B08_Att_5_Geotechical_Report.pdf

504 Redwood Blvd., Suite 220 Novato, California 94947 T (415) 382-3444 F (415) 382-3450

September 21, 2018 File: 1650.116bltr.doc

Golden Gate National Parks Conservancy 201 Fort Mason San Francisco, CA 94123

Attn: Mr. Rob LaPorte

Re: Geotechnical Data Report China Beach Wall and Slope Stabilization San Francisco, California

Introduction

This letter summarizes our geotechnical exploration, laboratory testing and recommendations regarding stabilization of several existing retaining structures and a landslide within the Golden Gate National Parks Conservancy’s (GGNPC) China Beach in San Francisco, California. The site is located near the Sea Cliff neighborhood in northwest San Francisco, as shown on the Site Location Map, Figure 1. We previously provided a geotechnical evaluation of the walls to provide temporary shoring recommendations as summarized in our letter dated October 10, 2017. Our current scope of services has included a site reconnaissance, subsurface exploration, geotechnical and environmental laboratory testing, and preparation of this report.

Project Description

We understand the project generally includes developing designs for rehabilitation of the Bathhouse and associated site work to meet the needs of the NPS Ocean Rescue program and a public program, and schematic designs for site infrastructure repairs which includes retaining wall repair, slope stabilization, wastewater system repair, and potable water service repair.

The primary geotechnical portions of the project include retaining wall and slope stabilization. We reviewed available geologic and other data pertaining to the existing walls as listed below.

Federal Highway Administration, Golden Gate National Recreation Area, Replace Deteriorated Retaining Walls at China Beach, Scope and Cost Validation Report, PMIS:

GOGA-004378, 2008.

United States Geological Survey, Geology of the San Francisco North Quadrangle, California, Miscellaneous Geologic Investigations Map I-272, 1958.

Contech Engineered Solutions LLC, Bin-Wall Retaining Wall Systems Catalog, 2012.

Site Reconnaissance and Surface Conditions

We performed an initial site reconnaissance September 2017 and supplemental reconnaissance in August 2018 to observe site conditions. China Beach is located within a small cove below a northerly-facing slope that ascends upward toward Sea Cliff Avenue. Existing improvements include an approximately 10,000-square-foot parking area at the southern end of the site, and an approximately 10- to 15-foot-wide, asphalt-paved service road which provides access to the beach from the parking area above. A “bathhouse” structure exists within the lower reaches of the site

Golden Gate National Parks Conservancy September 21, 2018 and provides restrooms and other amenities for park visitors. The existing site conditions are shown on the Site Plan, Figure 2.

Several retaining walls exist throughout the site to support various cuts and fills which were required to achieve the existing finished grades. The walls generally consist of either reinforced concrete walls or metal “bin” walls of variable dimensions and age. The metal bin walls are shown on Figure 2 and were previously described by FHWA as follows:

Wall 1: This wall supports a portion of the China Beach parking area and abuts a cast-in-place concrete gravity wall at the western end of the parking lot. This wall is approximately 180 feet long, has a maximum height of 13.5 feet, an average wall height of 11 feet, and an approximate total face area of 1,980 square feet.

Wall 2: This wall abuts the upper and middle portions of the service road. This wall is approximately 200 feet long, has a maximum wall height of 14 feet, an average wall height of 9 feet, and an approximate exposed face area of 1,900 square feet.

Wall 3: This wall is located along the service road just above the beach facilities. This wall is 78 feet in length, has a maximum wall height of 5.5 feet, an average wall height of 4 feet, and an approximate exposed face area of 310 square feet.

Wall 4: This wall is located along the uphill side of the beach facilities building and is 240 feet long, has a maximum height of 8 feet, an average wall height of 7 feet, and an approximate exposed face area of 1,830 square feet.

Corrosion of the corrugated metal panels is evident along much of the wall face. The degree of corrosion varies from minor pitting and scaling to localized areas where corrosion has resulted in partial deterioration and failure of the wall lagging. Several photographs from our 2017 site reconnaissance showing the condition of the bin walls are presented in Appendix A.

Regional Geology and Seismicity

Regional geologic mapping by the United States Geological Survey indicates the southern portion of the site is primarily underlain by Quaternary-age dune sand deposits. The northern portions of the site near the shoreline are mapped as a mixture of Quaternary beach sand, landslide deposits and bedrock units consisting of serpentine, sandstone and chert of Jurassic- to Cretaceous-age.

The 1958 mapping also indicates several faults located about a mile west of the site. A Regional Geologic Map is shown on Figure 3.

Seismicity The project site is located within the seismically active San Francisco Bay Area and will therefore experience the effects of future earthquakes. Earthquakes are the product of the build-up and sudden release of strain along a “fault” or zone of weakness in the earth's crust. Stored energy may be released as soon as it is generated, or it may be accumulated and stored for long periods of time. Individual releases may be so small that they are detected only by sensitive instruments, or they may be violent enough to cause destruction over vast areas.

Faults are seldom single cracks in the earth's crust but are typically comprised of localized shear zones which link together to form larger fault zones. Within the Bay Area, faults are concentrated along the San Andreas Fault zone. The movement between rock formations along either side of a fault may be horizontal, vertical, or a combination, and is radiated outward in the form of energy waves. The amplitude and frequency of earthquake ground motions partially depends on the material through which it is moving. The earthquake force is transmitted through hard rock in short, rapid vibrations, while this energy becomes a long, high-amplitude motion when moving through soft ground materials.

Regional Active Faults - An “active” fault is one that shows displacement within the last 11,000 years (i.e., Holocene) and has a reported average slip rate greater than 0.1 mm per year. The California Division of Mines and Geology has mapped various active and inactive faults in the region. These faults are shown in relation to the project site on the attached Active Fault Map, Figure 4. The nearest known active faults are the San Andreas, San Gregorio, and Hayward Faults which are located roughly 7.0 kilometers (4.3 miles) west, 11.6 kilometers (7.2 miles) west, and 22.7 kilometers (14.1 miles) east of the site, respectively.

Historic Fault Activity - Numerous earthquakes have occurred in the region within historic times.

The results of our USGS earthquake search catalogue indicates that at least 18 earthquakes with a Richter Magnitude of 5.0 or larger have occurred within 100 kilometers (62 miles) of the site between 1900 and 2017. The approximate locations of these earthquakes are shown on the Historic Earthquake Map, Figure 5.

Probability of Future Earthquakes - The site will likely experience moderate to strong ground shaking from future earthquakes originating on any of several active faults in the San Francisco Bay region. The historical records do not directly indicate either the maximum credible earthquake or the probability of such a future event. To evaluate earthquake probabilities in California, the USGS has assembled a group of researchers into the “Working Group on California Earthquake Probabilities” (USGS 2003, 2008, 2013) to estimate the probabilities of earthquakes on active faults.

These studies have been published cooperatively by the USGS, CGS, and Southern California Earthquake Center (SCEC) as the Uniform California Earthquake Rupture Forecast, Versions 1, 2, and 3. In these studies, potential seismic sources were analyzed considering fault geometry, geologic slip rates, geodetic strain rates, historic activity, micro-seismicity, and other factors to arrive at estimates of earthquakes of various magnitudes on a variety of faults in California.

Conclusions from the most recent UCERF3 and USGS indicate the highest probability of an earthquake with a magnitude greater than 6.7 originating on any of the active faults in the San Francisco Bay region by 2043 is assigned to the Hayward/Rodgers Creek Fault system. The Hayward Fault is located approximately 22.7 kilometers (14.1 miles) east of the site and is assigned a probability of 33 percent. The San Andreas Fault, located approximately 7.0 kilometers (4.3 miles) west of the site, is assigned a 22 percent probability of an earthquake with a magnitude greater than

6.7 by 2043. Additional studies by the USGS regarding the probability of large earthquakes in the Bay Area are ongoing. These current evaluations include data from additional active faults and updated geological data.

Field Exploration and Subsurface Conditions

We explored subsurface conditions within the project area with twelve test borings drilled with truck and portable equipment to depths between 6 and 26-feet below the ground surface. The locations of our borings are shown on Figure 2. We logged and sampled the materials encountered during our exploration as described in Appendix B. Selected samples of soil and weathered rock were tested in our laboratory to determine engineering properties. The subsurface exploration program is discussed in more detail in Appendix B. A Soil Classification Chart, Rock Classification Chart and boring logs are presented on Figures B-1 through B-16.

Laboratory testing to evaluate engineering properties includes determination of moisture content, dry density, unconfined compressive strength, percent passing the No. 200 sieve and sieve analyses. Most of these laboratory test results are presented on the boring logs and the sieve analyses results are present on Figures B-17 and B-18.

Environmental Testing

Background environmental testing was performed on upper 3.5 feet of soils from Borings 5, 6, 8 and 9. Samples were collected by drive sampler to acquire undisturbed soil in 2”x6” pre-cleaned and decontaminated brass liners on August 31, 2018. The drilling and sampling equipment were washed and decontaminated between samples and borings. We transported soil samples along with a chain of custody form to Analytical Sciences’ laboratory in Petaluma, CA. Sample were tested for heavy metals (CAM 17 metals), diesel/motor oil, chlorinated pesticides and polychlorinated biphenyls (PCBs). The results of the analytical tests are presented in Appendix C.

Interpreted Subsurface Conditions

The subsurface conditions encountered during exploration are generally consistent with the mapped geology. The soils behind Wall 1 in the upper parking area (Borings 1, 2 and 3) consist of clean sand fill over dune sand. In the central portion of the parking area, the sand fill and dune sand extend to a depth of about 20 feet. Farther to the east and closer to Sea Cliff Avenue the thickness of the sand fill / dune sand is about 10 feet. Underlying the fill /dune sands are few feet of clayey sands associated with colluvial and residual soils. Franciscan Melange bedrock was encounter a about 25 feet below grade closer to the wall near center of parking and 15 feet below grade at east end.

Subsurface conditions within the roadway (Borings 4, 5, 6 and 8) vary from the parking area down to the boat house. At the higher elevations, subsurface conditions consist of fill material over dune sand. At the lower elevations (near boathouse) subsurface conditions are clayey sand colluvial / residual soils over weathered bedrock at shallow depth. In general, would expect the fill layer to be thicker on the outer portion of the roadway and thinner on the upslope side.

Subsurface conditions on the slope between walls (Borings 7, 9 and 12) generally include a thin fill layer (less than a few feet) over dune sand in the higher elevations, and over clayey sand colluvial / residual soils at lower elevations.

Within the landslide area (Borings 10 and 11), subsurface conditions consist primarily of loose, clayey/sandy gravel with larger sandstone cobble and boulder inclusions. Caving conditions are present, and the bore holes would collapse upon auger removal. Borings were terminated at 10 feet due to difficulty advancing the hole with portable equipment through caving conditions and larger debris. Bedrock is exposed in the headscarp and near the toe of the landslide area.

Free groundwater was not observed in the borings. However, the borings were not left open for an extended period may not represent a stabilized groundwater level. Would expect groundwater flow along the top of the colluvium / residual soil / bedrock surface during winter months.

Geologic Hazards Evaluation

Based on our review of regional geologic mapping, site observations and subsurface exploration, we have evaluated a variety of geologic hazards which could impact project planning and design.

We judge that the primary geologic hazards to be considered include strong seismic ground shaking, seismic densification, erosion, and slope instability. Other hazards, including liquefaction, flooding, expansive soils, and others, are judged relatively insignificant with regards to the planned project and are therefore not discussed in detail. More detailed discussion of significant hazards is presented in the following sections.

Seismic Ground Shaking The site will likely experience seismic ground shaking similar to other areas in the seismically active San Francisco Bay Area. Earthquakes along several active faults in the region, as shown on Figure 4, could cause moderate to strong ground shaking at the site. Estimates of peak ground accelerations are based on either deterministic or probabilistic methods. Deterministic methods are commonly used for most residential and commercial development, while probabilistic analyses are typically used for “critical” facilities, such as schools and hospitals.

Deterministic methods use empirical attenuation relations that provide approximate estimates of median peak ground accelerations. A summary of the active faults that could most significantly affect the planning area, their maximum credible magnitude, closest distance to the center of the planning area, probable peak ground accelerations, and 84th percentile peak ground accelerations are summarized in Table 1. The calculated accelerations should only be considered as reasonable estimates. Many factors (e.g., soil conditions, orientation to the fault, etc.) can influence the actual ground surface accelerations.

Table 1 – Deterministic Peak Ground Accelerations for Active Faults

Fault

Moment Magnitude for Characteristic Earthquake

Closest Estimated

Distance (km)

Median Peak Ground

Acceleration (g)

84% Peak Ground

Acceleration (g)

San Andreas 8.0 7.0 0.39 0.61

San Gregorio 7.4 11.6 0.29 0.46

Hayward 7.3 22.7 0.18 0.29

Rodgers Creek 7.3 42.4 0.11 0.18

Calaveras 6.9 39.8 0.10 0.16

Reference: Caltrans ARS Online v2.3.09 accessed on September 21, 2018.

Probabilistic Seismic Hazard Analysis analyzes all possible earthquake scenarios while incorporating the probability of each individual event to occur. The probability is determined in the form of the recurrence interval, which is the average time for a specific earthquake acceleration to be exceeded. The design earthquake is not solely dependent on the fault with the closest distance to the site and/or the largest magnitude, but rather the probability of given seismic events occurring on both known and unknown faults.

We calculated the peak ground acceleration for two separate probabilistic conditions; the 2 percent chance of exceedance in 50 years (2,475-year statistical return period) and the 10 percent chance of exceedance in 50 years (475-year statistical return period). The peak ground acceleration values were calculated utilizing the USGS Unified Hazard Tool (USGS, 2018). The results of the probabilistic analyses are presented below in Table 2.

Table 2 – Probabilistic Peak Ground Accelerations for Active Faults

Probability of Exceedance

Statistical

Return Period Magnitude Peak Ground

Acceleration (g)

2% in 50 years 2,475 years 7.6 0.89

10% in 50 years 475 years 7.5 0.54

Reference: USGS Unified Hazard Tool accessed on September 21, 2018.

The potential for strong seismic shaking at the project site is high. The San Andreas Fault would produce the most significant ground shaking and the Hayward Fault is the most likely source for a future earthquake. The most significant adverse impact associated with strong seismic shaking is potential damage to existing retaining structures and improvements.

Evaluation: Less than significant with mitigation.

Mitigation: Mitigation for seismic shaking includes designing the structures in accordance with the most recent edition of the California Building Code (2016 CBC). For existing retaining structures, underpinning and providing additional lateral support is needed to significantly improve stability. New retaining structures would need to be founded on deeper foundation system and designed to withstand seismic surcharge loading.

Slope Instability Coastal bluffs are subject to periodic instability due to wave erosion at the base. Review of aerial photos (below) do not show significant changes in the bluff between 1938 and 2018. Retreat and bluff instability typically occurs in episodes which could happen at any point in time, but more likely during strong winter storms.

A landslide exists in the eastern portion of the project area. The head scarp is located immediately below residential development and the toe is at beach level. It appears the toe of the landslide is being eroded from wave action. Aerial photos show a lack of vegetation growth within the landslide area over time, indicating active, shallow soil movement. Subsurface exploration within the landslide encountered unstable, collapsible soils to depths in excess of 10 feet. Based on site conditions and exploration, the potential for future instability of the landslide area is high.

Corrosion of the corrugated metal panels is evident along much of the wall face. The degree of corrosion varies from minor pitting and scaling to localized areas where corrosion has resulted in partial deterioration and failure of the wall. Retaining wall soil backfill has “run” out through the wall in locations where corrosion is more severe, and lagging has failed. There potential for additional corrosion and wall failures at the project site high.

We understand that construction drawings are not available for the existing bin wall structures.

However, information provided in the Contech Bin-Wall catalogue indicates the gravity structures are composed of a series of front, rear and transverse corrugated panels which form a “bin” that is backfilled with soil. A schematic drawing for a typical bin wall is presented in the catalogue which is included under Appendix D.

July 1938

The potential for slope instability at the site to affect existing improvements or off-site residential property is moderate to high.

Evaluation: Significant unavoidable and less than significant with mitigation.

Mitigation: The potential for slope instability associated with coastal bluff retreat is a significant unavoidable hazard the exists. The seawall below the bathhouse and more resistant bedrock areas result in slower erosion and reduce the potential for instability.

Stability of the active landslide should be improved, or the landslide repaired.

Improvement could include a retaining structure or placement of large rip-rap at the toe of the landslide to reduce erosion. Retaining structures could be constructed to support the landslide scarp and reduce the potential to undermine upslope properties. Scarp and landslide stabilization could also geobrugg mesh with rock

May 2018 anchors. Repair of the landslide could include excavation of landslide material, installation of subsurface drainage, and reconstruction with a reinforced earth slope.

Repair could also be performed with a series of retaining structures.

Repair of the more significantly deteriorated walls (e.g. the east and west end of Wall

1) should be performed soon to prevent continued raveling of the sand backfill which could undermine upslope improvements. The existing walls should be repaired and stabilized. One method well suited to the site conditions is a new reinforced shotcrete facing on the existing metal bin wall with soil nails installed through the walls as needed for increase stability.

Erosion Sandy soils on moderately steep slopes or clayey soils on steep slopes are susceptible to erosion when exposed to concentrated surface water flow. The potential for erosion is increased when established vegetation is disturbed or removed during normal construction activity. The project site lies in steeply-sloping terrain and is underlain by loose to medium-dense sandy soils which are prone to erosion. Currently the storm drainage system discharges through the seawall below the bathhouse, and we did not observe any significant erosion near the outfall.

Evaluation: Less than significant with mitigation.

Mitigation: Existing surface and subsurface drainage improvements and utilities should be evaluated to determine existing conditions and repaired as needed. Erosion control measures during and after construction should be in accordance with a prepared Storm Water Pollution Prevention Plan and should conform to the most recent version of the California Stormwater Quality Association.

Seismic Densification Seismic ground shaking can induce settlement in unsaturated, loose, granular soils. Settlement occurs as loose soil particles rearrange into a denser configuration when subjected to seismic ground shaking. Varying degrees of settlement can occur throughout a deposit, resulting in total and differential settlement of structures founded on such deposits.

Loose, granular soils were encountered throughout the site with the potential for seismic densification and settlement during strong ground shaking. Resultant settlements would likely be several inches given the density and thickness of the loose soils. Therefore, the risk of seismic densification impacting structures is generally high within the upper portion of the project site.

Evaluation: Less than significant with mitigation.

Mitigation: Mitigation measures should include underpinning existing retaining structures to reduce settlements associated with seismic densification. Ground improvement could be performed to solidify or densify loose granular soils. This would be a fairly extensive and expensive operation. Excepting to risk of post seismic settlements and repairing existing improvements as needed may be a more practical approach.

Environmental Contaminants and Hazardous Materials Properties with potential subsurface chemical contamination that require a grading or building permit may be regulated under the San Francisco Maher Ordinance: Article 22A of the San

Francisco Health Code and Article 106A.3.4.2 of the San Francisco Building Code. The Maher Ordinance covers areas with current or historical industrial use or zoning, areas within 100 feet of current or historical underground tanks, filled former Bay, marsh or creek areas and areas within 150 feet of a current or former elevated highway. Per the City and County of San Francisco Planning Department’s official map1, the site is not located within an area subject to the provisions of the Maher Ordinance.

We understand that environmental personnel from Golden Gate National Recreation Area (GGNRA) will review environmental testing and provide consultation regarding the presence of hazardous materials.

Evaluation: Less than significant with mitigation.

Mitigation: Evaluation and mitigation of environmental issues should be handled by GGNRA or other suitably qualified professionals.

Supplemental Services

Supplemental services may include additional subsurface exploration, laboratory testing, geotechnical consultation, geo-civil design of the retaining structure, preparation of construction plans and technical specifications, and assistance during bidding and permitting. Future services may also include observation and testing during construction to confirm conditions are as anticipated and the work is performed in accordance with the contract documents. We can provide supplemental services as requested.

We trust that this letter contains the information you require at this time. If there are any questions or comments, please call.

Very truly yours, MILLER PACIFIC ENGINEERING GROUP REVIEWED BY:

Rusty Arend Scott Stephens Geotechnical Engineer No. 3031 Geotechnical Engineer No. 2398 (Expires 6/30/19) (Expires 6/30/19)

Attachments: Figures 1 to 5, Appendices A, B, C and D

1 http://www.sf-planning.org/ftp/files/publications_reports/library_of_cartography/Maher%20Map.pdf

REFERENCE: USGS, Point Bonita and San Francisco North 7.5' Quadrangles, 2015.

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F 415 / 382-3450 www.millerpac.comFILENAME: 1650.116 Figures.dwg

A CALIFORNIA CORPORATION, 2017, ALL RIGHTS RESERVED

SITE LOCATION MAP

China Beach Restoration San Francisco, California

1650.116

RCA

PARKING AREA

BATHHOUSE

STRUCTURE

SERVICE ROAD

WALL 1

WALL 2

WALL 4

WALL 3

CONCRETE SEAWALL

B-4

B-2

B-3

B-1

B-5

B-6

B-8

B-9

B-7

B-12

B-11

B-10

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Designed

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504 Redwood Blvd.

Suite 220

Novato, CA 94947

T 415 / 382-3444

F 415 / 382-3450 www.millerpac.com

A CALIFORNIA CORPORATION, 2018, ALL RIGHTS RESERVED

FILE: 1650.116 Figures.dwg

China Beach Restoration San Francisco, California

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SITE PLAN - EXISTING CONDITIONS

RCA

SAS

SCALE

0 30 60 120 FEET N

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H

REFERENCE: USGS, Point Bonita and San Francisco North 7.5' Quadrangles, 2015.

REGIONAL GEOLOGIC MAP

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REGIONAL GEOLOGIC MAP

China Beach Restoration San Francisco, California

1650.116

RCA

LEGEND:

DUNE SAND (Qd) Clean, well sorted, fine to medium sand; yellowish brown to light gray

MODERN BEACH DEPOSITS (Qb) Predominantly well sorted, medium to coarse gray sand; coarse gravel and large cobbles in some places.

LANDSLIDE DEPOSITS (Ql) Generally unstratisfied mixtures of bedrock, sand, silt, and clay in varying proportions.

SERPENTINE (Sp) Mostly soft, sheared rock containing hard knobs of unsheared serpentine, rodigonite or rocks of the Franciscan Formation

SANDSTONE (KJss) Thick-bedded and massive, graywacke sandstone interbedded with thin layers of shale and fine-grained sandstone;

some thick conglomerate lenses.

RADIOLARIAN CHERT AND SHALE (KJc) Reddish-brown, alternate beds of hard brittle chert and firm brittle shale. Locally includes bodies of massive chert.

Qd

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FILE: 1650.116 FM.dwg

ACTIVE FAULT MAP

1650.116

China Beach Restoration San Francisco, California

9/21/2018

A CALIFORNIA CORPORATION, 2018, ALL RIGHTS RESERVED

MMT

N O

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HSCALE

0 12.5 25 50 MILES

DATA SOURCE:

1) U.S. Geological Survey, U.S. Department of the Interior, "Earthquake Outlook for the San Francisco Bay Region 2014-2043", Map of Known Active Faults in the San Francisco Bay Region, Fact Sheet 2016-3020, Revised August 2016 (ver. 1.1).

SITE

25 M

ILES

50 M

ILES

SITE COORDINATES: LAT. 37.7878, LON. -122.4909

THE GEYSERS

San Rafael

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FILE: 1650.001 HM.dwg

HISTORIC FAULT ACTIVITY

1650.116

China Beach Restoration SanSan Francisco, California

9/21/2018

A CALIFORNIA CORPORATION, 2018, ALL RIGHTS RESERVED

MMT

N O

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H

DATA SOURCE:

1) U.S. Geological Survey, U.S. Department of the Interior, "Earthquake Outlook for the San Francisco Bay Region 2014-2043", Map of Earthquakes Greater Than Magnitude 2.0 in the San Francisco Bay Region from 1985-2014, Fact Sheet 2016-3020, Revised August 2016 (ver. 1.1).

SITE COORDINATES: LAT. 37.7878 LON. -122.4909 SCALE

0 12.5 25 50 MILES

50 M

ILES

SITE

25 M

ILES

AutoCAD SHX Text

THE GEYSERS

AutoCAD SHX Text

THE GEYSERS

APPENDIX A

SITE PHOTOGRAPHS FROM 9/29/17 SITE RECONNAISSANCE

Photo 1 – Deterioration of the metal panels and loss of backfill at Wall 1.

Photo 2 – Failure of panel and panel/connector welds.

Photo 3 – View of Wall 4 looking west.

Photo 4 – Severely corroded connection between panel and vertical connector.

APPENDIX B

SUBSURFACE EXPLORATION

MAJOR DIVISIONS SYMBOL DESCRIPTION

C

O A

R S

E G

R A

IN

E

D S

O

IL

S ov er

0% s an d an d gr av el

CLEAN GRAVEL

GW Well-graded gravels or gravel-sand mixtures, little or no fines

GRAVEL

with fines

CLEAN SAND

SAND

with fines

GP

GM

GC

SW

SP

SM

SC

Poorly-graded gravels or gravel-sand mixtures, little or no fines

Silty gravels, gravel-sand-silt mixtures

Clayey gravels, gravel-sand-clay mixtures

Well-graded sands or gravelly sands, little or no fines

Poorly-graded sands or gravelly sands, little or no fines

Silty sands, sand-silt mixtures

Clayey sands, sand-clay mixtures

F

IN

E G

R A

IN

E

D S

O

IL

S ov er

0% s ilt a nd c la y

SILT AND CLAY

liquid limit <50%

SILT AND CLAY

liquid limit >50%

ML

CL

OL

MH

CH

OH

PTHIGHLY ORGANIC SOILS

ROCK

Inorganic silts and very fine sands, rock flour, silty or clayey fine sands or clayey silts with slight plasticity

Inorganic clays of low to medium plasticity, gravely clays, sandy clays, silty clays, lean clays

Organic silts and organic silt-clays of low plasticity

Inorganic silts, micaceous or diatomaceous fine sands or silts, elastic silts

Inorganic clays of high plasticity, fat clays

Organic clays of medium to high plasticity

Peat, muck, and other highly organic soils

Undifferentiated as to type or composition

KEY TO BORING AND TEST PIT SYMBOLS

CLASSIFICATION TESTS

PI

SA

HYD

P200

P4

PLASTICITY INDEX

SIEVE ANALYSIS

HYDROMETER ANALYSIS

PERCENT PASSING NO. 200 SIEVE

PERCENT PASSING NO. 4 SIEVE

STRENGTH TESTS

TV

UC

TXCU

TXUU

FIELD TORVANE (UNDRAINED SHEAR)

LABORATORY UNCONFINED COMPRESSION

CONSOLIDATED UNDRAINED TRIAXIAL

UNCONSOLIDATED UNDRAINED TRIAXIAL

UC, CU, UU = 1/2 Deviator Stress

SAMPLER TYPE

MODIFIED CALIFORNIA

STANDARD PENETRATION TEST

X DISTURBED ORTHIN-WALLED / FIXED PISTON

HAND SAMPLER

ROCK CORE

SAMPLER DRIVING RESISTANCE

BULK SAMPLE

Modified California and Standard Penetration Test samplers are driven 18 inches with a 140-pound hammer falling 30 inches per blow. Blows for the initial 6-inch drive seat the sampler. Blows for the final 12-inch drive are recorded onto the logs. Sampler refusal is defined as 50 blows during a 6-inch drive. Examples of blow records are as follows:

25 sampler driven 12 inches with 25 blows after initial 6-inch drive

85/7" sampler driven 7 inches with 85 blows after initial 6-inch drive

50/3" sampler driven 3 inches with 50 blows during initial 6-inch drive or beginning of final 12-inch drive

NOTE: Test boring and test pit logs are an interpretation of conditions encountered at the excavation location during the time of exploration. Subsurface rock, soil or water conditions may vary in different locations within the project site and with the passage of time. Boundaries between differing soil or rock descriptions are approximate and may indicate a gradual transition.

LL LIQUID LIMIT

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Project No. Date: 9/21/2018

504 Redwood Blvd.

Suite 220

Novato, CA 94947

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B-1

SOIL CLASSIFICATION CHART

China Beach Restoration San Francisco, California

JARS

no affect on cementation coated with clay, oxides or carbonates

Subsurface rock, soil and water conditions may differ in other locations and with the passage of time.

Test boring and test pit logs are an interpretation of conditions encountered at the location and time of exploration.NOTE:

Rock unaffected by weathering, no change with depth, rings under hammer impact

A few stained fractures, slight discoloration, no mineral decomposition, Fracture surfaces coated with weathering minerals, moderate or localized discoloration

Rock decomposition, thorough discoloration, all fractures are extensively Minerals decomposed to soil, but fabric and structure preserved

Fresh

Slight Moderate

High Complete

WEATHERING

Withstands many heavy hammer blows, yields dust, small fragments Withstands few heavy hammer blows, yields large fragments Indentations <1/8 inch with moderate blow with pick end of rock hammer Crumbles under light hammer blows Crumbles by rubbing with fingers

Very strong Strong Moderate Weak Friable

STRENGTH

Rock scratches metal Difficult to scratch, knife scratch leaves dust trace Easily scratched with a knife, friable Carved or gouged with a knife

Very hard Hard Moderate Low

HARDNESS

Very thickly bedded Thickly bedded Medium bedded Thinly bedded Very thinly bedded Laminated greater than 6 feet 2 to 6 feet 8 to 24 inches 2-1/2 to 8 inches 3/4 to 2-1/2 inches less than 3/4 inch

Very widely fractured Widely fractured Moderately fractured Closely fractured Intensely fractured Crushed

Bedding ClassificationSpacingFracture Classification

FRACTURING AND BEDDING

FIGURE

Drawn

Checked

Project No. Date: 9/21/2018

504 Redwood Blvd.

Suite 220

Novato, CA 94947

T 415 / 382-3444

F 415 / 382-3450 www.millerpac.comFILENAME: 1650.116 BL.dwg

A CALIFORNIA CORPORATION, 2018, ALL RIGHTS RESERVED

B-2

ROCK CLASSIFICATION CHART

China Beach Restoration San Francisco, California

*REFERENCE: Google Earth, 2018

ELEVATION: 87 - feet*

DATE: 8/7/18

S

Y M

B O

L (4

S A

M P

LE

D E

P T

H fe et m et er s

W E

IG

H

T p cf

2) D

R Y

U N

IT

C O

N T

E N

T

M O

IS

T

U R

E

B

LO

W S

F

O O

T

1)

S T

R E

N G

T H p sf

3)

S H

E A

R

O T

H E

R T

E S

T D

A T

ABORING 1

NOTES:

(3) METRIC EQUIVALENT STRENGTH (kPa) = 0.0479 x STRENGTH (psf)

(2) METRIC EQUIVALENT DRY UNIT WEIGHT kN/m = 0.1571 x DRY UNIT WEIGHT (pcf)

(4) GRAPHIC SYMBOLS ARE ILLUSTRATIVE ONLY

(1) UNCORRECTED FIELD BLOW COUNTS

O T

H E

R T

E S

T D

A T

A

44 115 6.4

3" Asphalt Concrete over 6" Aggregate Baserock

Water level encountered during drilling

Water level measured after drilling

15 102 3.8

FIGURE

Drawn

Checked

Project No. Date: 9/21/2018

504 Redwood Blvd.

Suite 220

Novato, CA 94947

T 415 / 382-3444

F 415 / 382-3450 www.millerpac.comFILENAME: 1650.116 BL.dwg

A CALIFORNIA CORPORATION, 2018, ALL RIGHTS RESERVED

B-3

BORING LOG

China Beach Restoration San Francisco, California

1650.116

JARS

SAND (SP)

Dark brown, meduim dense, dry to moist, fine to medium grained sand, trace rounded to sub-rounded gravels (<5%), trace clay (~5-10%) [Fill/Dune Sand]

Grades to slightly more moist, slight increase in clay. [Fill/Dune Sand]

Grades to slightly lighter color, dry, medium dense in situ, loose when extruded. [Dune Sand]

22 107 7.8

18 103 1.4

EQUIPMENT: Truck Mounted B24 Drill Rig with 4.0-inch Solid Flight Auger

P200 8.8%

P200 <1.0%

UC

UC

Grades to lighter color. [Dune Sand] P200 <1.0%

SA

S Y

M B

O L

(4

S A

M P

LE

D E

P T

H fe et m et er s

W E

IG

H

T p cf

2) D

R Y

U N

IT

C O

N T

E N

T

M O

IS

T

U R

E

B

LO

W S

F

O O

T

1)

S T

R E

N G

T H p sf

3)

S H

E A

R

O T

H E

R T

E S

T D

A T

ABORING 1

NOTES:

(3) METRIC EQUIVALENT STRENGTH (kPa) = 0.0479 x STRENGTH (psf)

(2) METRIC EQUIVALENT DRY UNIT WEIGHT kN/m = 0.1571 x DRY UNIT WEIGHT (pcf)

(4) GRAPHIC SYMBOLS ARE ILLUSTRATIVE ONLY

Serpentinite Green gray, hard, friable, very stiff [Bedrock]

(1) UNCORRECTED FIELD BLOW COUNTS

O T

H E

R T

E S

T D

A T

A

(CONTINUED)

Water level encountered during drilling

Water level measured after drilling

Boring terminated at 26.5' No groundwater encountered during exploration

FIGURE

Drawn

Checked

Project No. Date: 9/21/2018

504 Redwood Blvd.

Suite 220

Novato, CA 94947

T 415 / 382-3444

F 415 / 382-3450 www.millerpac.comFILENAME: 1650.116 BL.dwg

A CALIFORNIA CORPORATION, 2018, ALL RIGHTS RESERVED

B-4

BORING LOG

China Beach Restoration San Francisco, California

1650.116

JARS

45 28.8

SAND (SP)

Dark brown, meduim dense, dry to moist, fine to medium grained sand, trace rounded gravels.

[Colluvium]

ELEVATION: 90 - feet*

DATE: 8/7/18

S

Y M

B O

L (4

S A

M P

LE

D E

P T

H fe et m et er s

W E

IG

H

T p cf

2) D

R Y

U N

IT

C O

N T

E N

T

M O

IS

T

U R

E

B

LO

W S

F

O O

T

1)

S T

R E

N G

T H p sf

3)

S H

E A

R

O T

H E

R T

E S

T D

A T

ABORING 2

NOTES:

(3) METRIC EQUIVALENT STRENGTH (kPa) = 0.0479 x STRENGTH (psf)

(2) METRIC EQUIVALENT DRY UNIT WEIGHT kN/m = 0.1571 x DRY UNIT WEIGHT (pcf)

(4) GRAPHIC SYMBOLS ARE ILLUSTRATIVE ONLY

(1) UNCORRECTED FIELD BLOW COUNTS

O T

H E

R T

E S

T D

A T

A

28 112 8.3

3" Asphalt Concrete over 6" Aggregate Baserock

Water level encountered during drilling

Water level measured after drilling

8 102 5.1 P200 2.8%

FIGURE

Drawn

Checked

Project No. Date: 9/21/2018

504 Redwood Blvd.

Suite 220

Novato, CA 94947

T 415 / 382-3444

F 415 / 382-3450 www.millerpac.comFILENAME: 1650.116 BL.dwg

A CALIFORNIA CORPORATION, 2018, ALL RIGHTS RESERVED

B-5

BORING LOG

China Beach Restoration San Francisco, California

1650.116

JARS

Clayey SAND (SC) Dark brown, dry to moist, loose, fine to medium grained sand, ~35% low to medium plasticity clay.

[Fill/Dune Sand]

SAND (SP)

Medium tan to brown, dry to moist, very loose medium grained sand. [Fill/Dune Sand]

EQUIPMENT: Truck Mounted B24 Drill Rig with 4.0-inch Solid Flight Auger

10 104 4.4

14 105 4.9

SAND (SP)

Light brown, dry to moist, loose, medium grained sand, trace fines. [Dune Sand]

UC

UC

P200 1.7%

S Y

M B

O L

(4

S A

M P

LE

D E

P T

H fe et m et er s

W E

IG

H

T p cf

2) D

R Y

U N

IT

C O

N T

E N

T

M O

IS

T

U R

E

B

LO

W S

F

O O

T

1)

S T

R E

N G

T H p sf

3)

S H

E A

R

O T

H E

R T

E S

T D

A T

ABORING 2

NOTES:

(3) METRIC EQUIVALENT STRENGTH (kPa) = 0.0479 x STRENGTH (psf)

(2) METRIC EQUIVALENT DRY UNIT WEIGHT kN/m = 0.1571 x DRY UNIT WEIGHT (pcf)

(4) GRAPHIC SYMBOLS ARE ILLUSTRATIVE ONLY

(1) UNCORRECTED FIELD BLOW COUNTS

O T

H E

R T

E S

T D

A T

A

25 99 4.1

(CONTINUED)

Water level encountered during drilling

Water level measured after drilling

Boring terminated at 21.5' No groundwater encountered during exploration

FIGURE

Drawn

Checked

Project No. Date: 9/21/2018

504 Redwood Blvd.

Suite 220

Novato, CA 94947

T 415 / 382-3444

F 415 / 382-3450 www.millerpac.comFILENAME: 1650.116 BL.dwg

A CALIFORNIA CORPORATION, 2018, ALL RIGHTS RESERVED

B-6

BORING LOG

China Beach Restoration San Francisco, California

1650.116

JARS

SAND (SP)

Medium tan to brown, dry to moist, medium dense, medium grained sand. [Dune Sand]

P200 <1.0%

ELEVATION: 96 - feet*

DATE: 8/7/18

EQUIPMENT: Portable Hydraulic Drill Rig with 4.0-inch Solid Flight Auger

S Y

M B

O L

(4

S A

M P

LE

D E

P T

H fe et m et er s

W E

IG

H

T p cf

2) D

R Y

U N

IT

C O

N T

E N

T

M O

IS

T

U R

E

B

LO

W S

F

O O

T

1)

S T

R E

N G

T H p sf

3)

S H

E A

R

O T

H E

R T

E S

T D

A T

ABORING 3

NOTES:

(3) METRIC EQUIVALENT STRENGTH (kPa) = 0.0479 x STRENGTH (psf)

(2) METRIC EQUIVALENT DRY UNIT WEIGHT kN/m = 0.1571 x DRY UNIT WEIGHT (pcf)

(4) GRAPHIC SYMBOLS ARE ILLUSTRATIVE ONLY

(1) UNCORRECTED FIELD BLOW COUNTS

O T

H E

R T

E S

T D

A T

A

33 119 7.6 P200 14.6%

3" Asphalt Concrete over 6" Aggregate Base

Water level encountered during drilling

Water level measured after drilling

15 3.2

FIGURE

Drawn

Checked

Project No. Date: 9/21/2018

504 Redwood Blvd.

Suite 220

Novato, CA 94947

T 415 / 382-3444

F 415 / 382-3450 www.millerpac.comFILENAME: 1650.116 BL.dwg

A CALIFORNIA CORPORATION, 2018, ALL RIGHTS RESERVED

B-7

BORING LOG

China Beach Restoration San Francisco, California

1650.116

JARS

Clayey SAND (SC) Dark brown, dry to moist, medium dense, fine to medium grained sand, ~20-25% medium to high plasticity clay. [Fill]

Clayey SAND (SC) Tan, moist, medium dense, fine grained sand, ~30-50% low plasticity clay, fragment of serpentinite present in sampler. [Fill/Dune Sand]

Clayey SAND (SC) Dark brown, dry to moist, medium dense, fine to medium grained sand, ~20-25% medium to high plasticity clay. [Colluvium/Residual Soil]

Franciscan Melange Hard, strong, green gray [Bedrock]

Boring terminated at 16.5' No groundwater encountered during exploration

60 25.5 92

28 87 13.9

UC

UC

UC

ELEVATION: 86 - feet*

DATE: 8/7/18

EQUIPMENT: Truck Mounted B24 Drill Rig with 4.0-inch Solid Flight Auger

S Y

M B

O L

(4

S A

M P

LE

D E

P T

H fe et m et er s

W E

IG

H

T p cf

2) D

R Y

U N

IT

C O

N T

E N

T

M O

IS

T

U R

E

B

LO

W S

F

O O

T

1)

S T

R E

N G

T H p sf

3)

S H

E A

R

O T

H E

R T

E S

T D

A T

ABORING 4

NOTES:

(3) METRIC EQUIVALENT STRENGTH (kPa) = 0.0479 x STRENGTH (psf)

(2) METRIC EQUIVALENT DRY UNIT WEIGHT kN/m = 0.1571 x DRY UNIT WEIGHT (pcf)

(4) GRAPHIC SYMBOLS ARE ILLUSTRATIVE ONLY

(1) UNCORRECTED FIELD BLOW COUNTS

O T

H E

R T

E S

T D

A T

A

32 122 8.8

3" Asphalt Concrete over 5" Aggregate Base

Water level encountered during drilling

Water level measured after drilling

9 102 3.5

FIGURE

Drawn

Checked

Project No. Date: 9/21/2018

504 Redwood Blvd.

Suite 220

Novato, CA 94947

T 415 / 382-3444

F 415 / 382-3450 www.millerpac.comFILENAME: 1650.116 BL.dwg

A CALIFORNIA CORPORATION, 2018, ALL RIGHTS RESERVED

B-8

BORING LOG

China Beach Restoration San Francisco, California

1650.116

JARS

Clayey SAND (SC) Dark brown, dry to moist, medium dense, fine to medium grained sand, ~20-25% medium plasticity clay. [Fill]

SAND with Clay (SP-SC) Dark brown, dry to moist, loose to medium dense, fine to medium grained sand, 5-15% low plasticity clay. [Fill/Dune Sand]

Grades to medium dense.

Boring terminated at 11.0' No groundwater encountered during exploration

13 113 7.8

23 109 5.4 P200 8.1%

Grades loose. [Dune Sand]

UC

UC

P200 12.6%

ELEVATION: 82 - feet*

DATE: 8/31/18

EQUIPMENT: Truck Mounted B24 Drill Rig with 4.0-inch Solid Flight Auger

S Y

M B

O L

(4

S A

M P

LE

D E

P T

H fe et m et er s

W E

IG

H

T p cf

2) D

R Y

U N

IT

C O

N T

E N

T

M O

IS

T

U R

E

B

LO

W S

F

O O

T

1)

S T

R E

N G

T H p sf

3)

S H

E A

R

O T

H E

R T

E S

T D

A T

ABORING 5

NOTES:

(3) METRIC EQUIVALENT STRENGTH (kPa) = 0.0479 x STRENGTH (psf)

(2) METRIC EQUIVALENT DRY UNIT WEIGHT kN/m = 0.1571 x DRY UNIT WEIGHT (pcf)

(4) GRAPHIC SYMBOLS ARE ILLUSTRATIVE ONLY

(1) UNCORRECTED FIELD BLOW COUNTS

O T

H E

R T

E S

T D

A T

A

2" Asphalt Concrete

Water level encountered during drilling

Water level measured after drilling

FIGURE

Drawn

Checked

Project No. Date: 9/21/2018

504 Redwood Blvd.

Suite 220

Novato, CA 94947

T 415 / 382-3444

F 415 / 382-3450 www.millerpac.comFILENAME: 1650.116 BL.dwg

A CALIFORNIA CORPORATION, 2018, ALL RIGHTS RESERVED

B-9

BORING LOG

China Beach Restoration San Francisco, California

1650.116

JARS

Sandy GRAVEL with Clay (GC) Medium brown, moist, ~30% fine to coarse sand, angular gravel up to 3/4" diameter, ~12% low plasticity clay [Fill]

Clayey SAND (SC) Medium brown, moist, medium dense, fine to medium grained sand, ~25-30% low plasticity clay. [Fill]

SAND with Silt (SP-SM) Medium brown, moist, medium dense, fine to medium grained sand, ~10-15% low plasticity silt.

[Dune Sand]

Boring terminated at 8.5' No groundwater encountered during exploration

22 113 8.8

17 112 4.5

26.0%

ELEVATION: 70 - feet*

DATE: 8/31/18

EQUIPMENT: Truck Mounted B24 Drill Rig with 4.0-inch Solid Flight Auger

S Y

M B

O L

(4

S A

M P

LE

D E

P T

H fe et m et er s

W E

IG

H

T p cf

2) D

R Y

U N

IT

C O

N T

E N

T

M O

IS

T

U R

E

B

LO

W S

F

O O

T

1)

S T

R E

N G

T H p sf

3)

S H

E A

R

O T

H E

R T

E S

T D

A T

ABORING 6

NOTES:

(3) METRIC EQUIVALENT STRENGTH (kPa) = 0.0479 x STRENGTH (psf)

(2) METRIC EQUIVALENT DRY UNIT WEIGHT kN/m = 0.1571 x DRY UNIT WEIGHT (pcf)

(4) GRAPHIC SYMBOLS ARE ILLUSTRATIVE ONLY

(1) UNCORRECTED FIELD BLOW COUNTS

O T

H E

R T

E S

T D

A T

A

29 89 6.0

4" Asphalt Concrete

Water level encountered during drilling

Water level measured after drilling

FIGURE

Drawn

Checked

Project No. Date: 9/21/2018

504 Redwood Blvd.

Suite 220

Novato, CA 94947

T 415 / 382-3444

F 415 / 382-3450 www.millerpac.comFILENAME: 1650.116 BL.dwg

A CALIFORNIA CORPORATION, 2018, ALL RIGHTS RESERVED

B-10

BORING LOG

China Beach Restoration San Francisco, California

1650.116

JARS

Clayey GRAVEL with Sand (GC) Medium brown, moist, medium dense, angular gravel up to 3/4" diameter, ~30% fine to coarse sand, ~25-30% low plasticity clay [Fill/Aggregate Baserock]

Clayey SAND with Gravel (SC) Medium gray, moist, medium dense, fine to medium grained sand, ~20-25% low plasticity clay, ~10% angular gravel. [Fill]

SAND (SP)

Medium brown, moist, loose, fine to medium grained sand, ~10-15% low plasticity clay. [Dune Sand]

Boring terminated at 8.5' No groundwater encountered during exploration

26 130 11.1

9 111 6.7 P200 11.8%

UC

UC

ELEVATION: 52 - feet*

DATE: 8/17/18

EQUIPMENT: Truck Mounted B24 Drill Rig with 4.0-inch Solid Flight Auger

S Y

M B

O L

(4

S A

M P

LE

D E

P T

H fe et m et er s

W E

IG

H

T p cf

2) D

R Y

U N

IT

C O

N T

E N

T

M O

IS

T

U R

E

B

LO

W S

F

O O

T

1)

S T

R E

N G

T H p sf

3)

S H

E A

R

O T

H E

R T

E S

T D

A T

ABORING 7

NOTES:

(3) METRIC EQUIVALENT STRENGTH (kPa) = 0.0479 x STRENGTH (psf)

(2) METRIC EQUIVALENT DRY UNIT WEIGHT kN/m = 0.1571 x DRY UNIT WEIGHT (pcf)

(4) GRAPHIC SYMBOLS ARE ILLUSTRATIVE ONLY

(1) UNCORRECTED FIELD BLOW COUNTS

O T

H E

R T

E S

T D

A T

A

10 107 6.8

Water level encountered during drilling

Water level measured after drilling

FIGURE

Drawn

Checked

Project No. Date: 9/21/2018

504 Redwood Blvd.

Suite 220

Novato, CA 94947

T 415 / 382-3444

F 415 / 382-3450 www.millerpac.comFILENAME: 1650.116 BL.dwg

A CALIFORNIA CORPORATION, 2018, ALL RIGHTS RESERVED

B-11

BORING LOG

China Beach Restoration San Francisco, California

1650.116

JARS

Clayey SAND (SC) Dark brownish gray, moist, loose, fine to medium grained sand, ~25-30% low to medium plasticity clay. [Fill]

Clayey SAND with Gravel (SC) Dark gray, moist, medium dense, fine to medium grained sand, ~10-15% low plasticity clay, ~10% angular gravel. [Colluvium/ Residual Soil]

Sandstone Gray, hard. [Bedrock]

Boring terminated at 8.0' 3.0" No groundwater encountered during exploration

20 115 6.9

50/3" 2.9

Hard drilling at 9.0

UC

UC

28.4%

ELEVATION: 25 - feet*

DATE: 8/31/18

EQUIPMENT: Truck Mounted B24 Drill Rig with 4.0-inch Solid Flight Auger

S Y

M B

O L

(4

S A

M P

LE

D E

P T

H fe et m et er s

W E

IG

H

T p cf

2) D

R Y

U N

IT

C O

N T

E N

T

M O

IS

T

U R

E

B

LO

W S

F

O O

T

1)

S T

R E

N G

T H p sf

3)

S H

E A

R

O T

H E

R T

E S

T D

A T

ABORING 8

NOTES:

(3) METRIC EQUIVALENT STRENGTH (kPa) = 0.0479 x STRENGTH (psf)

(2) METRIC EQUIVALENT DRY UNIT WEIGHT kN/m = 0.1571 x DRY UNIT WEIGHT (pcf)

(4) GRAPHIC SYMBOLS ARE ILLUSTRATIVE ONLY

(1) UNCORRECTED FIELD BLOW COUNTS

O T

H E

R T

E S

T D

A T

A

2" Asphalt Concrete over 4" Aggregate Base

Water level encountered during drilling

Water level measured after drilling

FIGURE

Drawn

Checked

Project No. Date: 9/21/2018

504 Redwood Blvd.

Suite 220

Novato, CA 94947

T 415 / 382-3444

F 415 / 382-3450 www.millerpac.comFILENAME: 1650.116 BL.dwg

A CALIFORNIA CORPORATION, 2018, ALL RIGHTS RESERVED

B-12

BORING LOG

China Beach Restoration San Francisco, California

1650.116

JARS

Clayey SAND (SC) Gray brown, moist, medium dense, fine to medium grained sand, ~20-30% medium plasticity clay.

[Colluvium/Residual Soil]

Sandstone Medium to dark gray, hard, strong, fine grained matrix. [Bedrock]

Boring terminated at 6 feet 2 inches No groundwater encountered during exploration

87/11" 3.2

50/2" 29.9

ELEVATION: 36 - feet*

DATE: 8/31/18

EQUIPMENT: Truck Mounted B24 Drill Rig with 4.0-inch Solid Flight Auger

S Y

M B

O L

(4

S A

M P

LE

D E

P T

H fe et m et er s

W E

IG

H

T p cf

2) D

R Y

U N

IT

C O

N T

E N

T

M O

IS

T

U R

E

B

LO

W S

F

O O

T

1)

S T

R E

N G

T H p sf

3)

S H

E A

R

O T

H E

R T

E S

T D

A T

ABORING 9

NOTES:

(3) METRIC EQUIVALENT STRENGTH (kPa) = 0.0479 x STRENGTH (psf)

(2) METRIC EQUIVALENT DRY UNIT WEIGHT kN/m = 0.1571 x DRY UNIT WEIGHT (pcf)

(4) GRAPHIC SYMBOLS ARE ILLUSTRATIVE ONLY

(1) UNCORRECTED FIELD BLOW COUNTS

O T

H E

R T

E S

T D

A T

A

Water level encountered during drilling

Water level measured after drilling

FIGURE

Drawn

Checked

Project No. Date: 9/21/2018

504 Redwood Blvd.

Suite 220

Novato, CA 94947

T 415 / 382-3444

F 415 / 382-3450 www.millerpac.comFILENAME: 1650.116 BL.dwg

A CALIFORNIA CORPORATION, 2018, ALL RIGHTS RESERVED

B-13

BORING LOG

China Beach Restoration San Francisco, California

1650.116

JARS

Clayey SAND (SC) Medium brown to gray, moist, medium dense, fine to medium grained sand, 15-30% low to moderate plasticity clay. [Fill]

SAND (SP)

Light brown, dry, loose, fine to medium grained sand, ~5-10% medium plasticity clay. [Dune Sand]

Boring terminated at 6 feet 6 inches No groundwater encountered during exploration

12 95 3.3

18 111 2.3 Grades to moist, medium dense.

9.3%

ELEVATION: 20 - feet*

DATE: 8/17/18

EQUIPMENT: Truck Mounted B24 Drill Rig with 4.0-inch Solid Flight Auger

S Y

M B

O L

(4

S A

M P

LE

D E

P T

H fe et m et er s

W E

IG

H

T p cf

2) D

R Y

U N

IT

C O

N T

E N

T

M O

IS

T

U R

E

B

LO

W S

F

O O

T

1)

S T

R E

N G

T H p sf

3)

S H

E A

R

O T

H E

R T

E S

T D

A T

ABORING 10

NOTES:

(3) METRIC EQUIVALENT STRENGTH (kPa) = 0.0479 x STRENGTH (psf)

(2) METRIC EQUIVALENT DRY UNIT WEIGHT kN/m = 0.1571 x DRY UNIT WEIGHT (pcf)

(4) GRAPHIC SYMBOLS ARE ILLUSTRATIVE ONLY

(1) UNCORRECTED FIELD BLOW COUNTS

O T

H E

R T

E S

T D

A T

A

7 119 11.4

Water level encountered during drilling

Water level measured after drilling

FIGURE

Drawn

Checked

Project No. Date: 9/21/2018

504 Redwood Blvd.

Suite 220

Novato, CA 94947

T 415 / 382-3444

F 415 / 382-3450 www.millerpac.comFILENAME: 1650.116 BL.dwg

A CALIFORNIA CORPORATION, 2018, ALL RIGHTS RESERVED

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BORING LOG

China Beach Restoration San Francisco, California

1650.116

JARS

GRAVEL with Sand and Clay (GW) Tan and gray, moist, loose, angular sandstone gravel, ~10% fine grained sand, ~10-15% low plasticity clay. [Landslide Debris]

Clayey GRAVEL with Sand (GC) Medium brown, moist to wet, fine to coarse gravel, ~20-30% medium plasticity clay, ~20-30% fine to coarse grained sand. [Landslide Debris]

Boring terminated at 11.5' No groundwater encountered during exploration

11.9

Hole would collapse when auger withdrawn.

X X X

ELEVATION: 53 - feet*

DATE: 8/17/18

EQUIPMENT: Truck Mounted B24 Drill Rig with 4.0-inch Solid Flight Auger

S Y

M B

O L

(4

S A

M P

LE

D E

P T

H fe et m et er s

W E

IG

H

T p cf

2) D

R Y

U N

IT

C O

N T

E N

T

M O

IS

T

U R

E

B

LO

W S

F

O O

T

1)

S T

R E

N G

T H p sf

3)

S H

E A

R

O T

H E

R T

E S

T D

A T

ABORING 11

NOTES:

(3) METRIC EQUIVALENT STRENGTH (kPa) = 0.0479 x STRENGTH (psf)

(2) METRIC EQUIVALENT DRY UNIT WEIGHT kN/m = 0.1571 x DRY UNIT WEIGHT (pcf)

(4) GRAPHIC SYMBOLS ARE ILLUSTRATIVE ONLY

(1) UNCORRECTED FIELD BLOW COUNTS

O T

H E

R T

E S

T D

A T

A

12 91 7.1

Water level encountered during drilling

Water level measured after drilling

FIGURE

Drawn

Checked

Project No. Date: 9/21/2018

504 Redwood Blvd.

Suite 220

Novato, CA 94947

T 415 / 382-3444

F 415 / 382-3450 www.millerpac.comFILENAME: 1650.116 BL.dwg

A CALIFORNIA CORPORATION, 2018, ALL RIGHTS RESERVED

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