural engineer using the following geotechnical parameters. These are only minimum criteria, and should not be considered a structural design, or to preclude more restrictive criteria of governing agencies or the structural engineer. All foundations for the new structures are anticipated to bear within compacted fill. ... 6.5.1 Conventional Slab-on-Grade Foundation Recommendations -... -.... ,.. -- -... -- ,,. .. Allowable Bearing: (Compacted Fill) Minimum Footing Width: 2,000 lbs/ft2 (allow a½ increase for short-term wind or seismic loads). 12inches Minimum Footing Depth: 18 inches below lowest adjacent soil grade Minimum Reinforcement: Two No. 4 bars at top and bottom 6.5.2 Post-Tension Slab Foundations Provided that remedial grading is conducted per our recommendations, most of the residential lots at the site will be underlain by compacted fill with a low expansion potential (El<S0). The following preliminary post-tension slab foundation design parameters are considered applicable to buildings that will be underlain by such conditions. Note that these recommendations should be considered preliminary, and subject to revision based on the conditions observed by the geotechnical ~ A GROUP DELTA .. ... --.. ,.. .... .... --- -- --... - ... ... .... ,,,. .. -... .. - ... -.. .., .. -... AGR□UPDELTA ... APPENDIXC STORM WATER INFILTRATION ASSESSMENT --... -... .. ... --- --.... -... - .... -,.. --.. --,,,. -... ... .... -... ... .... -.. .... INFILTRATION TESTING Each proposed storm water infiltration BMP requires exploratory borings and in situ testing to justify an infiltration recommendation. During the planning phase, City of Carlsbad, BMP Design Manual dated February 16, 2016 (referred to hereon as Design Manual) recommends a feasibility screening to assess the site conditions and potential for infiltration. Our investigation included test borings at least ten feet below the potential BMP elevations, and one infiltration test to assess preliminary infiltration rates. The results of our field tests are shown in Figures C-1.1 and C-1.2. The test results are considered preliminary and are not based on a specific site plan. Our preliminary conclusions about storm water infiltration BMPs, based on the requirements of the Design Manual, are attached in the completed Worksheet 1-8. The factor of safety applied for planning phase feasibility screening is 2.5 and shown attached in the completed Worksheet 1-9. The Borehole Percolation Test was used to help approximate infiltration rates of the soils near the proposed infiltration zones. The test was set up by excavating a six-inch diameter test hole using a hand-operated power auger (Appendix A). The hole was cleaned of loose material down to the desired test depth. Perforated PVC casing was placed in the open hole. Open-graded gravel was used to fill the annular space between the casing and the sidewalls of the test hole to support the sidewalls of the test hole and prevent sloughing during saturation of the soil. Each hole was pre- soaked prior to testing to more closely model saturated conditions and to achieve a stabilized percolation rate. The Borehole Percolation Test requires the hole to be filled with water to the test depth and the rate of fall of water (percolation rate) to be measured periodically. To measure the percolation rate, the drop of water in the hole (LlH) is measured at regular time intervals (M). After each reading, or a number of readings, when the water column has measurably dropped from the desired test depth, water is added to the hole to maintain a relatively constant column of water in the test hole (Havg). During the test, water percolates into the surrounding ground both horizontally through the side walls of the hole and vertically through the bottom of the hole. To more accurately approximate the desired vertical infiltration rate (It), the percolation rate is modified mathematically. The Design Manual recommends using a formula called the simplified Porchet method, shown below in Equation 1. The simplified Porchet method assumes an open hole is used to measure the percolation rate (LlH/Llt). Our hole was cased with perforated PVC pipe and gravel to stabilize the hole. The measured drop in water (LlH) is amplified by the fact that some space in the hole was occupied by gravel, and not water. To account for this, the corrected drop in water (LlHc) is calculated by reducing the measured drop in water by the ratio of the area of the hole occupied by water to the total area of the hole. The porosity of the gravel was assumed to be 0.4 based on laboratory testing of similar gravel. t"\ ~ GR□UP DELTA ------------.. ... ,.. --.. -------... - --... ... .... .. -... The percolation rate, and in turn, the infiltration rate, generated from the field tests are dependent on the head pressure present during the tests. The percolation tests were run with approximately 13 inches of water (head pressure, Havg}, as shown in Figure C-1.1. If the BMP is designed to accommodate significantly different head pressures, the infiltration rate provided based on these field tests may not be applicable. Equation 1 {simplified Porchet method): Where: A GRCUP DELTA I, =AH~ = AH 60 r ~ At(1tl' +21trHavg) At(r+2Havg) I, = tested infiltration rate, inches/hour AH = change in head over the time interval, inches At = time interval, minutes • r = effective radius of test hole Havg = average head over the time interval, inches ... - --.. ... -- -.. ... ... ... ... --... ... - .. ... -.... ... ... ... ... .. ... BOREHOLE PERCOLATION TEST Data Sheet Project Name: 330 Chinquapin -Multi Family Residence Date Drilled: 10/10/2018 Project Number: 5D589 Logged By: TSL Test Hole No: 1-1 Date Tested: 10/11/2018 Drilling Method: Hand Auger Tested By: TSL Average Head Measured Time Initial Final Depth of Reading Interval Depth of Water of Water Drop in Water Number Level (min.) Water (ft.) (ft.) (in.) (in.) --------------------------------------------------------------------------------------4t Hav1 4H Pre-Soak 100 3.00 ------ Pre-Soak 14 (<25) 3.48 4.30 12.12 9.84 Pre-Soak 13 (<25) 3.39 4.20 13.26 9.72 1 10 3.51 4~12 13.02 7.32 2 10 3.55 4.14 12.66 7.08 3 10 3.48 4.10 13.32 7.44 4 10 3.48 4.11 13.26 7.56 5 10 3.50 4.12 13.08 7.44 6 10 3.53 4.11 12.96 6.96 7 10 3.53 4.09 13.08 6.72 8 10 3.54 4.09 13.02 6.60 9 10 3.44 4.04 13.92 7.20 Borehole Radius (*r): 3 in. Depth of Hole as Drilled: 4.9 ft Depth of Hole as Tested: 4.9 ft Test Depth: 3.5' -5.1' Corrected Corrected Measured Drop in Water Percolation Infiltration Level1 Rate1 Rate2 (in.) (in./hour) (in./hour) -----------------------------·-------------- 4Hc 4HJ4t It ------ 6.56 28.11 3.10 6.48 29.91 3.04 4.88 29.28 3.02 4.72 28.32 3.00 4.96 29.76 3.01 5.04 30.24 3.07 4.96 29.76 3.06 4.64 27.84 2.89 4.48 26.88 2.77 4.40 26.40 2.73 4.80 28.80 2.80 Stabilized 1: Porosity of gravel assumed to be 0.4 to correct drop in water. See text of Appendix C for details . Infiltration Rate2: 2: Porchet method used to convert percolation rate to infiltration rate. See text of Appendix C for 2.76 inch/hour details. A Project No. S0589 GFitCUP DELTA 1-1 Document No. 18-0136 FIGURE C-1.1 3.5 3.25 ... 3 :::s 0 ~ 2.75 :§. cu 2.5 .. 111 0::: C 0 2.25 .. 111 ... .. iE 2 -= ,, cu ... 1.75 0 ti 111 1.5 u.. 1.25 1 BOREHOLE PERCOLATION TEST Measured Infiltration Rates During Test ~-· ...... . ... ~............ ~ ··············•· ...... . ... ~.. . ....... ~'1~-.... ,,.:.:··.:..:.···~•_,1· ,_-.,.~.~-:'!". 0 10 20 30 40 50 60 _.,___ Measured lnflltration Rate2 (in./hour) ... ••·· • • Average Infiltration Rate: 2.76 in./hour 70 80 Duration of Test (minutes) Preliminary Factored Infiltration Rate: 1.1 in./hr. Feasibility Screening Factor of Safety, F.S. * = 2.5 Factored Infiltration Rate* Design Condition* Below 0.05 No Infiltration 0.05 to 0.5 Partial Infiltration Above 0.50 Full Infiltration 'Reference: The City of Carlsbad, BMP Design Manual (2016). 90 GFilCIUP DEL TA 1-1 Project No. SD589 Document No. 18-0136 FIGURE C-1.2 Appendix I: Forms and Checklists Categorization of Infiltration Feasibility Form 1-8 Condition 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 Is the estimated reliable infiltration rate below proposed facility locations greater than 0.5 inches per hour? The response to this Screening Question shaU be based on a comprehensive evaluation of the factors presented in Appendix C.2 and Appendix D. Yes Provide basis: Results should be confirmed or revised, as necessary, based on more detailed design-level investigation and analysis during BMP design. See Section "Storm Water Infiltration" of this report (Group Delta Consultants -Report of Geotechnical Investigation, 330 Chinquapin Avenue, dated November 15, 2018). No Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/ data source applicability. 2 Can infiltration greater than 0.5 inches per hour be allowed without increasing risk of geotechnical hazards (slope stability, g roundwater mounding, utilities, or other factors) that cannot be mitigated to an 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: Results should be confirmed or revised, as necessary, based on more detailed design-level investigation and analysis during BMP design. See Section "Storm Water Infiltration" of this report (Group Delta Consultants -Report of Geotechnical Investigation, 330 Chinquapin Avenue, dated November 15, 201 8). Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/ data source applicability. 1-3 February 2016 Criteri a 3 Appendix I: Forms and Checklists Form 1-8 Page 2 of 4 Screening Question Can infiltration greater than 0.5 inches per hour be allowed without increasing risk of groundwater contamination (shallow water table, storm water pollutants or other factors) that cannot be mitigated to an acceptable level? The response to this Screening Question shall be based on a comprehensive evaluation of the factors presented in Appendix C.3. Yes No ✓ Provide basis: Results should be confirmed or revised, as necessary, based on more detailed design-level investigation and analysis during BMP design. See Section "Storm Water Infiltration" of this report (Group Delta Consultants -Report of Geotechnical Investigation, 330 Chinquapin Avenue, dated November 15, 2018). Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/ data source applicability. 4 Can infiltration greater than 0.5 inches per hour be allowed without causing potential water balance issues such as change of seasonality of ephemeral streams 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: Results should be confirmed or revised, as necessary, based on more detailed design-level investigation and analysis during BMP design. See Section "Storm Water Infiltration" of this report (Group Delta Consultants -Report of Geotechnical Investigation, 330 Chinquapin Avenue, dated November 15, 2018). Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/ data source applicability. Part 1 Result * If all answers to rows 1 -4 are "Yes" a full infiltration design is potentially feasible. The feasibility screening category is Full Infiltration If any answer from row 1-4 is "No", infiltration may be possible to some extent but would not generally be feasible or desirable to achieve a "full infiltration" design. Proceed to Part 2 YES *To be completed using gathered s1te mformaaon and best professional Judgment cons1dermg the defulition of MEP in the MS4 Permit. Additional testing and/or studies may be required by the City to substantiate findings. 1-4 February 2016 Appendix I: Forms and Checklists Form 1-8 Page 3 of 4 Part 2 -Partial Infiltration vs. No Infiltration Feasibility Screening Criteria Would infiltration of water in any appreciable amount be physically feasible without any negative consequences that cannot be reasonably mitigated? Criteria 5 Screening Question 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: Yes No Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/ data source applicability and why it was not feasible to mitigate low infiltration rates. 6 Can Infiltration in any appreciable quantity be allowed without increasing risk of geotechnical hazards (slope stability, groundwater mounding, utilities, or other factors) that cannot be mitigated to an 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: Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/ data source applicability and why it was not feasible to mitigate low infiltration rates. 1-5 February 2016 Appendix I: Forms and Checklists Criteria 7 Form 1-8 Page 4 of 4 Screening Question Can Infiltration in any appreciable quantity be allowed without posing significant risk for groundwater related concerns (shallow water table, storm water pollutants or other factors)? The response to this Screening Q uestio n shall be based on a comprehensive evaluation of the factors presented in Appendix C.3. Provide basis: Yes No Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/ data source applicability and why it was not feasible to mitigate low infiltration rates. 8 Can infiltration be allowed without violating downstream water rights? The response to this Screening Question shall be based on a comprehensive evaluation of the factors presented in Appendix C.3. Provide basis: Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of smdy / data source applicabil.ity and why it was not feasible to mitigate low infiltration rates. Part 2 Result* If all answers from row 5-8 are yes then partial infiltration design is potentially feasible. The feasibility screening category is Partial Infiltration. If any answer from row 5-8 is no, then infiltration of any volume is considered to be infeasible within the drainage area. The feasibility screening category is N o Infiltration. *To be completed using gathered site information and best professional judgment considering the definition of MEP in the MS4 Permit. Additional testing and/ or studies may be required by the City to substantiate findings. 1-6 February 2016 Appendix I: Forms and Checklists Factor of Safety and Design Infiltration Rate Worksheet Form 1-9 Factor Descriptio n Assigned Factor Product (p) Factor Category Weight (w) Value (v) p =w xv Soil assessment methods 0.25 2 0.5 Predominant soil texture 0.25 1 0.25 Suitability Site soil variability 0.25 1 0.25 A Assessment Depth to groundwater I rmperv10us 0.25 1 0.25 layer Suitability Assessment Safety Factor, SA = :Ep 1.25 Level of pretreatment/ expected 0.5 1 sediment loads 2 B Design Redundancy/ resiliency 0.25 2 0.5 Compaction during construction 0.25 2 0.5 Design Safety Factor, Sn = :Ep 2 Combined Safety Factor, St0ta1= s.~ X Sn 2.5 Observed Infiltration Rate, inch/hr, !<observed (corrected for test-specific bias) 2.76 Design Infiltration Rate, in/hr, l<(le,ign = !<observed / S,otal 1.1 Supporting Data Briefly describe infiltration test and provide reference to test forms: See Section "Storm Water Infiltration" of this report (Group Delta Consultants -Report of Geotechnical Investigation, 330 Chinquapin Avenue, dated November 15, 2018). 1-7 February 2016 ------------------------------------... - APPENDIX C LABORATORYTESTS- GROUP DELTA (2018) -----.... -------.. .. --.. ---------------.. ---- Sample Number EXPANSION INDEX (ASTM 04829) Soil Description FILL: Red-Brown Silty Sand (SM) Expansion Index B-2@0'-5' B-5 @0'-5' FILL/Formation Blend: Red-Brown Silty Sand/ Poorly-graded Sand with Silt (SM/SP-SM) 0 0 Expansion Index Oto 20 21 to 50 51 to 90 91 to 130 Above 130 AGRCUPDELTA Potential Expansion Very Low Low Medium High Very High LABORATORY TEST RESULTS Project No. SD589 Document No. SD18-0136 Figure B-2 -----------------... ----- - --- ---... .... -- Sample Number B-3@0'-5' pH 7.58 SULFATE CONTENT[%] 0.00 to 0.10 0.10 to 0.20 0.20 to 2.00 Above 2.00 SOIL RESISTIVITY Oto 1,000 1,000 to 2,000 2,000 to 5,000 5,000 to 10,000 Above 10,000 CHLORIDE {Cl) CONTENT [%] 0.00 to 0.03 0.03 to 0.15 Above 0.15 A GROUP DEL TA CORROSIVITY (ASTM D516, CTM 643) RESISTIVITY [OHM-CM] SULFATE CONTENT [%] CHLORIDE CONTENT [%] 7075 SULFATE EXPOSURE Negligible Moderate Severe Very Severe 0.01 <0.01 CEMENT TYPE II, IP(MS), IS(MS) V V plus pozzolan GENERAL DEGREE OF CORROSIVITY TO FERROUS METALS Very Corrosive Corrosive Moderately Corrosive Mildly Corrosive Slightly Corrosive GENERAL DEGREE OF CORROSIVITY TO METALS Negligible Corrosive Severly Corrosive LABORATORY TEST RESULTS Project No. SD589 Document No. SD18-0136 Figure B-3 ... -... -------.. ---... ---.. -... ... ---.. ------... --... .. - Sample Number B-4@0'-5' Location of Sample R-VALUE {CTM 301) Sample Description R-Value Proposed Drive/Parking Area FILL: Orange-Brown Silty Sand (SM) 70 LABORATORY TEST RESULTS Project No. SD589 Document No. SD18-0136 Figure 8-4 APPENDIX D OS HPD 330 Chinquapin Avenue, Carlsbad, CA Latitude, Longitude: 33.1480, -117.3416 \\ 9 El8n Tamarack~' \ Carl sbad Vacation Shores Apartments T \ \\\ Mama's Cookie Jar' ' \\,\ Vigilucci's Se,af~od ~ \ & Steakhouse T \ CJ ~ \ ~ Go gle Date Design Code Reference Document Risk Category Site Class Type Ss s, Value 1.092 0.394 1.161 Da ly & Associates \ ~ Real Estate Group '\ <.p. ~~e c:;,e°'~0'~ 9 \,~arbor Drive Trail' f Untethered ~l'o\ers A 3951 -3999 Carlsbad T Blvd Parkinq Description 10/27/2021, 8:07:00 AM ASCE7-16 II D -Stiff Soil MCER ground motion. (for 0.2 second period) SMS SM1 Sos So1 null -See Section 11.4.8 0. 7 51 0.774 MCER ground motion. (for 1.0s period) Site-modified spectral acceleration value Site-modified spectral acceleration value Numeric seismic design value at 0.2 second SA Numeric seismic design value at 1.0 second SA null -See Section 11.4.8 0 .501 Type Value Description SOC null -See Section 11.4.8 D Seismic design category Fa 1.063 Site amplification factor at 0.2 second F v null -See Section 11.4.8 1. 9O6site amplification factor at 1.0 second PGA 0.483 FPGA 1.117 PGAM 0.539 TL 8 SsRT 1.092 SsUH 1.224 SsD 1.5 S1RT 0.394 S1UH 0.436 S1D 0.6 PGAd 0.591 CRs 0.892 CR1 0.904 MCEG peak ground acceleration Site amplification factor at PGA Site modified peak ground acceleration Long-period transition period in seconds Probabilistic risk-targeted ground motion. (0.2 second) Factored uniform-hazard (2% probability of exceedance in 50 years) spectral acceleration Factored deterministic acceleration value. (0.2 second) Probabilistic risk-targeted ground motion. (1.0 second) Factored uniform-hazard (2% probability of exceedance in 50 years) spectral acceleration. Factored deterministic acceleration value. (1.0 second) Factored deterministic acceleration value. (Peak Ground Acceleration) Mapped value of the risk coefficient at short periods Mapped value of the risk coefficient at a period of 1 s Map data ©2021