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HomeMy WebLinkAboutAppendix E_OMP_Geotechnical Investigation Appendix E Geotechnical Investigation (Cotton, Shires and Associates, Inc. 2018) CONSULTING ENGINEERS AND GEOLOGISTS COTTON, SHIRES AND ASSOCIATES, INC. 330 Village Lane,Los Gatos, California 95030 (408) 354-5542 Fax (408) 354-1852 6417 Dogtown Road, San Andreas, California 95249 (209) 736-4252 Fax (209) 736-1212 2804 Camino Dos Rios, Suite 201, Thousand Oaks, California 91320 (805) 375-1050 Fax (805) 375-1059 Prepared for: LOTUS WATER 215 Kearney Street San Francisco, California 94108 June 2018 GEOTECHNICAL INVESTIGATION STORMWATER CAPTURE PROJECT ORANGE MEMORIAL PARK SOUTH SAN FRANCISCO, CALIFORNIA Northern California Office Central California Office Southern California Office 330 Village Lane 6417 Dogtown Road 2804 Camino Dos Rios, Suite 201 Los Gatos, CA 95030-7218 San Andreas, CA 95249-9640 Thousand Oaks, CA 91320-1170 (408) 354-5542 • Fax (408) 354-1852 (209) 736-4252 • Fax (209) 736-1212 (805) 375-1050 • Fax (805) 375-1059 www.cottonshires.com COTTON, SHIRES AND ASSOCIATES, INC. CONSULTING ENGINEERS AND GEOLOGISTS June 1, 2018        E5038  Robert Dusenbury  LOTUS WATER  215 Kearny Street  San Francisco, CA  94108    SUBJECT: Geotechnical Investigation – Stormwater Capture Project   RE: Orange Memorial Park    South San Francisco, California    Dear Mr. Dusenbury:     Cotton, Shires and Associates, Inc. (CSA) is pleased to provide Lotus Water with the  following report in which we describe the findings, conclusions and recommendations of our  geotechnical investigation for the proposed Storm Water Capture Project at the Orange  Memorial Park, located in South San Francisco, California.  This investigation was performed in  accordance with our proposal to you dated October 24, 2017.       In this report, we characterize the geotechnical conditions surrounding and underlying  the two alternative sites and provide conclusions and recommendations regarding geotechnical  hazards, foundation type and design criteria, and site grading.     We appreciate the opportunity to have been of service to you on this project.  If you have  any questions regarding this report, please feel free to contact us.      Sincerely,  COTTON, SHIRES AND ASSOCIATES, INC.      David T. Schrier  Principal Geotechnical Engineer  GE 2334       Andrew T. Mead   Senior Engineering Geologist  AM:DTS:TS:TRH:st CEG 2560  COTTON, SHIRES AND ASSOCIATES, INC.  i GEOTECHNICAL INVESTIGATION  ORANGE MEMORIAL PARK STORM WATER CAPTURE PROJECT South San Francisco, California    Table of Contents     Page    EXECUTIVE SUMMARY ..............................................................................................  1   Conclusions ..........................................................................................................  1   Recommendations ...............................................................................................  2    1.0 INTRODUCTION  .............................................................................................  3   1.1 Project Description .................................................................................  3   1.2 Purpose and Scope of Work ..................................................................  4    2.0 PHYSICAL AND GEOLOGIC SETTING .....................................................  4   2.1 Terrain ......................................................................................................  4   2.2 Geologic Setting ......................................................................................  4   2.3 Seismic Setting ........................................................................................  5   2.3.1 Peak Ground Acceleration .......................................................  5    3.0 SITE CONDITIONS ..........................................................................................  5   3.1 Surface Conditions .................................................................................  5   3.2 Subsurface Conditions ...........................................................................  6    3.2.1 Laboratory Testing ....................................................................  6   3.3 Groundwater Conditions ......................................................................  7    4.0 POTENTIAL GEOTECHNICAL HAZARDS AND BUILDING LOCATION 8   4.1 Seismic Hazards .....................................................................................  8   4.2 Static Settlement Behavior .....................................................................  13   4.3 Expansive Soils .......................................................................................  14   4.4 Sulfate Attack on Concrete ....................................................................  15   4.5 Infiltration and Raising Groundwater Levels ....................................  15    5.0 RECOMMENDATIONS .....................................................................................  16   5.1 Site Considerations...................................................................................  16   5.2 Soil Improvement Alternative ................................................................  16   5.3 Deep Foundation Alternative................................................ .................  17   5.4 Stormcapture Design................................................................................  17    COTTON, SHIRES AND ASSOCIATES, INC.  ii Table of Contents (cont.)  Page   5.5 Site Grading................................................ ...............................................  18    5.5.1 Site Preparation ...........................................................................  18    5.5.2 Compacted Fill .............................................................................  18    5.5.3 Utility Trench Backfill .................................................................  19    5.5.4 Temporary Cut Slope Design ....................................................  19    5.5.5 Pavement Subgrade Preparation ..............................................  19   5.6 Pavement Design................................................ ......................................  19   5.7 Surface Drainage................................................................................... ....  20   5.8 Seismic Design..................................................................................... .....  20   5.9 Technical Review.................................................................................... ..  21   5.10 Earthwork Construction Observation and Testing.............................  21    6.0 INVESTIGATION LIMITATIONS ................................................................  21    7.0 REFERENCES ......................................................................................................  23   7.1 Maps and Reports................................................ ...................................  23    APPENDIX A ‐ Field Investigation and Logs of Exploratory Borings   Field Investigation  ..............................................................................................  A‐1   Logs of Exploratory Borings ..............................................................................  Follows A‐1    APPENDIX B ‐ Laboratory Testing  .............................................................................  B‐1       FIGURES  Follows Page  1 Site Location Map .............................................................................................  3  2 Regional Geologic Map ...................................................................................  4  3 San Francisco Bay Area Fault Map ................................................................  5  4 Boring Location Map – North Parcel .............................................................  6  5 Boring Location Map – Ballfield ....................................................................  6  6 Engineering Geologic Cross Section A‐A’ ....................................................  6  7 Engineering Geologic Cross Section B‐B’ .....................................................  6  8 Engineering Geologic Cross Section C‐C’ .....................................................  6   COTTON, SHIRES AND ASSOCIATES, INC.  1 EXECUTIVE SUMMARY    In this Executive Summary, we provide a summary of some of the most pertinent conclusions  and recommendations resulting from our Geotechnical Investigation performed for Lotus Water  for a storm water capture facility to be located in Orange Memorial Park in South San Francisco,  California.  We understand that the proposed project consists of constructing an underground  capture facility either adjacent to, or below Colma Creek.  In addition to the capture facility, the  structure could include trash racks and collectors, diversion pipes and possibly an infiltration  system.  A more detailed discussion of our findings, conclusions and recommendations is  presented in the main body of this technical report.    Conclusions    • The proposed construction of a buried stormwater capture system at either the North  Parcel or the Ballfield is primarily constrained by liquefiable and densifiable, loose to  medium dense sands.    • The site will likely be subjected to very strong seismic ground shaking within the life of  the structure.  The proposed stormwater capture sites are located approximately 2 miles  (3.2 kilometers) northeast of the mapped main trace of the San Andreas Fault.  Peak  horizontal ground accelerations of up to 0.87g to 0.88g should be anticipated at the sites.     • The proposed stormwater capture sites are situated along a broad alluvial filled valley,  close to the bay margin, in an area characterized by level to gentle (0 to 10 degrees  inclination) natural topography.      • Groundwater was encountered at a depth of 25 feet below ground surface in the North  Parcel borings and 18 feet below ground surface in the Ballfield borings.  However,  groundwater levels could be higher at other times and locations.    • We calculate that there is a high potential for seismically induced  liquefaction/densification of portions of the subsurface materials.  We calculated  unmitigated potential liquefaction/densification induced ground surface settlements of  up to 5‐3/4 inches at the North Parcel and 9 inches at the Ballfield.  We also calculated up  to 1 inch and 2 inches of static load induced settlement at the North Parcel and Ballfield  sites, respectively.   COTTON, SHIRES AND ASSOCIATES, INC.  2   Recommendations    • To reduce the potential for adverse effects of differential foundation movement due to  liquefaction/densification, the stormwater capture system can be supported on a layer of  improved, overlapping deep soil mixed columns (DSM).  Alternatively, the stormwater  capture structures can be supported on deep foundations such as auger cast piles (ACP)  or drilled displacement columns (DDC).    • Based on collected geotechnical data, site grading for the stormwater capture structures,  including excavating, should be within the capabilities of moderate excavation  equipment (i.e., dozer, backhoes, excavators and pile driving rigs).  During the dry  season, temporary cut slopes of 2:1 (H:V) should be satisfactory (depending on  monitoring) for construction purposes.  We are not anticipating that fill will be placed on  the site, except to backfill around the excavation.    • The final drawings and specifications should be reviewed and approved by a  representative of our firm to confirm that the recommendations of this report have been  incorporated into the design of the project.    • Earthwork construction activities should be observed and tested by a representative of  our firm to confirm that the recommendations of this report are incorporated into the  construction of the project and to address potential unanticipated soil conditions not  encountered during site investigation.   COTTON, SHIRES AND ASSOCIATES, INC.  3 GEOTECHNICAL INVESTIGATION  ORANGE MEMORIAL PARK STORMWATER CAPTURE PROJECT South San Francisco, California      1.0 INTRODUCTION    1.1 Project Description     In this report, Cotton, Shires and Associates, Inc. (CSA) presents the results of our geotechnical  investigation for a stormwater capture facility to be located in Orange Memorial Park in South  San Francisco, California.  We understand that the proposed project is for the City of South San  Francisco (City) and consists of constructing an underground stormwater capture facility either  adjacent to, or below Colma Creek.  In addition to the capture facility, the structure will likely  include trash racks and collectors, diversion pipes and possibly an infiltration system.    We understand that presently several alternative sites are being considered including the North  Parcel, the South Parcel, the Ballfield, and an instream location.  We further understand that the  North and South Parcels were previously occupied by greenhouses associated with a carnation  growing company.  CSA’s scope of work was focused on investigating the subsurface conditions  at the North Parcel and the Ballfield sites (See Figure 1).    We also understand that stormwater capture systems (structures) are typically buried reinforced  concrete, prefabricated cells that are joined together in groups of four or more, and that  individual cells are 5.5‐ to 9‐foot tall, 8‐foot wide and 16‐foot long, and bear on a layer of crushed  rock/aggregate (typically 12 to 21 inches thick) and isolated (sandwiched) with two layers of  filter fabric (Oldcastle Precast, Storm Capture).  These structures can be capped with between  0.5 feet and 5 feet of soil cover, resulting in a total depth of excavation/improvement of 7 feet to  15.75 feet.  We further understand that these storm capture structures are typically pre‐fabricated  with either an open bottom for maximum infiltration, or a closed, slab‐on‐grade floor.  While we  have not been provided with typical loading for the capture systems, we note that Oldcastle  Precast Storm Capture brochure indicates that soil bearing capacities above 1,999 psf do not  require special care.      280 101 South San Francisco 101 880 680 5 580 380 580 780 205 Oakland San Francisco Paci f ic Ocean 101280 4 1 17 101 San Jose Area of Map CONSULTING ENGINEERS AND GEOLOGISTS APPROVED BY GEO/ENG BY SCALE NTS DATE FIGURE NO. PROJECT NO. COTTON, SHIRES AND ASSOCIATES, INC. E5038DTS DTS JUNE 2018 1 South San Francisco, California SITE LOCATION MAP ORANGE MEMORIAL PARK STORM WATER N Reference: Google Maps NORTH PARCEL SITE BALLFIELD SITE CAPTURE PROJECT  COTTON, SHIRES AND ASSOCIATES, INC.  4 1.2 Purpose and Scope of Work    The purpose of our investigation was to develop geotechnical data and recommendations for  project design.  Our objectives were to: 1) evaluate surface and subsurface conditions; and 2)  develop conclusions and recommendations regarding geotechnical hazards, site grading,  foundation type and design criteria.  The specific scope of work performed for our investigation  included the following tasks:      1) Review of in‐house geologic data and the previous report provided to us;  2) Attendance at the kick‐off meeting;  3) Participation in conference calls;  4) Geotechnical reconnaissance;  5) Subsurface exploration;  6) Laboratory testing;  7) Geotechnical engineering and geologic analyses;  8) Formulation of conclusions and recommendations; and  9) Preparation of this report.      2.0 PHYSICAL AND GEOLOGIC SETTING    2.1 Terrain    The North Parcel and the Ballfield sites are relatively level and located at roughly elevation 27  to 28 feet and 24 to 25 feet, respectively.  Natural grades in the area slope down toward Colma  Creek.    2.2 Geologic Setting    The North Parcel and the Ballfield sites are located in a broad northwest‐southeast trending  valley close to the bay margin, and between San Bruno Mountain to the north and Skyline Ridge  to the southwest.  The concrete‐lined Colma Creek runs down the center of the valley and  borders the North Parcel to the southwest, and the Ballfield to the northeast.  The sites are  mapped as being underlain by alluvium (Bonilla, M. G., Preliminary Geologic Map of the San   COTTON, SHIRES AND ASSOCIATES, INC.  5 Francisco South 7.5’ Quadrangle and Parts of the Hunters Point 7.5’ Quadrangle, California; see  attached Figure 2, Regional Geologic Map).      The site is close to the transform fault boundary (the San Andreas Fault) between the Pacific and  North American tectonic plates.     2.3       Seismic Setting    The alternative stormwater capture facility sites are situated in an area of high seismicity.  The  nearest and controlling active fault, with respect to site seismicity, is the San Andreas Fault,  located approximately 2 miles (3.2 km) to the southwest (see attached San Francisco Bay Area  Fault Map, Figure 3).  Other active faults close to the site include the San Gregorio Fault (7.7  miles/12.4 km to the southwest) and the Hayward Fault (16.3 miles/26.2 km to the northeast).    2.3.1 Probabilistic Analysis ‐ We performed a peak ground acceleration analysis of the  site employing the USGS Seismic Design Tool, with the 2010 ASCE 7 (with March 2013 errata)  Design Code.  The results of our analysis indicate an appropriate Maximum Considered  Earthquake Geometric Mean (MCEG) Peak Ground Acceleration (PGAM) of 0.87g to 0.88g.    Taking into account the faults described above, the 2016 California Building Code (CBC), the  ASCE 7‐10 code coefficients presented in Section 5.8 of this report, and the results of the peak  ground acceleration analysis, it is our opinion that the proposed storm water capture facility  could experience a peak horizontal ground acceleration (PGAM) as high as 0.87g to 0.88g.        3.0 SITE CONDITIONS    3.1 Surface Conditions    The North Parcel is presently unoccupied by improvements and is covered with weeds.  We  observed several utility covers in the area, indicating possible underground utilities.  We also  observed mounds of fill placed adjacent to the skate park located to the southeast of the parcel.    The Ballfield is presently occupied by baseball fields.    COTTON,S HIRES AND ASSOCIATES, INC. CONSULTING ENGINEERS AND GEOLOGISTS South San Francisco, CALIFORNIA E5038 DTS DTS JUNE 2018 1"=2000' FIGURE NO. PROJECT NO. DATE SCALE APPROVED BY GEO/ENG BY REGIONAL GEOLOGIC MAP 2 ORANGE MEMORIAL PARK STORMWATER CAPTURE PROJECT 0'2000'4000' Scale 1" = 2000' N EXPLANATION Reference:Bonilla, M.G., 1971, Preliminary Geologic Map of the San Francisco South Quadrangle and Parts of the Hunter Point 7.5' Quadrangle, San Francisco Bay Area, California, Digital Database Prepared By Carl Wentworth, Marjorie Lucks, Heather Schoonover, Scott Graham and Thomas May, 1998 NORTH PARCEL SITE BALLFIELD SITE Qsr Qal Qaf/tf Slope Debris and Ravine Fill Alluvium Artificial Fill, Artificial Fill over tidal flat Qc Colma Formation Ql Landslide Deposit KJS Franciscan Complex Sandstone and Shale KJG Franciscan Complex Greenstone KJU Franciscan Complex Sheared Rocks KJSK Franciscan Complex Sandstone and Shale QTm Merced Formation Type A Fault (with segmentation boundaries) Type B Fault San Andreas Fault Zone Segments SAFZ-1 North Coast Segment SAFZ-2 Peninsula Segment SAFZ-3 Santa Cruz Mountains Segment SAFZ-4 Creeping Segment Abbreviated Faults M Maacama Fault MB Monterey Bay - Tularcitos Fault MDT Mount Diablo Thrust Fault MV Monta Vista - Shannon Fault O Ortigalita Fault PR Point Reyes Fault QS Quien Sabe Fault R Rinconada Fault S Sargent - Berrocal Fault WN West Napa Fault Z Zayante - Vergeles Fault CONSULTING ENGINEERS AND GEOLOGISTS APPROVED BY GEO/ENG BY SCALE 1"=25 mi DATE FIGURE NO. PROJECT NO. COTTON, SHIRES AND ASSOCIATES, INC. E5038DTS DTS JUNE 2018 3 SAN FRANCISCO BAY AREA FAULT MAP ORANGE MEMORIAL PARK STORMWATER South San Francisco, California ORANGE MEMORIAL PARK STORMWATER CAPTURE PROJECT CAPTURE PROJECT  COTTON, SHIRES AND ASSOCIATES, INC.  6 The adjacent concrete-lined Colma Creek channel is about 35 to 40 feet wide, and the bottom of the channel is about 10 feet below the top of the channel wall. 3.2 Subsurface Conditions    We explored subsurface conditions at the North Parcel and the Ballfield sites between April 3  and April 5, 2018 by means of eight (four at each site) exploratory boring drilled to depths of  31.5 feet to 46.5 feet at the locations shown on Figures 4 and 5.  In our borings we generally  encountered alluvial sands, silts and clays. In the borings drilled at the North Parcel site, we  generally encountered 15.5 to 19 feet of loose to medium dense sand and silty sand, overlying a  4‐ to 6.5‐foot layer of stiff to very stiff clay.  This clay layer was encountered in all four of the  North Parcel borings.  Below the clay, we encountered varying thicknesses of sands, clays and  some silts to the bottom of the borings.  In several of the North Parcel site borings we  encountered a thin silt or clay layer at or near the ground surface (Figure 6).    In the borings drilled at Ballfield site, we generally encountered a 4.5‐ to 5‐foot thick layer of  medium stiff to stiff clayey fill overlying loose, medium dense, dense and very dense alluvial  sands, and silty or clayey sands.  In Borings CSA/SD‐4, CSA/SD‐5 and CSA/SD‐7 we encountered  a 4‐ to 5‐foot thick clay layer beginning at depths of 23 feet, 25 feet, and 18 feet, respectively  (Figure 7 and 8).  In CSA/SD‐4 we also encountered a stiff sandy clay below a depth of 40 feet.      3.2.1 Laboratory Testing ‐ We performed laboratory tests on disturbed and relatively  undisturbed soil samples obtained from our borings.  Those tests included Atterberg limits, in‐ situ unit weight, natural moisture content, consolidation tests, and sieve analysis.  Based on the  results of these tests, it appears that the sandy soils in the upper 15.5 to 19 feet at the North Parcel  site have low to high fines content (8% to 42%) and moderate dry unit weights (100 pcf).  The  laboratory test results on the underlying 4‐ to 6.5‐foot thick clay layer indicates that this material  has high plasticity (Liquid Limits = 56 to 57, Plasticity Indices = 27 to 38), low dry unit weights  (89 pcf to 102 pcf), and low to moderate compression and recompression indices (Cc  = 0.141  and, Cr = 0.033).  We also performed laboratory testing on the sands, clays and silts underlaying  the 4‐ to 6.5‐foot clay layer and found that these sands had moderate to high fines content (28%  to 44%) and moderate dry unit weights (109 pcf), while the clays had high sand content (37% to  47%) low plasticity (Liquid Limits = 38, Plasticity Indices = 18), and the silts had high sand  content (41%), and low plasticity (Liquid Limits = 32, Plasticity Indices = 13).    CSA / B-2 CSA / B-1 CSA / B-8 CSA / B-3 A A' EXISTING COLMA CREEK CANAL NORTH PARCEL COTTON,S HIRES AND ASSOCIATES, INC. CONSULTING ENGINEERS AND GEOLOGISTS SOUTH SAN FRANCISCO, CALIFORNIA E5038 DTS DTS JUNE 2018 1"=50' FIGURE NO. PROJECT NO. DATE SCALE APPROVED BY GEO/ENG BY BORING LOCATION MAP - NORTH PARCEL 4NorthNorth02550100 (feet) ORANGE MEMORIAL PARK STORMWATER CAPTURE PROJECT Explanation Location of small-diameter exploratory boring Location of engineering geologic cross section CSA/B-1 A A' CSA / B-4 CSA / B-5 CSA / B-7 CSA / B-6 B B' C C' BALLFIELD EXISTING COLMA CREEK CANAL COTTON,S HIRES AND ASSOCIATES, INC. CONSULTING ENGINEERS AND GEOLOGISTS E5038 DTS DTS JUNE 2018 1"=60' FIGURE NO. PROJECT NO. DATE SCALE APPROVED BY GEO/ENG BY 5NorthNorth03060120 (feet) SOUTH SAN FRANCISCO, CALIFORNIA BORING LOCATION MAP - BALLFIELD ORANGE MEMORIAL PARK STORMWATER CAPTURE PROJECT Explanation Location of small-diameter exploratory boring Location of engineering geologic cross section CSA/B-1 A A' DISTANCE (feet)ELEVATION (feet)0 20 40 60 80 100 120 140 160 180 200 220 240 -20 0 20 40 -20 0 20 40 A'A CSA/SD-2 (proj. 25' NW) CSA/SD-8 (proj. 45' SE) SM/SP ML/CL CH SM/SP CL SM/SP CL/ML SM/SP ML/CL/CH SM/SP CL/ML TD = 36.5' SM/SP SM/SP CL/ML ML/CL/CH Colma Creek Canal TD = 41.5'ELEVATION (feet)20 CL Af ALLUVIUM ML ? TD = 36.5' EXPLANATION Earth Materials Map Symbols Assumed Geologic Contact Groundwater Location of Small-Diameter Exploratory Boring CSA/SD-8 (proj. 45' SE) Af (SM)Fill - Silty Sand SM/SP Alluvium - Near-Surface Silty Sand, Sand Alluvium - Near-Surface Silt and ClayML/CL SM/SP Alluvium - Deep Silty Sand, Sand Alluvium - Deeper Silt and Clay ML/CL/ CH Alluvium - Deep Clay and SiltCL/ML COTTON,S HIRES AND ASSOCIATES, INC. CONSULTING ENGINEERS AND GEOLOGISTS E5038 DTS DTS JUNE 2018 1"=20' FIGURE NO. PROJECT NO. DATE SCALE APPROVED BY GEO/ENG BY 6 SOUTH SAN FRANCISCO, CALIFORNIA ENGINEERING GEOLOGIC CROSS SECTION A-A' NORTH PARCEL ORANGE MEMORIAL PARK STORMWATER CAPTURE PROJECT 50 30 10 -10 -300 20 40 60 80 100 120 140 160 180 200 220 240 260 280 300 320 340 380 400 420 440 460 480 50 30 10 -10 -30 B'B CSA/SD-6 CSA/SD-4 Af (CL) SP/SM CH/CL SP-SM CL Af (CL) SP/SM CL Colma Creek Canal TD = 33.5' TD = 46.5'ELEVATION (feet)DISTANCE (feet)ELEVATION (feet)Af ALLUVIUM ? TD = 35.5' EXPLANATION Earth Materials Map Symbols Assumed Geologic Contact Groundwater Location of Small-Diameter Exploratory Boring CSA/SD-6 Af (CL)Fill - Clay SM/SP Alluvium - Near-Surface Silty Sand, Sand Alluvium - Deeper Silt and ClayCH/CL Alluvium - Deep ClayCL/ML COTTON,S HIRES AND ASSOCIATES, INC. CONSULTING ENGINEERS AND GEOLOGISTS E5038 DTS DTS JUNE 2018 1"=40' FIGURE NO. PROJECT NO. DATE SCALE APPROVED BY GEO/ENG BY 7 SOUTH SAN FRANCISCO, CALIFORNIA ENGINEERING GEOLOGIC CROSS SECTION B-B' BALLFIELD ORANGE MEMORIAL PARK STORMWATER CAPTURE PROJECT 0 20 40 60 80 100 120 140 160 180 200 220 240 260 280 300 320 340 360 380 400 420 -20 0 20 40 -20 0 20 40 C'C CSA/SD-7 CSA/SD-5 Colma Creek Canal SP-SM CL SC Af (CL)Af (CL) SP-SM CL SC SP-SMTD = 38.5' TD = 31.5'SP-SM 30ELEVATION (feet)DISTANCE (feet)ELEVATION (feet)ALLUVIUM Af ? TD = 38.5' EXPLANATION Earth Materials Map Symbols Assumed Geologic Contact Groundwater Location of Small-Diameter Exploratory Boring CSA/SD-7 Af (CL)Fill - Clay SM/SP Alluvium - Near-Surface Silty Sand, Sand Alluvium - Deeper Silt and ClayCH/CL SC/SM/SP Alluvium - Deep Clayey Sand, Silty Sand, Sand COTTON,S HIRES AND ASSOCIATES, INC. CONSULTING ENGINEERS AND GEOLOGISTS E5038 DTS DTS JUNE 2018 1"=30' FIGURE NO. PROJECT NO. DATE SCALE APPROVED BY GEO/ENG BY 8 SOUTH SAN FRANCISCO, CALIFORNIA ENGINEERING GEOLOGIC CROSS SECTION C-C' BALLFIELD ORANGE MEMORIAL PARK STORMWATER CAPTURE PROJECT  COTTON, SHIRES AND ASSOCIATES, INC.  7 Based on the consolidation test results and our analysis, it appears that the 4‐ to 6.5‐foot thick  clay layer at a depth of 15.5 to 19 feet is slightly over‐consolidated with an Over Consolidation  Ratio (OCR) of 1.6.    Based on the results of laboratory test results on samples taken from the Ballfield site, the near‐ surface clayey fill material has a low plasticity (Liquid Limits = 23, Plasticity Indices = 8) and  moderate dry unit weights (107 to 108 pcf).  The laboratory test results also indicate that the  underlying sandy soils have moderate to high fines content (19% to 48%).  Laboratory test results  on the soils below the sandy layer indicate that the clays have low dry unit weight (102 pcf),  moderate to high sand content (24% to 47%) and moderate to high plasticity (Liquid Limits = 34  to 56, Plasticity Indices = 18 to 35), while the sands had moderate to high fines content (30% to  45%) and low plasticity (Liquid Limits = 26, Plasticity Indices = 11).     The results of the laboratory tests performed on representative samples are presented on the  boring logs in Appendix A (Field Investigation) and in Appendix B (Laboratory Testing).    A detailed description of the exploration program and our logs of the exploratory borings are  presented in Appendix A.    3.3 Groundwater Conditions    Groundwater was encountered in the north Parcel site (during drilling) in the following borings  at the corresponding depths:    Borings CSA/SD‐2: 25 feet   Borings CSA/SD‐3: 40 feet     We also encountered groundwater in our borings at the adjacent California Water Service  Company at a depth of 32 feet, in 2015, and as high as 7 feet in 1997.      Groundwater was encountered in the Ballfield site (during drilling) in the following borings at  the corresponding depths:    Borings CSA/SD‐4: 18 feet   Borings CSA/SD‐5: 20 feet    COTTON, SHIRES AND ASSOCIATES, INC.  8 Borings CSA/SD‐6: 32 feet   Borings CSA/SD‐7: 32 feet     It should be understood that we were recently in a period of protracted drought and that  fluctuations in groundwater levels could occur from variations in rainfall, flooding and other  factors.  Groundwater levels may be different at different times, climatic conditions and  locations.        4.0 POTENTIAL GEOTECHNICAL HAZARDS AND BUILDING LOCATION    In the following sections, we list identified potential geotechnical hazards at the North Parcel   and Ballfield sites, along with the corresponding degrees of estimated potential risk, and we  provide recommendations for possible mitigation measures.    4.1 Seismic Hazards    Seismic ground shaking associated with a large earthquake on the San Andreas, San Gregorio or  Hayward fault is considered to be a high potential hazard in the project area.  Peak ground  accelerations of up to 0.87g to 0.88g should be anticipated at the site (see report Section 2.3).    No active faults have been recognized on, or mapped through, the subject property.  Thus, the  potential for surface faulting and ground rupture on the property is considered to be low.  The  San Andreas Fault is the closest mapped active fault to the site and is located approximately 2.0  miles to the southwest.    Other seismically‐induced ground failure mechanisms include: landsliding, liquefaction, lateral  spreading, lurching, and differential compaction.  The potential for strong ground shaking to  trigger a landslide that fails into the canal is considered to be moderate to high due to the  relatively loose consistency of the adjacent soils, and we have no information about the canal  wall design and whether they were designed to resist the landslide forces and full hydrostatic  pressures.   The proposed stormwater capture structures excavation will likely remove  approximately 7 to 15.5 feet of the loose soil that is susceptible to mobilizing, where the  structures are installed, which in turn should mitigate the high risk of landslides to the  structures.   COTTON, SHIRES AND ASSOCIATES, INC.  9 Soil liquefaction is a phenomenon in which a saturated, cohesionless or non‐plastic, near‐surface  soil layer loses strength during cyclic loading (such as that typically generated by earthquakes).   During the loss of strength, the soil develops mobility sufficient to permit both horizontal and  vertical movements.  Soils that are most susceptible to liquefaction are loose, saturated, fine‐ grained sands and non‐plastic silts and clays that are generally located within 50 feet of the  ground surface.  Because groundwater depths of 18 feet and deeper were encountered during  our subsurface investigation, it would be tempting to assume that liquefaction will only occur  below that depth at the two sites; however, wetter years and/or proposed stormwater infiltration  from this project could significantly raise the groundwater levels.  While historic groundwater  data for this area was not available, we assumed that the groundwater could rise to within 10  feet of the existing ground surface.  Based on the assumed high groundwater level of 10 feet, the  procedure outlined in the Soil Liquefaction During Earthquakes monograph (Idriss, Boulanger),  and a site peak ground acceleration of 0.87g to 0.88g, we judge that the potential for liquefaction  (below a depth of 10 feet), dry densification (above a depth of 10 feet) to be high at both the  North Parcel and the Ballfield sites.      We determined the factors of safety against triggering liquefaction (FSl) (and/or dry  densification) by calculating the ratio of: 1) the horizontal cyclic shear stress necessary to trigger  liquefaction (and/or dry densification), to 2) the average horizontal cyclic shear stress induced  by the design earthquake.  When this ratio is 1.3 or less (i.e., FSl≤1.3), liquefaction (and/or dry  densification) is predicted to occur or could potentially be a problem (the State of California  considers a FS=1.3 as the threshold for identifying the site as having a liquefaction hazard).    In the following tables we present a summary of the results of our liquefaction and dry  densification and associated settlement analysis by boring, and separated into the two  alternative sites:                     COTTON, SHIRES AND ASSOCIATES, INC.  10 North Parcel  CSA/SD‐1  Depth of  Liquefiable/Densifiable  Materials  (ft) N60 N160 CRRl CSReq N160cs  Volumetric  Strain (%)  Settlement   (in)  0‐3 5 10 0.15 0.56 16 2.8 1.04  3‐5.5 5 10 0.15 0.55 16 2.8 0.84  5.5‐12.5 7 12 0.12 0.53 13 3.2 2.50   Total: 4.38 inches   Total Below 10 feet: 0.75 inches  CSA/SD‐2  Depth of  Liquefiable/Densifiable  Materials  (ft) N60 N160 CRRl CSReq N160cs  Volumetric  Strain (%)  Settlement   (in)  2‐5.5 6 12 0.17 0.55 18 2.6 1.09  5.5‐9 6 11 0.11 0.54 12 3.7 1.55  9‐15.5 10 17 0.22 0.50 23 2.1 1.64   Total: 4.28 inches   Total Below 10 feet: 1.45 inches  CSA/SD‐3  Depth of  Liquefiable/Densifiable  Materials  (ft) N60 N160 CRRl CSReq N160cs  Volumetric  Strain (%)  Settlement   (in)  6‐11 11 19 0.19 0.52 21 2.3 1.38  11‐19 13 22 0.23 0.45 24 1.9 1.82  34‐40 7 9 0.10 0.26 12 3.1 2.23   Total: 5.43 inches   Total Below 10 feet: 4.33 inches         COTTON, SHIRES AND ASSOCIATES, INC.  11 CSA/SD‐8  Depth of  Liquefiable/Densifiable  Materials  (ft) N60 N160 CRRl CSReq N160cs  Volumetric  Strain (%)  Settlement   (in)  2‐8 6 11 0.16 0.54 18 2.6 1.87  8‐13 10 16 0.23 0.50 24 2.0 1.20  13‐18 7 10 0.11 0.41 11 3.8 2.28  22‐24 12 17 0.20 0.32 23 1.9 0.45   Total: 5.80 inches   Total Below 10 feet: 3.45 inches  Based on our liquefaction/dry densification settlement calculations summarized in the above  tables, we anticipate total settlements of between to 4‐1/2 and 5‐3/4 inches and differential  settlements of up to 2‐3/4 inches over 30 feet during or immediately following the design  seismic event, under the current conditions at the North Parcel site.  Assuming that the  stormwater capture structures are installed at a depth of 10 feet (including the aggregate  bearing layer), then the loose and medium dense sands above that depth would be removed,  and we anticipate that the remaining liquefiable soils below 10 feet could potential settle  between 3/4 inch to 4‐1/2 inches with at least 2‐1/4 inches of differential settlement over 30  feet.    Ballfield  CSA/SD‐4  Depth of  Liquefiable/Densifiable  Materials  (ft) N60 N160 CRRl CSReq N160cs  Volumetric  Strain (%)  Settlement   (in)  4.5‐9 8 15 0.21 0.53 21 2.3 1.24  9‐13 6 10 0.16 0.50 17 2.6 1.25  13‐16 7 11 0.17 0.45 18 2.5 0.90  16‐23 12 18 0.22 0.38 23 2.1 1.76  28‐35 7 10 0.14 0.36 16 2.7 2.27  36‐40 5 7 0.11 0.36 13 3.2 1.54   Total: 8.96 inches   Total Below 10 feet: 7.41 inches   COTTON, SHIRES AND ASSOCIATES, INC.  12 CSA/SD‐5  Depth of  Liquefiable/Densifiable  Materials  (ft) N60 N160 CRRl CSReq N160cs  Volumetric  Strain (%)  Settlement   (in)  4.5‐9 7 13 0.18 0.53 19 2.5 1.35  9‐13 4 7 0.13 0.51 13 3.2 1.54  13‐18.5 13 21 0.41 0.42 30 0.5 0.33  18.5‐25 11 17 0.21 0.35 22 2.2 1.72   Total: 4.94 inches   Total Below 10 feet: 3.21 inches  CSA/SD‐6  Depth of  Liquefiable/Densifiable  Materials  (ft) N60 N160 CRRl CSReq N160cs  Volumetric  Strain (%)  Settlement   (in)  4.5‐7.5 5 10 0.156 0.55 17 2.8 1.00   Total: 1.00 inches   Total Below 10 feet: 0.0 inches  CSA/SD‐7  Depth of  Liquefiable/Densifiable  Materials  (ft) N60 N160 CRRl CSReq N160cs  Volumetric  Strain (%)  Settlement   (in)  5.0‐10.0 4 7 0.12 0.53 13 3.4 2.04  10.0‐18.0 6 9 0.14 0.48 16 2.9 2.78  22.0‐27.0 6 8 0.13 0.32 15 3.0 1.80   Total: 6.62 inches   Total Below 10 feet: 4.58 inches    Based on our liquefaction/dry densification settlement calculations summarized in the above  tables, we anticipate total settlements of between to 1 and 9 inches and differential settlements of  at least 4‐1/2 inches over 30 feet during or immediately following the design seismic event, under  the current conditions at the Ballfield site.  Assuming that the stormwater capture structures are  installed to a depth of 10 feet (including the aggregate bearing layer), then the loose and medium   COTTON, SHIRES AND ASSOCIATES, INC.  13 dense sands would be removed to that depth, and we anticipate that the remaining liquefiable  soils below 10 feet could potentially settle between 0 to 7‐1/2 inches with at least 3‐3/4 inches of  differential settlement over 30 feet.    In addition to liquefaction induced settlement, there is a high potential for sand boils and ejecta  at both sites.  Not only would sand boils and ejecta significantly increase the magnitude of  differential settlement, but it could also result in a bearing failure.    If the adjacent the walls of the adjacent Colma Creek were not designed to resist full hydrostatic  and seismic loading combined, then there a high potential that the canal walls could fail  resulting in lateral spreading triggered by liquefaction which would impact the proposed  stormwater capture structures, at both the North Parcel and the Ballfield sites.    In summary, the soils underlying the North Parcel and Ballfield sites are loose to medium dense  and highly susceptible to liquefaction/densification, and if not mitigated, could cause significant  distress to the proposed stormwater capture system.  In order to mitigate the high potential for  liquefaction/densification, we have considered several alternatives to either densify the  potentially liquefiable soils (deep soil cement mixing), or to install deep foundations (auger cast  piles, drilled displacement columns) which extend below the zone of liquefiable soils to support  the stormwater capture structures.  Either option will likely increase the density of the  underlying soils which will reduce the infiltration capacity of the soil.    4.2 Static Settlement Behavior    For our settlement analysis, we identified three potential sources for static settlement, including  immediate settlement of loose to medium dense sand, consolidation (recompression) of the  roughly 6‐foot thick clay layer encountered between 15 and 25 feet, and immediate compression  of the clay layer.  We assumed that the stormwater capture structures would be supported on a  roughly 16‐ to 20‐foot wide (two cells side‐by‐side) slab‐on‐grade floor foundation bearing on a  layer of gravel (aggregate) bearing 10 feet below existing and final grade and supporting a  maximum load of 2,500 psf for the dead‐plus‐live‐load.  Based on these assumptions, we  calculated the following total and differential static settlement for the stormwater capture  system:       COTTON, SHIRES AND ASSOCIATES, INC.  14 North Parcel  Immediate Sand Settlement – 1/3 inch    Clay Consolidation (recompression) – 1/3 inch    Clay Immediate Compression – 1/2 inch  Combined Total and Differential Settlement: 1 inch, and 1/2 inch (over 30 feet).    This static settlement is in addition to the previously discussed (Section 4.1) seismic induced  settlement (liquefaction and densification), if not mitigated.      Ballfield  Immediate Sand Settlement – 1‐1/4 inches    Clay Consolidation (recompression) – 1/4 inch    Clay Immediate Compression – 1/2 inch    Combined Total and Differential Settlement: 2 inches, and 1 inch (over 30 feet).    This static settlement is in addition to the previously discussed (Section 4.1) seismic induced  settlement (liquefaction and densification), if not mitigated.      If the soils are improved to mitigate the high potential for liquefaction/densification, or if deep  foundations are installed, these static settlement magnitudes would likely be reduced as well.   Please contact us if ground improvement is selected or alternative foundation dimensions and/or  loading alternatives are required, or to discuss alternative settlement reduction options, if  desired.    4.3 Expansive Soils    Based on the results of our laboratory testing and our experience with these earth materials, the  roughly 6‐foot thick clay layer encountered between 15 and 25 feet is potentially highly  expansive.  Highly expansive soils could be subjected to volume changes due to seasonal  fluctuations in moisture content; however, provided that the bottom of the stormwater capture   COTTON, SHIRES AND ASSOCIATES, INC.  15 structure is greater than 3 feet above the clay layer and that the moisture content of the remains  constant (close to saturated), we don’t anticipate that these expansive soils will adversely impact  the structures.    4.4 Sulfate Attack on Concrete    We recommend that corrosivity testing be completed on the earth materials proposed for backfill  against the stormwater capture structures to determine the potential for corrosion of metallic  and concrete structures at the selected sites.  If the soils are found to be potentially corrosive,  then alternative backfill material can be imported.    4.5 Infiltration and Raising Groundwater Levels    We understand that one of the options being considered is to infiltrate a portion of the captured  storm water into the subgrade.  Due to the loose to medium dense consistency of the sands  encountered between depths of about 10 feet (assumed bottom of the capture structure) and the  top of the 4‐ to 6.5‐foot thick clay layer at depths of 15 to 20 feet (North Parcel), the moderate  fines content (8% to 48%), and the present depth to groundwater (18 to > 46.5 feet), we anticipate  moderate rates of infiltration.  While infiltration testing wasn’t part of our scope, Fugro  Consultants, Inc. (Fugro) performed three infiltration tests at a depth of 15 feet on the South  Parcel (situated on the southern side of the canal from the North Parcel), and recorded  infiltration rates of 0.3 inch/hour to 3.4 inches/hour.  We anticipate that, during wetter periods,  the infiltrated water will collect on the 4‐ to ‐6.5‐foot thick clay layer and raise the groundwater  level, which will reduce the infiltration rate.    If infiltration is to be part of the stormwater capture design, then we recommend that a  comprehensive infiltration testing and monitoring program be undertaken under the direction  of a hydrogeologist.  Such a program will help to evaluate the effectiveness of the proposed  infiltration, and potential on‐ and off‐site impacts.  Such impacts include raising the  groundwater levels and increasing the extent of potentially liquefiable soils, contributing to  water collecting in crawl spaces of neighboring residents (especially adjoining the Ballpark site),  exacerbating expansive soil movement, triggering foundation movement and distress of shallow  supported structures (especially at and adjoining the Ballpark site), and increasing the load on  the canal walls.  Also, high groundwater levels could result in buoyancy impacts on the  stormwater capture structures and associated piping.   COTTON, SHIRES AND ASSOCIATES, INC.  16 5.0 RECOMMENDATIONS    5.1 Site Considerations    The principal factor affecting the proposed stormwater capture system is the significant  thickness of potentially liquefiable and densifiable sandy soils underlying both sites.  We have  provided recommendations to improve the soils (densify) or to construct deep foundations that  extend below the zone of liquefaction.  Either of these alternatives should mitigate the potential  liquefaction induced settlement to acceptable ranges.    5.2 Soil Improvement Alternative    While there are various soil improvement options, in order to mitigate liquefaction induced  settlement and the potential for bearing failure associated with liquefaction (sand boils and  ejecta), we recommend that the soil beneath the stormwater capture structures be improved with  deep soil mixing (DSM), also referred to as wet soil mixing.  The DSM columns should overlap  to uniformly treat the soil beneath the stormwater capture structures and at least 5‐foot out in  all directions, unless the canal wall is within 5 feet, in which the treatment should extend to the  canal wall.  At the North Parcel, the DSM treatment should extend to at least a depth of 35 feet  below existing ground surface, or 25 feet below the bottom of the stormwater capture aggregate  layer, whichever is deeper.  At the Ballfield site, the DSM treatment should extend at least to a  depth of 40 feet, or 30 feet below the bottom of the stormwater capture aggregate layer,  whichever is deeper.  At least 20% of the DSM columns should be cored and inspected to  demonstrate successful soil/cement mixing.  The successfully completed soil improvement  should be shown by at least six evenly spaced CPT’s to reduce the maximum calculated total  and differential seismically induced settlement (liquefaction and densification) under the  stormwater capture structure to 2 inches and 1 inch over 30 feet, respectively.  In addition, static  load induced settlement for the soil improved alternative should be less than 1 inch total and 1/2  inch differential over 30 feet.  The successfully installed soil improvement should provide a  minimum uniform dead‐plus‐live load bearing capacity of at least 2,500 psf, and a minimum  coefficient of base friction of 0.34 across the bottom of the structure.  Typically, DSM and similar  soil improvement options are constructed by a design/build contractor.  The prospective  design/build contractor should be provided with our report and consult with us throughout the  design and build process to confirm that our recommendations are being incorporated into their  design and construction.   COTTON, SHIRES AND ASSOCIATES, INC.  17 5.3 Deep Foundations Alternatives    As an alternative to mitigate liquefaction induced settlement and the potential for bearing failure  associated with liquefaction (sand boils and ejecta), we recommend that the stormwater capture  structure be supported by a deep foundation such as Auger Cast Piles (ACP), Drilled  Displacement Piles (DDP), Auger Cast Columns (ACC) or Drilled Displacement Columns  (DDC).  These deep foundations should be spaced as determined by the design build contractor  and the project structural engineer to support the loads of the stormcapture structures during  liquefaction and resist movement.  We recommend that the deep foundations extend to depths  of at least 50 feet below existing ground surface or 40 feet below the bottom of the capture  structure, whichever is deeper, at both the North Parcel, and the Ballfield.  A successfully  installed deep foundation should result in less than 1 inch total settlement and 1/2 inch  differential (between piles) due to static loads, and 2 inches total and 1 differential due to seismic  (liquefaction/densification) loading.  Typically, auger cast piles and deep foundation options are  designed and constructed by a design/build contractor.  At least four of these deep foundations  at each site should performance tested using dynamic pile test methods (CAPWAP with PDA or  similar) to confirm the estimated pile capacity.  The prospective design/build contractor should  be provided with our report and consult with us throughout the design and build process to  confirm that our recommendations are being incorporated into their design and construction.    5.4 Stormcapture Structure Design    The Stormcapture structure should be designed to resist at rest equivalent fluid pressure of at  least 60 pounds per cubic foot (pcf) for horizontal backfill, assuming no hydrostatic pressure.  If  the groundwater could rise above a depth of about 10 feet (or the bottom of the structure), then  the structure should be designed to resist a full hydrostatic equivalent fluid pressure lateral load  of 90 pounds per cubic foot (pcf).    The lateral loads can be resisted by a coefficient of base friction of 0.34 for the soil improvement  alternative, and passive resistance against the sides of the piles (design criteria to be determined  by the design build contractor) for the deep foundation option.           COTTON, SHIRES AND ASSOCIATES, INC.  18 5.5 Site Grading    Based on our field investigation, grading excavations should be within the capabilities of  moderate excavation equipment (i.e., drill rigs, backhoes, excavators and dozers).  Dewatering  should be anticipated below depths of 25 feet or higher depending on the season at the North  Parcel, and 18 feet at the Ballfield site.       5.5.1 Site Preparation ‐ All loose material, vegetation, existing concrete foundations,  concrete curbs, asphalt, debris, and other deleterious material should be stripped and removed  from the areas to be occupied by the new building.  This material should be disposed of in a  suitable location off‐site.    The site should be excavated as necessary for planned grades, we are not anticipating that fill  will be placed other than to backfill around and over the stormcapture structures.  The bottom  of the excavation for the stormwater capture structures may be wet to saturated, and could  require pumping to lower the groundwater to allow for construction to proceed.  The excavation  subgrade should be cleared of all loose debris and standing water prior to placing the  manufacturer recommended non‐woven geotextile fabric.     5.5.2. Compacted Fill – In general, the on‐site materials should be suitable for re‐use as  compacted fill, provided they are not too wet or have plasticity index (PI) greater than 20.   Imported fill should be free of organic material; it should contain no material larger than 4  inches; it should have a plasticity index (PI) of less than 16; it should be free of hazardous  contamination (per State of California requirements); and it should be free of Asphaltic Concrete  grindings.  The fill should be placed in horizontal lifts not exceeding 8 inches in loose thickness,  moisture conditioned to at least optimum moisture content, and compacted to at least 95 percent  relative compaction beneath structures and 18 inches below the aggregate base rock for  pavements, and 90 percent relative compaction elsewhere, all based on ASTM D‐1557‐12.   Approximately 18 inches (Old Castle Technical Note SC‐01) of manufacturer recommended  aggregate (No. 56 or 57 Stone, per ASTM C33) should be placed on the geotextile.  Compaction  methods and equipment should be used that are suitable for compacting against the stormwater  capture structures without damaging the structures or pipes.  If the excavated material is too wet  to use for backfilling the excavation, or if the exposed ground surface is soft and yielding,  Controlled Low Strength Material (CLSM) or Controlled Density Fill (CDF) can be used instead  provided it has a compressive strength of at least 100 psi.   COTTON, SHIRES AND ASSOCIATES, INC.  19 5.5.3 Utility Trench Backfill ‐ Planned pipelines should be placed at least 3 feet below  final ground surface.  Utility trenches should be backfilled with approved, on‐site soil.  Bedding  materials for pipes should be graded and placed in accordance with the manufacturerʹs  recommendations.  The backfill should be compacted to at least 90 percent relative compaction  based on based on ASTM D‐1557‐12.  Equipment and methods should be used that are suitable  for work in confined areas without damaging trench walls or conduits.       5.5.4 Temporary Cut Slope Design ‐  We understand that the preferred excavation  method is by open excavation, during the dry season, temporary cut slopes of 2:1 (H:V), should  generally be satisfactory for construction purposes, provided that they are inspected and  approved by our field representative at the time of construction and monitored daily during  construction.  However, shoring will likely be required adjacent to the canal to avoid  undermining and damaging the canal.  Excavation methods, shoring, bracing and safety of  excavations are the responsibility of the contractor.  All excavations should comply with  applicable local, State and Federal safety regulations.  If requested, CSA can review the  Contractor’s shoring calculation and provide input.    Care should be taken to ensure that other existing structures are not undermined during  temporary construction excavations.  We recommend that the Contractor implement a  monitoring program and schedule to evaluate the safety of the excavation.  The Contractor  should also prepare an emergency buttressing plan, and be prepared to implement it if  movement in excess of 1 inch (horizontal or vertical) is detected.       5.5.5 Pavement Subgrade Preparation ‐ After general compaction and compaction of  the utility trench backfills, pavement areas (if appropriate) should be checked for yielding areas  by proof‐rolling with a loaded water truck or equivalent.  Any yielding areas should be  excavated and replaced with compacted fill.  The upper 12 inches should be moisture  conditioned to at least optimum moisture content, and compacted to at least 95 percent relative  compaction based on ASTM D‐1557‐12.    5.6 Pavement Design    Testing of the R‐value of the on‐site soils was outside the scope of our services; however, in the  event that new pavement is planned, based on an assumed R‐value of 5 (for a highly expansive  soil), an assumed Traffic Index of 5.5, corresponding to relatively light loading and service   COTTON, SHIRES AND ASSOCIATES, INC.  20 vehicle use, we recommend that the pavement section consist of a minimum of 3.5 inches  thickness of asphaltic concrete underlain by a minimum of 12 inches of aggregate base rock  compacted to a minimum of 95% relative compaction (ASTM D1557‐12).      Asphaltic concrete should be placed and compacted in accordance with the requirements of  Section 39 of the Caltrans Standard Specifications; aggregate base rock should conform to the  provisions of Section 26 (Caltrans) for 3/4‐inch maximum Class 2 Aggregate Base, and should be  compacted to at least 95 percent relative compaction based on ASTM D‐1557‐12 rather than  Caltrans Method 216.    5.7 Surface Drainage    We recommend that all surface drainage be permanently diverted away from the planned  structures at a minimum 2% grade into an appropriate catch basin/storm drain system, or natural  swale.  All roof downspouts should be connected to tight line drain pipes that are directed, in  turn, into an appropriate catch basin/storm drain system or natural swale.    5.8 Seismic Design    A peak ground acceleration of 0.87g to 0.88g should be anticipated for design purposes at the  site.  Based on our geotechnical investigation, the site location, our interpretation of the 2016  CBC documents related to Earthquake Loads and using the USGS U.S. Seismic Design Maps tool  (ASCE 7‐10, errata March 2013), we are providing the following parameter recommendations for  the two sites:    Northern Parcel    Parameter Value Site Classification D  Mapped Spectral Acc. 0.2 Sec. (g) Ss = 2.265  Mapped Spectral Acc. 1 Sec. (g) S1 = 1.084  Fa – Site Coefficient 1.0  Fv – Site Coefficient 1.5  SMS = FaSs 2.265  SM1 = FvS1 1.626  SDS=2/3 SMS 1.510  SD1=2/3 SM1 1.084   COTTON, SHIRES AND ASSOCIATES, INC.  21 Ballfield Site    Parameter Value Site Classification D  Mapped Spectral Acc. 0.2 Sec. (g) Ss = 2.253  Mapped Spectral Acc. 1 Sec. (g) S1 = 1.077  Fa – Site Coefficient 1.0  Fv – Site Coefficient 1.5  SMS = FaSs 2.253  SM1 = FvS1 1.616  SDS=2/3 SMS 1.502  SD1=2/3 SM1 1.077    5.9 Technical Review    Supplemental geotechnical design recommendations should be provided by our firm based on  specific design needs developed by the other project design professionals.  This report, and any  supplemental recommendations, should be reviewed by the contractor as part of the bid process.   It is strongly recommended that no construction be started nor grading undertaken until the  final drawings, specifications, and calculations have been reviewed and approved in writing by  a representative of Cotton, Shires and Associates, Inc.    5.10 Earthwork Construction Observation and Testing    All excavations including pier drilling and ground improvement should be observed by a  representative of Cotton, Shires and Associates, Inc. prior to filling or pouring of concrete  foundations.  Any grading should also be observed and tested as appropriate to assure adequate  stripping and compaction.  Our office should be contacted with a minimum of 48 hours advance  notice of construction activities requiring inspection and/or testing services and a minimum of  72 hours advance notice and provision of representative laboratory compaction curve samples  for testing of fill.      6.0 INVESTIGATION LIMITATIONS    Our services consist of professional opinions and recommendations made in accordance with  generally accepted engineering geology and geotechnical engineering principles and practices.    COTTON, SHIRES AND ASSOCIATES, INC.  22 No warranty, expressed or implied, or merchantability of fitness, is made or intended in  connection with our work, by the proposal for consulting or other services, or by the furnishing  of oral or written reports or findings.  It was not within our scope to investigate the site for  environmental concerns such as contaminated soils and therefore we accept no liability  associated with such materials being present.    Any recommendations and/or design criteria presented in this report are contingent upon our  firm being retained to review the final drawings and specifications, to be consulted when any  questions arise with regard to the recommendations contained herein, and to provide testing  and inspection services for earthwork and construction operations.  Unanticipated soil and  geologic conditions are commonly encountered during construction which cannot be fully  determined from existing exposures or by limited subsurface investigation.  Such conditions  may require additional expenditures during construction to obtain a properly constructed  project.  Some contingency fund is recommended to accommodate these possible extra costs.    This report is issued with the understanding that it is the responsibility of the owner, or of his  representative, to ensure that the information and recommendations contained herein are called  to the attention of the project architect and/or engineer and incorporated into the plans.   Furthermore, it is also the responsibility of the owner, or of his representative, to ensure that the  contractor and subcontractors carry out such recommendations in the field.   COTTON, SHIRES AND ASSOCIATES, INC.  23 7.0 REFERENCES    7.1 Maps and Reports  Bonilla, M. G. 1971, Preliminary Geologic Map of the San Francisco South Quadrangle and  Parts of the Hunter Point 7.5’ Quadrangle, San Francisco Bay Area, California, Digital  Database Prepared by Carl Wentworth, Marjorie Lucks, Heather Schoonover, Scott  Graham and Thomas May, 1988.  Bowles, J.E., Foundation Analysis and Design, Third Edition, 1982, McGraw‐Hill Book  Company, Page 184, and Tables 2‐6 and 2‐7.  Bray, J.D., Sancio, R.B., Assessment of Liquefaction Susceptibility of fine‐Grained Soils, Journal  of Geotechnical and Geoenvironmental Engineering, September 2006, Volume 132, No. 9.  California Geological Survey, Guidelines for Evaluating and Mitigating Seismic Hazards in  California: Special Publication 117A, 2008.  California Department of Conservation, Division of Mines and Geology, Seismic Hazard Zones  Map for the Mountain View Quadrangle 7.5‐Minute Quadrangle, 2006.  Duncan J.M., Horz R.C., and Yang T.L., August 1989, Shear Strength Correlations for  Geotechnical Engineering, Virginia Tech, Department of Civil Engineering, Geotechnical  Engineering.  Fugro Consultants, Inc., Preliminary Geotechnical Feasibility Study, Proposed Orange Park  Storm Water Capture Project, South San Francisco, California, dated December 1, 2016.  Gordon A. Tillson & Associates, Colma Creek Zone Channel Improvements STA 97+62 to STA  110+45, prepared for the San Mateo County Flood Control District, dated April 5, 1985.  Idriss I.M., Boulanger R.W., Soil Liquefaction During Earthquakes monograph, Earthquake  Engineering Research Institute, 2008.  Lawson and others, 1908, Report of the California Earthquake Commission, The California Earthquake of April 18, 1906, Volume 1, Page 247-248. Oldcastle Precast Storm Capture Total Stormwater Management System, Technical Notes SC-01. Oldcastle Storm Solutions drawings for SC-5 ft and SC2-10 ft clamshell. USGS U.S. Seismic Design Maps Tool Web Application, ASCE 7‐10, errata March 2013.   COTTON, SHIRES AND ASSOCIATES, INC.  24 U. S. Department of the Navy, 1982, Design Manual Soil Mechanics, Foundations, and Earth  Structures, NAVFAC DM‐7.2.          COTTON, SHIRES AND ASSOCIATES, INC.  APPENDIX A    Field Investigation  Logs of Exploratory Borings            COTTON, SHIRES AND ASSOCIATES, INC.   A‐1  APPENDIX A  FIELD INVESTIGATION      We explored subsurface conditions at the North Parcel and Ballfield sites in South San  Francisco, California on between April 3 and April 5, 2018, by means of eight small‐ diameter exploratory borings drilled to a depth of 31.5 to 46.5 feet using track‐mounted  hollow‐stem auger drilling equipment.  The locations of the borings are shown on Figures  4 and 5.  The engineer who logged the borings visually classified the soils in accordance  with ASTM D‐2487.  We obtained relatively undisturbed samples of the materials  encountered at selected depths.  These samples were obtained in stainless steel liners that  were 2.5 inches in outside diameter by 6 inches long, and placed inside a 3‐inch diameter  modified split‐barrel California Sampler for sampling.  The California Sampler was driven  with an automatic 140‐pound hammer that was allowed to freely fall about 30 inches.  We  also performed Standard Penetration Tests (SPT) at selected depths.  The depths of the  sampling are shown on the boring logs.  The number in the circle at the conclusion of the  sampling interval represents the Standard Penetration Test blow count derived by  multiplying the Modified California Sampler blow count by a factor of 0.68.    Descriptive logs of the borings are presented in this appendix.  These logs depict our  interpretation of the subsurface conditions at the dates and locations indicated, based on  representative samples collected at roughly five‐foot sampling intervals.  It is not  warranted that they are representative of subsurface conditions at other times and  locations.  The contacts on the logs represent the approximate boundaries between earth  materials, and the transitions between these materials may be gradual.  COTTON, SHIRES AND ASSOCIATES, INC. LOG OF EXPLORATORY DRILLING Project Location Drilling Contractor/Rig Ground Surface Elev. Surface Logged By Boring Project No. Date of Drilling Hole Diameter Weather Remarks Depth(feet)GraphicLogUSCSClass.Sheet 1 of 2 HIRES AND ASSOCIATES, INC.SC CONSULTING ENGINEERS AND GEOLOGISTS OTTON, 2 4 6 8 10 12 14 16 18 20 22 24 26 28 Geotechnical Description SampleDesig.MoistureContent (%)SPTBlows/ftSampleTypeRecov.(%)TRH Dry UnitWeight(pcf)CSA/SD-1Orange Memorial Park E5038 04/04/2018 2 4 6 8 10 12 14 16 18 20 22 24 26 28 Driller: Paul Britton Helpers: Dave Start Time = 11:10 22' E of PP, 28' N of channel (North Parcel) Britton Exploration / CME 550 8" HSA Old Farmland w/ Vegetation Cloudy 2 3 4 MCT-1 T-2 2 2 3 08:203 3 4 7 7 8 SPTSPT-1 SPTSPT-2 SPTSPT-3 SPTSPT-4 2 3 3 08:34 7 7 8 MCT-3 T-4 7 9 12 MC T-5 SPTSPT-5 2 3 2 0.0'-12.0' Silty Sand - Tan-brown, loose, moist to wet, fine sand SM 3.0' - Fine to medium sandSM 7.0' - Moist, fine sandSM 12.0'-17.5' Sand - Tan to tan-brown, medium dense, moist to wet, fine to medium sand, trace gravel SP 17.5'-24.0' Clay - Black, stiff, wet, high plasticity, rootlets CH 24.0'-29.0' Sandy Clay - Mottled blue-gray to brown, stiff, dry to moist CL 29.0'-31.5' Sandy Clay - Black, stiff, wetCL 0.0'-BOH: ALLUVIUM 5 7 15 6 10 14 5 5 Consol8931.1 100 13.7 Sieve: 90% Sand, 8% Fines Sieve: 37% Sand, 63% Fines LL=57, PI=38 ~28 feet Project Boring Remarks Depth(feet)GraphicLogUSCSClass.Sheet 2 of 2 Date HIRES AND ASSOCIATES, INC.SC CONSULTING ENGINEERS AND GEOLOGISTS OTTON, 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60 62 Geotechnical Description SampleDesig.MoistureContent (%)SPTBlows/ftSampleTypeRecov.(%)Dry UnitWeight(pcf)CSA/SD-1Orange Memorial Park 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60 62 04/04/2018 Finished sampling @ 12:52 Finished backfill @ 13:18 SPTSPT-6 6 3 2 SPTSPT-7 3 7 8 7 15 15 12:09 8 13 18 MCT-6 T-7 MCT-8 T-9 Zero recovery, redrove with sand trap. All samples to BOH used sand trap. 29.0'-31.5' Sandy Clay - Black, stiff, wetCL 31.5'-35.5' Silty Sand - Blue-gray, dense, wet to saturated SM 35.5'-40.5' Sandy Clay - Blue-gray, stiff, wet to saturated CL 40.5'-45.0' Sandy Clay - Blue-gray, very stiff, wet to saturated CL 45.0'-BOH' Clayey Sandy Silt - Tan, stiff to very stiff, wet ML 21 5 15 20Total Depth = 46.5 feet No groundwater Encountered 109 19.8 Sieve: 56% Sand, 44% Fines Sieve: 47% Sand, 53% Fines LL=32, PI=13 COTTON, SHIRES AND ASSOCIATES, INC. LOG OF EXPLORATORY DRILLING Project Location Drilling Contractor/Rig Ground Surface Elev. Surface Logged By Boring Project No. Date of Drilling Hole Diameter Weather Remarks Depth(feet)GraphicLogUSCSClass.Sheet 1 of 2 HIRES AND ASSOCIATES, INC.SC CONSULTING ENGINEERS AND GEOLOGISTS OTTON, 2 4 6 8 10 12 14 16 18 20 22 24 26 28 Geotechnical Description SampleDesig.MoistureContent (%)SPTBlows/ftSampleTypeRecov.(%)TRH Dry UnitWeight(pcf)CSA/SD-2Orange Memorial Park E5038 04/05/2018 2 4 6 8 10 12 14 16 18 20 22 24 26 28 Driller: Paul Britton Helpers: Sergio + Dave Start Time = 11:20 215' W of fence, 170' N of channel (North Parcel) Britton Exploration / CME 550 8" HSA Old Farmland w/ Vegetation Cloudy 4 6 8 MCT-1 T-2 5 3 3 08:20 1 2 4 4 6 4 SPTSPT-1 SPTSPT-2 SPTSPT-3 SPTSPT-4 2 3 4 08:34 10 11 12 MCT-3 T-4 SPTSPT-5 6 8 12 0.0'-2.0' Sandy Silt - Dark-brown, stiff, moist ML 2.0'-6.0' Silty Sand - Tan-brown, loose, moistSM 0.0'-BOH: ALLUVIUM 6.0'-15.0' Silty Sand - Tan-brown, loose, moist SM 4.0' - Brown 15.0'-15.5' Silty Sand - Tan-brown, loose, wetSM 15.5'-20.0' Silty Clay - Dark-brown, very stiff, wet, rootlets CL 20.0'-21.0' Sand - Tan-brown, medium dense, saturated, fine to medium sand SP 21.0'-25.0' Clay - Black, stiff, wetCH 25.0'-30.0' Silty Sand - Tan-brown, medium dense, saturated, fine sand SM 9 6 10 7 15 20 6 115 10.1 Sieve: 79% Sand, 21% Fines SM Sieve: 39% Sand, 61% Fines ~28 feet Project Boring Remarks Depth(feet)GraphicLogUSCSClass.Sheet 2 of 2 Date HIRES AND ASSOCIATES, INC.SC CONSULTING ENGINEERS AND GEOLOGISTS OTTON, 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60 62 Geotechnical Description SampleDesig.MoistureContent (%)SPTBlows/ftSampleTypeRecov.(%)Dry UnitWeight(pcf)CSA/SD-2Orange Memorial Park 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60 62 04/05/2018 Finished sampling @ 12:40 Finished backfill @ 13:05 3 7 19 SPTSPT-7 13 24 23 12:09 MCT-5 Zero recovery, redrove with sand trap. All samples to BOH used sand trap. SPTSPT-6 3 1 1 30.0'-35.0' Clay - Black, stiff to very stiff, saturated SM 40' - Fine to coarse sand, dense. CL 35.0'-BOH Silty Sand - Blue-gray, medium dense, saturated Total Depth = 41.5 feet Groundwater - 25 feet at time of drilling 2 17 47 LL=38, PI=18 COTTON, SHIRES AND ASSOCIATES, INC. LOG OF EXPLORATORY DRILLING Project Location Drilling Contractor/Rig Ground Surface Elev. Surface Logged By Boring Project No. Date of Drilling Hole Diameter Weather Remarks Depth(feet)GraphicLogUSCSClass.Sheet 1 of 2 HIRES AND ASSOCIATES, INC.SC CONSULTING ENGINEERS AND GEOLOGISTS OTTON, 2 4 6 8 10 12 14 16 18 20 22 24 26 28 Geotechnical Description SampleDesig.MoistureContent (%)SPTBlows/ftSampleTypeRecov.(%)TRH Dry UnitWeight(pcf)CSA/SD-3Orange Memorial Park E5038 04/05/2018 2 4 6 8 10 12 14 16 18 20 22 24 26 28 Driller: Paul Britton Helpers: Sergio + Dave Start Time = 09:27 520' W of fence, 35' N of channel (North Parcel) Britton Exploration / CME 550 8" HSA Old Farmland w/ Vegetation Cloudy 4 5 7 MCT-1 T-2 4 6 8 4 6 5 4 7 6 SPTSPT-1 SPTSPT-2 SPTSPT-3 SPTSPT-4 2 3 2 09:41 4 7 9 MC T-3 SPTSPT-5 3 3 6 SP 0.0'-BOH: ALLUVIUM 18.0'-19.0' Silty Sand - Gray, loose, wet 19.0'-20.5' Clay - Black, stiff, wet 09:47 0.0'-1.5' Sand - Tan, loose, moist 1.5'-3.5' Sandy Silt - Dark-brown, stiff to very stiff, moist ML 3.5'-8.5' Silty Sand - Tan-brown, medium dense, moist, fine sand SM 8.5'-18.0' Silty Sand - Tan-brown, medium dense, moist, fine sand SP-SM 13.0' - Wet, fine to medium sand SM CL 20.5'-25.0' Clay - Black, stiff, wetCH 25.0'-30.0' Sandy Silt - Gray, medium stiff, moist to wet, rootlets ML 14 11 13 11 9 8 5 91 30.1 Sieve: 55% Sand, 42% Fines Sieve: 91% Sand, 9% Fines ~28 feet Project Boring Remarks Depth(feet)GraphicLogUSCSClass.Sheet 2 of 2 Date HIRES AND ASSOCIATES, INC.SC CONSULTING ENGINEERS AND GEOLOGISTS OTTON, 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60 62 Geotechnical Description SampleDesig.MoistureContent (%)SPTBlows/ftSampleTypeRecov.(%)Dry UnitWeight(pcf)CSA/SD-3Orange Memorial Park 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60 62 04/05/2018 Finished sampling @ 10:37 Finished backfill @ 11:05 SPTSPT-7 8 4 3 10:17 SPTSPT-6 6 7 6 5 7 7 MCT-4 T-5 SPTSPT-8 5 7 5 30.0'-40.0' Silty Sand - Blue-gray, medium dense, wet SM 40.0'-BOH Sandy Silt - Blue-gray, stiff to very stiff, saturated, rootlets ML Total Depth = 46.5 feet Groundwater - 40 feet at time of drilling 13 7 9 12 Sieve: 41% Sand, 59% Fines - loose below 35.5' COTTON, SHIRES AND ASSOCIATES, INC. LOG OF EXPLORATORY DRILLING Project Location Drilling Contractor/Rig Ground Surface Elev. Surface Logged By Boring Project No. Date of Drilling Hole Diameter Weather Remarks Depth(feet)GraphicLogUSCSClass.Sheet 1 of 2 HIRES AND ASSOCIATES, INC.SC CONSULTING ENGINEERS AND GEOLOGISTS OTTON, 2 4 6 8 10 12 14 16 18 20 22 24 26 28 Geotechnical Description SampleDesig.MoistureContent (%)SPTBlows/ftSampleTypeRecov.(%)TRH Dry UnitWeight(pcf)CSA/SD-4Orange Memorial Park E5038 04/04/2018 2 4 6 8 10 12 14 16 18 20 22 24 26 28 Driller: Paul Britton Helpers: Dave Start Time = 08:03 45' S of channel, 270' W of Orange Ave (Ballfield) Britton Exploration / CME 550 8" HSA Grass Sports Field Sunny, Clear 4 5 7 MCT-1 T-2 2 3 3 08:203 3 5 3 3 3 SPTSPT-4 2 3 4 3 4 6 MCT-3 T-4 8 10 11 09:05 No Recovery SPTSPT-1 SPTSPT-2 SPTSPT-3 SPTSPT-5 4 5 7 SPTSPT-6 1 2 2 MC 08:34 SM CL 8 6 Af 0.0'-4.5': ARTIFICIAL FILL 0'-2.0' Sandy Clay - Dark brown, medium stiff to stiff, moist to wet, medium plasticity 4.5'-BOH: ALLUVIUM 4.5'-18.0' Silty Sand - Tan-brown, loose, dry, fine sand CL 2.0'-4.5' Sandy Clay - Dark brown to tan-brown, medium stiff to stiff, moist 7.0' - Dry to moist 10.0' - Tan-brown to gray 13.5' - Dark gray, wet 18.0'-23.0' Silty Sand - Dark gray, medium dense, saturated SM SM SM SM 23.0'-24.5' Clay - Black, medium stiff, saturated, spongy, rootlets CH 28.0'-35.0' Silty Sand - Blue-gray, loose, saturated SM 8 6 7 7 12 14 4 108 13.3 102 24.1 Sieve: 42% Sand/Gravel, 58% Fines Sieve: 70% Sand, 30% Fines Sieve: 52% Sand, 48% Fines Sieve: 63% Sand, 37% Fines Sieve: 80% Sand, 19% Fines Sieve: 24% Sand, 76% Fines LL=56, PI=35 LL=34, PI=18 24.5'-28.0' Clay - Black, medium stiff, saturated, CL ~26 feet Project Boring Remarks Depth(feet)GraphicLogUSCSClass.Sheet 2 of 2 Date HIRES AND ASSOCIATES, INC.SC CONSULTING ENGINEERS AND GEOLOGISTS OTTON, 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60 62 Geotechnical Description SampleDesig.MoistureContent (%)SPTBlows/ftSampleTypeRecov.(%)Dry UnitWeight(pcf)CSA/SD-4Orange Memorial Park 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60 62 04/04/2018 SPTSPT-7 3 4 3 Finished sampling @ 09:57 Finished backfill @ 10:30 SPTSPT-8 2 2 3 SPTSPT-9 10 10 13 SPTSPT-10 8 13 12 Only shoe recovery. Put sand trap in sampler and re-sampled. All SPTs to BOH use sand trap. 09:45 28.0'-35.0' Silty Sand - Blue-gray, loose, saturated SM 35.0'-36.0' Sandy Clay - Black, wet, stiffCL 36.0'-40.0' Clayey Sand - Gray, loose, wetSC 40.0'-45.0' Sandy Clay - Gray, stiff, moistCL 45.0'-46.0' Sandy Clay - Gray, stiff, moist to wet CL 46.0'-BOH Sandy Clay - Olive-gray, stiff, saturated CL Total Depth = 46.5 feet Groundwater - 18 feet at time of drilling 7 5 25 23 Sieve: 47% Sand, 53% Fines Sieve: 26% Sand, 74% Fines COTTON, SHIRES AND ASSOCIATES, INC. LOG OF EXPLORATORY DRILLING Project Location Drilling Contractor/Rig Ground Surface Elev. Surface Logged By Boring Project No. Date of Drilling Hole Diameter Weather Remarks Depth(feet)GraphicLogUSCSClass.Sheet 1 of 2 HIRES AND ASSOCIATES, INC.SC CONSULTING ENGINEERS AND GEOLOGISTS OTTON, 2 4 6 8 10 12 14 16 18 20 22 24 26 28 Geotechnical Description SampleDesig.MoistureContent (%)SPTBlows/ftSampleTypeRecov.(%)TRH Dry UnitWeight(pcf)CSA/SD-5Orange Memorial Park E5038 04/03/2018 2 4 6 8 10 12 14 16 18 20 22 24 26 28 Driller: Paul Britton Helpers: Sergio + Dave Start Time = 08:50 140' S of channel, 80' W of Orange Ave (Ballfield) Britton Exploration / CME 550 8" HSA Grass Sports Field Sunny, Clear 3 4 4 MCT-1 T-2 2 2 4 MCT-3 T-4 3 4 7 MCT-5 T-6 2 3 3 MCT-7 T-8 SPTSPT-1 2 7 6 6 8 8 MCT-9 T-10 SPTSPT-2 1 3 4 09:04 09:19 09:27 SP 4.5'-BOH: ALLUVIUM SM 8.0'-10.0' Silty Sand - Tan-brown, loose, moist SM 15.0' - Gray, fine sand, medium dense below 15.0' 25.0'-30.0' Sandy Silty Clay - Dark gray, stiff, saturated, rootlets Af 0.0'-4.5': ARTIFICIAL FILL 0'-4.5' Silty Clay - Dark brown, medium tiff to stiff, wet, low plasticity 4.5'-8.0' Sand - Tan-brown, loose, moist, fine grain 5 7 CL SM 13 11 10.0'-25.0' Silty Sand - Light red-brown, loose, wet, iron oxide streaks 7 20' - Saturated CL 4 4 SM 99 9.4 107 18.5 88 33.9 98 25.4 ~26 feet Project Boring Remarks Depth(feet)GraphicLogUSCSClass.Sheet 2 of 2 Date HIRES AND ASSOCIATES, INC.SC CONSULTING ENGINEERS AND GEOLOGISTS OTTON, 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60 62 Geotechnical Description SampleDesig.MoistureContent (%)SPTBlows/ftSampleTypeRecov.(%)Dry UnitWeight(pcf)CSA/SD-5Orange Memorial Park 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60 62 04/03/2018 13 26 29 MC T-11 T-12 09:50 Finished sampling @ 09:55 Finished backfill @ 10:18 Total Depth = 31.5 feet Groundwater - 20 feet at time of drilling 35 30.0'-BOH Clayey Sand - Light gray, dense, moist, medium sand SC Sieve: 70% Sand, 30% Fines COTTON, SHIRES AND ASSOCIATES, INC. LOG OF EXPLORATORY DRILLING Project Location Drilling Contractor/Rig Ground Surface Elev. Surface Logged By Boring Project No. Date of Drilling Hole Diameter Weather Remarks Depth(feet)GraphicLogUSCSClass.Sheet 1 of 2 HIRES AND ASSOCIATES, INC.SC CONSULTING ENGINEERS AND GEOLOGISTS OTTON, 2 4 6 8 10 12 14 16 18 20 22 24 26 28 Geotechnical Description SampleDesig.MoistureContent (%)SPTBlows/ftSampleTypeRecov.(%)TRH Dry UnitWeight(pcf)CSA/SD-6Orange Memorial Park E5038 04/03/2018 2 4 6 8 10 12 14 16 18 20 22 24 26 28 Driller: Paul Britton Helpers: Sergio + Dave Start Time = 12:46 95' N of Memorial Dr, 300' W of Orange Ave (Ballfield) Britton Exploration / CME 550 8" HSA Grass Sports Field Sunny, Clear 2 6 9 MCT-1 T-2 3 3 4 MC T-3 T-4 12:595 8 8 MCT-5 T-6 7 10 16 MC T-7 T-8 SPTSPT-1 7 15 26 9 11 17 MCT-9 T-10 9 15 41 MCT-11 T-12 SPTSPT-2 9 15 21 13:47 0'-4.5' Sandy Clay - Dark brown, medium stiff to stiff, moist 5 0.0'-4.5': ARTIFICIAL FILL 41 4.5'-BOH: ALLUVIUM 4.5'-7.5' Sand - Tan-brown, loose, dry, fine grain 37 CL SP 7.5'-10.0' Silty Sand - Tan-brown, medium dense, dry, fine grain SM 10.0'-11.5' Clayey Sand - Dark brown, loose to medium dense, dry SC 11.5'-25.0' Silty Sand - Tan-brown, medium dense, dry SM 25.0'-BOH Sand - Tan, dense, dry to moistSP 28.0' - Moist to wet 10 11 17 19 36 Sieve: 47% Sand, 53% Fines LL=23, PI=8 LL=38, PI=19 Non-Plastic 15.0' - Dense below 15.0' 20.0' - Medium dense below 20.0' ~26 feet Project Boring Remarks Depth(feet)GraphicLogUSCSClass.Sheet 2 of 2 Date HIRES AND ASSOCIATES, INC.SC CONSULTING ENGINEERS AND GEOLOGISTS OTTON, 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60 62 Geotechnical Description SampleDesig.MoistureContent (%)SPTBlows/ftSampleTypeRecov.(%)Dry UnitWeight(pcf)CSA/SD-6Orange Memorial Park 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60 62 04/03/2018 SPTSPT-3 12 31 50 Finished sampling @ 14:04 Finished backfill @ 14:35 81 32.0' - Tan-brown, very dense, saturated, fine to medium sand SP Total Depth = 33.5 feet Groundwater - 32 feet at time of drilling SP 25.0'-BOH Sand - Tan, dense, dry to moist COTTON, SHIRES AND ASSOCIATES, INC. LOG OF EXPLORATORY DRILLING Project Location Drilling Contractor/Rig Ground Surface Elev. Surface Logged By Boring Project No. Date of Drilling Hole Diameter Weather Remarks Depth(feet)GraphicLogUSCSClass.Sheet 1 of 2 HIRES AND ASSOCIATES, INC.SC CONSULTING ENGINEERS AND GEOLOGISTS OTTON, 2 4 6 8 10 12 14 16 18 20 22 24 26 28 Geotechnical Description SampleDesig.MoistureContent (%)SPTBlows/ftSampleTypeRecov.(%)TRH Dry UnitWeight(pcf)CSA/SD-7Orange Memorial Park E5038 04/03/2018 2 4 6 8 10 12 14 16 18 20 22 24 26 28 Driller: Paul Britton Helpers: Sergio + Dave Start Time = 10:30 175' N of Memorial Dr, 90' W of Orange Ave (Ballfield) Britton Exploration / CME 550 8" HSA Grass Sports Field Sunny, Clear 3 5 8 MCT-1 T-2 3 4 5 MC T-3 T-4 SPTSPT-1 1 2 2 SPTSPT-2 3 3 3 SPTSPT-3 3 4 3 SPTSPT-4 2 3 3 SPTSPT-5 13 23 31 10:37 10:49 10:59 Af 0.0'-5.0': ARTIFICIAL FILL 0'-5.0' Sandy Silty Clay - Brown, medium stiff to stiff, moist CL 12.0'-17.0' Silty Sand - Tan-brown, loose, dry, fine sand SM 17.0'-18.0' Silty Sand - Gray, loose, moist 8' - Moist 22.0'-27.0' Clayey Sand - Gray, loose, wet 9 4 5.0'-BOH: ALLUVIUM 5.0'-12.0' Sand - Tan-brown, loose, dry, fine sand 6 6 SP 7 SM CL 18.0'-22.0' Clay - Black, medium stiff, moist to wet, spongy SC SP 25.0'-37.0' Sand - Gray, dense to very dense, wet 6 54 Sieve: 70% Sand, 30% Fines Sieve: 55% Sand, 45% Fines LL=26, PI=11 ~26 feet Project Boring Remarks Depth(feet)GraphicLogUSCSClass.Sheet 2 of 2 Date HIRES AND ASSOCIATES, INC.SC CONSULTING ENGINEERS AND GEOLOGISTS OTTON, 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60 62 Geotechnical Description SampleDesig.MoistureContent (%)SPTBlows/ftSampleTypeRecov.(%)Dry UnitWeight(pcf)CSA/SD-7Orange Memorial Park 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60 62 04/03/2018 SPTSPT-6 9 20 28 SPTSPT-7 7 16 23 11:45 Finished sampling @ 12:05 Finished backfill @ 12:39 32.0' - Tan-brown, dense, saturated, fine to medium sand SP-SM SP 37.0'-BOH Sand with Silt - Tan-brown, dense, saturated, fine sand SP 25.0'-37.0' Sand - Gray, dense to very dense, wet 48 39Total Depth = 38.5 feet Groundwater - 32.0 feet at time of drilling HIRES AND S COTTON, SHIRES AND ASSOCIATES, INC. LOG OF EXPLORATORY DRILLING Project Location Drilling Contractor/Rig Ground Surface Elev. Surface Logged By Boring Project No. Date of Drilling Hole Diameter Weather Remarks Depth(feet)GraphicLogUSCSClass.Sheet 1 of 2 SPT-2 08:08 SPT 08:27T-5 ASSOCIATES, INC.C CONSULTING ENGINEERS AND GEOLOGISTS OTTON, 2 4 6 8 10 12 14 16 18 20 22 24 26 28 Geotechnical Description SampleDesig.MoistureContent (%)SPTBlows/ftSampleTypeRecov.(%)TRH Dry UnitWeight(pcf)CSA/SD-8Orange Memorial Park E5038 04/05/2018 2 4 6 8 10 12 14 16 18 20 22 24 26 28 Driller: Paul Britton Helpers: Sergio + Dave Start Time = 07:43 335' W of fence, 32' N of channel (North Parcel) Britton Exploration / CME 550 8" HSA Old Farmland w/ Vegetation Cloudy 3 4 6 MCT-1 T-2 CL 3 3 3 08:003 4 6 10.0'-16.0' Silty Sand - Tan-brown, loose, moist to wet 4 2 5 SPTSPT-1 SPT SPTSPT-3 25.0' - Moist 3 4 6 MC T-3 T-4 SPT-4 4 8 9 SM 5 10 8 MC 16.0'-18.0' Silt - Black, stiff to very stiff, wet 22.0'-30.0' Silty Sand - Blue-gray, medium dense, dry, rootlets 0.0'-1.5' Sandy Clay - Dark-brown, stiff, moist to wet 1.5'-5.0' Silty Sand - Brown, loose, moistSM 0.0'-BOH: ALLUVIUM 5.0'-10.0' Sandy Silt - Tan-brown, loose, moist, fine sand SM ML 18.0'-22.0' Clay - Black, stiff to very stiff, wet, high plasticity CH SM 7 6 10 7 7 12 17 Sieve: 71% Sand, 29% Fines LL=56, PI=27 ~28 feet Project Remarks USCSClass.Sheet 2 of 2 SSOCIATES, INC. 32 40 SPT-6 Boring Depth(feet)GraphicLogDate HIRES AND ASC CONSULTING ENGINEERS AND GEOLOGISTS OTTON, 34 36 38 42 44 46 48 50 52 54 56 58 60 62 Geotechnical Description SampleDesig.MoistureContent (%)SPTBlows/ftSampleTypeRecov.(%)Dry UnitWeight(pcf)CSA/SD-8Orange Memorial Park 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60 62 04/05/2018 Finished sampling @ 09:00 Finished backfill @ 09:20 SPT 6 10 11 08:47SPTSPT-5 4 7 12 35.0'-BOH Silty Sand - Gray, medium dense, dry, fine sand SM SM 30.0'-35.0' Silty Sand - Gray-brown, medium dense, moist, iron oxide streaks, fine to coarse sand 19 21Total Depth = 36.5 feet No groundwater Encountered Sieve: 73% Sand, 28% Fines  COTTON, SHIRES AND ASSOCIATES, INC.                   APPENDIX B    Laboratory Testing  Summary of Laboratory Testing  Triaxial Compression Test Results  Consolidation Test Results                 COTTON, SHIRES AND ASSOCIATES, INC. B‐1      APPENDIX B  LABORATORY TESTING        The laboratory analysis performed for the site consisted of limited testing of the representative  soil types sampled during the field investigation to evaluate index properties of subsurface  materials.  The soil descriptions and the field and laboratory test results were used to assign  parameters to the various materials at the site.  The results of the laboratory testing program are  presented in this appendix and on the boring logs.    The following laboratory tests were performed as part of this investigation:    1. Detailed soil description, ASTM D2487;  2. Natural moisture content of the soil, ASTM D2216;  3. In‐situ unit weight of the soil (wet and dry) ASTM D7263b;   4. Atterberg limits, ASTM D4318;  5. Unconsolidated, undrained triaxial compression test, ASTM D2850;  6. Consolidation, ASTM D2435; and   7. Percent minus the No. 200 sieve, ASTM D1140.      Job No.: Boring: Run By:MD Client: Sample:Reduced:PJ Project: Depth, ft.: Checked:PJ/DC Soil Type:Date:4/26/2018 Assumed Gs 2.65 Initial Final 31.1 25.0 88.8 99.5 0.863 0.663 95.4 100.0 Void Ratio: % Saturation: Dry Density, pcf: Moisture %: B-1 T-4 21-21.5E5038 Cotton, Shires & Associates 026-666 Black CLAY w/ Sand 0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0 18.0 20.0 10 100 1000 10000 100000Strain, % Effective Stress, psf Strain-Log-P Curve Consolidation Test ASTM D2435 Remarks: Project No.: Project: Client: Cu Cc COEFFICIENTS D10 D30 D60 REMARKS:GRAIN SIZE SOIL DESCRIPTIONPERCENT FINERSIEVEPERCENT FINERSIEVE LLPLAASHTOUSCS% CLAY% SILT% SAND% GRAVEL sizesize number Particle Size Distribution Report 10 20 30 40 50 60 70 80 90 0 100 PERCENT FINER100 10 1 0.1 0.01 0.001200 GRAIN SIZE - mm6 in.3 in.2 in.1-1/2 in.1 in.3/4 in.1/2 in.3/8 in.#4#10#20#30#40#60#100#140#200Figure % COBBLES 026-666 Orange Memorial Park - E5038 Cotton, Shires & Associates Source: B-1 Sample No.: SPT-2 Elev./Depth: 7-8.5' 2.55 1.21 0.0873 0.153 0.222 7.990.41.7 inches Yellowish Brown Poorly Graded SAND w/ Silt COOPER TESTING LABORATORY Source: B-1 Sample No.: T-5 Elev./Depth: 24-24.5' 62.837.2 Olive Gray Sandy CLAY Source: B-1 Sample No.: T-7 Elev./Depth: 33-33.5' 0.0954 43.856.2 Gray Silty SAND 98.3 97.1 93.2 89.4 80.7 28.6 7.9 #4 #10 #30 #40 #50 #100 #200 100.0 98.8 98.8 3/4" 1/2" 3/8" 100.0 99.8 99.7 99.6 97.3 62.8 100.0 99.9 99.6 99.2 97.6 84.6 43.8 Project No.: Project: Client: Cu Cc COEFFICIENTS D10 D30 D60 REMARKS:GRAIN SIZE SOIL DESCRIPTIONPERCENT FINERSIEVEPERCENT FINERSIEVE LLPLAASHTOUSCS% CLAY% SILT% SAND% GRAVEL sizesize number Particle Size Distribution Report 10 20 30 40 50 60 70 80 90 0 100 PERCENT FINER100 10 1 0.1 0.01 0.001200 GRAIN SIZE - mm6 in.3 in.2 in.1-1/2 in.1 in.3/4 in.1/2 in.3/8 in.#4#10#20#30#40#60#100#140#200Figure % COBBLES 026-666 Orange Memorial Park - E5038 Cotton, Shires & Associates Source: B-1 Sample No.: SPT-7 Elev./Depth: 40-41.5' 0.0836 52.847.2 inches Gray Sandy CLAY COOPER TESTING LABORATORY Source: B-2 Sample No.: SPT-3 Elev./Depth: 10-11.5' 0.103 0.188 20.579.30.2 Yellowish Brown Silty SAND Source: B-2 Sample No.: SPT-4 Elev./Depth: 15-16.5' 61.338.7 Dark Yellowish Brown Sandy CLAY 100.0 100.0 99.9 99.8 99.5 91.4 52.8 #4 #10 #30 #40 #50 #100 #200 3/8"99.8 98.6 94.7 91.6 85.4 46.1 20.5 100.0 100.0 99.8 99.6 99.3 91.2 61.3 Project No.: Project: Client: Cu Cc COEFFICIENTS D10 D30 D60 REMARKS:GRAIN SIZE SOIL DESCRIPTIONPERCENT FINERSIEVEPERCENT FINERSIEVE LLPLAASHTOUSCS% CLAY% SILT% SAND% GRAVEL sizesize number Particle Size Distribution Report 10 20 30 40 50 60 70 80 90 0 100 PERCENT FINER100 10 1 0.1 0.01 0.001200 GRAIN SIZE - mm6 in.3 in.2 in.1-1/2 in.1 in.3/4 in.1/2 in.3/8 in.#4#10#20#30#40#60#100#140#200Figure % COBBLES 026-666 Orange Memorial Park - E5038 Cotton, Shires & Associates Source: B-3 Sample No.: SPT-1 Elev./Depth: 3-4.5' 0.130 42.455.42.2 inches Dark Olive Brown Clayey SAND COOPER TESTING LABORATORY Source: B-3 Sample No.: SPT-3 Elev./Depth: 13-14.5' 5.33 1.12 0.0838 0.205 0.446 8.790.80.5 Dark Reddish Brown Poorly Graded SAND w/ Silt Source: B-3 Sample No.: SPT-8 Elev./Depth: 45-46.5' 0.0767 58.841.2 Dark Gray Sandy CLAY 97.8 96.4 93.9 92.2 88.1 65.2 42.4 #4 #10 #30 #40 #50 #100 #200 100.0 99.0 1/2" 3/8" 99.5 95.7 71.0 58.1 44.6 20.1 8.7 100.0 100.0 100.0 99.9 99.9 99.9 95.3 58.8 Project No.: Project: Client: Cu Cc COEFFICIENTS D10 D30 D60 REMARKS:GRAIN SIZE SOIL DESCRIPTIONPERCENT FINERSIEVEPERCENT FINERSIEVE LLPLAASHTOUSCS% CLAY% SILT% SAND% GRAVEL sizesize number Particle Size Distribution Report 10 20 30 40 50 60 70 80 90 0 100 PERCENT FINER100 10 1 0.1 0.01 0.001200 GRAIN SIZE - mm6 in.3 in.2 in.1-1/2 in.1 in.3/4 in.1/2 in.3/8 in.#4#10#20#30#40#60#100#140#200Figure % COBBLES 026-666 Orange Memorial Park - E5038 Cotton, Shires & Associates Source: B-4 Sample No.: SPT-1 Elev./Depth: 3.5-5' 0.0816 ML57.638.83.6 inches Olive Brown Sandy CLAY COOPER TESTING LABORATORY Source: B-4 Sample No.: SPT-2 Elev./Depth: 7-8.5' 0.0759 0.145 29.570.40.1 Reddish Brown Silty SAND Source: B-4 Sample No.: SPT-3 Elev./Depth: 10-11.5' 0.0901 47.952.1 Olive Brown Clayey SAND 96.4 95.0 92.7 91.6 89.3 76.5 57.6 #4 #10 #30 #40 #50 #100 #200 100.0 96.8 96.8 3/4" 1/2" 3/8" 99.9 99.7 98.5 96.9 92.8 61.7 29.5 100.0 100.0 99.9 99.8 99.5 98.8 87.3 47.9 Project No.: Project: Client: Cu Cc COEFFICIENTS D10 D30 D60 REMARKS:GRAIN SIZE SOIL DESCRIPTIONPERCENT FINERSIEVEPERCENT FINERSIEVE LLPLAASHTOUSCS% CLAY% SILT% SAND% GRAVEL sizesize number Particle Size Distribution Report 10 20 30 40 50 60 70 80 90 0 100 PERCENT FINER100 10 1 0.1 0.01 0.001200 GRAIN SIZE - mm6 in.3 in.2 in.1-1/2 in.1 in.3/4 in.1/2 in.3/8 in.#4#10#20#30#40#60#100#140#200Figure % COBBLES 026-666 Orange Memorial Park - E5038 Cotton, Shires & Associates Source: B-4 Sample No.: SPT-4 Elev./Depth: 13-14.5' 0.0974 36.963.1 inches Dark Olive Gray Clayey SAND COOPER TESTING LABORATORY Source: B-4 Sample No.: SPT-5 Elev./Depth: 18-19.5' 0.0963 0.168 19.480.20.4 Very Dark Brownish Gray Clayey SAND Source: B-4 Sample No.: SPT-6 Elev./Depth: 23-24.5' 5621CH76.223.8 Black Fat CLAY w/ Sand 100.0 100.0 99.8 99.7 99.5 89.1 36.9 #4 #10 #30 #40 #50 #100 #200 3/8"99.6 99.1 97.7 96.5 92.3 52.7 19.4 100.0 100.0 99.8 99.6 99.5 99.1 94.9 76.2 Project No.: Project: Client: Cu Cc COEFFICIENTS D10 D30 D60 REMARKS:GRAIN SIZE SOIL DESCRIPTIONPERCENT FINERSIEVEPERCENT FINERSIEVE LLPLAASHTOUSCS% CLAY% SILT% SAND% GRAVEL sizesize number Particle Size Distribution Report 10 20 30 40 50 60 70 80 90 0 100 PERCENT FINER100 10 1 0.1 0.01 0.001200 GRAIN SIZE - mm6 in.3 in.2 in.1-1/2 in.1 in.3/4 in.1/2 in.3/8 in.#4#10#20#30#40#60#100#140#200Figure % COBBLES 026-666 Orange Memorial Park - E5038 Cotton, Shires & Associates Source: B-4 Sample No.: SPT-9 Elev./Depth: 40-41.5' 0.0836 53.346.7 inches Gray Sandy CLAY COOPER TESTING LABORATORY Source: B-4 Sample No.: SPT-10 Elev./Depth: 45-46.5' 74.025.90.1 Dark Olive Gray CLAY w/ Sand Source: B-5 Sample No.: T-11 Elev./Depth: 30-30.5' 0.0766 0.198 29.770.3 Gray Clayey SAND 100.0 99.8 99.6 99.0 89.7 53.3 #4 #10 #30 #40 #50 #100 #200 3/8"99.9 99.7 98.9 98.2 96.8 92.9 74.0 100.0 100.0 99.4 97.8 94.6 82.6 46.1 29.7 Project No.: Project: Client: Cu Cc COEFFICIENTS D10 D30 D60 REMARKS:GRAIN SIZE SOIL DESCRIPTIONPERCENT FINERSIEVEPERCENT FINERSIEVE LLPLAASHTOUSCS% CLAY% SILT% SAND% GRAVEL sizesize number Particle Size Distribution Report 10 20 30 40 50 60 70 80 90 0 100 PERCENT FINER100 10 1 0.1 0.01 0.001200 GRAIN SIZE - mm6 in.3 in.2 in.1-1/2 in.1 in.3/4 in.1/2 in.3/8 in.#4#10#20#30#40#60#100#140#200Figure % COBBLES 026-666 Orange Memorial Park - E5038 Cotton, Shires & Associates Source: B-6 Sample No.: T-4 Elev./Depth: 4.5-5' 0.0844 52.847.2 inches Dark Olive Brown Sandy SILT COOPER TESTING LABORATORY Source: B-7 Sample No.: SPT-2 Elev./Depth: 12-13.5' 0.143 30.269.70.1 Dark Olive Gray Clayey SAND Source: B-7 Sample No.: SPT-4 Elev./Depth: 22-23.5' 0.135 2615SC45.454.6 Dark Olive Gray Lean Clayey SAND 100.0 99.9 99.8 99.5 93.8 52.8 #4 #10 #30 #40 #50 #100 #200 3/8"99.9 99.4 96.7 94.4 90.7 62.3 30.2 100.0 100.0 99.9 99.1 96.7 87.9 63.2 45.4 Project No.: Project: Client: Cu Cc COEFFICIENTS D10 D30 D60 REMARKS:GRAIN SIZE SOIL DESCRIPTIONPERCENT FINERSIEVEPERCENT FINERSIEVE LLPLAASHTOUSCS% CLAY% SILT% SAND% GRAVEL sizesize number Particle Size Distribution Report 10 20 30 40 50 60 70 80 90 0 100 PERCENT FINER100 10 1 0.1 0.01 0.001200 GRAIN SIZE - mm6 in.3 in.2 in.1-1/2 in.1 in.3/4 in.1/2 in.3/8 in.#4#10#20#30#40#60#100#140#200Figure % COBBLES 026-666 Orange Memorial Park - E5038 Cotton, Shires & Associates Source: B-8 Sample No.: SPT-1 Elev./Depth: 5-6.5' 0.0769 0.144 28.871.10.1 inches Dark Reddish Brown Clayey SAND COOPER TESTING LABORATORY Source: B-8 Sample No.: SPT-6 Elev./Depth: 35-36.5' 0.0774 0.115 27.572.5 Greenish Gray Silty SAND 99.9 99.7 99.4 99.2 98.3 62.1 28.8 #4 #10 #30 #40 #50 #100 #200 100.03/8"100.0 99.6 96.1 94.6 92.1 75.4 27.5 Project: Remarks:Client:Project No. %<#200%<#40PIPLLLMATERIAL DESCRIPTION LIQUID AND PLASTIC LIMITS TEST REPORT Source: B-1 Sample No.: T-3 Elev./Depth: 20.5-21' Figure LIQUID AND PLASTIC LIMITS TEST REPORT COOPER TESTING LABORATORY USCS Cotton, Shires & Associates026-666 381957Black Fat CLAY Orange Memorial Park - E5038 Source: B-1 Sample No.: T-8 Elev./Depth: 45.5-46' 131932Olive Gray Sandy Lean CLAY Source: B-2 Sample No.: SPT-6 Elev./Depth: 30-31.5' 182038Black Sandy Lean CLAY Source: B-4 Sample No.: SPT-6 Elev./Depth: 23-24.5' CH76.299.5352156Black Fat CLAY w/ Sand Source: B-4 Sample No.: T-4 Elev./Depth: 26-26.5' 181634Black Lean CLAY w/ Sand 5 10 20 25 30 4026 34 42 50 58 66 NUMBER OF BLOWSWATER CONTENT10 30 50 70 90 110 LIQUID LIMIT 10 20 30 40 50 60 PLASTICITY INDEX4 7 CL-ML C L o r O L C H o r O H ML or OL MH or OH Dashed line indicates the approximate upper limit boundary for natural soils Project: Remarks:Client:Project No. %<#200%<#40PIPLLLMATERIAL DESCRIPTION LIQUID AND PLASTIC LIMITS TEST REPORT Source: B-6 Sample No.: T-2 Elev./Depth: 2-2.5' Figure LIQUID AND PLASTIC LIMITS TEST REPORT COOPER TESTING LABORATORY USCS Cotton, Shires & Associates026-666 81523Dark Olive Brown Lean Clayey SAND Orange Memorial Park - E5038 Source: B-6 Sample No.: T-7 Elev./Depth: 10-10.5' 191938Dark Reddish Brown Lean Clayey SAND Source: B-6 Sample No.: T-10 Elev./Depth: 21-21.5' NPNPGray Silty SAND Could not roll out. Sample slides in bowl. Non-plastic. Source: B-7 Sample No.: SPT-4 Elev./Depth: 22-23.5' SC45.496.7111526Dark Olive Gray Lean Clayey SAND Source: B-8 Sample No.: T-3 Elev./Depth: 18-18.5' 272956Black Sandy Fat CLAY 5 10 20 25 30 4016 26 36 46 56 66 NUMBER OF BLOWSWATER CONTENT10 30 50 70 90 110 LIQUID LIMIT 10 20 30 40 50 60 PLASTICITY INDEX4 7 CL-ML C L o r O L C H o r O H ML or OL MH or OH Dashed line indicates the approximate upper limit boundary for natural soils