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Home My WebLink AboutSDP 2020-0005; CHILDREN'S PARADISE; GEOTECHNICAL INVESTIGATION AND BOREHOLE PERCOLATION TESTING; 2020-01-29Geotechnical Investigation And Borehole Percolation Testing Proposed New Preschool Quarry Creek Development Marron Road, Carlsbad, California January 29, 2020 Prepared For: ACAL Engineering, Inc. 145 North Melrose Drive, Suite 200 Vista, California 92083 Prepared By: §.MS Geotechnical Solutions, Inc. 5931 Sea Lion Place, Suite 109 Carlsbad, California 92010 Project No. GI-19-11-155 .r :r, NOV v 5 2020 ci-,-( Or Cht...)LSBAD PLAN! /I. JC: _:. l_l!S. -::_,_ l .. -.. .. -- • - ---- • Project No. GI-19-11-155 January 29, 2020 ACAL Engineering, Inc. 145 North Melrose Drive, Suite 200 Vista, California 92083 §I§ GEOTECHNICAL SOLUTIONS, INC. Consulting Geotechnical Engineers 5931 Sea Lion Place, Suite 109 Carlsbad, California 92010 Offtce:760-602-7815 smsgeosoLinc@gmaiLcom GEOTECHNICAL INVESTIGATION AND BOREHOLE PERCOLATION TESTING, PROPOSED NEW PRESCHOOL, QUARRY CREEK DEVELOPMENT, MARRON ROAD, CARLSBAD, CALIFORNIA Pursuant to your request, Sl#IS Geotechnical Solutions, Inc. has completed the attached Geotechnical Investigation and borehole percolation testing report for the proposed preschool development project at the above--referenced property. The following report summarizes the results of our research and review of the pertinent documents and geotechnical reports, subsurface exploratory test excavations, field in-situ testing and sampling, laboratory testing, engineering analysis and provides conclusions and recommendations for the proposed development, as understood. From a geotecbnical engineering standpoint, it is our opinion that the planned preschool development at the study property is feasible, provided the recommendations presented in this report are incorporated into the design and construction of the project . If you have any questions or need clarification, please do not hesitate to contact this office. Reference to our Project No. GI-19-11-155 will help to expedite our response to your inquiries. We appreciate this opportunity to be of service to you. §I§ Geotechnical Solutions, Inc. R18 C1077 D3740 E329 ACCRE.OITEO .. "' .. .. - -- ... -.. .. -.. • .. .. - • -- TABLE OF CONTENTS I. INTRODUCTION ...................................................... 1 II. PERTINENT PRIOR GEOTECHNICAL REPORTS ..•••••••••••.•••••••.•. 1 III. SITE DESCRIPTION ................................................... 2 IV. PROPOSED DEVELOPMENT ........................................... 2 V. FIELD INVESTIGATION ............................................... 2 VI • VII. REGIONAL GEOLOGIC SETTING ...•..............•.•••••.••••••••••.• 3 GEOTECHNICAL CONDITIONS .••••..... A. Earth Materials B. Groundwater and Surface Drainage ..• C. Slope Stability .•.•.•••... D. Geologic Hazards •••...• E. Site Classification for Seismic Design F. Faults/Seismicity . .•..•...................... 3 .... 4 . ... 4 . ............•. 5 . .............. 5 .•..•.......... 5 G. Seismic Design Values ................................ . ......... 6 . ..... 8 . ......•.. 8 H. Laboratory Tests and Test Results ...•••..•....•••..•••.• VIII. SITE CORROSION ASSESSMENT •...•........••....•.•••••••••...••••• 12 IX. x. XI. XII. STO RMW ATER BMPs ................................................ 13 CONCLUSIONS ...................................................... 13 RECOMMENDATIONS .••.....•...•. A. Grading and Earthworks ....•.........•.. B. Footings and Slab-on-Grade Floor Foundations .............. C. Soil Design Parameters ................................... D. Exterior Concrete Slabs and Flatworks . E. F. Pavement Design . . ......... . General Recommendations ... . 16 16 ....... 21 ....... 23 • •• 24 • •• 25 • •• 29 GEOTECHNICAL ENGINEER OF RECORD (GER) ...••..•.••...•....•... 31 XIII. LIMITATIONS ....................................................... 32 .. .. - .. .. - - --- -.. .. • - .. -- - TABLE OF CONTENTS (continued} FIGURES Regional Index Map .•..••••••••••••••••••..••••••••.••••.••.••.•.•••••.••••••. 1 Geotechnical Site Plan ••••...••.••••••••••.•.••••••..••••.••.•••••••.•.....•.•. 2 Boring Logs • . • • . • • • • • • . • • . . . . • . • • . • • • . • • • . . . • • • • • • • • • • • . . . • • • . • • • • • . . • • • . • 3-5 Geologic Map •••.••••••••.....••••••...•••••••.••••••••••.•.••••••••.•••••.•• 6 Cross-Section A-A' ••••••••.•••••••••...••...•••.••..•••••••••••.•.•••...•••••• 7 Cross-Section B-B' .•....•.....•.•..•..•...••.••...•.•......•••.•••..•..•....•• 8 Fault-Epicenter Map •••..........•.....••.•.••••••••.....•..•.••.•...•.•.••••• 9 Grain S iz-e Analysis • . • • • • • • • • • • . • • • • • • • • • . • • • • • • • • • • • • • . . • • • • • • • . . • • • • • . . • • • • 10 Typical Retaining Wall Back Drainage ••.••••••••••.••.•.•.••••.•••••••........• 11 Typical Over-Excavation and Recompaction Detail ••••••••••••••••.•••••••.•..••• 12 Typical Isolation Joints and Re-Entrant Comer Reinforcement ••••••••••.••••.••.•• 13 Typical Permeable Interlocking Concrete Paver(PICP) Detail ••.••.•.•.•..•.•.••.••• 14 Typical Pipes Through or Trench Adjacent to Foundations ..••..•••.•.••••••.•••.•• 15 APPENDIX A: Seismic Design Values APPENDIX B: Borehole Percolation Testing for Planning Phase Feasibility of Stormwater Infiltration/Percolation --.. - -.. ----- -.. .. - • -• --.. .. .. - .. -.. GEOTECHNICAL INVESTIGATION AND BOREHOLE PERCOLATION TESTING PROPOSED NEW PRESCHOOL QUARRY CREEK DEVELOPMENT MARRON ROAD, CARLSBAD, CALIFORNIA I. INTRODUCTION The project property investigated herein consists of an existing recently graded nearly level vacant parcel located in the new Quarry Creek Development, south of Highway 78 and west of College Boulevard within the northern limits of the city of Carlsbad. The approximate site location is shown on a Regional Index Map attached to this report as Figure 1. The approximate site coordinates are 3 3 .177 5°N latitude and -117 .2998°W longitude. We understand that the project property is planned for development into a preschool facility with the associated interior parking stalls and drive lanes. Consequently, the purpose of this investigation was to evaluate soil and geotechnical conditions at the project property and to ascertain their influence upon the planned development. Document research and review, exploratory test boring and percolation borehole drilling, in-situ field borehole percolation (infiltration) testing, soil sampling, laboratory testing, and engineering analysis were among the activities conducted in connection with this effort which have resulted in conclusions and geotechnical development recommendations presented in the following sections. The existing nearly level vacant building pad is a recent development with new grading activities apparently performed under engineering observations and compaction testing provided by the original geotechnical consultant for the Quarry Creek Development. We further understand final pad fine/ contour grading is not yet completed and will also be carried out under engineering observations and testing services of the project geotechnical consultant, who will publish a final pad grading report(s) for the project at that time. II. PERTINENT PRIOR GEOTECHNICAL REPORTS Based on our research the following reports pertinent to the project property are available and were reviewed as a part of this study: A. "Update Geotechnical Investigation, Quarry Creek, Carlsbad/Oceanside, California," prepared byGeocon Incorporated, Project No. 07135-42-05, report dated February 24, 2015. B. "Preliminary Geotechnical Investigation, Quarry Creek II, Carlsbad/Oceanside, California," prepared by Geocon Incorporated, Project No. 07135-42-03, report dated May 11, 2012 . "' ... .. .. - • • -.. • • - - -.. -- Geotechnical Investigation and Borehole Percolation Testing, Proposed January 29, 2020 New Preschool, Quarry Creek Development, Marron Road, Carlsbad, California Page 2 III. SITE DESCRIPTION A Geotechnical Map depicting the existing general site conditions and proposed new development, utilizing the plan made available us as a base map, is included with this report as Figure 2. As shown, the property is an irregularly-shaped, nearly level vacant graded parcel bordered by Marron Road along the northern margins. A large, nearly 110-foot high graded cut slope ascending at 2 (horizontal) to 1 (vertical) gradients maximum with drainage terraces mark the southern property margins. An existing retaining wall is located in the eastern site margins, while an existing HOA drainage easement supporting a sediment trap pond occurs at the western comer of the property. The property appears to be graded cut surfaces, with shallow fills, thought to have originally been created during the Quarry Creek deep sands and gravels mining operation. Existing new nearly level pad grades were likely developed as a part of recent subsequent mass grading operations for the Quarry Creek development. IV. PROPOSED DEVELOPMENT Proposed site development is shown on the enclosed Figure 2. Based on our understanding of the project, the property is planned for development into a preschool facility with the associated interior parking stalls and drive lanes. Major ground modifications are not proposed, however, minor fine and/or contour grading, raising existing pad grades by approximately 2 feet maximum, and construction of short perimeter retaining walls for achieving final design elevations are anticipated. Final pad fine/contour grading will also be carried out under engineering observations and testing services of the project geotechnical consultant, who will publish a final pad grading report( s) for the project at that time . Construction is expected to consist of conventional wood framed with exterior stucco buildings with a light roof supported on shallow stiff concrete footings and slab-on-grade floor type foundations . Associated improvements will include underground utilities, interior asphalt (HMA) parking stalls and drive lane, new driveways off Marron Road, a trash enclosure and grease trap, and concrete sidewalks. The project will also likely include the installation of storm water treatment control BMP facilities. Pervious pavers, also known as Penneable Interlocking Concrete Pavers (PICP), are additionally anticipated as a part of the project stormwater BMP designs to reduce impervious surface areas in the perimeter yards and patio locations around the building. V. FIELD INVESTIGATION Subsurface conditions at the project site were chiefly evaluated by the excavation of four (4) percolation borehole and three (3) exploratory test borings. The percolation boreholes and exploratory test borings were drilled with a truck-mounted, 8-inch diameter hollow stem auger rotary drill rig. Geotechnical test borings (designated as B-101, B-102 and B-103 on Figure 2) were advanced to auger refusal depths into the underlying bedrock. Percolation boreholes ( designated as P-201 though P-204 on Figure 2) were also advanced to auger refusal depths into the underlying bedrock, developed for the purpose of evaluating apparent percolation/infiltration rates and feasibility ofbio-detention/BMP facilities at the designated site locations . .. .. - -... .. .. - - - .. .. - .. • - • - - .. Geotechnical Investigation and Borehole Percolation Testing, Proposed January 29, 2020 New Preschool, Quarry Creek Development, Marron Road, Carlsbad, California Page 3 Exploratory geotechnical borings and percolation boreholes were logged by our project geologist( s ), who also supervised in-situ testing and the collection of representative soil samples at selected intervals for subsequent laboratory testing. The approximate exploratory test boring and percolation borehole locations are shown on Figure 2. Exploratory geotechnical boring logs are included as Figures 3, 4, and 5. Laboratory test results and engineering properties of selected representative soil samples are summarized in following sections. Logs of the percolation boreholes are included as Figures i, ii, iii and iv of Appendix B . VI. REGIONAL GEOLOGIC SETTING The San Diego area is located in the Peninsular Ranges geomorphic batholith. The northwesterly- trending mountain ranges of this province generally consist of Jurassic metamorphic rocks intruded by Cretaceous igneous rocks. During the past 54 million years, the coastal flanks of these mountainous areas have undergone several episodes of marine inundation and subsequent regression. This has resulted in deposition of a thick sequence of marine and nonmarine sediments on the metamorphic and igneous basement rocks. In the Mount Soledad area, these rocks have been uplifted, tilted and faulted due to activity along the Newport-Inglewood/ Rose Canyon fault zone. Further discussion of faulting in regards to the site is discussed in the Geologic Hazards section of this report . A Geologic Map showing mapped units at and near the study site is attached as Figure 6 . VII. GEOTECHNICAL CONDITIONS The new nearly level pad is apparently a recently graded surface underlain by a shallow to relatively modest section of compacted fills placed over crystalline bedrock exposures and originally developed during the Quarry Creek deep sands and gravels mining operation. Recent grading and fill placement were supposedly carried out under engineering observation and compaction testing services provided by the project geotechnical consultant. We understand final pad fine/contour grading will raise the existing grades by nearly 2 feet, and is not yet completed. The planned final pad fine/contour grading will be carried out under engineering observations and testing services of the project geotechnical consultant, who will publish a forthcoming final pad grading report . Instability which could preclude the planned new development is not in evidence. Cross-Sections illustrating subsurface profile based on our exploratory test borings, existing site topography and final design grades is attached to this report as Figures 7 and 8. The following earth materials were recognized: .. .. .. -- - - - ---- --- - .. .. --- Geotechnical Investigation and Borehole Percolation Testing, Proposed January 29, 2020 New Preschool, Quarry Creek Development, Marron Road, Carlsbad, California Page 4 A. Earth Materials Bedrock (Kt): The project site is underlain at relatively shallow to modest depths by crystalline bedrock units consisting of Tonalite rocks associated with the Cretaceous age southern California batholith. Site bedrock units are also exposed on the existing large graded cut slope along the southern property margin. The underlying bedrock, as encountered in our exploratory excavations, consists of tan to grey brown color, massive hard to very hard units. Project bedrock are stable, competent units which typically perform well in natural hillside and graded slope conditions, and will provide suitable support for new fills and building and structural foundation support. Artificial Fills (Qaf): A relatively shallow to relatively modest section of artificial fills consisting of brown rocky to gravelly silty clayey sand to sandy clay materials mantle the property. Site fills, where exposed in our exploratory borings under the planned building areas, are on the order of 5.5 feet thick maximum, and are expected to thicken toward the front of the property and continue under the Marron Road. Underlying fills occur in moist and tight to well-compacted conditions overall. B. Groundwater and Surface Drainaa=e Subsurface groundwater was not encountered in our test borings, at the time of our field explorations, to the explored refusal depths, and is not expected to be a factor in the planned project development. As with all building sites, the proper control of flood waters and site surface drainage is a critical component to the overall stability of the graded building pad and perimeter improvements. Surface water should not pond upon graded surfaces, and irrigation water should not be excessive. Over-watering of site vegetation may also create perched water and the creation of excessively moist areas at finished pad surfaces and should be avoided. Perimeter building surfaces should direct run-off away from the building foundations and site improvements in a positive manner. A drainage and debris facility should be provided at the base of the rear cut slope. For this purpose the proposed partial toe retaining wall may be extended along the entire base of the slope and be provided with a minium 2-course high free board and a minimum 24-inch wide backside drainage bench. The toe retaining wall should also be provided with a subsurface back drainage system as specified in the following sections. Surface run-off should over the improved surfaces should also be properly captured and discharged into approved storm drainage facilities as shown on the project drainage improvement plans . ---- --- .... ---.. ... -.. ---.. -.. - .. -.. -- - Geotechnical Investigation and Borehole Percolation Testing, Proposed January 29, 2020 New Preschool, Quarry Creek Development, Marron Road, Carlsbad, California Page 5 C. Slope Stability Significant new graded slopes are not planned in connection with the proposed new development. There is an existing large ascending slope along the southern pad perimeter that was apparently created during the Quarry Creek deep sands and gravels mining operation. The existing southern slope is a maximum 2:1 gradient graded cut slope, nearly 110 feet in maximum vertical height, with drainage terraces exposing competent and stable crystalline bedrock units that typically perform well in natural or graded slope conditions. Based on our field observations, major instability due to adverse rock fracturing or gross failure conditions are not indicated. However, in order to protect downslope structures and improvements from any potential future slope face weathering and debris unraveling, a short retaining wall with a minimum 2-course high freeboard and at least 2 feet wide backside drainage bench is recommended at the base of the southern perimeter ascending cut slope. Landslides or other forms of deep-seated instability are not indicated at the subject slope . D. Geolo&ic Hazards Geologic hazards are not presently indicated at the project site. The existing southern perimeter ascending graded cut slope exposes competent and stable crystalline bedrock and does not indicate gross geologic instability. New large graded slopes are also not planned. The most significant geologic hazards at the property will be those associated with ground shaking in the event of a major seismic event. Liquefaction or related ground rupture failures are not anticipated. E. Site Classification for Seismic Desiin Site soils are classified based on the upper 100 feet maximum of a site profile. Site Classes A and B shall not be assigned to a site, if there is more than 10 feet of soil ( or fill) between the top of the underlying rock surface and bottom of the foundation. Site Classes A and B are most commonly supported by shear wave velocity determination (us, ft/s). Site Class F, which may require a site response analysis, consists of liquefiable or collapsible soils and highly sensitive clay soil profile. Site Classes C, D, and E soils may specifically be classified from subsurface explorations and using an average Standard Penetration Resistance (N) method for soil layers based on Section 20.4.2 of ASCE 7. Site Classification is then established based on Table 20.3-1 of ASCE 7. Appropriate soil properties are also permitted to be estimated by the project geotechnical consultant based on known geotechnical conditions. Based on our study, an average in-situ Standard Penetration Resistance (N) of greater than 50 may be conservatively presumed to be representative of the upper 100 feet of the site subsoil profile, and Site Class C (Very Dense Soil and Soft Rock) may be considered for the project design purposes. Geotechnical Investigation and Borehole Percolation Testing, Proposed January 29, 2020 New Preschool, Quarry Creek Development, Marron Road, Carlsbad, California Page 6 F. Faults/Seismicity Faults or significant shear zones are not indicated on or near proximity to the project site. As with most areas in California, the San Diego region lies within a seismically active zone; however, coastal areas of the county are characterized by low levels of seismic activity relative to inland areas to the east. During a 40-year period (1934-1974), 37 earthquakes were recorded in San Diego coastal areas by the California Institute of Technology. None of the recorded events exceeded a Richter magnitude of 3. 7, nor did any of the earthquakes generate more than modest ground shaking or significant damages. Most of the recorded events occurred along various offshore faults which characteristically generate modest earthquakes. Historically, the most significant earthquake events which affected local areas originated along well known, distant fault zones to the east and the Coronado Bank Fault to the west. Based upon available seismic data, compiled from California Earthquake Catalogs, the most significant historical event in the area of the study site occurred in 1800 at an estimated distance of 12.3 miles from the project area. This event, which is thought to have occurred along an offshore fault, reached an estimated magnitude of 6.5 with an estimated bedrock acceleration value of 0.104g at the project site. The following list represents the most significant faults which commonly impact the region. Estimated ground acceleration data compiled from Digitized California Faults (Computer Program EQF AULT VERSION 3 .00 updated) typically associated with each fault is also tabulated. TABLEl ~ FAULTZONE DIS11~CE FROM SITE FROB~L'E ACCEtEifATI@~ C'.R:H.) Rose Canyon Fault 7.6 miles 0.146g Newport-lngelwood Fault 7.6 miles 0.145g Elsinore-Temecula Fault 21.4 miles 0.101g Coronado Bank Fault 23.7 miles 0.129g The locations of significant faults and earthquake events relative to the study site are depicted on a Fault -Epicenter Map attached to this report as Figure 9. Geotechnical Investigation and Borehole Percolation Testing, Proposed January 29, 2020 New Preschool, Quarry Creek Development, Marron Road, Carlsbad, California Page 7 Recently, the number of seismic events that affect the region appears to have somewhat heightened. Nearly 40 earthquakes of magnitude 3 .5 or higher have been recorded in coastal regions between January 1984 and August 1986. Most of the earthquakes are thought to have been generated along offshore faults. For the most part, the recorded events remain as moderate shocks which typically resulted in low levels of ground shaking to local areas. A notable exception to this pattern was recorded on July 13, 1986. An earthquake of magnitude 5.3 shook county coastal areas with moderate to locally heavy ground shaking. This resulted in $700,000 in damages, one death, and injuries to 30 people. The quake occurred along an offshore fault located nearly 30 miles southwest of Oceanside. A series of notable events shook county areas with a (maximum) magnitude 7.4 shock in the early morning of June 28, 1992. These quakes originated along related segments of the San Andreas Fault, approximately 90 miles to the north. Locally high levels of ground shaking over an extended period of time resulted; however, significant damages to local structures were not reported. The increase in earthquake frequency in the region remains a subject of speculation among geologists; however, based upon empirical information and the recorded seismic history of county areas, the 1986 and 1992 events are thought to represent the highest levels of ground shaking that can be expected at the study site as a result of seismic activity. In recent years, the Rose Canyon Fault has received added attention from geologists. The fault is a significant structural feature in metropolitan San Diego that includes a series of parallel breaks trending southward from La Jolla Cove through San Diego Bay toward the Mexican border. Test trenching along the fault in Rose Canyon indicated that at that location the fault was last active 6,000 to 9,000 years ago. More recent work suggests that segments of the fault are younger having been last active 1,000 -2,000 years ago. Consequently, the fault has been classified as active and included within an Alquist-Priolo Special Studies Zone established by the State of California. Furthermore, a more recent study concluded that the coastal region of San Diego may experience earthquakes up to magnitudes 7 .3 and 7.4 (Sahakian et al, 2017). This study used the Newport-Ingelwood/Rose Canyon fault offshore. An earthquake of this magnitude has likely not occurred in the last 100,000 years, according to the data. Fault zones tabulated in the preceding table are considered most likely to impact the region of the study site during the lifetime of the project. The faults are periodically active and capable of generating moderate to locally high levels of ground shaking at the site. Ground separation as a result of seismic activity is not expected at the property. Geotechnical Investigation and Borehole Percolation Testing, Proposed January 29, 2020 New Preschool, Quarry Creek Development, Marron Road, Carlsbad, California Page 8 I G. Seismic Desi~n Values Seismic design values are presented in the attached Appendix A in accordance with Chapter 16, Section 1613 of the 2019 California Building Code (CBC) and ASCE 7 Standard. Presented values are generated using ASCE developed web interface that uses the United States Geological Survey (USGS) web services and retrieves the seismic design data in a report format. H. Field and Laboratory Tests and Test Results Earth deposits encountered in our exploratory test borings were closely examined and sampled for laboratory testing. Based upon our test boring and field exposures, site soils have been grouped into the following soil types: TABLE2 Soill'~e I Descri2tion I 1 Tan to light-olive brown silty clayey sand to sandy clay (fill) 2 Dark grey crystalline rock (Bedrock) The following tests were conducted in support of this investigation: 1. Standard Penetration Tests: Standard penetration tests (SPT) were performed at the time of borehole drilling in accordance with ASTM standard procedure D1586 using rope and cathead. The procedure consisted of a standard 51 MM outside diameter sampler without liner, 457 MM in length and 35 MM in inside diameter driven with a 140-pound hammer, dropped 30 inches using 5-foot long AW drill rods. The bore hole was 200 MM (8 inches) in diameter and drill fluid or water was not necessary to aid drilling. The test results are indicated at the corresponding locations on the attached geotechnical exploratory Boring Logs (Figures 3, 4 and 5). 2. Specific Gravity Test: A specific gravity test was performed on Soil Type 1 to determine ratio of the mass of a unit volume of a soil solids to the mass of the same volume of gas-free distilled water at 20 degrees Celsius in accordance with the Method B of ASTM D854 test procedure. The test results are presented in Table 3. TABLE3 l ~l====L=oc=a=ti=on==*=S=o=il=T=zy~e=?===========G=s(=2=0)============:II _I B-102@ I' 1 2.73 I_ Geotechnical Investigation and Borehole Percolation Testing, Proposed January 29, 2020 New Preschool, Quarry Creek Development, Marron Road, Carlsbad, California Page 9 3. Grain Size Analyses: Grain size analyses were performed on representative samples of Soil Type 1. The test results are presented in Table 4, and graphically illustrated on the attached Figure 10. TABLE4 Sieve Size #30 mao #100 #200 Location Soil Type Percent Passing B-102 l' 100 98 95 86 82 63 50 4. Liquid Limit, Plastic Limit and Plasticity Index: Liquid limit, plastic limit and plasticity index tests were performed on representative samples of Soil Type 1 m accordance with ASTM D4318. The test results are presented in Table 5. TABLES Location Soil Ty,pe Uguid'It.imit Plastic Limit J!lasbcib' lnclex LL(%)J PL(%"), atL-PL=~D B-103@ l' 1 32 16 16 5. Maximum Dry Density and Optimum Moisture Content: The maximum dry density and optimum moisture content of Soil Type 1 was determined in accordance with ASTM D 1557. The test results are presented in Table 6. Location B-102 I' Soil 'I t .e TABLE6 127 11 6. Unit Wei~ht & Moisture Content Tests: In-place dry density and moisture content of representative soil deposits beneath the site were determined from relatively undisturbed ring samples using the Direct Measurement test method (Method B) in accordance with ASTM D7263, and Water Content of Soil and Rock by Mass test method in accordance with ASTM D2216. The test results are presented in Table 7 and tabulated on the attached Boring Logs at corresponding locations. Geotechnical Investigation and Borehole Percolation Testing, Proposed January 29, 2020 New Preschool, Quarry Creek Development, Marron Road, Carlsbad, California Page 10 Sample Locatio.n B-101@ 1' 1 B-102@ 1.5' 1 B-103 @2' 1 TABLE7 Mar.Di;y Densi.ty (rllli'pcf) 9 104.9 127 8 114.2 127 7 120.4 127 Assumptions and Relationships: In-place Relative Compaction= (Id+ Tm) Xl00 Gs= 2.73 e= (Gs Yw +Yd)-1 S=(wGs)+e 83 39 90 43 95 47 7. Expansion Index Test: One expansion index (EI) test was performed on a representative sample of onsite Soil Type 1 in accordance with the ASTM D4829. The test results, are presented in Table 8. S2lmpte Location I B-103@ l' S'oil Type 9.8 TABLES 50.2 19 110.3 w = moisture content in percent. Measur1d El 39 Elso = Eimeas -(50 -Smeas) ((65 + Elmeas) + (220 -Smeas)) Expansion Index (ED Expansion Potential 0 -20 Very Low 21-50 Low 51 -90 Medium 91-130 High ) 130 Ve Hi h EI 5'0% Saturation 39 8. Direct Shear Test: One direct shear test was performed on a representative remolded sample of onsite Soil Type I in accordance with ASTM D3080. The prepared specimen was soaked overnight, loaded with normal loads of 1, 2, and 3 kips per square foot respectively, and sheared to failure in an undrained condition. The test results are presented in Table 9 below. Geotechnical Investigation and Borehole Percolation Testing, Proposed January 29, 2020 New Preschool, Quarry Creek Development, Marron Road, Carlsbad, California Page 11 Sample Location B-102 l' Soil Tme 1 TABLE9 Remolded to 90% of Y m % wo t 126.5 29 130 9. pH and Resistivity Test: pH and resistivity of a representative sample of onsite Soil Type 1 were determined using "Method for Estimating the Service Life of Steel Culverts," in accordance with the California Test Method (CTM) 643. The test result is tabulated in Table 10. TABLE 10 Sample,Location B-101@ 2.5' I 1 990 8.9 10. Sulfate Test: A sulfate test was performed on a representative sample of onsite Soil Type 1 in accordance with the California Test Method (CTM) 417. The test result is presented in Table 11 . TABLE 11 Sample ~ation B-101 @2.5' 0.007 11. Chloride Test: A chloride test was performed on a representative sample of onsite Soil Type 1 in accordance with the California Test Method (CTM) 422. The test result is presented in Table 12. TABLE 12 Sample l!;ocation oun o a er hloriae In Soil % b t B-101 @2.5' 1 0.011 Geotechnical Investigation and Borehole Percolation Testing, Proposed January 29, 2020 New Preschool, Quarry Creek Development, Marron Road, Carlsbad, California Page 12 VIII. SITE CORROSION ASSESSMENT A site is considered to be corrosive to foundation elements, walls and drainage structures if one or more of the following conditions exist: * Sulfate concentration is greater than or equal to 2000 ppm (0.2 percent by weight). * Chloride concentration is greater than or equal to 500 ppm (0.05 percent by weight). * pH is less than 5 .5. For structural elements, the minimum resistivity of soil ( or water) indicates the relative quantity of soluble salts present in the soil (or water). In general, a minimum resistivity value for soil (or water) less than 1000 ohm-cm indicates a potential for presence of high quantities of soluble salts and a higher propensity for corrosion. Appropriate corrosion mitigation measures for corrosive conditions should be selected depending on the service environment, amount of aggressive ion salts ( chloride or sulfate), pH levels and the desired service life of the structure. Results oflimited laboratory tests performed on selected representative of site soil samples indicated that the minimum resistivity is approaching but less than 1000 ohm-cm suggesting a potential for presence of high quantities of soluble salts. However, test results further indicated that pH levels are greater than 5.5, sulfate concentrations are less than 2000 ppm and chloride concentration levels are less than 500 ppm, suggesting non-corrosive site conditions. §N§ Geotechnical Solutions, Inc. does not consult in the field of corrosion engineering and the client, project architect or structural engineer should agree on the required level of corrosion protection, or consult a corrosion engineer as warranted. However, based on the result oflimited testing of onsite soil sample, the amount of water soluble sulfate (SO4) was found to be 0.007 percent by weight (70 ppm) which is considered negligible according to ACI 318 (SO Exposure Class with Not Applicable severity). Watersolublechloride(CL)was found0.011 percent by weight (I 10 ppm), and the project property is not located within 1000 feet of salt or brackish water (anticipated concrete dry or protected from moisture). Consequently, exposures to chloride may also be considered negligible (CO Exposure Class with Not Applicable severity). In our opinion the project site may be considered non-corrosive, and as a minimum, concrete consisting of Portland cement Type II (ASTM C 150) with minimum 28 days compressive strength (f' c) of 2500 psi and maximum 0.50 water-cement ratio is considered typically adequate for SO and CO Class exposures, unless otherwise specified, or noted on the project plans. Table 13 is appropriate based on the pH-Resistivity test results, and adequate protective measures against corrosion should be considered for all buried metal pipes, connections, elbows, conduits, improvements and structures, as necessary. Buried metal pipes and conduits should be wrapped and provided with appropriate protective cover where applicable and appropriate. Geotechnical Investigation and Borehole Percolation Testing, Proposed January 29, 2020 New Preschool, Quarry Creek Development, Marron Road, Carlsbad, California Page 13 TABLE 13 -Il~!_~SQil ~ G!!!gJ ~ J i 1i 10 ~ 1. 1 Years to Perforation of Metal Culverts 30 40 55 70 85 IX. STORMW ATER BMPs Borehole percolation testing was performed at the project site as a part of this effort to evaluate feasability of storm water infiltration bio-detention and B MP facilities at the designated site locations. Summary of test results including the estimated apparent observed and design infiltration rates and detail discussions on feasability of stormwater infiltration facilities are provided in the attached Appendix B. X. CONCLUSIONS Based on the foregoing investigation, the planned new preschool development project, substantially as proposed, is feasible from a geotechnical viewpoint. The project property consists of newly graded, nearly level pad surfaces mantled by shallow to a relatively modest section of compacted fills placed over very hard crystalline bedrock cut surfaces apparently created during the Quarry Creek deep sands and gravels mining operation. The following factors are unique to the project site studied herein and will most impact development procedures and associated construction costs from a geotechnical viewpoint: A. Landslides, faults or significant shear zones are not present at the project property and are not considered a geotechnical factor in planned site redevelopment. The study site is not located near or within the Alquist -Priolo earthquake fault zone established by the State of California. Moderate to locally high levels of ground shaking, however, are expected at the site during occasional periods of seismic activity along distant active faults. B. The project property is directly underlain by a shallow to modest section of compacted fills placed over competent bedrock units. Site existing fills were apparently placed as part of mass grading operations for the Quarry Creek Development under engineering observations and compaction testing of the project geotechnical consultant. Grading records for the existing site fills are not yet available. We understand final pad fine/contour grading which will raise the existing grades by nearly 2 feet, and is not yet completed. Final pad fine/contour grading will be carried out under the engineering observations and compacting testing services to be provided by the project geotechnical consultant, who will publish a forthcoming final pad grading compaction report. The underlying bedrock are very hard and stable units that can suitably support the upper fills and planned new structures and improvements. .. .. .. ... -- -.. .. - • - • -.. .. -- -- Geotecbnical Investigation and Borehole Percolation Testing, Proposed January 29, 2020 New Preschool, Quarry Creek Development, Marron Road, Carlsbad, California Page 14 C. Upper exposures of site existing fills have experienced weathering and saturation from recent rains and currently occur in soft and compressible conditions, and should be regraded as specified below. Below the impacted upper weathered and soft zone, site fills occur in tight and compacted conditions and are considered suitable for structural support. Estimated minimum stripping (removal) depths are provided in the following sections. D. The project property is an existing nearly level graded pad and major grading or creation of large new graded slopes is not planned. However, proposed development will include fine/contour grading and raising the existing pad by nearly 2 feet for achieving the final design pad grades. Added fills and raising pad grades should only be carried out after completion of the remedial grading and stabilization of existing loose to soft surficial fill exposures. E. Stripping and remedial grading earthwork of existing surficial fill exposures will be required under all proposed new structures and site and improvements in order to construct uniform bearing and subgrade soil conditions throughout, as specified in the following sections . F. Earth deposits generated from the stripping and over-excavations of onsite surficial fill exposures will predominantly consist of gravelly silty clayey sand to sandy clay deposits which are considered suitable for reuse as new fills, provided they are properly prepared and manufactured into a uniform mixture. New import soils required for raising pad grades should consist of good quality sandy granular (D. G.) deposits conforming to the requirements of this report. Project new fills and backfills should be adequately processed, throughly mixed, placed in thin horizontal lifts and mechanically compacted as specified in the following sections . G. Based on our field observations and laboratory testing, final foundation bearing soils at the project property are expected to chiefly consist of gravely silty clayey sand to sandy clay (SM-SC/CL) deposits with low expansion potential ( expansion index less than 50) based on ASTM D4829 classification. Potentially expansive bearing soils ( expansion index greater than 20 per CBC 1803.5.3) will require special treatment including removals or specific moisture conditioning procedures and foundation/slab deign mitigation (CBC 1808.6), as provided in the following sections . Actual classification and expansion characteristics of the finish grade soil mixture can only be provided in the final as-graded compaction report based upon proper testing of foundation bearing soils when rough finish pad grades are achieved. ... ... .. .. ... .. - - -------.. - .. -.. -- Geotechnical Investigation and Borehole Percolation Testing, Proposed January 29, 2020 New Preschool, Quarry Creek Development, Marron Road, Carlsbad, California Page 15 H. The existing large ascending graded cut slope along the southern building pad margin is provided with drainage ditches and developed at 2: 1 maximum gradients. The cut slope exposes very hard and competent crystalline bedrock, which typically performs well in natural and graded slope conditions. Based on our field observations and geologic mapping, the southern graded cut slope will be grossly stable with respect to deep seated and surficial failure modes at the current gradient and maximum vertical height. However, downslope structures and improvements should be protected from any potential future slope face weathering and debris unraveling by construction of a short toe retaining wall with a minimum 2-course high freeboard and at least 2 feet wide backside drainage bench. I. Groundwater was not encountered in our test borings advanced to refusal depths ( 6 feet maximum) below the existing ground surfaces (BGS), and is not expected to be a major factor in the site development and recommended necessary remedial grading works. As with all graded sites, the proper control of surface drainage and storm water is a critical component to overall site and building performance. Run off water should not pond upon graded surfaces, and irrigation water should not be excessive. Over-watering of site vegetation may also create perched water and the creation of excessively moist areas at finished surfaces and should be avoided. Stormwater and drainage control facilities should be designed and installed for proper control and disposal of surface water as shown on the approved grading or drainage improvement plans. The proposed toe retaining wall with a free board and a backside drainage bench recommended at the base of the southern ascending cut slope should also be designed and constructed as a toe drainage and debris control facility. The toe retaining wall should also be provided with a subsurface back drainage system. J. Site grading and earthwork activities are not expected to impact the adjacent properties and right-of-ways provided our recommendations are incorporated into the final designs and implemented during the construction phase. Added field recommendations, however, may also be necessary and should be given by the project geotechnical consultant for the protection of adjacent properties and should be anticipated. K. Liquefaction, seismically induced settlements and soil collapse, are not considered to be major geotechnical factors in the development of the project property, provided our remedial grading, fill placement and compaction procedures, and foundation recommendations are followed. L. Settlement of foundation bearing soils is not expected to be a major geotechnical factor in the construction of the planned new building, structures and site improvements provided our recommendations are followed. Post construction foundation bearing soil settlements are expected to be less than approximately 1-inch and should occur below the heaviest loaded footing( s ). The magnitude of post construction differential settlements, as expressed in terms of angular distortion, is not anticipated to exceed ½-inch in a distance between similarly loaded adjacent structural elements, or a maximum distance of20 feet. -------.. -- --- -.. .. .. -- Geotecbnical Investigation and Borehole Percolation Testing, Proposed January 29, 2020 New Preschool, Quarry Creek Development, Marron Road, Carlsbad, California Page 16 XI. RECOMMENDATIONS The following recommendations are consistent with the indicated geotechnical conditions at the project site and should be reflected in the final plans and implemented during the construction phase. Added or modified recommendations may also be appropriate and should be provided in a plan review report when development plans are finalized: A. Gradin& and Earthwork: Relatively minor pad fine/contour grading and raising pad elevations approximately 2 feet by import filling is planned in order to achieve final design grades. We also understand that final pad fine/contour grading will be carried out under the engineering observations and compacting testing services to be provided by the project geotechnical consultant, who will publish a forthcoming pad grading compaction report. Added fills and raising pad grades should only be carried out after completion remedial grading of existing upper loose to soft surficial fill exposures. All excavations, grading, earthwork, construction and bearing soil preparation should be completed in accordance with Chapter 18 (Soils and Foundations) and Appendix "J" (Grading) of the 2019 California Building Code (CBC), the Standard Specifications for Public Works Construction, City of Carlsbad Ordinances, the requirements of the governing agencies and following sections, wherever appropriate and as applicable: 1. Existing Underground Utilities and Buried Structures: All existing underground waterlines, sewer lines, pipes, storm drains, utilities, tanks, structures and improvements at or nearby the project site should be thoroughly potholed, identified and marked prior to the initiation of the actual grading and earthworks. Specific geotechnical engineering recommendations may be required based on the actual field locations and invert elevations, backfill conditions and proposed grades in the event of a grading conflict. Utility lines may need to be temporarily redirected, if necessary, prior to earthwork operations and reinstalled upon completion of earthwork operations. Alternatively, permanent relocations may be appropriate as shown on the approved plans. Abandoned irrigation lines, pipes and conduits should be properly removed, capped or sealed off to prevent any potential for future water infiltrations into the foundation bearing and subgrade soils. Voids created by the removals of the abandoned underground pipes, tanks and structures should be properly backfilled with compacted fills in accordance with the requirements of this report. ... --... --.. .. - • - .. ... Geotechnical Investigation and Borehole Percolation Testing, Proposed January 29, 2020 New Preschool, Quarry Creek Development, Marron Road, Carlsbad, California Page 17 2. Clearing and Grubbing: Remove all existing surface and subsurface structures, tanks, vaults, pipes, old foundations and slabs, improvements, large rocks, vegetation, tree roots, stumps, and all other unsuitable materials and deleterious matter from all areas proposed for new fills, improvements, and structures throughout the pad, where possible and as approved in the field. All debris generated from the site clearing and grubbing works, trash, debris and vegetation removals should also be properly disposed of from the site. Trash, vegetation and debris shall not be allowed to occur or contaminate new site fills and backfills. The prepared ground should be observed and approved by the project geotechnical consultant or his designated field representative prior to grading and earthworks. 3. Stripping and Removals: Stripping (removal) and recompaction of existing upper soft and wet surficial fills resulted from recent winter rains and weathering impacts, will be required throughout the entire site to the minimum depths specified herein. Based on our field explorations and laboratory testing, existing soft to loose and wet surficial fills removals should extend to a minimum depth of 2 feet (BOS), exposing well-compacted fills below. Actual removal depths, however, may be expected to vary throughout the property and should be established in the field by the project geotechnical consultant or his designated field representative. Locally deeper removals may be necessary and should be anticipated, as recommended in the field. Bottom of all removals should be additionally ripped, prepared and recompacted to a minimum depth of 6 inches, as a part of initial fill lift placement, as directed in the field by the project geotechnical consultant. The exposed stripping, removals and over- excavations bottoms should be additionally observed and tested for suitable well- compacted fills exposures (minimum 90 percent in-place relative densities) and approved prior to backfilling. 4. Fine/Contour Grading and Minor Import Filling: Import filling and raising pad grades by nearly 2 feet, associated with the required fine/contour grading efforts, are anticipated in connection with the project development. Fine/contour grading efforts should establish final design elevations and positive drainage patterns per the project precise grading and drainage improvement plans. New fills should be placed and properly compacted in accordance with the applicable ordinances and requirements of this report, under engineering observations and compaction testing provided by the project geotechnical consultant. .. ... - ------.. .. - .. .. -... - ... ... Geotechnical Investigation and Borehole Percolation Testing, Proposed January 29, 2020 New Preschool, Quarry Creek Development, Marron Road, Carlsbad, California Page 18 Import soils, required to complete fine/contour grading and achieve final design pad grades, should be good quality sandy granular non-corrosive deposits (SM/SW) with very low expansion potential ( 100 percent passing 1-inch sieve, more than 50 percent passing #4 sieve and less than 18 percent passing #200 sieve with expansion index less than 20). Import soils should be observed, tested as necessary, and approved by the project geotechnical engineer prior to delivery to the site. Import soils should also meet or exceed engineering characteristic and soil design parameters as specified in the following sections. 5. Trenching and Temporary Construction Slopes: Temporary open excavations and trenching necessary for the project development are expected to be minor (less than 5 feet deep maximum). Consequently, significant construction impacts on the nearby off-site structures and improvements are not anticipated. Excavations and removals adjacent to the existing property lines, foundations, improvements and structures should be performed under observation of the project geotechnical engineer. Undermining adjacent neighboring properties, existing public right-of-ways and underground utilities, foundations, structures, and improvements to remain should not be allowed by the project excavations and earthwork operations. Temporary excavations and trenching less than 3 feet height maximum may be developed at near vertical gradients, unless otherwise noted or directed in the field. Excavations and trenching greater than 3 feet maximum may be constructed at near vertical gradients within the lower 3 feet and laid back at 1: 1 gradients maximum within the upper portions. More specific recommendations should be given in the field by the project geotechnical consultant based on actual site exposures. Revised temporary excavation and trenching recommendations including flatter laid back slopes, larger setbacks, completing excavations and remedial grading in limited sections and the need for temporary shoring/trench shield support may also be necessary and should be anticipated. The project contractor shall also obtain appropriate permits, as needed, and conform to Cal- OSHA and local governing agencies' requirements for trenching/open excavations and safety of the workmen during construction . 6. Fill/Backfill Materials: Stripping, removals and excavations at the project site are expected to chiefly generate gravelly silty clayey sand to sandy clay deposits that are considered suitable for reuse as site new fills and backfills, provided that they are adequately prepared, processed, placed in thin lifts and compacted in accordance with the requirements of this report. New fills should be free of vegetation, roots and tree stumps, buried pipes and conduits, construction debris, and organic matter consisting of minus 6-inch maximum particles and include at least 40 percent finer than #4 sieve materials .. - .. -- --.. --- .. .... - - Geotechnical Investigation and Borehole Percolation Testing, Proposed January 29, 2020 New Preschool, Quarry Creek Development, Marron Road, Carlsbad, California Page 19 by weight. Trench and wall backfills should consist of a minimum of 3-inch particles and maintain the minimum specified fines to rock ratio. Import soils should conform to the requirements of this report, as specified. 7. Fill/Backfill Placement, Spreading and Compaction: Uniform bearing and sub grade soil conditions should be constructed throughout the building and improvement surfaces by the project remedial grading and import filling operations. New fills and backfills should be adequately processed, thoroughly mixed, moisture conditioned to slightly (2%- 3%) above the optimum moisture levels, as established in the field based on the final mixture, placed in thin (8 inches maximum) uniform horizontal lifts and mechanically compacted to a minimum of90 percent of the corresponding laboratory maximum dry density per ASTM D 15 57, unless otherwise approved or recommended in the field. 8. Toe Retaining Wall: A toe retaining wall is recommended herein along the entire base of the southern margin ascending cut slope for drainage and debris control. The recommended toe retaining wall should be provided with a minium 2-course high free board and a minimum 24 inches wide backside drainage bench. The toe retaining wall should also be provided with a subsurface hack drainage system consisting of a minimum 4-inch diameter, Schedule 40 (SDR 35) perforated pipe surrounded with a minimum of l ½ cubic feet per foot of ¾-crushed rocks ( 12 inches wide by 18 inches deep) installed at the depths of the wall foundation level and wrapped in filter fabric (Mirafi 140-N). If Caltrans Class 2 permeable aggregate is used in lieu of the crushed rocks, the filter fabric can be deleted. The wall back drain should be installed at suitable elevations to allow for adequate fall via a non-perforated solid pipe (Schedule 40 or SDR 35) to an approved outlet. Protect pipe outlets as appropriate. All wall back drain pipes and outlets should be shown on the final as-build plans. A retaining wall back drain system schematic is depicted on the enclosed Typical Retaining Wall Back Drainage detail, Figure 11. Provide appropriate waterproofing where applicable as indicated on the project pertinent construction plans. 9. Surface Drainage and Erosion Control: A critical element to the continued stability of project graded building pad and improvement site is an adequate stormwater and surface drainage control. Surface water should not be allowed to flow toward and pond near the building foundations or impact the graded construction and improvement sites. For this purpose, establishing positive drainage (minimum 5 percent) during fine/contour grading efforts away from the building and site improvements onto a suitable drainage collection and disposal facility should be considered. Roof gutters and area drains should be installed. Over-watering of the site landscaping should also not be allowed. Only the amount of water to sustain vegetation should be provided . .. - .. ... - - --... --- --- .. -... .. ------ Geotechnical Investigation and Borehole Percolation Testing, Proposed January 29, 2020 New Preschool, Quarry Creek Development, Marron Road, Carlsbad, California Page 20 Temporary erosion control facilities and silt fences should be installed during the construction phase periods and until landscaping is fully established. Site drainage improvements should be completed as shown on the project approved grading/erosion control plans. 10. Engineering Observations and Testing: All earthworks operations including excavations, removals (stripping), suitability of earth deposits used as compacted fills and backfills, and compaction procedures should be continuously observed and tested by the project geotechnical consultant and presented in a final pad grading compaction report. The nature of finished bearing and subgrade soils should be confirmed in the final report at the completion of project earthworks construction. Geotechnical engineering observations and testing should include but are not limited to the following: * Initial observation -After clearing and grading limits have been staked, but before demolition work/brushing and excavation starts. * Stripping, removals and bottom excavation observation -After the minimum recommended removal depths are completed and suitable (minimum 90 percent in- place relative densities) compacted fill soils are confirmed for receiving new fill or backfill, but before new backfills or fills are placed. * Temporary trenching and excavation observations -After the excavation is started but before the vertical depth of excavation is more than 3 feet. Local and Cal-OSHA safety requirements for open excavations apply. * Fill/backfill observation -After the fill/backfill placement is started but before the vertical height of fill/backfill exceeds 2 feet. A minimum of one test shall be required for each 100 lineal feet maximum in every 2 feet vertical gain, with the exception of wall backfills where a minimum of one test shall be required for each 30 lineal feet maximum. Wall backfills should consist of minus 3-inch maximum particle sizes and mechanically compacted to a minimum of 90 percent compaction levels, unless otherwise specified or directed in the field. Finish rough and final pad grade tests shall be required regardless of fill thickness. * Foundation trench and subgrade soils observation -After the foundation trench excavations but prior to the placement of steel reinforcing for proper moisture and specified compaction levels. * Geotechnical foundation/slab steel observation -After the steel placement is completed but before the scheduled concrete pour. -.. - - -----.. --- --... .. • --- -- Geotechnical Investigation and Borehole Percolation Testing, Proposed January 29, 2020 New Preschool, Quarry Creek Development, Marron Road, Carlsbad, California Page 21 * Underground utility, plumbing and storm drain trench observation -After the trench excavations but before placement of pipe bedding or installation of the underground facilities. Local and Cal-OSHA safety requirements for open excavations apply. Observations and testing of pipe bedding may also be required by the project geotechnical engineer. * Underground utility, plumbing and storm drain trench backfill observation -After the backfill placement is started above the pipe zone but before the vertical height of backfill exceeds 2 feet. Testing of the backfill within the pipe zone may also be required by the governing agencies. Pipe bedding and backfill materials shall conform to the governing agencies' requirements and project soils report if applicable. All trench backfills should consist of minus 3-inch maximum particles sizes and mechanically compacted to a minimum of 90 percent compaction levels, unless otheiwise specified. Plumbing trenches more than 12 inches deep maximum under the interior floor slabs should also be mechanically compacted and tested for a minimum of 90 percent compaction levels. Flooding or jetting techniques as a means of compaction method should not be allowed. * Pavement/improvements base and subgrade observation -Prior to the placement of concrete or asphalt for proper moisture and specified compaction levels. B. FootinKs and Slab-on-Grade Floor Foundations The following recommendations are consistent with the anticipated gravely silty clayey sand to sandy clay (SM-SC/CL) deposits with low expansion potential ( expansion index less than 50) based on ASTM D4829 classification), and site indicated geotechnical conditions. All design recommendations should be confirmed and/or revised as necessary in the project as- graded compaction report, and further verified at the time of final plan review phase: 1. Shallow stiff concrete strip and spread pad footings may be considered for support of the planned new preschool building. All foundations should be supported on minimum 90 percent compacted fills, placed in accordance with the requirements of this report. There shall be at least 24 inches of well-compacted fills below bottom of the deepest footing(s) . 2. Perimeter and interior continuous strip footings should be sized at least 15 inches wide by 18 inches deep for single and two-story building loading conditions. Spread pad footings, if any, should be at least 30 inches square and 18 inches deep and structurally interconnected with grade beams. Interconnecting grade beams should be a minimum of 12 inches wide by 18 inches deep. Footing depths are measured from the lowest adjacent ground surface, not including the sand/gravel layer underneath floor slabs. Exterior continuous footings should enclose the entire building perimeter. Flagpole footings also need to be tied together if the footing depth is less than 4 feet below rough finish grade. .. .. ... ... ----- - - ------.. ... .. .. .. - --.. -- Geotechnical Investigation and Borehole Percolation Testing, Proposed January 29, 2020 New Preschool, Quarry Creek Development, Marron Road, Carlsbad, California Page 22 Foundation trenching should be completed in substantial conformance with the Typical Foundation Formwork Detail included in the attached Figure 12. Continuous interior and exterior footings should be reinforced by at least 2-#5 reinforcing bars placed near the top and 2-#5 reinforcing bars placed near the bottom. Interconnecting grade beams should be reinforced with minimum 2-#4 bars top and bottom and #3 ties at 30 inches center to center maximum. Reinforcement details for spread pad footings should be provided by the project architect/structural engineer. 3. All interior concrete floor slabs should be a minimum 5 inches in thickness, reinforced with #4 reinforcing bars spaced 18 inches on center each way, placed mid-height in the slab. Also, provide re-entrant comer reinforcement for all interior slabs. Re-entrant comers will depend on slab geometry and/or interior column locations. The enclosed Figure 13 may be used as a general guideline. Slabs should be underlain by 4 inches of clean sand (SE 30 or greater) which is provided with a well performing moisture barrier/vapor retardant (minimum 10-mil Stego) placed mid-height in the sand. Alternatively, a 4-inch thick base of compacted ½-inch clean aggregate provided with the vapor barrier (minimum 15-mil Stego) in direct contact with (beneath) the concrete may also be considered provided a concrete mix which can address bleeding, shrinkage and curling are used Provide "softcut" contraction/control joints consisting of sawcuts spaced 10 feet on centers each way for all interior slabs. Cut as soon as the slab will support the weight of the saw and operate without disturbing the final finish which is normally within 2 hours after final finish at each control joint location or 150 psi to 800 psi. The saw cuts should be minimum I-inch in depth but should not exceed I ¼-inches deep maximum. Anti- ravel skid plates should be used and replaced with each blade to avoid spalling and raveling. A void wheeled equipment across cuts for at least 24 hours . 4. Foundations located within 10 feet (horizontal radial distance) of the project BMP bio- retention basin(s) and/or filtration facilities should be properly protected from potential saturation ofbearing soils. For this purpose, foundations should be adequately deepened or a concrete slurry cutoff wall constructed for protection of the building foundations . Specific recommendations should be provided by the project geotechnical consultant at the plan review phase when final development and building foundation plans are available. 5. The sub grade and foundation bearing soils should not be allowed to dry prior to pouring the concrete or additional ground preparation and moisture reconditioning will be necessary as directed in the field. The required moisture content of the bearing soils is approximately 2 percent to 3 percent over the optimum moisture content to the depth of 18 inches below subgrade. Attempts should be made to maintain as-graded moisture contents in order to preclude the need for additional subgrade and bearing soils moisture reconditioning and preparation work. --.. - --- - --- - - .... ... ------ Geotechnical Investigation and Borehole Percolation Testing, Proposed January 29, 2020 New Preschool, Quarry Creek Development, Marron Road, Carlsbad, California Page 23 6. Foundation trenches and slab subgrade soils should be observed and tested for exposing suitable bearing strata, proper moisture and specified compaction levels and approved by the project geotechnical consultant prior to steel placement or pouring concrete. C. Soil Desi&n Parameters The following soil design parameters are based upon tested representative samples of onsite earth deposits. All parameters should be re-evaluated when the characteristics of the final as-graded soils have been specifically determined: 1. Design soil unit weight= 126 pcf. 2. Design angle of internal friction of soil = 29 degrees. 3. Design active soil pressure for retaining structures = 44 pcf (EFP), level backfill, cantilever, unrestrained walls. 4. Design active soil pressure for retaining structures = 72 pcf (EFP), 2: 1 sloping backfill, cantilever, unrestrained walls (also see notes below). 5. Design at-rest soil pressure for retaining structures = 66 pcf (EFP), non-yielding, restrained walls. 6. Design passive soil resistance for retaining structures= 363 pcf (EFP), level ground surface on the toe side (soil mass on the toe side extends a minimum of 10 feet or 3 times the height of the surface generating passive resistance). 7. Design coefficient of friction for concrete on soils= 0.35. 8. Net allowable foundation pressure= 2000 psf. 9. Allowable lateral bearing pressure (all structures except retaining walls)= 200 psfi'ft. Notes: * Added lateral pressures caused by surcharge loading of by nearby foundations and improvements should also be considered in the wall designs, if applicable and where appropriate. * In case of the recommended toe retaining wall at the based of site existing southern margin cut slope exposing very hard and competent crystalline bedrock, a design active soil pressure of 50 pcf (EFP) may be considered for a 2: 1 sloping backfill, cantilever, unrestrained wall condition . * An additional seismic force due to seismic increments of earth pressure should also be considered in the project designs, if appropriate and where applicable. A seismic lateral inverted triangular earth pressure of 19 pcf (EFP), acting at 0.6H (His the retained height) above the base of the wall should be considered. Alternatively, seismic loading based on Mononobe-Okake (M-0) coefficients may be considered for seismic force due to seismic increments of earth pressure. The following relationships and design values are appropriate: Geotechnical Investigation and Borehole Percolation Testing, Proposed January 29, 2020 New Preschool, Quarry Creek Development, Marron Road, Carlsbad, California Page 24 TABLE 14 Wall Total Seismic Lateral y KA Ko Kh KAE KOE Condition Lat.era! Pressure tPressure , (ocf) Unrestrained PAE=PA +PAE L\P AE=3/eKh YH2 0.35 -0.15 0.5 -126 Restrained POE=Po+POE L\PoE=KhYH2 -0.52 0.15 -0.67 126 * Use a minimum safety factor of 1. 5 for wall over-turning and sliding stability. However, because large movements must take place before maximum passive resistance can be developed, a minimum safety factor of 2 may be considered for sliding stability particularly where sensitive structures and improvements are planned near or on top of retaining walls. * When combining passive pressure and :frictional resistance, the passive component should be reduced by one-third. The upper 6 inches of ground surfaces should not be included in the design for passive soil resistance, unless otherwise noted or specified. * The design net allowable foundation pressure provided herein was determined based on a minimum 12 inches wide by 12 inches deep footings and may be increased by 20 percent for each additional foot of depth and 10 percent for each additional foot of width to a maximum of 4,500 psf. The allowable foundation pressures provided herein also apply to dead plus live loads and may be increased by one-third for wind and seismic loading. * The lateral bearing earth pressures may be increased by the amount of designated value for each additional foot of depth to a maximum 1500 pounds per square foot. D. Exterior Concrete Slabs and Flatworks 1. All exterior slabs (walkways, patios) supported on low expansive subgrade soils should be a minimum of 4 inches in thickness, reinforced with #3 bars at 18 inches on center in both directions placed mid-height in the slab. The subgrade soils should be compacted to minimum 90 percent compaction levels at the time of fine grading and before placing the slab reinforcement. Reinforcements lying on subgrade will be ineffective and shortly corrode due to lack of adequate concrete cover. Reinforcing bars should be correctly placed extending through the construction joints tying the slab panels. In construction practices where the reinforcements are discontinued or cut at the construction joints, slab panels should be tied together with minimum 18 inches long #3 dowels at 18 inches on centers placed mid-height in the slab (9 inches on either side of the joint). .. .. -... ... - - --- - ... -.. - - Geotechnical Investigation and Borehole Percolation Testing, Proposed January 29, 2020 New Preschool, Quarry Creek Development, Marron Road, Carlsbad, California Page 25 2. Provide ''tool joint" or "softcut" contraction/control joints spaced l O feet on center (not to exceed 12 feet maximum) each way. The larger dimension of any panel shall not exceed 125 percent of the smaller dimension. Tool or cut as soon as slab will support weight, and can be operated without disturbing the final finish which is normally within two (2) hours after final finish at each control joint location or 150 psi to 800 psi. Tool or softcuts should be a minimum of 1-inch but should not exceed 1 ¼-inch deep maximum. In case of softcut joints, anti-ravel skid plates should be used and replaced with each blade to avoid spalling and raveling. A void wheeled equipment across cuts for at least 24 hours. Joints shall intersect free-edges at a 90-degree angle and shall extend straight for a minimum of 1 ½ feet from the edge. The minimum angle between any two intersecting joints shall be 80 degrees. Align joints of adjacent panels. Also, align joints in attached curbs with joints in slab panels. Provide adequate curing using approved methods (curing compound maximum coverage rate= 200 sq. ft./gal.). 3. All exterior slab designs should be confirmed in the final as-graded compaction report. 4. Subgrade soils should be tested for proper moisture and specified compaction levels and approved by the project geotechnical consultant prior to the placement of concrete. 5. Exterior concrete slabs and paving surfaces located within IO feet (horizontal radial distance) of the project BMP bio-retention basin(s) and/or filtration facilities should be properly protected from potential saturation of subgrade soils. For this purpose, exterior concrete slabs and paving sections may be provided with adequately deepened edge restraint, or a concrete slurry cutoff wall may be constructed for the protection of the site improvements and paving surfaces. Specific recommendations should be project by the project geotechnical consultant at the plan review phase when final development and building foundation plans are available. E. Pavement Desip. 1. Asphalt Concrete Paving (HMA): Specific HMA pavement designs can best be provided at the completion of rough fine/contour grading based on R-value tests of the actual finish subgrade soils. However, the following pavement structural section may be considered for initial planning phase and cost estimating purposes only (not for construction): * A minimum section of 4 inches HMA (AC) over 6 inches of Class 2 aggregate base (AB), or the minimum structural section required by City of Carlsbad, whichever is more, may be considered for the onsite asphalt paving surfaces outside the private and public right-of-way. Final pavement sections should be confirmed and/or revised as necessary at the completion of rough pavement grading by R-value testing performed on finish subgrade soils and design TI, and approved by the City of Carlsbad. .. ------ --- - - -- - - .. .. .. -... - Geotechnical Investigation and Borehole Percolation Testing, Proposed January 29, 2020 New Preschool, Quarry Creek Development, Marron Road, Carlsbad, California Page 26 * Maximum lift for asphalt concrete (HMA) shall not exceed 3 inches. The asphalt concrete (4-inch layer) should consist of2.5 inches of a binder/base course (¾-inch aggregate) and 1.5 inches of finish top course (½-inch aggregate) topcoat, placed in accordance with the applicable local and regional codes and standards. * The Class 2 aggregate or recycled base (AB) shall meet or exceed the requirements set forth in the current California Standard Specification (Caltrans Section 26-1.02). Base materials should be compacted to a minimum 95 percent of the corresponding maximum dry density (ASTM D 1557). Subgrade soils beneath the asphalt paving surfaces should also be compacted to a minimum 95 percent of the corresponding maximum dry density within the upper 12 inches. Base materials and sub grade soils should be tested for proper moisture and minimum 95 percent compaction levels and approved by the project geotechnical consultant prior to the placement of the base or asphalt layers. 2. PCC Pavings: PCC driveways, and parking supported on low expansive (expansion index less than 50) subgrade soils should be a minimum of 5.5 inches in thickness, reinforced with #3 reinforcing bars at 16 inches on centers each way placed at mid-height in the slab. Trash enclosure slabs should be provided with minimum 4 inches of 95 percent compacted Class Base 2 base materials, and consist of minimum of 6 inches thick concrete section reinforced with minimum #4 reinforcing bars at 16 inches on centers each way placed at mid-height in the slab. Trash enclosure slabs should also be provided with a minimum 12 inches wide by 12 inches deep ( depth measured from finish subgrade level) thickened edge reinforced with minimum 2-#4 bars top and bottom at the opening. Subgrade soils beneath the PCC driveways and parking should be compacted to a minimum 90 percent of the corresponding maximum dry density, unless otherwise specified, while subgrade soils beneath trash enclosure slabs should be compacted to minimum 95 percent. Use minimum Green Book 560-C-3250 concrete for PCC pavings and trash enclosure slab. Reinforcing bars should be correctly placed extending through the construction ( cold) joints tying the slab panels. In construction practices where the reinforcements are discontinued or cut at the construction joints, slab panels should be tied together with minimum 18 inch long (9 inches on either side of the joint) #3 dowels at 16 inches on centers placed mid-height in the slab . ---- --- - - ---------- -.. -.. ------ Geotechnical Investigation and Borehole Percolation Testing, Proposed January 29, 2020 New Preschool, Quarry Creek Development, Marron Road, Carlsbad, California Page 27 Provide "tool joint" or "softcut" contraction/control joints spaced IO feet on center (not to exceed 15 feet maximum) each way. The larger dimension of any panel shall not exceed 125 percent of the smaller dimension. Tool or cut as soon as the slab will support the weight and can be operated without disturbing the final finish which is normally within 2 hours after final finish at each control joint location or 150 psi to 800 psi. Tool or softcuts should be a minimum of I-inch in depth but should not exceed 1 ¼-inches deep maximum. In case of softcut joints, anti-ravel skid plates should be used and replaced with each blade to avoid spalling and raveling. A void wheeled equipment across cuts for at least 24 hours. Joints shall intersect free-edges at a 90-degree angle and shall extend straight for a minimum of 1 ½ feet from the edge. The minimum angle between any two intersecting joints shall be 80 degrees. Align joints of adjacent panels. Also, align joints in attached curbs with joints in slab panels. Provide adequate curing using approved methods ( curing compound maximum coverage rate= 200 sq. ft./gal.). 3. Permeable (Pervious) Interlocking Concrete Pavers (PICP): Permeable (Pervious) Interlocking Concrete Pavers (PICP), may be considered as a part of the project development stormwater quality treatment BMPs. However, the following recommendations are appropriate and should be considered in the final designs and implemented during the construction phase, where appropriate: * Project storm water BMP permeable (pervious) interlocking pavers should consist of a self-contained system disallowing saturation of adjacent foundation bearing soils, graded embankments, wall backfills and site improvement subgrade. In general, PICP pavement finish subgrade should be sloped away at a minimum 2 percent onto a minimum 12 inches wide by 12 inches deep collector trench near the center and provided with a 4-inch diameter (Sch. 40 or SDR 35) underdrain pipe surrounded with ¾-inch crushed rocks. A conceptual detail is shown in the enclosed Typical Permeable Paver Detail, Figure 14. The perforated underdrain pipe should discharge collected water into an appropriate storm drainage facility. Perimeter cut off walls and curb restraints should be provided, and bottom and sides of the system lined with an impervious liner (minimum 30-mil HDPE or PVC Geomembrane), as shown. PICP pavements closer than 10 feet to building foundations or adjacent site improvements may also be allowed provided additional mitigation measures such as construction of a minimum 8 inches wide, 3-sack concrete cutoff wall extending a minimum of24 inches below bottom of the foundations or adjacent improvement is provided, or adjacent footings are deepened a minimum depth of 2 feet below the bottom of the pavement base course section (ASTM No. 57 stone). Specific recommendations should be provided by the project geotechnical engineer at the plan review phase. Geotechnical Investigation and Borehole Percolation Testing, Proposed January 29, 2020 New Preschool, Quarry Creek Development, Marron Road, Carlsbad, California Page 28 * PICP pavement structural section should consist of minimum 3 Ye-inch, heavy traffic rates PICP over a minimum of 2 inches of ASTM No. 8 bedding course/choke stone over a minimum 8 inches of ASTM No. 57 stone base course over a minimum of 12 inches of 95 percent compacted subgrade (per ASTM D-1557). Bedding course/choke stone and base course stone should also be well compacted, consolidated and interlocked (avoid crushing the underdrain pipes) with heavy construction equipments. ASTM No. 8, No. 9 or No. 89 should be used for joint materials depending on the joint size and per manufacturer recommendations. ieve Size 1½" l" ½" 3/s" No.4 No. 8 No. 16 No. 50 Gradation requirements for ASTM No. 57, No. 8, No. 89 and No. 9 are as follows: TABLE 15 100 95 to 100 25 to 60 100 100 85 to 100 90 to 100 100 0 to 10 10 to 30 20 to 55 85to100 0 to 5 0 to 10 5 to30 10 to 40 0 to 5 0 to 10 0 to 10 0 to 5 0 to 5 * An adequate storage capacity (with a minimum safety factor of 2) should be considered in the design of the project BMP facility. * All foundations bearing and site improvements subgrade soils within 10 feet of the project BMP bio-retention basin(s) and/or filtration facilities should be compacted to minimum 95 percent compaction levels, unless otherwise noted or approved. * Underground utility trenches under or within 10 feet (horizontal radial distance) of the project PICP should be backfilled with concrete slurry. ... - -... ... ... .. -- .. .. .. Geotechnical Investigation and Borehole Percolation Testing, Proposed January 29, 2020 New Preschool, Quarry Creek Development, Marron Road, Carlsbad, California Page 29 4. Concrete Curbs, Gutters and Sidewalks: Subgrade preparation and base section per structural section design will be required for all surfaces subject to traffic including roadways, travelways, drive lanes, driveway approaches and ribbon (cross) gutters. Driveway approaches within the public right-of-way should have 12 inches subgrade compacted to a minimum of95 percent compaction levels and provided with a 95 percent compacted Class 2 base section per the structural section design. Sub grade preparations will also be required for all curbs, gutters and sidewalks. Provided a minimum of 6 inches of Class 2 crushed aggregate base (AB) under curb and gutters, unless otherwise approved. A base section may not be required under concrete sidewalks, unless otherwise noted or specified. Base layer under curb and gutters should be compacted to a minimum 95 percent, while subgrade soils under curb, gutters and sidewalks should be compacted to a minimum 90 percent compaction levels, unless otherwise specified. Use minimum Green Book (Standard Specifications For Public Works Construction) 560-C- 3250 Concrete Class for concrete curbs and gutters. We also recommend providing at least 1-#3 continuous reinforcing bar in all concrete curbs. Base and subgrade soils should be tested for proper moisture and specified compaction levels, and approved by the project geotechnical consultant prior to the placement of the base or asphalt/PCC/PICP finish surface . F. General Recommendations 1. The minimum foundation design and steel reinforcement provided herein are based on soil characteristics and are not intended to be in lieu of reinforcement necessary for structural considerations. 2. Adequate staking and grading control are critical factors in properly completing the recommended remedial and site grading operations. Grading control and staking should be provided by the project grading contractor or surveyor/civil engineer, and is beyond the geotechnical engineering services. Staking should apply the required setbacks shown on the approved plans, and field verified by the project contractor to conform setback requirements established by the governing agencies and applicable codes for off-site private and public properties and property lines, utility easements, right-of-ways, nearby structures and improvements, leach fields and septic systems, and graded embankments. Inadequate staking and/or lack of grading control may result in illegal encroachments or unnecessary additional grading which will increase construction costs . 3. Open or backfilled trenches parallel with a footing shall not be below a projected plane having a downward slope of I-unit vertical to 2 units horizontal ( 50 percent) from a line 9 inches above the bottom edge of the footing, and not closer than 18 inches from the face of such footing. The Typical Trench Adjacent to Foundation is provided in the enclosed Figure 15 and may be used as a general guideline. - - -.. - Geotechnical Investigation and Borehole Percolation Testing, Proposed January 29, 2020 New Preschool, Quarry Creek Development, Marron Road, Carlsbad, California Page 30 4. Where pipes cross under-footings, the footings shall be specially designed. Pipe sleeves shall be provided where pipes cross through footings or footing walls, and sleeve clearances shall provide for possible footing settlement, but not less than I-inch all around the pipe. A schematic detail entailed Pipes Through or Below Foundation is included on the enclosed Figure 15. 5. Foundations where the surface of the ground slopes more than 1 unit vertical in 10 units horizontal (10 percent slope) shall be level or shall be stepped so that both top and bottom of such foundations are level. Individual steps in continuous footings shall not exceed 18 inches in height and the slope of a series of such steps shall not exceed 1 unit vertical to 2 units horizontal (50 percent) unless otherwise specified. The steps shall be detailed on the structural drawings. The local effects due to the discontinuity of the steps shall also be considered in the design of foundations as appropriate and applicable. 6. Expansive clayey soils shall not be used for backfilling of any retaining structure. All retaining walls should be provided with a 1 : 1 wedge of sandy granular, compacted backfill measured from the base of the wall footing to the finished surface and a well- constructed back drain system as shown on the enclosed Figure 11. Planting large trees behind site retaining walls should be avoided. 7. All underground utility and plumbing trenches should be mechanically compacted to a minimum of90 percent of the maximum dry density of the soil unless otherwise required or specified. Care should be taken not to crush the utilities or pipes during the compaction of the soil. Trench backfill materials and compaction beneath pavements within the public right-of-way shall conform to the requirements of governing agencies. Underground utilities within 10 feet (horizontal radial distance) of proposed BMP facilities should be backfilled with concrete slurry. 8. Finish ground surfaces immediately adjacent to the building foundations shall be sloped away from the building at a minimum 5 percent for a minimum horizontal distance of 10 feet measured perpendicular to face of the building wall (CBC 1804.4 Site Grading). If physical obstructions or property lines prohibit 10 feet ofhorizontal distance, a 5 percent slope shall be provided with an alternative method for diverting water away from the foundation. Swales used for this purpose shall be sloped not less than 2 percent where located within 10 feet of the building foundation. Impervious surfaces ( concrete sidewalks) within 10 feet of the building foundation shall also be sloped at minimum 2 percent away from the building. 9. Care should be taken during the construction, improvements, and fine grading phases not to disrupt the designed drainage patterns. Rooflines of the buildings should be provided with roof gutters. Roof water should be collected and directed away from the buildings and structures to a suitable location. Area drains should be installed. ... .. .... -... .. - • • Geotechnical Investigation and Borehole Percolation Testing, Proposed January 29, 2020 New Preschool, Quarry Creek Development, Marron Road, Carlsbad, California Page 31 10. Final plans should reflect preliminary recommendations given in this report. Final plans should also be reviewed by the project geotechnical consultant for conformance with the requirements of the geotechnical investigation report outlined herein. 11. All foundation trenches should be observed by the project geotechnical consultant to ensure adequate footing embedment and confirm competent bearing soils. Foundation and slab reinforcements should also be observed and approved by the project geotechnical consultant. 12. The amount of shrinkage and related cracks that occur in the concrete slab-on-grades, flatwork and driveways depend on many factors, the most important of which is the amount of water in the concrete mix. The purpose of the slab reinforcement is to keep normal concrete shrinkage cracks closed tightly. The amount of concrete shrinkage can be minimized by reducing the amount of water in the mix. To keep shrinkage to a minimum the following should be considered: * Use the stiffest mix that can be handled and consolidated satisfactorily. * Use the largest maximum size of aggregate that is practical. For example, concrete made with %-inch maximum size aggregate usually requires about 40-lbs. more (nearly 5-gal.) water per cubic yard than concrete with I-inch aggregate . * Cure the concrete as long as practical. The amount of slab reinforcement provided for conventional slab-on-grade construction considers that good quality concrete materials, proportioning, craftsmanship, and control tests where appropriate and applicable are provided. 13. A preconstruction meeting between representatives of this office, the property owner or planner, city inspector as well as the grading contractor/builder is recommended in order to discuss grading and construction details associated with site development. XII. GEOTECHNICAL ENGINEER OF RECORD (GER) SNS Geotechnical Solutions, Inc. is the geotechnical engineer of record (GER) for providing a specific scope of work or professional service under a contractual agreement unless it is terminated or canceled by either the client or our firm. In the event a new geotechnical consultant or soils engineering firm is hired to provide added engineering services, professional consultations, engineering observations and compaction testing, SMSGeotechnical Solutions, Inc. will no longer be the geotechnical engineer of the record. Project transfer should be completed in accordance with the California Geotechnical Engineering Association (CGEA) Recommended Practice for Transfer of Jobs Between Consultants. ... .. - .... ... - - ... .. • ... .. ... Geotechnical Investigation and Borehole Percolation Testing, Proposed January 29, 2020 New Preschool, Quarry Creek Development, Marron Road, Carlsbad, California Page 32 The new geotechn.ical consultant or soils engineering firm should review all previous geotechn.ical documents, conduct an independent study, and provide appropriate confirmations, revisions or design modifications to his own satisfaction. The new geotecbnical consultant or soils engineering firm should also notify in writing 6M6 Geotechnical Solutions, Inc. and submit proper notification to the City of Carlsbad for the assumption of responsibility in accordance with the applicable codes and standards (1997 UBC Section 3317.8). XIII. LIMITATIONS The conclusions and recommendations provided herein have been based on available data obtained from the review of pertinent reports and plans, subsurface explorations well as our experience with the soils and formational materials located in the general area. The materials encountered on the project site and utilized in our laboratory testing are believed representative of the total area; however, earth materials may vary in characteristics between excavations. Of necessity, we must assume a certain degree of continuity between exploratory excavations and/or natural exposures. It is necessary, therefore, that all observations, conclusions, and recommendations be verified during the site excavations and construction operations. In the event discrepancies are noted, we should be contacted immediately so that an observation can be made and additional recommendations issued if required . The recommendations made in this report are applicable to the site at the time this report was prepared. It is the responsibility of the owner/developer to ensure that these recommendations are carried out in the field. It is almost impossible to predict with certainty the future performance of a property. The future behavior of the site is also dependent on numerous unpredictable variables, such as earthquakes, rainfall, and on-site drainage patterns. The firm of 6116 Geotechnical Solutions, Inc., shall not be held responsible for changes to the physical conditions of the property such as addition of fill soils or changing drainage patterns which occur without our observation or control. This report should be considered valid for a period of one year and is subject to review by our firm following that time. If significant modifications are made to your tentative construction plan, especially with respect to finish pad elevations and room addition final layout, this report must be presented to us for review and possible revision . This report is issued with the understanding that the owner or his representative is responsible for ensuring that the information and recommendations are provided to the project architect/structural engineer so that they can be incorporated into the plans. Necessary steps shall be taken to ensure that the project general contractor and subcontractors carry out such recommendations during construction . • ... --- -- - -.. • ... - Geotechnical Investigation and Borehole Percolation Testing, Proposed January 29, 2020 New Preschool, Quarry Creek Development, Marron Road, Carlsbad, California Page 33 The project geotechnical engineer should be provided the opportunity for a general review of the project final design plans and specifications in order to ensure that the recommendations provided in this report are properly interpreted and implemented. If the project geotechnical engineer is not provided the opportunity of making these reviews, he can assume no responsibility for misinterpretation of his recommendations. 6116 Geotechnical Solutions, Inc., warrants that this report has been prepared within the limits prescribed by our client with the usual thoroughness and competence of the engineering profession. No other warranty or representation, either expressed or implied, is included or intended. Once again, should any questions arise concerning this report, please do not hesitate to contact this office. Reference to our Project No. GI-19-11-155 will help to expedite our response to your inquiries. We appreciate this opportunity to be of service to you. 6116 Geotechnical Solutions, Inc. gmeer s~~ Engineering Geologist ~~ Kevin McFarla Staff Geologist Distribution: Addressee (3, e-mail) 6616 Geotechnical Solutions, Inc. - - - ----.. -.. .. --.. • - - - REFERENCES Annual Book of ASTM Standards, Section 4 -Construction, Volume 04.08: Soil and Rock {I); D420 -D5876, 2019. -Annual Book of ASTM Standards, Section 4-Construction, Volume 04.09: Soil and Rock (II); D5877 -Latest, 2019. -Highway Design Manual, Caltrans. Fifth Edition. -Corrosion Guidelines, Caltrans, Version 1.0, September 2003. -California Building Code (CBC), California Code of Regulations Title 24, Part 2, Volumes 1 & 2, 2019, International Code Council. -"The Green Book" Standard Specifications For Public Works Construction, Public Works Standards, Inc., BNi Building News, 2015 Edition. -California Geological Survey, 2008 (Revised), Guidelines for Evaluating and Mitigating Seismic Hazards in California, Special Publication 117 A, 108p. -California Department of Conservation, Division of Mines and Geology ( California Geological Survey), 1986 (revised), Guidelines for Preparing Engineering Geology Reports: DMG Note 44. -California Department of Conservation, Division of Mines and Geology (California Geological Survey), 1986 (revised), Guidelines to Geologic and Seismic Reports: DMG Note 42. -EQFAULT, Ver. 3.00, 1997, Deterministic Estimation of Peak Acceleration from Digitized Faults, Computer Program, T. Blake Computer Services and Software. -EQSEARCH, Ver 3.00, 1997, Estimation of Peak Acceleration from California Earthquake Catalogs, Computer Program, T. Blake Computer Services and Software. -Tan S.S. and Kennedy, M.P., 1996, Geologic Maps of the Northwestern Part of San Diego County, California, Plate(s) 1 and 2, Open File-Report 96-02, California Division of Mines and Geology, 1 :24,000. -"Proceeding ofThe NCEER Workshop on Evaluation ofLiquefaction Resistance Soils," Edited by T. Leslie Youd and Izzat M. Idriss, Technical Report NCEER-97-0022, Dated December 31, 1997 . -"Recommended Procedures For Implementation ofDMG Special Publication 117 Guidelines For Analyzing and Mitigation Liquefaction In California," Southern California Earthquake Center; USC, March 1999. .. ... -- ----- - -... ----- - REFERENCES (continued) "Soil Mechanics," Naval Facilities Engineering Command, DM 7.01. -"Foundations & Earth Structures," Naval Facilities Engineering Command, DM 7.02. -"Introduction to Geotechnical Engineering, Robert D. Holtz, William D. Kovacs. -"Introductory Soil Mechanics and Foundations: Geotechnical Engineering," George F. Sowers, Fourth Edition. -"Foundation Analysis and Design," Joseph E. Bowels. -Caterpillar Performance Handbook, Edition 29, 1998. -Jennings, C. W ., 1994, Fault Activity Map of California and Adjacent Areas, California Division of Mines and Geology, Geologic Data Map Series, No. 6. -Kennedy, M.P., 1977, Recency and Character of Faulting Along the Elsinore Fault Zone in Southern Riverside County, California, Special Report 131, California Division of Mines and Geology, Plate 1 (East/West), 12p . Kennedy, M.P. and Peterson, G.L., 1975, Geology of the San Diego Metropolitan Area, California: California Division of Mines and Geology Bulletin 200, 56p. -Kennedy, M.P. and Tan, S.S., 1977, Geology of National City, Imperial Beach and Otay Mesa Quadrangles, Southern San Diego Metropolitan Area, California, Map Sheet 24, California Division of Mines and Geology, 1:24,000. Kennedy, M.P., Tan, S.S., Chapman, R.H., and Chase, G.W., 1975, Character and Recency of Faulting, San Diego Metropolitan Areas, California: Special Report 123, 33p. -"An Engineering Manual For Slope Stability Studies," J.M. Duncan, A.L. Buchignani and Marius De Wet, Virginia Polytechnic Institute and State University, March 1987. -"Procedure To Evaluate Earthquake-Induced Settlements In Dry Sandy Soils," Daniel Pradel, -ASCE Journal OfGeotechnical & Geoenvironm.ental Engineering, Volume 124, #4, 1998. --... -- -- -"Minimum Design Loads For Buildings and Other Structures," ASCE 7-16, American Society of Civil Engineers (ASCE). -"Seismic Constraints on The Architecture of The Newport-Ingelwood/Rose Canyon Fault: Implications For The Length And Magnitude of Future Earthquakes," Sahakian, V., Bormann, J.,Driscoll, N.,Harding,A. Kent, G. Wesnousky, S. (2017),AGU.doi:10.1002/2016JB 013467. 0 N ~ z 0 " IQ IQ :e rri l"I TOPO! map printed on 12/02/19 from 0SanOlego.tpo• and 'Untitled.tpg• 117.31667° w 117.30000° W WGS84 117.28333° W --· n ·• . /~ ' . / ~~--~- ~.. ,.r,..... \ o -......___,....,....,.... r ~·,..· -:;-.-.~.-r- . . .. . . . · ..... .. ·. . . :-: . :. - ··'',) \ <;::--\. --? ·l, 'A,~,~ .. )-'--"-'--".._~-~ _J -\ -;---w--; 'J ·. r------.::h ~--( ·~ ~ ~ ,tJ,_. ... -------~ c:-------------.--·1 ; .. ,;,: ·1 ._--.. ., ·._, ~ .;'$-\'¢.-.... ,J-.;;_-✓ rl ✓----· ('" -:}_::t:·~---✓f/,~-) /' . "" ,----~ ,--,. ,,, • ,,• r , .-:··· '• :--..~,, q ,_, J'' ,J ., (../ > ( .' T ~ y I ~,_)1 '\'\.-. ~• -.;: •i-v', ~ """ • Qr t~-·· -~ • ·-........ \ ..-: ., ~ ('J ,:•,.1 .. " ,,., > . 'V'!: ,t '~\ ~ ,,. ·\ ... ~ ' \ ~ ·'\ ~. .,.. . "'°' __.£...:-\.. z ~ l"I Cl) Pi l"I • , ~ ~c. '--... ~ '"<. ~::, -..., + o:' ,~ u r _,,q . ., t ---., --...._,,;: • ., l' /"\ ~--_.. ,/"' J \__ " • :'.-' ( '.xo·-rc----, _/ i') •, ~ \-•~, _\ O ~ I , ,: ),,_ ,1 ~~ J -.---. Z n , ;I ·1 ~ / c;; ~ /: ;\ ?'"' ~l "\ . C,r o' -, o ,-") r ' -,> --~''\ '\. ~ 4' ( ~ ~r~-;c; Hi . -YL~---~~la~* • /2 . I ". ,. 5 .»• ~ ! ... f l/ ( / t~ter \,:' • V ' --"~1 ,,. "• l•"\..... -/, Pi ·-.: > N ·1>· _, 'f\"k 1 • ( .; ,. I '-.-yl ,· l I½ fv-J / '"\,, ~ l"I I C ? ,• > (.' -/ ). • "~ ;, ~ '>~ \ L --/ / I ! ri '\· ,J \ ·~· ;f ,.~.,,-✓~ 1· \;/ \ ,✓_:z;\.----r -r -(i'' 7 A '\ l-, .,,/J ~ /' i / J7 ( '-S'\v. > J • 1\'',. ·:->,y-C-""' '°')~/"°, ~ J ..,. '? ,, • ·•\ j I . , -· --r ., ' --. ; ) >/ :,",'-·: ,...------/~ i , > . ~ ) • __ _,,,/: " } '\----~ W9ter~ I ~ \ ' ..,, , r' J{ .'I: ~ ~ ) /'Tank •1 . ,. ( . _,, ""-/ ,J •. • • \ \ ----' .,,.., '$ , '\ I ,._J ,, 5--1,•:• \.,. '·~, /Grav~I, \-, • J/ "--) \ \~ 10 ,, '-.._ ,1 Pit.,... ,,_. 1 • ... ~ i <'-, /'.,,--'/! --.::.'f' -4 ..... i ~ ; ~ ~1/r , f · ·'t A -/ .l, .. , u E I I F 1• / M J.r-1,. \'C"' .,, ""...,. ),1 Job Site Coordinates : Lat. 33.1775°, Lon. 117.2998° 117.31667° w 117.30000° W WGS84 117.28333° W 'f::::::=======~=======::::::!MU I I ''r° fm , I I I I !'M I I I I JIIOOM ?rinttd frO\Jl TOPO C 1999 \\']dilowtr ?rcductron, ,"""'.!DPO com) UNIFIED SOIL CLASSIFICATION SYSTEM (USCS) Criteria for Assigning Group Symbols and Group Names Using Laboratory Tests" Soll Ctasstflcatlon Group Group Name 5 mbot ~ Clt•o Gravels GW Well-l"aded gravel' Less than 5" fines< Not meettn1 above 1radatlon for GW GP Poorly graded gravel' coarse Gl'flntd s011s More than 50" retained on #200 More than 50" of coarse fraction retained on #4 sieve Gravel, with Fines More than 12" fines' Fines classify as ML or MH Fines classify as CL or CH GM SIity gravel'·..,.. GC Clayey gravef•.a,H Si!!D Cleans.ncb Less than 5" flnes0 C.. 2: 6 and ls C, S 3' Not meeting above gradation for SW SW Well-graded sand' SP Poorly graded sand' 50" or more of coarse fraction passes #4 sieve sands with Fines More than 12" flnesD Fines classify as ML or MH Fines classlfy as CL or CH SM SIity sand8•") SC Clayey sand-><) Fine Grained Soils 50% or more passes the #200 sieve• Slits and Clays Liquid llmtt less than 50 Silts and Om Liquid limit 50 or more Inorganic organic Inorganic organic Pl > 7 and plots on or above • A" llne' Pl< 4 and plots below "A" llne' Liquid Limit -oven dried Liquid Limit-not dried Pl plots on or above • A• line Pl plots below "A" line Liquid Limit -oven dried Liquid Limit-not dried Cl lean dat:"4 Ml Sflt"-i.M <0.75 OL Organic clay«-'-M"' Organic silt'(,1,M.0 CH Fatdaf':.., MH <0.75 OH Organic dar'.·i.M·• Organic sJft«.i.M.0 Highly organic soils Primartly organic matter, dark In color, and organic odor PT Peat • For soils having 5 to 12" passing the No. 200 sieve, use a dual symbol such as GW-GC. " Based on the material passing the 3 in. (75 mm) sieve. 8 If field sample contained cobbles or boulders, or both, add "with cobbles or boulders, or both" to group name. c Gravels with 5'6 to 12'6 fines require dual symbols: GW-GM well-graded gravel with silt, GW-GC well-graded gravel with clay, GP-GM poorly graded gravel with silt, GP-GC poorly graded gravel with clay. 0 Sands with 5'6 to 12" fines require dual symbols: SW-SM well-graded sand with silt, SW-SC well-graded sand with clay, SP-SM poorly graded sand with silt, SP-SC poorly graded sand. For classifications of fine-grained soils and fine-grained fraction of coarse- grained soils. Equation of" A" line. Horizontal at Pl=4 to LL=25.S, then Pl=O. 73 (LL-20). Equation of "U" line. Vertical at LL=16 to Pl=7, then Pl = 0.9 (LL-8) 60 so ~ 40 X QJ 'O E 30 > ..., ·u ·.:; Vl rt, ci: 20 10 7 4 0 F If soil contains :z:15'6 sand, add "with sand" to group name. G If fines classify as Cl-Ml, use dual symbol GC-GM, or SC-SM H If fines are organic, add "with organic fines" to group name. If soil contains 2:15'6 gravel, add "with graver to group name. If Atterberg limits plot in shaded area, soil is a CL-ML, silty clay. K If soil contains 15% to 29% plus No. 200, add "with sand" or "with gravel" whichever is If soil contains 2:30'6 plus No. 200 predominantly sand, add "sandy" to group name. M If soil contains 2:30% plus No. 200 predominantly gravel, add #gravelly" to group name. N Pl 2:4 and plots on or above "A" line. 0 Pl <4 or plots below "A" line. P Pt plots on or above "A" line. Q Pl plots below "A" line L H MH orOH 0 10 16 20 30 40 50 60 70 80 100 Liquid Limit (LL) ~~~ Geotechnical So lut ions, Inc. KEY TO BORING / TEST PIT LOGS DRIUING & SAMPLING SYMBOLS: e ST: Split Spoon -1 -3/8• 1.0., 2" 0.0., Unless otherwise noted Thin-Walled Tube -2• 0.0., Unless otherwise noted HS: PA: Hollow Stem Auger Power Auger □ Chunk Sample Sandcone Density Test OB: Ring Sampler-2.375" 1.0., 2S 0.0., Unless otherwise noted Diamond Bit Coring-4", N, B HA: RB: Hand Auger Rock Bit ■ Bulk Sample or Auger Sample WB: Wash Boring or Mud Rotary The number of blows required to advance a standard 2-fnch 0.0. split-spoon sample (SS) the last 12 inches of the total 18-inch penetration with a 140-pound hammer falling 30 Inches Is considered the •standard Penetration" or "N-value". For 2.s• 0.0. ring samplers (RS) the penetration value Is reported as the number of blows required to advance the sampler 12 inches using a 140-pound hammer falling 30 inches, reported as •blows per foot• and is not considered equivalent to the "Standard Penetration• or "N-value•. WATER LEVEL MEASUREMENT SYMBOLS WL: WCI: DCI: AB: Water Level Wet Cave In Ory Cave In After Boring WS: WO: BCR: ACR: While Sampling While Drilling Before Casing Removal After Casing Removal N/E: Not Encountered Water levels indicated on the boring logs are the levels measured In the borings at the times indicated. Groundwater levels at other times and other locations across the site could vary. In pervious soils, the Indicated levels may reflect the location of groundwater. In low permeability soils, the accurate determination of groundwater levels may not be possible with only short-term observation. DESCRIPTIVE SOIL CLASSIACATION: Soil classification is based on the unified classification system. Coarse Grained Soils have more than 50% of their dry weight retained on a #200 sieve; their principal descriptors are: boulders, cobbles, gravel or sand. Fine Grained Soils have less than 50% of their dry weight retained on a #200 sieve; they are principally described as clays If they are plastic, and silts If they are slightly plastic or non-plastic. Major constituents may be added as modifiers and minor constituents may be added according to relative proportions based on grain size. In addition to gradation, coarse-grained soils are defined on the basis of their In-place relative density and fine-grained soils on the basis of their co.nsistency. CONSISTENCY OF FINE-GRAINED SOILS Unconfined Standard Compressive Penetration or N- Strenctfl. OU. psf Yflue (SS) Blows/Ft. < 500 < 2 500 -1000 2 -3 1001-2000 2001-4000 4001-8000 8000+ 4-6 7-12 13-26 26+ Consistency Very Soft Soft Medium Stiff Stiff Very Stiff Hard RELATIVE PROPORTION OF SAND AND GRAVEL RELATM DENSITY Of COARSE-GRAlNEO SOILS Stanard Penetration or N- value (SSI Blows/Ft. 0 -3 4 -9 10-29 30-49 SO+ Ring Sampler fRSI Blows/Ft. 0-6 7-18 19-58 59-98 99 + GRAIN SIZE TERMINOLOGY Relative Density Very Loose Loose Medium Dense Dense Very Dense Desqlptive Term(s) of other constituents Trace With Modifiers Percent of Ory Weicht < 15 Malor Component of Sample Boulders Partlde Size Over 12 In. (300 mm) 15-29 > 30 RELATIVE PROPORTION OF FINES Descriptive Term(s) of other constituents Trace With Modifiers Percent of Dry Weight < 15 lS -12 > 12 Cobbles Gravel Sand Silt or Clay Term Non-plastic low Medium High U in. to 3 in. (300 mm to 75 mm) 3 in. to #4 sieve (75 mm to 4.75 mm) #4 Sieve to #200 Sieve (4.7S mm to 0.075 mm) Passing #200 Sieve (0.075 mm) PLASTICITY DESCRIPTION Plasticity lndeic 0 1 -10 11-30 30 + ~fMtl~ Geotechnical Solutions, Inc. .. SMS GEOTECHNICAL SOLUTIONS, INC . Boring: B-101 PROJECT: Proposed Preschool CLIENT: ACAL Enaineertna. Inc. PROJECT No.: GI-19-11-155 PROJECT LOCATION: Marron Rd .. Carlsbad DATE LOGGED: 12/12/2019 BOREHOLE DIA: a· LOGGED BY: S.J.M. CONTRACTOR: Scott's Drilling DRIU METHOD: Truck-Mounted Rotarv Drill. 8-lnch Hollow Stem Auaer. SAMPLE METHOD: 140 LB. Hammer dronned 30-inches bv rooe & cathead. 5-Foot AW rods. REMARKS: No cavina. No oroundwater. -~ c,.i ~Ul !i-l::c ~~ ... 5 ~~ Oi;: IDEPlll !§ MATERIAL DESCRIPTION c.i ~~ i::--!;;:;i ~ ... !!l i iu,~ (ft) c,.i <~ iile ~~ ffi-ii:!-0 ;:) Ul j8 A .::i< ~ F1LL (aft: Silty clayey sand. Tan to olive-brown color. Low plastic. Includes small rock fragment and gravel. Moist. Loose '-1 -X to medium dense. From 1 foot, silty sand. Gray-brown color. Slightly ~ 50/5" 9 104.9 83 39 X moist. Dense to very tight. -- -2-X £ -Blow counts may be inflated due to rock and gravel in ISCJS:. sampler. -ST-1 ... 3 - 23-45-22 (67) -.. . --.... 4 y ~ BEDROCK (Kt): -Granitic bedrock. Gray color. Very hard. Auger refusal at 4.25 feet. -ST-2 Bottom of borehole at 4.3 feet. -- .. .. ---B STANDARD 1%1 MODIFIED ■ BULK "Sl GROUND FIGURE 3 PENETRATION CAUFORNIA SAMPLE TEST SAMPLER -WATER SMS GEOTECHNICAL SOLUTIONS, INC. Boring : B-102 PROJECT: Proposed Preschool CLIENT: ACAL Enalneerina. Inc. PROJECT No.: GI-19-11-155 PROJECT LOCATION: Marron Rd. Carlsbad DATE LOGGED: 12/12/2019 BOREHOLE DIA: 8" LOGGED BY: S.J.M. CONTRACTOR: Scott's Drilling DRILL METHOD: Truck-Mounted Rotarv Drill. 8-lnch Hollow Stem Auaer. SAMPLE METHOD: 140 LB. Hammer dronned 30-inches bv rooe & cathead. 5-Foot AW rods. REMARKS: No cavina. No aroundwater. (.) c,:i "' ;t:J! ~I-t:c: !l;!~ ... 6 ~§ ..li.i ~~l ~~ 0,: OEPTH MATERIAL DESCRIPTION ~ ...... s8 i:::--!i# ~~ i"'~ (ft) l'I) ~~ ffi-0 -:;j "' IOU 00 Q I!:< 0 ::EU Q .[X FILL (a!}: -1 -[X Silty clayey sand to sandy clay. Tan to light brown C color. Low plastic. Moist to wet. -X SC/C: H -2-Includes small rock fragment and gravel. Loose in near 13-50/5" 8 114.2 90 43 -X n ,.. surface exposures. Tight and well-compacted below. '-3 -~ At 3 feet, continues moist and tight. -ST-1 -4- X -5-X 13-26-50 (76) £ ~ BEDROCK (Kt): Crystalline rock (Tonalite). Dark gray color. Coarse-grained. Slightly weathered. Very hard. Auger refusal at 6 feet. ST-2 Bottom of borehole at 6.0 feet. B STANDARD 1%1 MODIFIED ■ BULK 'SI.. GROUND FIGURE 4 PENETRATION CALIFORNIA SAMPLE TEST SAMPLER -WATER --SMS GEOTECHNICAL SOLUTIONS, INC. Boring: B-103 PROJECT: Proposed Preschool CLIENT: ACAL Enaineerina. Inc. -PROJECT No.: GI-19-11-155 PROJECT LOCATION: Marron Rd .. Carlsbad -DATE LOGGED: 12/12/2019 BOREHOLE DIA: s· LOGGED BY: $.J.M. -CONTRACTOR: Scott's Drilling DRILL METHOD: Truck-Mounted Rotarv Drill. 8-lnch Hollow Stem Auaer. SAMPLE METHOD: 140 LB. Hammer dronned 30-inches bv rooe & cathead. 5-Foot AW rods. REMARKS: No cavina. No aroundwater. --5:l ,,; ~Ill ~~ i~-!::c:-~~ "'6 DEPTil !§ u ~! 01= MATERIAL DESCRIPTION g~ i::--"'i-::s'"" i<n~ I:! ! (ft) ,,; ~~ !!lz~ ~~ s'j- c:, ::i =t.i ~8 Q ~< --iX FILL(afi: SC/CI ---- -1 -X Clayey sand to sandy clay. Brown color. Very miost. C Medium plastic. Soft to loose. -~ From l 1, changes to silty clayey sand with small rock ~2-fragment and gravel. Light brown color. Moist. Very tight. SC/S~ u -45-50 7 120.4 95 47 -3-X At 2 feet, moist. Continues rocky to gravelly and tight. • Well-compacted. ST-1 -" / --4--BEDROCK {Kt}: 25-30-31 (61) ---I: Crystalline rock {Tonalite). Dark gray color. -Coarse-grained. Weathered. Dense. -At 4.5 feet, becomes very hard. -Auger refusal at 5 feet. ST-2 -Bottom of borehole at 5.0 feet. .. - .. -B STANDARD 1%1 MODIFIED ■ BULK "Sl.. GROUND PENETRATION CALIFORNIA SAMPLE FIGURES TEST SAMPLER -WATER - GEOLOGIC MAP MARRON ROAD, CARLSBAD Geologic Units: Alluvial flood-plain deposits (l ate Holocene) Tonalite, und ivided (mid-Cretaceous) Exerpt From the Geologic Map of the Oceanside 30' x 60' Quadrangle, California Michael P. Kennedy and Siang S. Tan 2007. SMS GEOTECHN !CAL SOLUTIONS, INC. 593 I Sea Lion Place, Sunc I 09 Carlsbad, CA 920 I 0 Scale I :33,333 Project Number: GI-19-11-155 Figure umber: 6 CROSS-SECTI ON A-A' Legend MARRON ROAD, CARLSBAD, CA ~ Boring and Percolation Test Location ---?---Geologic Contact Approximated Approximated SCALE: l" = 40' O' 40' r-- I Proposed Structure ~ -Compacted -Existing Grade Fill -----Proposed Grade ~ Bedrock A A' 220 Slope Extends Approx. Additional 70 Vertical Feet 200 /Ditch 180 160 140 ~ -L_ Existing Grade -' \ ---._---._---._---._---._ _\ Prnpo"' R,tainiogiWall ', ----...., .......... ...___ Proposed Planter Proposed Grade r ---------------, : : / Proposed Sidewalk PL I Proposed Building I / Existing Grade I I 1 ' ' ' Marron Road I I 1 : Proposed Parking 1 __ _ Bedrock (Kt) .:::g:. =...-_ :.{J:" _____ ,_ 7 Compacted Fill (Qaf) P204(p d) . _______ , __ ., • roJecte B-102 (Projected) · · · 120 Bedrock (Kt) 100--'------------------------------------------------------' SMS GEOTECHNICAL SOLllTIONS INC 5931 Sea Lion Place, Suite I 09 -~rlsbad, CA 920 I 0 Project Number: Gl-19-11-155 Figure Number: 7 CROSS -SECTION B-B' Legend MARRON ROAD, CARLSBAD, CA ~ Boring and Percolation --? Geologic Contact Test Location ·--Approximated Approximated SCALE: 1" = 40' O' 40' ,-- Proposed Structure ~ Compacted I Fill ---Existing Grade ~ Bedrock ----Proposed Grade B B' 220 200 Slope Extends Approx. Additional 70 Vertical Feet 180 160 140 120 -. . . . Proposed Grad!! ~ ~ E"stmg G,.d, ExistiagSo!,m,at / PL(?} ........._ ........._ l Trap Pond I -......_ . Marron Road -......_ ........_ J Proposed Parking .___1 __ _ ----.. ....-'---::u::: ____ ?-+--1 "--·--1 P-202 (Projected) Compacted Fill (Qaf) · Bedrock (Kt) Bedrock (Kt) 100------------------------------=----------....J Sl\1S GEOTECHNICAL SOLUTIONS INC 5931 Sea Lion Place, Suite: I 09 __ C~lsbad, CA 92010 Project Number: Cl-19-11-155 Figure Number: 8 \ FAULT EPICENTER MAP SAN DIEGO COUNTY REGION - EPICENTER MAP LEGEND Period 1800• 1868 11'6!1 · 1932· 1931 199., -,.o ---~ ... ~ 65·€9 !. 2 6.0-6.4 ••• S.S•S,9 • • • S.0-~.4 • • • H:.toncal Fa1., ... ,ng -- Hr~tne Faulttng -- H Jh._ ,.., .. (Ma,or) -- u~as T' • LastlWOd11·•0IM~6S '-lt\hquake '/Car Indicated Earthquake Events Through a 200 Year Period Map is reproduced from California Division of Mines and Geology, "Epicenters of I and Areas Damaged by M > 5 California Earthquakes, 1800-1999". SMS GEOTECHNICAL SOLUT(ONS, INC. 5CJ3 l Sea Lion Place, Suite I 09 Project Number: Gl-19-11-155 Figure Number: 9 Carlsbad. CA 92010 SMS Geotechnical Solutions, Inc. 5931 Sea Lion place, Suite 109 Carlsbad, CA 92010 Sieve Analysis ASTM D 6913 -04 Project ACAL Engineering, Inc. Job# Address Date Gl-19-11-155 Supervising Lab Tech Supervising Lab Manager 100 90 80 70 0.0 60 C: 'iii V) ro 0. so ...., C: Q) u .... 40 Q) 0. 30 20 10 0 500 Location B-102 "" .... lD 100 Cobbles B-102@ 1' 060 030 010 Depth Symbol 1' • S.B. Marron Rd. S.M.S. 1/2/2020 Tech S.B. so 10 5 1 0.5 0.1 0.05 0.01 Grain Size (mm) Gravel Sand Coarse I Fine Coarse I Medium I Fine Silt or Clay 060 060 060 030 030 030 010 010 010 uses NAT,w¾ LL PL Pl Cu (060/010) Cc (D2 30/D60•010 ) SC/ CL 15 l Figure 10 I Typical RetaininK Wall Back DrainaKe Schematic, No-Scale RETAINING WALL FILTER MATERIAi., 3/◄' · t~• CRUSHED ROCKS (WRAPPED IN FILTER FABRIC OR CAL TRANS CLASS 2 PERMEABLE MATERIALS (SEE SPECIFICATIONS) WATERPROOFING (TYP) --- FINISH GRADE y .-S-P-EC-lf-lCA~Tt-:-O~NS~f:-::O~R-=CAL~TRANS~~ CLASS 2 PERMEABLE MATERW. (68-1 .025) U.S. STANDARD SIEVE SIZE 1' J/◄ 3/8 No. 4 No.8 No. 30 No. 50 No. 200 "PASSING 100 90-100 ,0-100 25-◄0 18-33 5-15 0-7 0-3 SAND EQUIVALENT > 75 6"MIN. CONCRETE-LINED DRAINAGE DITCH FILTER MATERIAL, 3/◄• · If CRUSHED ROCKS (WRAPPED IN FILTER FABRIC OR CALTRANS CLASS 2 PERMEABLE MATERIALS (SEE SPECIACATIONS) PROPOSED GRADE CONSTRUCTION SPECIFICATIONS: GROUND SURFACE APPROVED FILTER FABRIC (MIRAFI 140N) 12' OVERI.AP, TYP. ◄' PVC PERFO!tATED PIPE MIN. (SCH 40 OR SOIU5) MIN. 1 /2% FALL TO APPROVED OUTLET (SEE REPORT) NATURAi. Ofl GRADED SLOPE TEMPORAAY 1 : 1 Cl/T SLOPE PROPERLY COMPACTED !MIN. 901') BACKFILLED GROUND -----BENCH AND TIGHTLY KEY INTO TEMPORAAY z w w !a. BACKCl/T ~ BACKFIWNG PROGRESSES APPROVED FILTER FABRIC (MIRAFI I ◄ON} 12' 0¥ERI.AP, TYP. .__ _____ ◄• PVC PERFORATED PIPE MIN. (SCH -40 OR SDR.35) MIN. 112" FAil. TO APPROVED OUTtET (SEE REPOR'Tl 1. Provide granular, non-expansive backfill soil in 1 :1 gradient wedge behind wall. Compact backfill to minimum 90% of laboratory standard. 2. Backdrain should consist of 4" diameter PVC pipe (Schedule 40 or equivalent} with perforations down. Drain to suitable at minimum½%. Provide¼" -1-½" crushed rocks filter materials wrapped in fabric (Mirafi 140N or equivalent}. Delete filter fabric wrap if Caltrans Class 2 permeable material is used. Compact Class 2 permeable material to minimum 90% of laboratory standard. · 3. Seal back of wall with approved waterproofing in accordance with architect's specifications. 4. Provide positive drainage to disallow ponding of water above wall. Drainage to flow away from wall at minimum 2%. Provide concrete-lined drainage ditch for slope toe retaining walls. 5. Use 1-½ cubic feet per foot with granular backfill soil and 4 cubic feet per foot if expansive backfill is used . Project No: G 1-1 9-11 -1 55 .6..ll.6GEOTECHNICAL SOLUTIONS, INC. 5931 Sea Lion Place, Suite 109 Carlsbad, California 92010 Figure: 11 Notes: Typical Over-Excavation And Recompaction Detail Schematic, No-Scale ~GRAOZ---. SEE NOTE:I ----. LNOF~ NATM MATaL\L t1Dl e&Jil.C)D(i F(»C)ATIGN SJILDD(;PAO EL!VAT10N '11N. ~ACTED FILL !DER eon.& Nl:r'ORf. 5E! Al.90 NOTE: '2 1. Minimum depth of over-excavation per soils report, but not less than 2' below the bottom of deepest footing(s) or depth of approved dense native ground, whichever greater. 2. New fills shall be compacted to minimum 90o/e compaction level per ASTM D1557 at approximately 2% above the optimum moisture content, unless otherwise specified in the soils report or directed in the field. Notes: Typical Foundation Formwork Detail AFTER !ET CLEAN. TO RB'10vE UITANCE 'ea,-,:----- E>cCAvJ.TION P'IIST eE KEPT ~EAN AND AliEE OF 0EeRI9 Schematic, No-Scale 1. Foundation concrete shall be poured directly against neat trench excavation exposing approved bearing soil strata. 2. Foundation trench walls shall be stable. Sloughing or disturbed trench side walls shall not be allowed. 3. Foundation trenches shall be observed and approved by the project geotechnical consultant to insure clean excavation immediately prior to, and during placing of concrete. 4. Formwork is not permitted below grade unless fully formed. 5. Stakes are not permitted within the footing section. Project No: Gl-19-11-155 6116GEOTECHNICAL SOLUTIONS, INC. 5931 Sea Lion Place, Suite 109 Carlsbad, California 92010 Figure: 12 NOTES: (a) RE-ENTRANT CORNER REINFORCEMENT NO. 3 BARS PLACED MID-HEIGHT IN SLAB ISOLATION JOINTS CONTRACTION JOINTS (c) I NOSCALE I (b) RE-ENTRANT CORNER CRACK 1. Isolation joints around the columns should be either circular as shown in (a) or diamond shaped as shown in (b). If no isolation joints are used around columns, or if the corners of the isolation joints do not meet the contraction joints, radial cracking as shown in (c) may occur (reference ACI). 2. In order to control cracking at the re-entrant corners(+/ -270 degree corners), provide reinforcement as shown in (c). 3. Re-entrant corner reinforcement shown herein is provided as a general guideline only and is subject to verification and changes by the project architect and / or structural engineer based upon slab geometry, location, and other engineering and construction factors. TYPICAL ISOLATION JOINTS AND SMS GEOTECHNICAL SOLUTIONS1 INC. RE-ENTRANT CORNER Consulting Geotechnical Engineers & Geologists REINFORCEMENT 5931 Sea Lion Place, Suite 109 Carlsbad, California 92010 PROJECT NO. FIGURE NO. 760-602-7815 smsgeosol.inc@gmail.com Gl-19-1 1-155 13 Typical Permeable Interlocking Concrete Paver (PICP) Detail 6" CURB Schematic & Conceptual Only No-Scale NO. B AGGREGATES IN OPENINGS PER MANUFAC1tJRER SPECS. P£RMEA8L£ PA \-£RS (TRAFF"IC RA TED) J-1/B,. THICK CONCRETt PA VERS, TRAmc LOADING 6" CONCRETE EDGE RESTRAIN ~ • • l 2" BEDDING COURSE (NO. 8 AGCREGA T[ · • OR PER MANUFACTURER SPECS) 12· THICK OPEN GRADED BASE, r.JTH MIN. S" P£R HOUR INF1L TRA nON RAT[ ~~~~~~11~~~~~~~~~~,,~~~t---'-r(No. 57 STONE -J/.f• MAX.) ~% /( ~ " /, :< ~~~~~~ ~l~~-0,:~~~~"<-«::< v'THICKNESS AT~ ~~~~~~ /.(<(LEAST JOM/L 0( ~~~~~ ~~~~' ~~ ,~'½~ ~~ »~~~/;V/2¥/;V/;V/;,V~V~-t~ ;, ~%(~%%>-~«~«;"~,,-,__~~/'>'?'>-»}Y""' ' . , / " / /. OPEN GRADcD A,/,,(.._ Project No: Gl-19-11 -155 BASE (NO. 57 SOIL SUBGRAD£ STDNE-J/4" MAX.) UPPER 12" AT 95% COMPACnON. (ASTM 01557) Schematic And Conceptual Only· No-Scale (Also See Report) 8118GEOTECHNICAL SOLUTIONS, INC. .s I: ;h"°' (\) - -----314" GRA\IEL 4• PERFORATED UNDERDRAIN SCH. 40 PVC. Figure: 14 z Typical Pipes Through or Trench Adjacent to Foundations SPREADFTG., CONT. FTG., OR GRADEBEAM Schematic, No-Scale LOCATI: TRENCH SO --- THAT FOOTINGS ARE NOT UNDERMINED BACKFILL TRENCH PER G£0TECHN1CAl REPORT NOTES: 1. DO NOT PLACE SLEEVES OR CONDUIT IN ISC1ATED SPREAD FCXJ'TtfGS ·RUNAROUND OR BB.CM n£SE FOOTINGS. 2 SL.EMS ARE NOTTO PASS THROUGH CONT1flJOUS FOOTINGS ~ ...... ~ ------J 1L' . 2 >· NO EXCAVA~~~ ___/' '"- OR GRACE BEAMS utl.£SS SHOWN OTHERWISE · WHERE st.EEVES ARE PERMITTED, SEE SEE SECTION aaow BElOW THIS LINE SI.AS GRADE Trench Adjacent to F~undation CONT. FOOTNG ORGRADEBENJ • . : . ~ . t . . . .. . . " .. . . -. . . . . . ~ A SEE NOTE2 PROVIDE PiPE ~ ll,D. 7' LARGER THAN pg:e O.D.} WHERE ADJACENT TO CONC. • lYPiCAl L rr OISiAHCE BETWEEN SLEEVES TO NO LESS 1liAN -----. I.AAGER SLEEVE OUTSIDE DIAMETER OR 6" ELEVATION A-A CONT.FOO'ffiG OftGRADEIEAM . . • . . . . . · ..... . . . ' ..__ ___ EXTEND FOOTING MIN. s• BELOW SLEEVE (TYP.) A Project No: G 1-1 9-11 -1 55 Pipes Through or Below Foundation 6JISGEOTECH1 'ICAL SOLUTIONS, INC. 5931 Sea Lion Place, Suite 109 Carlsbad, California 92010 Figure: 15 APPENDIX A Address: No Address at This Location htlps ·tasce7hazardtool online/ ASCE 7 Hazards Report Standard: ASCE/SEI 7-16 Risk Category: Ill Soil Class: C -Very Dense Soil and Soft Rock Page 1 of 3 Elevation: 138.83 ft (NAVO 88) Latitude: 33.1775 Longitude: -117.2998 ) \ .. , .. ' ,. ,t ... ,,,.,.;. \ .,u .. \ •r •• \ •u LI\Y(• Mon Dec 23 2019 .. --ASCE .. AMBICllf~IFIM.ENatel!S Seismic --Site Soil Class: ,. Results: .. Ss : -S1 Fa .. Fv -SMS SM1 -Sos -seis~c De~ Category ata cces : -Date Source: - - .. ---- .. ----https.1,asce 7hazardtool. onlint:!i -- C -Very Dense Soil and Soft Rock 0.95 So1 0.35 0.35 Tl : 8 1.2 PGA: 0.413 1.5 PGAM: 0.496 1.141 FPGA 1.2 0.524 le 1.25 0.76 c. : 1.088 ijon Dec 23 2019 USGS Seismic Design Maps based on ASCE/SEI 7-16 and ASCE/SEI 7-16 Table 1.5-2. Additional data for site-specific ground motion procedures in accordance with ASCE/SEI 7-16 Ch. 21 are available from USGS. Page 2 of 3 Mon Dec 23 2019 ... - ------------ -.. --- ASCE AMEl!lrNtso:Effil'IM.Ela&IIS The ASCE 7 Hazard Tool is provided for your convenience, for informational purposes only, and is provided •as Is" and without warranties of any kind. The location data included herein has been obtained from information developed, produced, and maintained by third party providers; or has been extrapolated from maps incorporated in the ASCE 7 standard. While ASCE has made every effort to use data obtained from reliable sources or methodologies, ASCE does not make any representations or wanantles as to the accu,acy, completeness, rellabilty, currency, or quality of any data provided herein. Any third-party Inks provided by this Tool should not be construed as an endorsement, affiliation, relationship, or sponsorship of such third-party content by or from ASCE. ASCE does not intend, nor should anyone Interpret, the resuls provided by this Tool to replace the sound Judgment of a competent p,ofessiona~ having knowledge and experience in the appropriate field(•) of pracllce, nor to substitute for the standard of care required of such professionals in Interpreting and applying the contents of this Tool or the ASCE 7 standard. In using this Tool, you expressly assume an risks associated with your use. Under no circumstances shaD ASCE or its officers, dinlc:tors, employees, members, affiliates, or agents be liable to you or any other person for any direct, indirect, special, Incidental, or consequentlal damages arising from or related to your use of, or rellance on, the Tool or any Information obtained therein. To the fuNeat extent permitted by law, you agree to release and hold hannless ASCE from any and all liability of any nature arising out of or resulting from any use of data provided by the ASCE 7 Hazard Tool. https://asce?hazardtool.online/ Page 3 of 3 Mon Dec 23 2019 -.. .. - .. -- - - - -- - ------- -- APPENDIXB BOREHOLE PERCOLATION TESTING FOR PLANNING PHASE FEASIBILITY OF STORMWATER INFILTRATION/PERCOLATION PROPOSED PRESCHOOL QUARRY CREEK DEVELOPMENT MARRON ROAD, CARLSBAD .. - - --.. -- - -.. I. Introduction Borehole percolation testing was performed at selected locations of the proposed new preschool building site as part of our study, to evaluate the general suitability of stormwater infiltration/percolation bio-detention basins and BMP facilities. Borehole percolation testing was performed in substantial conformance with the requirements of the County of San Diego BMP Design Manual. II. General Site Description General areas of the proposed preschool building site initially considered for a potential storm water infiltration percolation bio-detention basin(s) and BMP facilities are delineated on the enclosed Figure 2 (areas of P-201, P-202, P-203 and P-204). The project property is a graded cut ground underlain at shallow depths by very hard and massive crystalline bedrock units, apparently created during the Quarry Creek deep sands and gravels mining operation. A section of shallow gravelly silty clay sand (SC/SM) compacted fills, on the order of 5 feet thick maximum was subsequently placed over the exposed very hard and massive bedrock units to develop the existing nearly level graded unimproved surfaces. We understand the property is planned to receive additional compacted fills on the order of 2 feet maximum to achieve final design pad grades, increasing maximum fill thickness to nearly 7 feet. III. Simple Feasibility Criterial (In Substantial Conformance With The County of San Diego BMP Design Manual) A drainage management area (OMA) should be classified as No Infiltration condition when one of the following standards cannot be avoided: 1. Fill materials are greater than 5 feet thick. 2. BMP is proposed within 10 feet (horizontal radial distance) of existing/proposed underground utilities, foundations, buildings, structures and retaining walls. 3. BMP is proposed within 50 feet of a natural slope {)25 percent) or within a distance of 1.5H from fill slopes where H is the slope height of the fill slope. 4. BMP is proposed within 100 feet of a contaminated soil or groundwater sites. 5. BMP is proposed where other physical impairments (i.e. fire road egress, public safety considerations, etc.) occur . -IV. Field Investigation ... .. - -- - Borehole percolation test method was utilized to evaluate the apparent percolation/infiltration rate for the proposed bio-detention and/or BMP facilities. Test boreholes were drilled at selected locations in the general vicinity of the anticipated drainage management areas (OMA). Boreholes were advanced to refusal depths into the underlaying bedrock, using a truck-mounted 8-inch diameter hollow stem auger rotary drill rig. Approximate borehole locations in the anticipated drainage management areas (DMA) are depicted on the enclosed Figure 2 of the report. Borehole Logs are presented as Figures i, ii, iii and iv of this Appendix B. -1- ... - -----... - -- • .... -- Subsurface exploratory drilling completed at the project site for both percolation testing and geotechnical study did not encounter groundwater conditions to the maximum drill refusal depths (6 feet maximum) below the existing ground surfaces (BOS). V. General Borehole Percolation Test Procedure Test procedures were performed in substantial accordance with the Riverside County-Low Impact Development BMP Design Handbook.. In general, the Shallow Percolation Test procedure was utilized, which consisted of an 8-inch diameter drilled borehole, less than 10 feet deep, to allow for the test hole to be filled with water to a minimum depth. The bottom elevation of the test hole is considered to correspond to be very near or at the bottom elevation of the proposed bio-infiltration detention basin(s). The bottom of the test hole is then covered with 2 inches of gravel, and a 3-inch diameter perforated pipe surrounded by gravel is installed in the test hole to avoid any potential collapse of the borehole. The test hole is then filled with water to at least five times the hole's radius (H/r) 5, or 20 inches minimum for an 8-inch diameter test hole), above the gravel at the bottom of the test hole, prior to each test interval. Test results are presented in the enclosed Percolation Test Data Sheets, Figures v through viii. As presented, initially two test trials at 25 minutes intervals were first completed at each test hole to evaluate whether greater than or equal to 6 inches percolation rates for "sandy soils" criteria could be met. Test results indicated less than 6 inches percolation rates in two consecutive 25 minutes trials, indicating "non-sandy soils" requiring the pre-soaking procedures. Percolation holes were pre-soaked by inverting a full 5 gallon bottle ( or more as necessary) of clear water supported over the hole so that the water flow into the holes maintained a constant level of at least 5 times the hole's radius above the gravel at the bottom of the test hole. Testing then commenced after all of the water percolated through the test hole or after 15 hours (no later than 26 hours) had elapsed since initiating the per-soak. After completion of the pre-soak, 12 measurements (one every 30 minutes) were obtained for percolation over a 6-hour time period (or when same consecutive readings are recorded indicating continuous stability in percolation rate). Testing was carried out by recording the drop in the water level from a fixed referenced point with a precision of0.125 (1/a) inches. Test holes were refilled after each test, as necessary. The drop that occurred during the final reading is used to calculate the percolation/infiltration rate. VI. Test Results Summary The Porchet Method of Percolation Rate Conversion was used to obtain the apparent infiltration rates. Percolation rate conversions to the corresponding apparent infiltration rates are presented on the enclosed Figure ix. A summary of the percolation test results and conversions to apparent infiltration rates are provided in the following table: -2- Table 1 The Data Colleted At The Final Test Interval Is Used To Calculate The Percolation Rate (Ap >■rent Infiltration Rate) Pere At DT r Do Df AD Percol'n Ho Hf AH Havg .~pparent ' Hole (min) (in) (in) (in) (in) (in) Rate (in) (in) (in) ("m) Infilt'n Rate I No ,, iiilii7h:i) fn~lri'nifl* P-201 30 27.0 4 4.875 5.125 0.25 1¥> 22.125 21.875 0.250 22.00 opi.z -P-202 30 48.0 4 11.375 11.875 0.500 .§Q 36.625 36.125 0.50 36.38 ,&.g P-203 30 42.0 4 15.250 15.625 0.375 8.0 26.750 26.750 0.375 26.56 Q,95} P-204 30 54.0 4 9.875 10.500 0.625 , __ 1'8 44.125 43.500 0.625 43.81 0.055 * Porchet Method of conversion. VII. Test Results and Findin&s Based on the foregoing percolation testing, apparent percolation rates at the indicated depths (BGS) at the anticipated DMA test sites range from 120 to 48 min.fin, with corresponding apparent infiltration rates ranging from 0.042 to 0.055 in./hr. The indicated percolation/infiltration rates, in our opinion, may generally not be considered fully consistent with the underlying subsoil profile below the upper shallow fill sections, consisting of very hard, massive and impervious crystalline rocks consistency with the anticipated lesser orno infiltration properties. Although, small infiltration may be attributed to some rock fractures and jointing features. The measured apparent ( observed) infiltration rates are corrected to design infiltration rates using an appropriate safety factor based on the BMP Design Manual procedure. Correction procedures for Full Infiltration condition assign a weighting factor for each design consideration (factor values of 3, 2 and 1 for high, medium and low concerns, respectively) for estimating an appropriate safety factor, while a safety factor of 2 is used for Partial Infiltration condition. The appropriate safety factor is then applied to the measured apparent ( observed) infiltration rates to obtain the corrected design infiltration rates, as presented in the following table: -3- Table 2 (In Substantial Conformance With Annendix D of Countv of San Diee:o BMP Desie:n Manual) Factor Category Factor Description Assigned Factor Product (p) Weie:ht lw) Value lv) p=wxv Soil assessment methods 0.25 NIA NIA Predominant soil texture 0.25 NIA NIA A Suitability Site soil variability 0.25 NIA NIA Assessment Depth to groundwater I impervious layer 0.25 NIA NIA Suitability Assessment Safety Factor, SA=L,p NIA Level of pretreatment I expected sediment 0.5 NIA NIA loads B Design Redundancy I resiliency 0.25 NIA NIA Compaction during construction 0.25 NIA NIA Design Safety Factor, SB= LP NIA Combined Safety Factor, Stotal = SA x SB NIA (Minimum of2 and Maximum of9) Apparent observed Infiltration Rate, inch/hr, Kobserved P-201 P-202 P-203 P-204 (corrected for test-specific bias) 0.042 0.052 0.053 0.055 Full Infiltration Design Rate, in/hr, KdesJgn = Kobserved I Stotal NIA NIA NIA NIA Partial Infiltration Design Rate, in/hr, Kdesign = Kobserved / 2 0.021 0.026 0.026 0.027 Supporting Data Shallow percolation borehole test method with boring logs. Porchet method of percolation rate conversion. Notes: Aooarent Observed Infiltration Rates are less than 1 in/hr. VIII. Conclusions and Recommendation Based on results of the borehole percolation tests and indicated design infiltration rates, the DMA test sites are not considered suitable for full or partial infiltration, and No Infiltration condition should be considered for the project BMP designs. The Worksheet C.4-1 : Categorization of Infiltration Feasibility Condition Based On Geo technical Conditions is also completed as part of this effort and is attached herein as an Attachment. -4- Site soil data based on a review ofNRCS Soil Survey Map (see Figures x, xi & xii), indicate Gravel Pits, (Map Unit Symbol GP) in the areas of the project site. Subsmface data generated during the site geotechnical study also indicated very hard, massive and impervious crystalline rocks below the existing upper shallow fill sections, which may be characterized as Group D hydro logic classification (based on San Diego Hydrology Manual classification). Stormwater BMP facilities required in connection with the project development should consist of suitably sized, self-contained filtration system(s), as design by the project design consultant. In general, a self-contained filtration system consisting of a suitably sized excavated basin(s) with specially engineered sand filter media and a perforated underdrain pipe(s) surrounded with ¾-inch crushed rocks, and provided with impervious liner on sides and bottom may be considered. Captured water should be filtered and slowly discharge via a storm drain pipe to an approved storm drain facility. Schematic concepts of a Typical BMP Swale and a Typical Bio-Retention Detail are attached herein as Figures xiii and xiv. Actual designs should be provided by the project design consultant. Properly sized bio-detention basin(s) should include adequate storage capacity with filtrations completed not more than 72 hours and vegetation carefully managed to prevent creating mosquito and other vector habitats. Revised or additional more specific recommendations should be provided by the project geotechnical consultant, as necessary and appropriate, at the time of final plan review phase. -5- SMS Geotechnical Solutions, Inc. Percolation: P-201 PROJECT: Proposed Preschool CLIENT: ACAL Enlrlneerimz. Inc. PROJECT No.: GI-19-11-lSS PROJECT LOCATION: Marron Road Date Excavated: 12/12/19 Logged By: S.J.M. Equipment: Truck-Mounted Rotarv Drill. Hollow Stem Au2er (8 Inches Diameter). Remarks: No cavin11. No irroundwater. u c,j Ill ::l!z t::c ~~ "'o DEPTil rfg u ..l!ll ~~~ ~s 01= MATERIAL DESCRIPTION "'"' ~--~i~ c,j ~~ :s"'~ (ft) ~,..l ~:z:~ ~~ i5~ 0 -::i "' 00 ::.lo ~< (,:, l;U 0 X FILL {af): ~ -~ Silty to clayey sand. Tan to green-brown Color. Low SC/S~ plastic. Rocky to gravelly. Moist to wet. Moderately I -compacted to compacted. ST-1 1- I BEDROCK {Kt}: ~ 2 - Granitic bedrock. Gray to dark gray color. Very hard. ,- Slow drilling. Auger refusal at 2.25 feet. ST-2 Bottom of borehole at 2.3 feet. ■ BULK □ CHUNK T NUCLEAR GAUGE 'v GROUND SAMPLE DENSITY TEST WATER FIGURE i SMS Geotechnical Solutions, Inc. PROJECT: Proposed Preschool Percolation : P-202 CLIENT: ACAL Enoineerin2. Inc. PROJECT No.: GI-19-11-155 PROJECT LOCATION: -=M=ar=r=on=-=R=oa=d"---------------t Date Excavated: -=12/=12/~1=9-Logged By: --~s=.J~.M~. -- Equipment: Truck-Mounted Rotarv Drill. Hollow Stem Auizer (8 Inches Diameter). Remarks: No cavimz. No IZI'oundwater. u DEPTH ~8 (ft) ~ ..I 0 MATERIAL DESCRIPTION FILL (af): Silty to clayey sand. Tan to green-brown color. Gravelly. Loose. Low plastic. Very moist to wet. From 1.5 feet, silty to clayey sand with some gravel. Dark brown color. Moist to slightly moist. Moderately compacted. ST-1 ,Ji cj ,Ji ::i SC/S~ - BEDROCK (Kt): ..... _________ _._ _ _.._ _ _.__ .... ■ BULK SAMPLE Granitic bedrock. Gray to dark gray color. Very hard. Auger refusal at 4 feet. ST-2 □ Bottom of borehole at 4.0 feet. CHUNK DENSITY W NUCLEAR GAUGE CT GROUND T TEST V WATER FIGURE ii SMS Geotechnical Solutions, Inc. PROJECT: Proposed Preschool Percolation : P-203 CLIENT: ACAL Enmneerin2. Inc. PROJECT No.: GI-19-11-155 PROJECT LOCATION: ~M=ar=r~on=R=oa=d~--------------1 Date Excavated: __ 12_/_12_/_19_ Logged By: --~s~.J~.M~. -- Equipment: Truck-Mounted Rotarv Drill. Hollow Stem Auger (8 Inches Diameter). Remarks: No cavimz. No szroundwater. S:l ~EPTH ~8 (ft) ,,2 ,..J 0 X 1X _x 2-X --X 3 IX MATERIAL DESCRIPTION FILL (af): Silty clayey sand. Tan to olive-brown color. Gravelly. Low plastic. Loose. Wet to saturated. From 1.5 feet, becomes slighty moist to moist and moderately compacted. ST-1 v.i cj v.i ::i SC/S~ ,- .,____...~~ ....... BEDROCK (Kt): -_ __._ _ __._ _ __._ _ __.__ ......... __ ■ BULK SAMPLE Granitic bedrock. Gray color. Very hard. Slow drilling. Auger refusal at 3.5 feet. ST-2 □ Bottom of borehole at 3.5 feet. CHUNK DENSITY W NUCLEAR GAUGE n GROUND T TEST V WATER FIGURE iii SMS Geotechnical Solutions, Inc. PROJECT: Proposed Preschool Percolation : P-204 CLIENT: ACAL Emtlneerin2. Inc. PROJECT No.: GI-19-11-155 PROJECT LOCATION: -=M=ar=r-=on=-=R=-oa=d"--------------1 Date Excavated: __ 12/_12/--'-19_ Logged By: --~S_.J~.M~. __ Equipment: Truck-Mounted Rotarv Drill. Hollow Stem Auger (8 Inches Diameter). Remarks: No cavin2. No !lroundwater. ~ IDEPTII ::i:g (ft) ~ ...l C, MATERIAL DESCRIPTION FILL (af): Silty clayey sand. Tan to olive-brown color. Gravelly. Low plastic. Loose. Very moist to wet. From 3 feet, silty clayey sand. Tan to orange to olive-brown color. Slightly moist to moist. Moderately compacted to compacted. <A cJ <A ;:i SC/Stv ,,._S_T_-1 __________________ __,,,- BEDROCK (Kt): .... _......__......__......__.....___.....__ _ _,. ■ BULK SAMPLE Granitic bedrock. Gray to dark gray color. Very hard. Slow drilling. Auger refusal at 4.5 feet. ST-2 □ Bottom of borehole at 4.5 feet. CHUNK DENSITY FIGURE iv SMS Geotechnical Solutions, Inc. 5931 Sea Lion place, Suite 109 Carlsbad, CA 92010 Percolation Test Data Sheet Project Name ____ A_CA_L _En_g_in_e_e_r_in_g_, l_n_c. ___ ! Project Nol.._ _____ G_l-_19_-_1_1-_1_5_5 ____ _, Date I 12/12/19 & 12/13/191 Test Hole No .._ _______ P-_2_0_1 ______ ___,I Tested by !._ ______ s._s. _____ ___, Depth ofTest Hole, Dr I 27" uses Soil Classification !compacted Fill over Hard Rockl • Test Hole Dimension (inches) ' Diameter (if round) I 8" Sides (if rectangular) I Length I N/ A I Width I N/ A I Sandy Soil Criteria Test I ~ Trial No Start Time Stop Time Time Interval, Initial Depth to Final Depth to Change In Water Greater than or (min) Water (in.) Water (In.) Level (in.) Equal to 6" ? (y/n) 1 9:25 9:50 25 5.750 7.125 1.375 No 2 9:50 10:15 25 6.375 7.500 1.125 No If two consecutive measurements show that six inches of water seeps away in less than 25 minutes, the test shall be run for an additional hour with measurements taken every 10 minutes. Otherwise, pre-soak (fill) overnight. Obtain at least twelve measurements per hole over at least six hours (approximately 30 minute intervals) with a precision of at least 0.25" . • LlT Do Dr LlD Trial No Start Time Stop Time Time Interval, Initial Depth to Final Depth to Change In Water Percolation Rate (min) Water (in.} Water (in.) Level (in.) (min./in.) I j 1 9:15 9:45 30 7.000 7.625 0.625 48.00 -2 9:45 10:15 30 6.875 7.375 0.500 60.00 0. 3 10:15 10:45 30 6.750 7.125 0.375 80.00 4 10:45 11:15 30 6.625 7.000 0.375 80.00 5 11:15 11:45 30 6.500 6.875 0.375 80.00 6 11:45 12:15 30 6.000 6.375 0.375 80.00 7 12:15 12:45 30 5.875 6.250 0.375 80.00 G 8 12:45 1:15 30 6.000 6.375 0.375 80.00 9 1:15 1:45 30 5.750 6.125 0.375 80.00 I t 10 1:45 2:15 30 5.500 5.875 0.375 80.00 -11 2:15 2:45 30 5.250 5.500 0.250 120.00 12 2:45 3:15 30 4.875 5.125 0.250 120.00 13 14 15 Comments: Sunny (65° F). First two measurements did not meet sandy soil criteria. Pre-soaked overnight. I Figure V ■ I - L [ - ,... SMS Geotechnical Solutions, Inc. S931 Sea Lion place, Suite 109 Carlsbad, CA 92010 Percolation Test Data Sheet Project Name .._ ___ A_CA_L_En_g_i_ne_e_r_in_g_, _In_c_. __ _.I Project Nol 1. _____ G_l-_1_9-_1_1_-1_5_5 ____ _. Date I 12/12/19 & 12/13/19 ! Test Hole No .__ _______ P_-2_0_2 ______ _____.! Tested by .._I ______ s._B_. _____ --1 Depth of Test Hole, Dr .I 48" , uses Soil Classification I compacted Fill over Hard Rockl Test Hole Dimension (inches) Diameter (If round) I 8" Sides (if rectangular) I Length I N/ A I Width I N/ A Sandy Soil Criteria Test Trial No Start Time Stop Time Time Interval, Initial Depth to Final Depth to Change in Water Greater than or (min) Water (in.) Water (In.) Level (in.) Equal to 6" ? (y/n) 1 9:30 9:55 25 9.875 11.750 1.875 No 2 9:55 10:20 25 10.250 11.375 1.125 No If two consecutive measurements show that six inches of water seeps away in less than 25 minutes, the test shall be run for an additional hour with measurements taken every 10 minutes. Otherwise, pre-soak (fill) overnight. Obtain at least twelve measurements per hole over at least six hours (approximately 30 minute intervals) with a precision of at lea.st 0.25". llT Do Dr llD Trial No Start Time Stop Time Time Interval, Initial Depth to Final Depth to Change in Water Percolation Rate (min) Water (in.) Water(in.) Level (in.) (min.fin.) 1 9:20 9:50 30 16.250 17.125 0.875 34.29 2 9:50 10:20 30 16.125 17.000 0.875 34.29 L' 3 10:20 10:50 30 15.375 16.125 0.750 40.00 4 10:50 11:20 30 15.000 15.750 0.750 40.00 5 11:20 11:50 30 14.500 15.250 0.750 40.00 6 11:50 12:20 30 13.500 14.125 0.625 48.00 7 12:20 12:50 30 13.250 13.875 0.625 48.00 r 8 12:50 1:20 30 13.125 13.750 0.625 48.00 9 1:20 1:50 30 11.750 12.375 0.625 48.00 10 1:50 2:20 30 11.625 12.250 0.625 48.00 -11 2:20 2:50 30 11.875 12.375 0.500 60.00 r 12 2:50 3:20 30 11.375 11.875 0.500 60.00 ~ 13 14 j 15 Comments : Sunny (65° F). First two measurement s did not meet sandy soil criteria. Pre-soaked overnight. I Figure vi ... I [ r L I I I I J ri - SMS Geotechnlcal Solutions, Inc. 5931 Sea Uon place, Suite 109 carlsbad, CA 92010 Percolation Test Data Sheet Project Name ____ A_CA_L_En_g_in_e_e_r"_rn_g,_l_n_c. __ __.l Project No .. I _____ G_l-_1_9-_1_1_-1_s_s ____ _, Date 112/12/19 & 12/13/191 Test Hole No _______ P-_2_03 _______ __,I Tested by ... I ______ S._B_. _____ __, Depth ofTest Hole, Dr _I 42" _ uses Soil Classification I compacted Fill over Hard Racki Test Hole Dimension (inches) Diameter (if round) I 8" Sides (if rectangular) I Length I N/ A I Width I N/ A Sandy Soil Criteria Test Trial No Start Time Stop Time Time Interval, Initial Depth to Final Depth to Change in Water Greater than or (min) Water (in.) Water(in.) Level (in.) Equal to 6" ? (y/n) 1 10:00 10:25 25 12.875 17.125 4.250 No 2 10:25 10:50 25 15.125 19.000 3.875 No If two consecutive measurements show that six inches of water seeps away in less than 25 minutes, the test shall be run for an additional hour with measurements taken every 10 minutes. Otherwise, pre-soak (fill) overnight. Obtain at least twelve measurements per hole over at least si hours ( pp ox·mately 30 · t · t I ) ·th f t I t O 25" X a r I mrnu e rn erva s wI a precIsIon o a eas ta Do Dr l:J.D Trial No Start Time Stop Time Time Interval, Initial Depth to Final Depth to Change in Water Percolation Rate (min) Water (in.) Water (in.) Level (in.) (min./ln.) 1 9:25 9:55 30 13.875 15.875 2.000 15.00 2 9:55 10:25 30 13.750 15.375 1.625 18.46 3 10:25 10:55 30 14.375 15.750 1.375 21.82 4 10:55 11:25 30 15.000 16.125 1.125 26.67 5 11:25 11:55 30 15.125 16.250 1.125 26.67 6 11:55 12:25 30 14.500 15.500 1.000 30.00 7 12:25 12:55 30 15.250 16.250 1.000 30.00 8 12:55 1:25 30 15.000 15.875 0.875 34.29 9 1:25 1:55 30 14.875 15.625 0.750 40.00 10 1:55 2:25 30 15.500 16.000 0.500 60.00 11 2:25 2:55 30 15.000 15.375 0.375 80.00 12 2:55 3:25 30 15.250 15.625 0.375 80.00 13 14 n 15 Comment s : Sunny (65° F). First two measurements did not meet sandy soil criteria. Pre-soaked overn ight. I Figure vii SMS Geotechnical Solutions, Inc. 5931 Sea Lion place, Suite 109 Carlsbad, CA 92010 Percolation Test Data Sheet Project Name ._ ___ A_C_A_L_E_ng_l_ne_e_r_in_g_, _ln_c_. __ ....,! Project No ._I _____ G_1-_1_9-_1_1_-1_5_5 ____ _. Date I 12/12/19 & 12/13/19 1 11111 I L -.. ~ I Ii -, Test Hole No _______ P_-_20_4 _______ ___.I Tested by ._I ______ s_.B_. _____ __J Depth of Test Hole, Dr .I 54" . uses Soil Classification jcompacted Fill over Hard Rockl Test Hole Dimension (inches) Diameter (if round) I 8" Sides (if rectangular) I Lengthl N/ A l Width l N/ A Sandy Soil Criteria Test Trial No Start Time Stop Time Time Interval, Initial Depth to Final Depth to Change in Water Greater than or (min) Water (in.) Water (in.) Level (in.) Equal to 6" 7 (y/n) 1 10:30 10:55 25 13.875 15.875 2.000 No 2 10:55 11:20 25 13.250 15.125 1.875 No If two consecutive measurements show that six inches of water seeps away in less than 25 minutes, the test shall be run for an additional hour with measurements taken every 10 minutes. Otherwise, pre-soak (fill) overnight. Obtain at least twelve measurements per hole over at least six hours (approximately 30 minute intervals) with a precision of at least 0.25". .6T Do Dt .6D Trial No Start Time Stop Time Time Interval, Initial Depth to Final Depth to Change in Water Percolation Rate {min) Water (in.) Water (in.) Level (in.) (min.fin.) 1 9:30 10:00 30 16.625 17.875 1.250 24.00 2 10:00 10:30 30 15.625 16.750 1.125 26.67 3 10:30 11:00 30 13.500 14.625 1.125 26.67 -4 11:00 11:30 30 13.125 14.125 1.000 30.00 5 11:30 12:00 30 12.500 13.500 1.000 30.00 6 12:00 12:30 30 11.750 12.625 0.875 34.29 7 12:30 1:00 30 11.500 12.250 0.750 40.00 D 8 1:00 1:30 30 11.125 11.875 0.750 40.00 9 1:30 2:00 30 11.875 12.625 0.750 40.00 11 10 2:00 2:30 30 10.625 11.250 0.625 48.00 -11 2:30 3:00 30 10.125 10.750 0.625 48.00 12 3:00 3:30 30 9.875 10.500 0.625 48.00 13 14 C 15 Comment s : Sunny (65° F). First two measurements did not meet sandy soil criteria. Pre-soaked overnight. I Figure viii SMS Geotechnlcal Solutions, Inc. 5931 Sea Uon place, Suite 109 Carlsbad, CA 92010 Percolation Test (Apparent Infiltration Rate, Porchet Method of Conversion) Project Name Ll __ A_CA_L _En...;g;...in_e_e_rin...;g;..,_ln_c_. _ __,I Project No LI ____ G_l-_1_9-_1_1-_1_5_5 ___ --1 Date 12/23/2019 tit DT Pere Hole No (min) (in) P-201 30 27.0 P-202 30 48.0 P-203 30 42.0 P-204 30 54.0 Time Interval = M Initial Depth to Water= Do Final Depth to Water= Df r (in) 4 4 4 4 Total Depth of the Test Hole = OT Test Hole Radius = r Do Df l\D Percol'n (in) (in) (in) Rate (min/in) 4.875 5.125 0.250 120.0 11.375 11.875 0.500 60.0 15.250 15.625 0.375 80.0 9.875 10.500 0.625 48.0 Initial Height of Water at Selected nme Interval = Ho = DT -Do Final Height of Water at Selected Time Interval = Hf= DT -Df Ho (in) 22.125 36.625 26.750 44.125 Change in Height of Water Over The Time Interval"' 6D = Df -Do= l\H = Ho -Hf Average Head Height Over The Interval =Havg = (Ho+ Hf)/ 2 Apparent Infiltration Rate = It= l\H*60*r / ( l\t*( r + 2*Havg )) Hf 6H Havg Apparent (in) (in) (in) lnfilt'n Rate (It, in/hr)* 21.875 0.250 22.00 36.125 0.500 36.38 26.375 0.375 26.56 43.500 0.625 43.81 I Figure ix 33° 10'46"'N 33" IO'JO"N I I I ;i: b !!? t ;i: b !!l ~ ~ 471890 471890 N A Soll Map-San Diego County Area, California (Proposed New Preschool Site) 47flllO 4718J0 fflro0 47197tl 472D«) 472110 471llll 4718:JJ 4719:Xl 47197tl 4720«) 472110 Map Scale: 1:3,3~ f pmed on A lands::ape (11" X 8.5") sheet ----====--------=======Meiers o ~ oo m m ----====-------========A!et 0 150 :m 8l) 11D Map projection: 1/,Jeb Men:ator Comer<DOl'di,ata: WGS84 Edge tics: UTM lone 11N WGS84 Natural Resources Conservation Service Vl/eb Soil Survey National Cooperative Soil Survey 472111'.l -02321) 472111) 47229) -02321) ;i: ~ !:; t 47ZB) 47ZB> ;i: ~ !:; 9 I I I I I I I 12/11/2019 Page 1 of3 33" 10'46"N 33" 10' 30" N F iaiirP. X ~ Soil Map-San Diego County Area, California (Proposed New Preschool Site) MAP LEGEND MAP INFORMATION Area of Interest (AOI) □ Area of Interest (AOI) Solis LJ Soil Mep Unit Polygons -Soil Map Unit Lines □ Soil Map Unit Points Speclal Point Features (2) C8I )( 0 X 0 A <!$ ;~ 0 0 "" + ,=;, ) 9 fJ Natural Resources Conservation Service Blowout Borrow Ptt Clay Spot Closed Depression Gravel Pit Gravelly Spot Landfill Lava Flow Marsh or swamp Mine or Quarry Miscellaneous Water Perennial Water Rock Outcrop Saline Spot Sandy Spot Severely Eroded Spot Sinkhole Slide or Slip SodicSpot § Spo~ Area ~ Stony Spot m Very Stony Spot ril;> ~i' Wet Spot 6 Other ~-Special Line Features Water Features ,,,..._, Streams and Canals Traneporutlon Rais +++ -Interstate Highways -US Routes Major Roads Local Roads Background • Aerial Photography Web Soil Survey National Cooperative Soll Survey The soil surveys that comprise your AOI were mapped al 1:24,000. Warning: Soil Map may not be valid al this scale. Enlargement of maps beyond the scale of mapping can cause misunderstanding of the detail of mapping and accuracy of soil line placement. The maps do not show the small areas of contrasting soils that could have been shown at a more detailed scale. Please rely on the bar scale on each map sheet for map measurements. Source of Map: Natural Resources Conservation Service Web Soil Survey URL: Coordinate System: Web Mercator (EPSG:3857) Maps from the Web Soil Survey are based on the Web Mercator projection, which preserves direction and shape but distorts distance and area. A projection that preserves area, such as the Albers equal-area conic projection, should be used if more accurate calculations of distance or area are required. This product is generated from the USDA-NRCS certified data as of the version date(s) listed below. Soil Survey Area: San Diego County Area, California Survey Area Data: Version 14, Sep 16, 2019 Soll map units are labeled (as space allows) for map scales 1 :50,000 or larger. Date(s) aerial images were photographed: Nov 3, 2014-Nov 22,2014 The orthophoto or other base map on which the soH lines were compiled and digitized probably differs from the background imagery displayed on these maps. As a result, some minor shifting of map unit boundaries may be evident. 12/11/2019 Page 2 of3 Fiaure : Soll Map-San Diego County Area, California Map Unit Legend Map Unit Symbol BIC2 CmrG oao OaE2 FeE2 GP LsE SbC Totals for Area of Interest USDA Natural Resources aiii Conservation Service Map Unit Name Acres In AOI BonseH sandy loam, 2 to 9 percent slopes, eroded Cleneba very rocky coarse sandy loam, 30 to 75 percent slopes Oieblo clay, 9 to 15 percent slopes, warm MAAT Oiablo clay, 15 to 30 percent slopes, eroded, warm MAAT Fallbrook rocky sandy loam, 9 to 30 percent slopes, eroded Gravel pits Linne clay loam, 9 to 30 percent slopes Salinas clay loam, 2 to 9 percent slopes Web Soil Survey National Cooperative Soil Survey 0.0 6.3 5.4 22.1 3.9 12.6 0.7 1.4 52.4 Proposed New Preschool Site Percent of AOI 0.1% 12.0% 10.3% 42.1% 7.5% 24.0% 1.4% 2.6% 100.0% 12/11/2019 Page 3 of 3 Figure x, Project No: Typical BMP Swale Schematic & Conceptual Only No-Scale ..,_ _______ PER Pl.AN ----~-----i IEPTH _[ ID Pt,W 6" MIi. EJaEER[J) sat. 'SEEN01f lELOW ·,• : . ._ · 10" Mil FlTfklElJIA: ,½r .. <Z? .. ~ JPMTQENIWASIEIJSANO 18" TO 1 PART J,AI" Qi'A'fl ~.._--2"-J~<J?A~ 9 \ ~~~~.,, -6" -J/4• CRtJSH£I) ROCK IIIPf.RJl£Nl[ {X{)-f MJRIC ,. REOIIRED BY Sf.IS ENCIIEIR. ,, ENCINEERfJJ 50!. lA>f1i SHMJ. IJE MMIIJll 6• DEEP SAIIJY LOAM Si.I: IIX tfTH NO IDlE 1HM 51 a.AY CONTENl 11£ 1B SHM1 CfliTMI !J0-60X ~ 20-JOZ COll'OST <R HARDrtXXJ IIU.QI, NIJ 2():-JOX TOPSO/l. 4' PERffRATfO SUJ/liAII PIPE !1.(1'£ AT IX 111N. AND CfllECT TO ai-S17f PRIVA TC IJRNNM£ SYS-TEii 6.116 GEOTECHNICAL SOLUTIONS, INC. Figure: xiii Project No: CAPPED CLEANOUTPORT TYPICAL BIO-DETENTION DETALL Schematic & Conceptual Only No-Scale ta • HOPE STORU DRAIN RISER W/A TR/UM VARIES ~":.:. :· ......... -~ y .· ... · . • • • •:, _. r r=~··.. '1 .~-~RO-MODIF1C4170N -:-:-:-:-.-: ;.;.·.:-:-:-:-:-... -: : ·.·.·.· .. ·.·.·.·.· .· ·.·.•.· ... ·.· ·.;··.;. . . ..... · · 'ONTJl.OLORIFICBAT -• 0.5~ (MIN) }. . ~~GUDE BLBYA.110N ·,· ., WL£1 :·. PIPE . • HDPE OR PVC GEOMEMBRANE THICKNfSS AT LEAST JOMIL 3• MIN/MUN (TYP) AGGRfGATE BELOW UNDERDRAIH TO A VOID CLOCGING . . MIN DE~;· ·,.s~ ~. SOIL FILTER MIX ·6• PERFORATED PIPE SLOPED AT 0.5% IN ¾" AGGREGATE BASE GRA \£!. 8£D. CONNECTED TO STORM DRAIN. 6116GEOTECHNICAL SOLUTIONS, INC. HOPE OR PVC GEOM£MBRAN£ THICKN£SS AT LEAST JOAIIL OUTlET PIPE Figure: xiv ATTACHMENT Appendix C: Geotechnical and Groundwater Investig at ion Requirements Worksheet C.4-1: categorization of Infiltration Feasibility Condition Based on Geotechnical Conditions' Categorization of Infiltration Feasibility Condition based on Worksheet c.,. t: Form l- Geotechnical Conditions RA '" Part 1 -Full Infiltration Feasibility Screening Criteria DMA(s) Being Analyzed: Project Phase: P-201, P-202, P-203, P-204 Planning Criteria 1: Infiltration Rate Screening Is the mapped hydrologic soil group according to the NRCS Web Soil Survey or UC Davis Soil Web Mapper Type A or B and corroborated by available site soil data11? D Yes; the DMA may feasibly support full infiltration. Answer "Yes" to Criteria 1 Result or continue to Step tB if the applicant elects to perform infiltration testing. 1A D No; the mapped soil types are A or B but is not corroborated by available site soil data (continue to Step tB}. Qg No; the mapped soil types are C, D, or "urban/unclassified" and is corroborated by available site soil data. Answer "No" to Criteria 1 Result. D No; the mapped soil types are C, D, or "urban/unclassified" but is not corroborated by available site soil data (continue to Step 1B). Is the reliable infiltration rate calculated using planning phase methods from Table D.3-1? 1B D Yes; Continue to Step 1C. D No; Skip to Step 1D. Is the reliable infiltration rate calculated using planning phase methods from Table D.3-1 greater than 0.5 inches per hour? 1C D Yes; the OMA may feasibly support full infiltration. Answer "Yes" to criteria 1 Result. D No; full infiltration is not required. Answer "No" to Criteria 1 Result. Infiltration Testing Method. Is the selected infiltration testing method suitable during the design phase (see Appendix D.3}? Note: Alternative testing standards may be allowed with 1D appropriate rationales and documentation. D Yes; continue to Step 1E. D No; select an appropriate infiltration testing method. 9 Note that it is not required to investigate each and every criterion in the worksheet, a single "no,, answer in Part 11 Part 21 Part 3, or Part 4 determines a full, partial, or no infiltration condition. 10 This form must be completed each time there is a change to the site layout that would affect the infiltration feasibility condition. Previously completed forms shall be retained to document the evolution of the site storm water design. 11 Available data includes site-specific sampling or observation of soil types or texture classes, such as obtained from borings or test pits necessary to support other design elements. C-16 The City of San Diego I Storm Water Standards I October 2018 Edit ion Pa rt 1: BMP Design Ma nual SD.) Appendix C: Geotechnical and Groundwater Investigation Requirements Categorization of lnfiltr.ition Fcasihility Condition based on Worksheet C.4 -1: Form 1- 1E IF lG Criteria 1 Result Gcotcchnical Conditions 8A1" Number of Percolation/Infiltration Tests. Does the infiltration testing method performed satisfy the minimum number of tests specified in Table D.3-2? □ Yes; continue to Step 1.F. D No; conduct appropriate number of tests. Factor of Safety. Is the suitable Factor of Safety selected for full infiltration design? See guidance in D.5; Tables D.5-1 and D.5-2; and Worksheet D.5-1 (Form I-9). □ Yes; continue to Step 1G. D No; select appropriate factor of safety. Full Infiltration Feasibility. Is the average measured infiltration rate divided by the Factor of Safety greater than 0.5 inches per hour? D Yes; answer "Yes11 to Criteria 1 Result. D No; answer "No" to Criteria 1 Result. Is the estimated reliable infiltration rate greater than 0.5 inches per hour within the OMA where runoff can reasonably be routed to a BMP? D Yes; the DMA may feasibly support full infiltration. Continue to Criteria 2. □ No; full infiltration is not required. Skip to Part 1 Result. Summarize infiltration testing methods, testing locations, replicates, and results and summarize estimates of reliable infiltration rates according to procedures outlined in D.5. Documentation should be included in project geotechnical report. See report C-17 The City of San Diego I Storm Water Standards I October 2018 Edition Part 1: BMP Design Manual Appendix C: Geotechnical and Groundwater Investigation Requirements Categorization of Infiltration Feasibility Condition based on Worksheet C.t.-1: Form 1- Geotcchnical Conditions SA w Criteria 2: GeologidGeotechnical Screening 2A 2A-1 2A-2 2A-3 2B 2B-1 2B-2 If all questions in Step 2A are answered "Yes, 11 continue to Step 2B. For any 11No11 answer in Step 2A answer "No11 to Criteria 21 and submit an "Infiltration Feasibility Condition Letter11 that meets the requirements in Appendix C.1.1. The geologic/geotechnical analyses listed in Appendix C.2.1 do not apply to the OMA because one of the following setbacks cannot be avoided and therefore result in the OMA being in a no infiltration condition. The setbacks must be the closest horizontal radial distance from the surface edge (at the overflow elevation) of the BMP. Can the proposed full infiltration BMP(s) avoid areas with existing fill materials greater than 5 feet thick below the infiltrating surface? Can the proposed full infiltration BMP(s) avoid placement within 10 feet of existing underground utilities, structures, or retaining walls? Can the proposed full infiltration BMP(s) avoid placement within 50 feet of a natural slope (>25%) or within a distance of 1.5H from fill slopes where H is the height of the fill slope? □Yes □Yes □Yes □No □No □No When full infiltration is determined to be feasible, a geotechnical investigation report must be prepared that considers the relevant factors identified in Appendix C.2.1. If all questions in Step 2B are answered "Yes," then answer 11Yes11 to Criteria 2 Result. If there are "No" answers continue to Step 2C. Hydroconsolidation. Analyze hydroconsolidation potential per approved ASTM standard due to a proposed full infiltration BMP. Can full infiltration BMPs be proposed within the OMA without increasing hydroconsolidation risks? Expansive Soils. Identify expansive soils (soils with an expansion index greater than 20) and the extent of such soils due to proposed full infiltration BMPs. Can full infiltration BMPs be proposed within the DMA without increasing expansive soil risks? □Yes □Yes □No □No C-1 8 The City of San Diego I Storm Water Standards I October 2018 Edition Part 1: BMP Design Manual Appendix C: Geotecbnical and Groundwater Investigation Requirements Categorization of Infiltration Feasibility Condition based on Worksheet C.4-1: Form I- Geotechnical Conditions SA"' 2B-3 2B-4 2B-5 2B-6 Liquefaction. If applicable, identify mapped liquefaction areas. Evaluate liquefaction hazards in accordance with Section 6.4.2 of the City of San Diego's Guidelines for Geotechnical Reports (2011 or most recent edition). Liquefaction hazard assessment shall take into account any increase in groundwater elevation or groundwater mounding that could occur as a result of proposed infiltration or percolation facilities. Can full infiltration BMPs be proposed within the DMA without increasing liquefaction risks? Slope Stability. If applicable, perform a slope stability analysis in accordance with the ASCE and Southern California Earthquake Center (2002) Recommended Procedures for Implementation of DMG Special Publication 117, Guidelines for Analyzing and Mitigating Landslide Hazards in California to determine minimum slope setbacks for full infiltration BMPs. See the City of San Diego's Guidelines for Geotechnical Reports (2011) to determine which type of slope stability analysis is required. Can full infiltration BMPs be proposed within the DMA without increasing slope stability risks? Other Geotechnical Hazards. Identify site-specific geotechnical hazards not already mentioned (refer to Appendix C.2.1). Can full infiltration BMPs be proposed within the DMA without increasing risk of geologic or geotechnical hazards not already mentioned? Setbacks. Establish setbacks from underground utilities, structures, and/or retaining walls. Reference applicable ASTM or other recognized standard in the geotechnical report. can full infiltration BMPs be proposed within the DMA using established setbacks from underground utilities, structures, and/or retaining walls? C-1 9 The City of San Diego I Storm Water Standards I October 2018 Edition Part 1: BMP Design Manual □Yes □Yes □Yes □Yes □No □No □No □No SD.) Appendix C: Geotechnical and Groundwater Investigation Requirements Categorization of Infiltration Feasibility Condition based on Worksheet c.1.-1: Form I- Gcotechnical Conditions 8A '" 2C Criteria 2 Result Mitigation Measures. Propose mitigation measures for each geologic/geotechnical hazard identified in Step 213. Provide a discussion of geologic/geotechnical hazards that would prevent full infiltration BMPs that cannot be reasonably mitigated in the geotechnical report. See Appendix C.2.1.8 for a list of typically reasonable and typically unreasonable mitigation measures. Can mitigation measures be proposed to allow for full infiltration BMPs? If the question in Step 2 is answered "Yes, 11 then answer "Yes" to Criteria 2 Result. If the question in Step 2C is answered "No," then answer "No11 to Criteria 2 Result. Can infiltration greater than 0.5 inches per hour be allowed without increasing risk of geologic or geotechnical hazards that cannot be reasonably mitigated to an acceptable level? Summarize findings and basis; provide references to related reports or exhibits. See report Part 1 Result-Full Infiltration Geotechnical Screening 12 If answers to both Criteria 1 and Criteria 2 are "Yes", a full □Yes □Yes Result infiltration design is potentially feasible based on Geotechnical D Full infiltration Condition conditions only. If either answer to Criteria 1 or Criteria 2 is "Non, a full infiltration design is not required. ~ Complete Part 2 □No □No 12 To be completed using gathered site information and best professional judgement considering the definition of MEP in the MS4 Permit. Additional testing and/or studies may be required by City Engineer to substantiate findings. C-20 The City of San Diego I Storm Water Standards I October 2018 Edition Part 1: BMP Design Manual SD.) Appendi x C: Geotecbnical and Groundwater Investigation Requirements Categorization of Infiltration Feasibility Condition bdsed on Worksheet C.4 -1: Form 1- Gcotl'rhniral Conditions 8Aw Part 2 -Partial vs. No Infiltration Feasibility Screening Criteria DMA(s) Being Analyzed: Project Phase: P-201, P-202, P-203, P-204 Planning Criteria 3: Infiltration Rate Screening 3A NRCS Type c, D, or "urban/unclassifiedn: Is the mapped hydrologic soil group according to the NRCS Web Soil Survey or UC Davis Soil Web Mapper is Type C, D, or "urban/unclassified.11 and corroborated by available site soil data? D Yes; the site is mapped as C soils and a reliable infiltration rate of 0.15 in/hr. is used to size partial infiltration BMPS. Answer "Yes" to Criteria 3 Result. D Yes; the site is mapped as D soils or "urban/unclassified" and a reliable infiltration rate of 0.05 in/hr. is used to size partial infiltration BMPS. Answer "Yes" to Criteria 3 Result. D No; infiltration testing is conducted (refer to Table D.3-1), continue to Step 3B. Infiltration Testing Result: Is the reliable infiltration rate (i.e. average measured infiltration rate/2) greater than 0.05 in/hr. and less than or equal to 0.5 in/hr? D Yes; the site may support partial infiltration. Answer "Yes" to Criteria 3 Result. mi No; the reliable infiltration rate (i.e. average measured rate/2) is less than 0.05 in/hr., partial infiltration is not required. Answer "No" to Criteria 3 Result. Is the estimated reliable infiltration rate (i.e., average measured infiltration rate/2) greater than or equal to 0.05 inches/hour and less than or equal to 0.5 inches/hour at any location Criteria 3 within each DMA where runoff can reasonably be routed to a BMP? Result D Yes; Continue to Criteria 4. Ci No: Skip to Part 2 Result. Summarize infiltration testing and/or mapping results (i.e. soil maps and series description used for infiltration rate). See report C-21 The City of Sa n Diego I Storm Water Standards I October 2018 Edition Part 1: BMP Design Manual SD.) Appendix C: Geotechnical and Groundwater Investigation Requirements Categorization of Infiltration Feasibility Condition based on Worksheet C.4-1: Form l- Geotcchnical Conditions 8A"' Criteria 4: Geologic/Geotechnical Screening 4A 4A-1 4A-2 4A-3 4B 4B-1 4B -2 [f all questions in Step 4A are answered "Yes, u continue to Step 2B. For any "No" answer in Step 4A answer "No11 to Criteria 4 Result, and submit an "Infiltration Feasibility Condition Letter" that meets the requirements in Appendix C.1.1. The geologic/geotechnical analyses listed in Appendix C.2.1 do not apply to the DMA because one of the following setbacks cannot be avoided and therefore result in the OMA being in a no infiltration condition. The setbacks must be the closest horizontal radial distance from the surface edge (at the overflow elevation) of the BMP. Can the proposed partial infiltration BMP(s) avoid areas with existing fill materials greater than 5 feet thick? Can the proposed partial infiltration BMP(s) avoid placement within 10 feet of existing underground utilities, structures, or retaining walls? Can the proposed partial infiltration BMP(s) avoid placement within 50 feet of a natural slope (>25%} or within a distance of 1.5H from fill slopes where His the height of the fill slope? □Yes □No □Yes □No □Yes □No When full infiltration is determined to be feasible, a geotechnical investigation report must be prepared that considers the relevant factors identified in Appendix c.2.1 If all questions in Step 4B are answered "Yes, n then answer "Yes" to Criteria 4 Result. If there are any "No11 answers continue to Step 4c. Hydroconsolidation. Analyze hydroconsolidation potential per approved ASTM standard due to a proposed full infiltration BMP. can partial infiltration BMPs be proposed within the OMA without increasing hydroconsolidation risks? Expansive Soils. Identify expansive soils (soils with an expansion index greater than 20) and the extent of such soils due to proposed full infiltration BMPs. Can partial infiltration BMPs be proposed within the DMA without increasing expansive soil risks? □Yes □Yes □No □No C-22 The City of San Diego I Storm Water Standards I October 201 8 Edition Part 1: BMP Design Manual Appendix C: Geotecbnical and Groundwater Investigation Requirements Categorization of Infiltration feasibility Condition based on Worksheet C.4-1: Form 1- Geotechnical Conditions 8/\"' 4B-3 4B-4 4B-5 4B-6 4C Liquefaction. If applicable, identify mapped liquefaction areas. Evaluate liquefaction hazards in accordance with Section 6.4.2 of the City of San Diego's Guidelines for Geotechnical Reports (2011). Liquefaction hazard assessment shall take into account any increase in groundwater elevation or groundwater mounding that could occur as a result of proposed infiltration or percolation facllities. Can partial infiltration BMPs be proposed within the DMA without increasing liquefaction risks? Slope Stability. If applicable, perform a slope stability analysis in accordance with the ASCE and Southern California Earthquake Center (2002) Recommended Procedures for Implementation of DMG Special Publication 117, Guidelines for Analyzing and Mitigating Landslide Hazards in California to determine minimum slope setbacks for full infiltration BMPs. See the City of San Diego's Guidelines for Geotechnical Reports (2011) to determine which type of slope stability analysis is required. can partial infiltration BMPs be proposed within the OMA without increasing slope stability risks? Other Geotechnical Hazards. Identify site-specific geotechnical hazards not already mentioned (refer to Appendix C.2.1). Can partial infiltration BMPs be proposed within the OMA without increasing risk of geologic or geotechnical hazards not already mentioned? Setbacks. Establish setbacks from underground utilities, structures, and/or retaining walls. Reference applicable ASTM or other recognized standard in the geotechnical report. Can partial infiltration BMPs be proposed within the OMA using recommended setbacks from underground utilities, structures, and/or retaining walls? Mitigation Measures. Propose mitigation measures for each geologic/geotechnical hazard identified in Step 4B. Provide a discussion on geologic/geotechnical hazards that would prevent partial infiltration BMPs that cannot be reasonably mitigated in the geotechnical report. See Appendix C.2.1.8 for a list of typically reasonable and typically unreasonable mitigation measures. Can mitigation measures be proposed to allow for partial infiltration BMPs? If the question in Step 4c is answered "Yes," then answer "Yes,, to Criteria 4 Result. If the question in Step 4C is answered 11No,,, then answer "No,, to Criteria 4 Result. C-23 The City of San Diego I Storm Water Standards I October 2018 Ed ition Part 1: BMP Des ign Manual □Yes □Yes □Yes □Yes □Yes □No □No □No □No □No SD.) Appendix C: Geotechnical and Groundwater Investigation Requirements Categorization of Infiltration Feasibility Condition based on Worksheet c.1.-1: Form 1- Gcotechnical Conditions 8A'" Criteria 4 Result Can infiltration of greater than or equal to 0.05 inches/hour and less than or equal to 0.5 inches/hour be allowed without increasing the risk of geologic or geotechnical hazards that cannot be reasonably mitigated to an acceptable level? Summarize findings and basis; provide references to related reports or exhibits. Part 2 -Partial Infiltration Geotechnical Screening Result13 □Yes Result □No If answers to both Criteria 3 and Criteria 4 are "Yes", a partial infiltration design is potentially feasible based on geotechnical conditions only. If answers to either Criteria 3 or Criteria 4 is "No", then infiltration of any volume is considered to be infeasible within the site. D Partial Infiltration Condition ClJ No Infiltration Condition 13 To be completed using gathered site information and best professional judgement considering the definition of MEP in the MS4 Permit. Additional testing and/or studies may be required by City Engineer to substantiate findings. C-24 The City of San Diego I Storm Water Standards I October 2018 Edition Part 1: BMP Design Manual