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Ninyo & Moore | 8285 Skyline Drive, San Diego, California | 108232002 R | June 29, 2017 i

CONTENTS

1 INTRODUCTION 1

2 SCOPE OF SERVICES 1

3 SITE AND PROJECT DESCRIPTION 1

4 SUBSURFACE EVALUATION AND LABORATORY TESTING 2

4.1 Geotechnical Laboratory Testing 2

4.2 Field Infiltration Testing 2

5 GEOLOGIC AND SUBSURFACE CONDITIONS 3

5.1 Regional Geologic Setting 4

5.2 Site Geology 4

5.2.1 Fill 4

5.2.2 Very Old Paralic Deposits 4

5.3 Groundwater 5

5.4 Landslides 5

5.5 Flood Hazards 5

5.6 Geologic Hazards 5

6 FAULTING AND SEISMICITY 5

6.1 Ground Motion 6

6.2 Surface Ground Rupture 6

6.3 Liquefaction and Seismically Induced Settlement 7

7 CONCLUSIONS 7

8 RECOMMENDATIONS 8

8.1 Earthwork 8

8.1.1 Pre-Construction Conference 8

8.1.2 Site Preparation 8

8.1.3 Excavation Characteristics 8

8.1.4 Fill Material 8

8.1.5 Fill Placement and Compaction 9

8.2 Seismic Design Considerations 10

8.3 Shallow Foundations 10

8.3.1 Bearing Capacity of Shallow Foundations 10

Ninyo & Moore | 8285 Skyline Drive, San Diego, California | 108232002 R | June 29, 2017 ii

8.3.2 Lateral Resistance of Shallow Foundations 11

8.3.3 Static Settlement 11

8.4 Shade Structure Foundations 11

8.5 Retaining Walls 12

8.6 Concrete Flatwork 12

8.7 Corrosivity 13

8.8 Concrete Placement 13

8.9 Drainage 13

8.10 Permanent Stormwater BMPs 14

9 PLAN REVIEW AND CONSTRUCTION OBSERVATION 14

10 LIMITATIONS 15

11 REFERENCES 16

TABLES

1 – Infiltration Test Results Summary 3

2 – 2016 California Building Code Seismic Design Criteria 10

FIGURES

1 – Site Location

2 – Boring/Infiltration Test Locations

3 – Geology

4 – Fault Locations

5 – Geologic Hazards

6 – Lateral Earth Pressures for Yielding Retaining Walls

7 – Retaining Wall Drainage Detail

APPENDICES

A – Boring Logs

B – Laboratory Testing

C – Infiltration Test Results

Ninyo & Moore | 8285 Skyline Drive, San Diego, California | 108232002 R | June 29, 2017 1

1 INTRODUCTION

In accordance with your request and authorization, we have performed a geotechnical

evaluation of the soil conditions for the proposed improvements at Skyline Hills Community Park

located at 8285 Skyline Drive in San Diego, California (Figure 1). The purpose of our

geotechnical services was to evaluate the near-surface soil conditions at the site and provide

recommendations for the design and construction of the proposed Americans with Disabilities

(ADA) improvements. This report presents our findings, conclusions, and recommendations

based on our subsurface evaluation, laboratory testing, and geotechnical analyses.

2 SCOPE OF SERVICES

Our scope of services included the following:

Reviewing background information including available geotechnical reports, geologic maps, groundwater data, and stereoscopic aerial photographs.

Performing a site reconnaissance to observe and map geotechnical conditions and mark boring locations for clearance by Underground Service Alert (USA).

Excavating and logging of two exploratory borings with hand auger equipment. The borings were advanced to depths up to approximately 6 feet.

Performing near-surface infiltration testing within the shallow borings. Infiltration testing was performed in general accordance with the guidelines presented in the City of San Diego BMP Design Manual dated January 2016.

Performing geotechnical laboratory testing on selected samples to evaluate soil parameters for design purposes. Our testing included evaluation of in-situ moisture content and dry density, shear strength, and soil corrosivity, including minimum resistivity, pH, chloride content, and sulfate content.

Compiling and performing engineering analyses of the data obtained.

Preparing a Geotechnical Evaluation Report providing our findings, conclusions, and geotechnical recommendations relative to geologic hazards, seismic parameters, grading and earthwork (i.e., site preparation, placement and compaction of fill, suitability of onsite soils for reuse as fill, excavatability, and import soils), foundations, corrosive soils, and in-situ infiltration rates.

3 SITE AND PROJECT DESCRIPTION

Skyline Hills Community Park is located at 8285 Skyline Drive in San Diego, California

(Figure 1). Currently, Skyline Hills Community Park consists of a single-story recreation center


building, asphalt concrete (AC) paved parking lot, grass athletic fields, hard-top

basketball/tennis courts, and a tot-lot/playground with sand and rubber mat surfacing.

Additionally, concrete hardscape and sidewalks and landscape areas extend around and

throughout the park. The park was originally constructed in the late 1960’s. Site elevations

range from approximately 440 to 460 feet above mean sea level (MSL).

The project will consist of constructing ADA improvements at the Park. Specifically, the project

will include constructing new ADA compliant sidewalks, ramps, and play areas. Additionally, a

new picnic shelter will be constructed on the east side of the tot-lot/play area. An approximately

4-foot tall retaining wall will be constructed within the landscape area between Skyline Drive and

the recreation center building to provide an ADA-compliant sidewalk/ramp. A portion of the

sidewalk/flatwork area along the south side of the existing parking lot will be designed and

constructed to support occasional maintenance vehicles.

4 SUBSURFACE EVALUATION AND LABORATORY TESTING

Our subsurface exploration was conducted on June 8, 2017. The subsurface exploration

consisted of excavating, logging, and sampling two small-diameter exploratory borings (IT-1 and

IT-2) to depths of up to approximately 6 feet below the existing ground surface. The two borings

were converted into infiltration tests after sampling and logging. The approximate locations of

the exploratory borings are shown on Figure 2. The purpose of the exploratory borings was to

observe the subsurface materials and to collect bulk and in-place soil samples for laboratory

testing. Representative samples were transported to our in-house geotechnical laboratory for

testing. Logs of the exploratory borings are presented in Appendix A.

4.1 Geotechnical Laboratory Testing

Geotechnical laboratory testing was performed on representative soil samples to evaluate the

in-situ moisture content, shear strength, and corrosivity. The results of the moisture content tests

are presented on the boring logs in Appendix A. The results of the other laboratory tests are

presented in Appendix B.

4.2 Field Infiltration Testing

Field infiltration testing was performed on June 8 and 9, 2017 in general accordance with the

City of San Diego BMP Design Manual (2016). As noted in Section 4, the borings were

excavated, logged, and sampled on June 8, 2017. Following excavation and sampling, the

borings were converted into infiltration tests by placing approximately 2 inches of gravel on the


bottom of each boring, installing a 2 inch diameter, perforated PVC pipe in the hole, and

backfilling the annulus with pea gravel. As part of the test procedure, presoaking of each hole

was performed to represent adverse conditions for infiltration. The presoak, which was

performed on June 8, 2017, consisted of maintaining approximately 1 to 2 feet of water in each

boring for approximately 4 hours. The water level was then allowed to drop overnight. On

June 9, 2017 testing proceeded by filling each infiltration test with approximately 1 to 2 feet of

water and measuring the water depth in approximately 30 minute intervals for the duration of the

test. During testing, the borings were refilled after the 30-minute readings, as needed, to

maintain the water level. Infiltration rates were then calculated using the Porchet method.

Measurements and calculations are included in Appendix C.

Table 1 – Infiltration Test Results Summary

Infiltration Test Depth of Test

(feet) Description

Adjusted Infiltration Rate (in/hr)

IT-1 6.0 Clayey SILTSTONE

(Formation) 0.02

IT-2 5.0 Sandy SILTSTONE

(Formation) 0.04

Note: in/hr = inches per hour

Based on the City of San Diego BMP Design Manual (2016), infiltration rates of less than

0.5 inches per hour may be suitable for partial infiltration and infiltration rates of 0.5 inches per

hour or greater per hour may be considered suitable for full infiltration design. The infiltration

rates presented above are based on in-situ testing (i.e., factor of safety of 1.0). The design

engineer should evaluate and apply an appropriate factor of safety when designing the

improvements. The City of San Diego BMP Design Manual (2016) provides additional

discussion and considerations for applying an infiltration factor of safety. Recommendations for

placement, design, and construction of permanent stormwater BMPs (if proposed) are

presented in Section 8.10 of this report.

5 GEOLOGIC AND SUBSURFACE CONDITIONS

Our findings regarding regional and site geology, including groundwater conditions, flood

hazards, faulting and seismicity, and landslides at the subject site are provided in the following

sections. Figures 3 and 4 are regional geology and fault location maps, respectively.


5.1 Regional Geologic Setting

The project area is situated in the coastal foothill section of the Peninsular Ranges Geomorphic

Province. This geomorphic province encompasses an area that extends approximately 900

miles from the Transverse Ranges and the Los Angeles Basin south to the southern tip of Baja

California (Norris and Webb, 1990; Harden, 1998). The province varies in width from

approximately 30 to 100 miles. In general, the province consists of rugged mountains underlain

by Jurassic metavolcanic and metasedimentary rocks, and Cretaceous igneous rocks of the

southern California batholith.

The Peninsular Ranges Province is traversed by a group of sub-parallel faults and fault zones

trending roughly northwest. Several of these faults are considered to be active. The Elsinore,

San Jacinto and San Andreas faults are active fault systems located northeast of the project

area and the Rose Canyon, Coronado Bank, San Diego Trough, and San Clemente faults are

active faults located west of the project area. The location of the site relative to these regional

faults is shown on Figure 4. The Rose Canyon Fault Zone, the nearest active fault system, has

been mapped approximately 8 miles west of the project site. Segments of the La Nacion fault

have been mapped approximately 1½ miles west of the site (see Figure 5). However, the La

Nacion Fault is not considered an active fault by the State of California. Major tectonic activity

associated with these and other faults within this regional tectonic framework consists primarily

of right-lateral, strike-slip movement

5.2 Site Geology

The site is mapped as being underlain by very old paralic deposits (Kennedy and Tan, 2008;

Figure 3). Geologic units encountered during our subsurface exploration included surficial fill

underlain by very old paralic deposits. Generalized descriptions of the earth units encountered

during our subsurface exploration and mapped at the site are provided in the subsequent sections.

Additional descriptions of the subsurface units are provided on the boring logs in Appendix A.

5.2.1 Fill

Surficial fill material was encountered in our borings to depths of approximately 6 inches. As

encountered, the fill soils generally consisted of brown and dark brown, dry to moist, medium

dense, silty sand. Scattered gravel and roots were encountered within the fill materials.

5.2.2 Very Old Paralic Deposits

Very old paralic deposits were encountered in our borings beneath the fill materials to the

depths explored. As encountered, the very old paralic deposits consisted of gray to brown


and yellowish brown, moist, weakly to moderately cemented, fine-grained silty sandstone

and moderately indurated, sandy and clayey siltstone. Gravel and cobbles up to

approximately 6 inches in diameter were encountered within the very old paralic deposits.

5.3 Groundwater

Groundwater was not encountered in our exploratory excavations at the site. Based on review

of monitoring well data in the site vicinity using the Geotracker website (2017), groundwater is

anticipated at depths greater than 30 feet. However, perched water may be encountered at

shallower depths. Fluctuations in the level of groundwater may occur due to variations in ground

surface topography, subsurface stratification, rainfall, irrigation practices, groundwater pumping,

and other factors which may not have been evident at the time of our field evaluation.

5.4 Landslides

Based on our background review and subsurface exploration, no landslides or related features

underlie the project site. The site is in an area mapped as being marginally susceptible to

landsliding (Tan, 1995). The potential for significant large-scale slope instability at the site is not

a design consideration.

5.5 Flood Hazards

Based on our review of Federal Emergency Management Agency (FEMA) Flood Insurance Rate

Maps (FIRM), the project site is located outside of the mapped 100-year flood zone. Therefore,

flooding is not a design consideration for the project.

5.6 Geologic Hazards

According to the City of San Diego Seismic Safety Study (2008), the project site lies within

Hazard Category 52 (Figure 5). Hazard Category 52 is defined as “other level areas, gently

sloping to steep terrain, favorable geologic structure, low risk.” Segments of the La Nacion fault

have been mapped approximately 1½ miles west of the site (see Figure 5). However, the La

Nacion Fault is not considered an active fault by the State of California.

6 FAULTING AND SEISMICITY

Based on our review of the referenced geologic maps and stereoscopic aerial photographs, as

well as on our geologic field mapping, the subject site is not underlain by known active or

potentially active faults (i.e., faults that exhibit evidence of ground displacement in the last


11,000 years and 2,000,000 years, respectively). However, like the majority of southern

California, the site is located in a seismically active area and the potential for strong ground

motion is considered significant during the design life of the proposed structures. As noted, the

nearest known fault is the La Nacion fault, segments of which have been mapped approximately

1½ miles west of the site. The nearest known active fault, the Rose Canyon fault is located

approximately 8 miles west of the site.

In general, hazards associated with faulting and seismic activity include strong ground motion, ground

surface rupture, and liquefaction. These considerations are discussed in the following sections.

6.1 Ground Motion

The 2016 California Building Code (CBC) specifies that the Risk-Targeted, Maximum

Considered Earthquake (MCER) ground motion response accelerations be used to evaluate

seismic loads for design of buildings and other structures. The MCER ground motion response

accelerations are based on the spectral response accelerations for 5 percent damping in the

direction of maximum horizontal response and incorporate a target risk for structural collapse

equivalent to 1 percent in 50 years with deterministic limits for near-source effects. The horizontal

peak ground acceleration (PGA) that corresponds to the MCER for the site was calculated 0.41g

using the United States Geological Survey (USGS, 2017) seismic design tool (web-based).

The 2016 CBC specifies that the potential for liquefaction and soil strength loss be evaluated,

where applicable, for the Maximum Considered Earthquake Geometric Mean (MCEG) peak

ground acceleration with adjustment for site class effects in accordance with the American Society

of Civil Engineers (ASCE) 7-10 Standard. The MCEG peak ground acceleration is based on the

geometric mean peak ground acceleration with a 2 percent probability of exceedance in 50 years.

The MCEG peak ground acceleration with adjustment for site class effects (PGAM) was calculated

as 0.40g using the USGS (2017) seismic design tool that yielded a mapped MCEG peak ground

acceleration of 0.35g for the site and a site coefficient (FPGA) of 1.151 for Site Class D.

6.2 Surface Ground Rupture

As noted, the nearest known fault is the La Nacion Fault, which has been mapped approximately 1½

miles west of the site. The nearest known active fault, the Rose Canyon fault is located

approximately 8 miles west of the site. Since the La Nacion Fault is not considered active, the

potential for ground rupture due to faulting at the site is considered low.


6.3 Liquefaction and Seismically Induced Settlement

Liquefaction of cohesionless soils can be caused by strong vibratory motion due to earthquakes.

Research and historical data indicate that loose granular soils and non-plastic silts that are

saturated by a relatively shallow ground water table are susceptible to liquefaction. Based on

the relatively dense nature of the very old paralic deposits and the absence of a shallow

groundwater table, liquefaction and seismically induced settlement are not design

considerations.

7 CONCLUSIONS

Based on our background review, subsurface and geotechnical laboratory evaluation, it is our

opinion that construction of the proposed improvements is feasible from a geotechnical stand-

point provided that the recommendations presented in this report are incorporated into the

design and construction. In general, the following conclusions were made:

The site is underlain by surficial fill soils in turn underlain by very old paralic deposits. The very old paralic deposits contained gravel and cobbles up to approximately 6 inches in diameter. The on-site materials are generally considered suitable for reuse provided that they are processed in accordance with the recommendations herein. Processing of the on-site materials may include removal of oversize materials and moisture conditioning.

Excavations are generally considered feasible with heavy-duty earthmoving equipment in good working order. However, very difficult drilling and/or excavating should be anticipated within the very old paralic deposits due to the scattered cobbles and potential for strongly cemented zones. The contractor should be prepared for these conditions.

Groundwater was not encountered during our subsurface exploration. However, seepage and/or perched conditions should be anticipated. Additionally, the depth to groundwater varies due to seasonal precipitation, subsurface conditions, irrigation, groundwater pumping, and other factors.

The site is not located within a State of California Earthquake Fault Zone (formerly Alquist-Priolo Special Studies Zone). Based on our review of published geologic maps and aerial photographs, no known active or potentially active faults underlie the site. The potential for surface fault rupture at the site is considered to be low.

Field infiltration testing indicated infiltration rates of 0.02 and 0.04 inches per hour based on a factor of safety of 1.0. However, an appropriate factor of safety should be applied to the measured infiltration rates during design. The design infiltration rates, which include an appropriate factor of safety, are anticipated to be near 0.01 inches per hour or less. Accordingly, infiltration at the site is not considered feasible. Recommendations for placement, design, and construction of permanent stormwater BMPs (if proposed) are presented herein.

Based on laboratory corrosion testing, the on-site soils are classified as corrosive in accordance with Caltrans (2015) guidelines and ACI 318. A corrosion engineer should be consulted during design to provide appropriate recommendations.


8 RECOMMENDATIONS

The geotechnical recommendations relative to the design and construction of the proposed

improvements are presented in the following paragraphs.

8.1 Earthwork

Earthwork at the site is anticipated to consist of minor grading. Earthwork should be performed

in accordance with the requirements of applicable governing agencies, and the

recommendations presented in the following sections.

8.1.1 Pre-Construction Conference

We recommend that a pre-construction conference be held. The owner and/or their

representative, the governing agencies’ representatives, the civil engineer, Ninyo & Moore,

and the contractor should be in attendance to discuss the work plan and project schedule

and earthwork requirements.

8.1.2 Site Preparation

Prior to performing site excavations, the surface areas should be cleared of existing

improvements, vegetation, surface obstructions, and other deleterious materials.

Construction materials, vegetation, and debris from the clearing operations should be

disposed of off-site. Obstructions that extend below the finished grade, if any, should be

removed and the resulting holes filled with compacted fill.

8.1.3 Excavation Characteristics

Based on our borings, the on-site earth materials should be generally excavatable with

heavy-duty earthmoving equipment in good working condition. However, the presence of

cobbles and/or potential cemented zones will result in the need for additional effort during

excavation.

8.1.4 Fill Material

In general, the existing on-site materials are considered suitable for reuse as fill, provided

that the oversize materials (i.e., materials with dimensions in excess of those outlined

herein) are removed from the soil mass prior to reuse. Fill material should be free of trash,

debris or other deleterious materials. Material for use as fill should not contain rocks or

lumps greater than approximately 4 inches in size.


Utility trench backfill material should not contain rocks or lumps over approximately 3 inches

in general. Soils classified as silts or clays should not be used for backfill in the pipe zone.

Larger chunks, if generated during excavation, may be broken into acceptably sized pieces

or disposed of offsite.

Imported fill material, if used, should generally be granular soils with a very low expansion

potential (i.e., an expansion index [EI] of 20 or less evaluated in accordance ASTM D 4829.

Import material should also be non-corrosive in accordance with the Caltrans (2015) corrosion

guidelines. Ninyo & Moore should evaluate materials for use as fill prior to filling or importing.

8.1.5 Fill Placement and Compaction

Prior to placement of compacted fill the contractor should request an evaluation of the

exposed ground surface by Ninyo & Moore. Unless otherwise recommended, the exposed

ground surface should then be scarified to a depth of approximately 8 inches and watered

or dried, as needed, to achieve generally consistent moisture contents above the laboratory

optimum. The scarified materials should then be compacted to 90 percent relative

compaction in accordance with ASTM D 1557. The evaluation of compaction by the

geotechnical consultant should not be considered to preclude any requirements for

observation or approval by governing agencies. It is the contractor's responsibility to notify

the geotechnical consultant and the appropriate governing agency when project areas are

ready for observation, and to provide reasonable time for that review.

Fill materials conforming to our recommendations for Materials for Fill, should be moisture

conditioned to generally above the laboratory optimum moisture content prior to placement.

The optimum moisture content will vary with material type and other factors. Moisture

conditioning of fill soils should be generally consistent within the soil mass.

Prior to placement of additional compacted fill material following a delay in the grading

operations, the exposed surface of previously compacted fill should be prepared to receive

fill. Preparation may include scarification, moisture conditioning, and recompaction.

Compacted fill should be placed in horizontal lifts of approximately 8 inches in loose

thickness. Prior to compaction, each lift should be watered or dried as needed to achieve

generally above optimum moisture content, mixed, and then compacted by mechanical

methods to a relative compaction of 90 percent as evaluated by ASTM D 1557. The upper 12

inches of subgrade for flatwork/sidewalks that will be subject to vehicle loading should be


compacted by mechanical methods to 95 percent as evaluated by ASTM D 1557. Successive

lifts should be treated in a like manner until the desired finished grades are achieved.

8.2 Seismic Design Considerations

Design of the proposed improvements should be performed in accordance with the

requirements of governing jurisdictions and applicable building codes. Table 2 presents the

seismic design parameters for the site in accordance with the CBC (2016) guidelines and

adjusted MCER spectral response acceleration parameters (USGS, 2017).

Table 2 – 2016 California Building Code Seismic Design Criteria

Seismic Design Factors Value

Site Class D

Site Coefficient, Fa 1.146

Site Coefficient, Fv 1.720

Mapped Spectral Acceleration at 0.2-second Period, Ss 0.885g

Mapped Spectral Acceleration at 1.0-second Period, S1 0.340g

Spectral Acceleration at 0.2-second Period Adjusted for Site Class, SMS 1.014g

Spectral Acceleration at 1.0-second Period Adjusted for Site Class, SM1 0.585g

Design Spectral Response Acceleration at 0.2-second Period, SDS 0.676g

Design Spectral Response Acceleration at 1.0-second Period, SD1 0.390g

8.3 Shallow Foundations

Based on our understanding of the project, the proposed retaining wall and other ancillary

structures will be supported on shallow continuous and/or spread foundations. The following

sections provide parameters for the design of shallow foundations bearing on formational

materials.

8.3.1 Bearing Capacity of Shallow Foundations

Shallow, spread or continuous footings bearing on formational material (very old paralic

deposits) may be designed using a net allowable bearing capacity of 2,500 pounds per

square foot (psf). This allowable bearing capacity may be increased by one-third when

considering loads of short duration such as wind or seismic forces. Shallow, spread or

continuous footings should be founded 15 inches or more below the lowest adjacent grade

and should have a width of 18 inches or more. The shallow, spread or continuous footings

should be reinforced in accordance with the recommendations of the project structural

engineer.


8.3.2 Lateral Resistance of Shallow Foundations

For resistance of footings to lateral loads, we recommend a passive pressure of 300 psf

per foot of depth be used with a value of up to 3,000 psf. This value assumes that the

ground is horizontal for a distance of 10 feet, or three times the height generating the

passive pressure, whichever is greater. We recommend that the upper 1 foot of soil not

protected by pavement or a concrete slab be neglected when calculating passive

resistance.

For frictional resistance to lateral loads, we recommend a coefficient of friction of 0.35 be

used between soil and concrete. The allowable lateral resistance can be taken as the

sum of the frictional resistance and passive resistance provided the passive resistance

does not exceed one-half of the total allowable resistance.

8.3.3 Static Settlement

We estimate that the proposed structures, designed and constructed with shallow

foundations bearing on formational materials as recommended herein, will undergo total

settlement on the order of 1 inch. Differential settlement on the order of ½ inch over a

horizontal span of 40 feet should be expected.

8.4 Shade Structure Foundations

Shade structure foundations should be supported on cast-in-drilled-hole piles. Shade structure

foundations typically impose relatively light axial loads on foundations. Although we anticipate

that pile dimensions will be generally controlled by the lateral load demand, we recommend that

drilled shade structure foundations have a diameter of 18 inches or more and be embedded 4

feet or more into the very old paralic deposits. The pile dimensions (i.e., diameter and

embedment) should be evaluated by the project structural engineer.

For axial, compressional loading, we recommend that the shade structure foundations be de-

signed for an allowable soil bearing value of 2,500 psf. This value can be increased by one-third

for loads of short duration, including wind and seismic loading. For resistance to uplift loads

(related to short-term transient loading such as wind and seismic forces), an allowable side

frictional resistance value of 100 psf can be assumed along the perimeter of piles that are

installed 4 feet or more into the very old paralic deposits.

For resistance of shade structure foundations to lateral loads that are founded in very old paralic

deposits, we recommend an allowable passive pressure of 300 psf per foot of depth be used

with a value of up to 3,000 psf. This value assumes that the ground is horizontal for a distance


of 10 feet, or three times the height generating the passive pressure, whichever is greater. We

recommend that the upper 1 foot of soil not protected by pavement or a concrete slab be

neglected when calculating passive resistance.

For frictional resistance to lateral loads, we recommend a coefficient of friction of 0.35 be used

between soil and concrete. The allowable lateral resistance can be taken as the sum of the

frictional resistance and passive resistance provided the passive resistance does not exceed

one half of the total allowable resistance.

The drilled pile construction should be observed by Ninyo & Moore during construction to

evaluate if the piles have been extended to the design depths. The drilled holes should be

cleaned of loose soil and gravel. It is the contractor's responsibility to (a) take appropriate

measures for maintaining the integrity of the drilled holes, (b) see that the holes are cleaned and

straight, and (c) see that sloughed loose soil is removed from the bottom of the hole prior to the

placement of concrete. Drilled piles should be checked for alignment and plumbness during

installation. The amount of acceptable misalignment of a pile is approximately 3 inches from the

plan location. It is usually acceptable for a pile to be out of plumb by 1 percent of the depth of

the pile. The center-to-center spacing of piles should be no less than three times the nominal

diameter of the pile.

8.5 Retaining Walls

The proposed retaining wall may be supported on a continuous footing bearing on very old

paralic deposits in accordance with Section 8.3 of this report. For the design of a site yielding

retaining wall that is not restrained against movement by rigid corners or structural connections,

lateral pressures are presented on Figure 6. These pressures assume select backfill materials

are used and free draining conditions. Measures should be taken to reduce the potential for

build-up of moisture behind the retaining walls. A drain should be provided behind the retaining

wall as shown on Figure 7. The drain should be connected to an appropriate outlet.

8.6 Concrete Flatwork

Conventional concrete flatwork should be 4 inches in thickness and should be reinforced with

No. 3 reinforcing bars placed at 18 inches on-center both ways. To reduce the potential

manifestation of distress to exterior concrete flatwork due to minor soil movement and concrete

shrinkage, we recommend that such flatwork be installed with crack-control joints at appropriate

spacing as designed by the structural engineer.


Concrete flatwork that will be subjected to vehicular loads should be 5½ inches in thickness and

should be reinforced with No. 4 reinforcing bars placed at 18 inches on-center both ways. To

reduce the potential manifestation of distress to exterior concrete flatwork due to minor soil

movement and concrete shrinkage, we recommend that such flatwork be installed with crack-

control joints at appropriate spacing as designed by the structural engineer.

8.7 Corrosivity

Laboratory testing was performed on a representative sample of the on-site earth materials to

evaluate pH and electrical resistivity, as well as chloride and sulfate contents. The pH and

electrical resistivity tests were performed in accordance with California Test (CT) 643 and the

sulfate and chloride content tests were performed in accordance with CT 417 and CT 422,

respectively. These laboratory test results are presented in Appendix B.

The results of the corrosivity testing indicated an electrical resistivity of 660 ohm-cm, a soil pH of

6.8, a chloride content of 315 parts per million (ppm) and a sulfate content of 0.246 percent (i.e.,

2,460 ppm). Based on the Caltrans corrosion (2015) criteria and ACI 318, the on-site soils would

be classified as corrosive. Corrosive soils are defined as the soils with electrical resistivities less

than 1,000 ohm-cm, more than 500 ppm chlorides, more than 0.2 percent sulfates, or a pH less

than 5.5. A corrosion engineer should be consulted with during design and construction to

provide recommendations.

8.8 Concrete Placement

Concrete in contact with soil or water that contains high concentrations of water-soluble sulfates

can be subject to premature chemical and/or physical deterioration. As stated above, the soil

sample tested in this evaluation indicated a water-soluble sulfate content of 0.246 percent by

weight (i.e., about 2,460 ppm). According to the American Concrete Institute (ACI) 318, the

potential for sulfate attack is severe for water-soluble sulfate contents ranging between 0.20 and

2.0 percent weight (i.e., between 2,000 and 20,000 ppm) in soils. Accordingly, we recommend that

Type V cement be used for concrete in contact with soil, that the water to cement ratio not exceed

0.45, and that the minimum 28-day compressive strength be 4,500 pounds per square inch (psi).

8.9 Drainage

Proper surface drainage is imperative for satisfactory site performance. Positive drainage

should be provided and maintained to direct surface water away from the new sidewalk and

retaining wall improvements. Positive drainage is defined as a slope of 2 percent or more over a

distance of 5 feet away from the foundations and tops of slopes. Runoff should then be directed


by the use of swales or pipes into a collective drainage system. Surface waters should not be

allowed to pond adjacent to footings or pavements.

8.10 Permanent Stormwater BMPs

As described earlier, results of in-situ testing of the underlying materials indicate infiltration rates

of 0.02 and 0.04 inches per hour. These rates are based on a factor of safety of 1.0. An

appropriate factor of safety should be applied for design purposes. Design infiltration rates,

which include an appropriate factor of safety, are anticipated to be on the order of 0.01 inches

per hour or less. Due to the anticipated low design infiltration rates measured at the site and the

relatively dense nature of the very old paralic deposits, infiltration will result in lateral migration

of subsurface water and potential stormwater ponding. Accordingly, infiltration is not considered

feasible at the site. We recommend permanent stormwater BMPs, if proposed, be designed and

constructed to mitigate the potential ponding of stormwater. Considerations may include

providing positive drainage and/or connecting to an existing outlet. Additional recommendations

and/or considerations should be provided by the project civil engineer.

9 PLAN REVIEW AND CONSTRUCTION OBSERVATION

The conclusions and recommendations presented in this report are based on analysis of

observed conditions in widely spaced exploratory excavations. If conditions are found to vary

from those described in this report, Ninyo & Moore should be notified, and additional

recommendations will be provided upon request. Ninyo & Moore should review the final project

drawings and specifications prior to the commencement of construction. Ninyo & Moore should

perform the needed observation and testing services during construction operations.

The recommendations provided in this report are based on the assumption that Ninyo & Moore

will provide geotechnical observation and testing services during construction. In the event that

it is decided not to utilize the services of Ninyo & Moore during construction, we request that the

selected consultant provide the client with a letter (with a copy to Ninyo & Moore) indicating that

they fully understand Ninyo & Moore’s recommendations, and that they are in full agreement

with the design parameters and recommendations contained in this report. Construction of

proposed improvements should be performed by qualified subcontractors utilizing appropriate

techniques and construction materials


10 LIMITATIONS

The field evaluation, laboratory testing, and geotechnical analyses presented in this

geotechnical report have been conducted in general accordance with current practice and the

standard of care exercised by geotechnical consultants performing similar tasks in the project

area. No warranty, expressed or implied, is made regarding the conclusions, recommendations,

and opinions presented in this report. There is no evaluation detailed enough to reveal every

subsurface condition. Variations may exist and conditions not observed or described in this

report may be encountered during construction. Uncertainties relative to subsurface conditions

can be reduced through additional subsurface exploration. Additional subsurface evaluation will

be performed upon request.

This document is intended to be used only in its entirety. No portion of the document, by itself, is

designed to completely represent any aspect of the project described herein. Ninyo & Moore

should be contacted if the reader requires additional information or has questions regarding the

content, interpretations presented, or completeness of this document.

This report is intended for design purposes only. It does not provide sufficient data to prepare an

accurate bid by contractors. It is suggested that the bidders and their geotechnical consultant

perform an independent evaluation of the subsurface conditions in the project areas. The

independent evaluations may include, but not be limited to, review of other geotechnical reports

prepared for the adjacent areas, site reconnaissance, and additional exploration and laboratory

testing.

Our conclusions, recommendations, and opinions are based on an analysis of the observed site

conditions. If geotechnical conditions different from those described in this report are

encountered, our office should be notified, and additional recommendations, if warranted, will be

provided upon request. It should be understood that the conditions of a site could change with

time as a result of natural processes or the activities of man at the subject site or nearby sites.

In addition, changes to the applicable laws, regulations, codes, and standards of practice may

occur due to government action or the broadening of knowledge. The findings of this report may,

therefore, be invalidated over time, in part or in whole, by changes over which Ninyo & Moore

has no control.

This report is intended exclusively for use by the client. Any use or reuse of the findings,

conclusions, and/or recommendations of this report by parties other than the client is

undertaken at said parties’ sole risk.


11 REFERENCES

American Concrete Institute (ACI), 2014, ACI 318 Building Code Requirements for Structural Concrete and Commentary.

Building News, 2015, “Greenbook,” Standard Specifications for Public Works Construction: BNI Publications.

California Building Standards Commission, 2016, California Building Code, Title 24, Part 2, Volumes 1 and 2: dated July 1.

California Department of Transportation (Caltrans), 2015, Corrosion Guidelines (Version 2.1), Division of Engineering Services, Materials Engineering and Testing Services, Corrosion and Structural Concrete Field Investigation Branch: dated January.

California Geological Survey (CGS), 1998, Maps of Known Active Fault Near-Source Zones in California and Adjacent Portions of Nevada: dated February.

City of San Diego, 1958, Metropolitan Topographic Survey (Orthotopo), Sheet 194-1761, Scale 1:2,400, revised 1970.

City of San Diego, 1986, Topographic Survey (Orthotopo), Sheet 194-1761, Scale 1:2,400.

City of San Diego, 2008, Seismic Safety Study, Geologic Hazards and Faults, Grid 19, Scale 1: 9,600.

City of San Diego, 2015, The “Whitebook”, Standard Specifications for Public Works Construction.

City of San Diego, Public Works Department, 2016, Standard Drawings for Public Works Construction.

City of San Diego BMP Design Manual, 2016, Storm Water Requirements for Development Applications: dated: January.

Geotracker, 2017, State Water Resources Control Board, https://geotracker.waterboards.ca.gov/: accessed June.

Google Earth, 2017, http://earth.google.com: accessed June.

Harden, D.R., 2004, California Geology – 2nd ed.: Prentice Hall, Inc.

Hart, E.W., and Bryant, W.A., 1997, Fault Rupture Hazard Zones in California, Alquist-Priolo Earthquake Fault Zoning Act with Index to Earthquake Fault Zone Maps: California Geological Survey, Special Publication 42, with Supplements 1 and 2 added in 1999.

Historic Aerials, 2017, Aerial Photographs, www.hisotricaerials.com: accessed in June.

Jennings, C.W., 2010, Fault Activity Map of California: California Geological Survey, California Geologic Data Map Series, Map No. 6, Scale 1: 750,000.

Kennedy, M.P., and Tan, S.S., 2008, Geologic Map of the San Diego 30’ x 60’ Quadrangle, California, California Geologic Survey, Regional Geologic Map No. 3, Scale 1:100,000.

Ninyo & Moore, In-House Proprietary Information.

Norris, R. M. and Webb, R. W., 1990, Geology of California, Second Edition: John Wiley & Sons, Inc.

Tan, S.S., 1995, Landslide Hazards in the Southern Part of the San Diego Metropolitan Area, San Diego County, California, Landslide Hazard Identification Map No. 33, DMG Open-File Report 95-03.

Treiman, J.A., 1993, The Rose Canyon Fault Zone, Southern California: California Geological Survey, Open File Report 93-02.


United States Department of the Interior, Bureau of Reclamation, 1989, Engineering Geology Field Manual.

United States Federal Emergency Management Agency (FEMA), 2012, Flood Insurance Rate Map (FIRM), Map Number 06073C1910G: effective date May 16.

United States Geological Survey (USGS), 2015, National City, California Quadrangle Map, 7.5 Minute Series: Scale 1:24,000.

United States Geological Survey (USGS), 2008, 2008 National Seismic Hazard Maps – Fault Parameters Database, World Wide Web, https://earthquake.usgs.gov/cfusion/ hazfaults_2008_search/query_main.cfm.

United States Geological Survey (USGS), 2017, U.S. Seismic Design Maps World Wide Web, http://earthquake.usgs.gov/designmaps/us/application.php: accessed June.

USDA, Aerial Photograph, Date 4-14-53, Flight AXN-10M, Number 114 and 115, Scale 1:20,000.

Ninyo & Moore | 8285 Skyline Drive, San Diego, California | 108232002 R | June 29, 2017

Appendix A

Photographic Documentation

FIGURES

Aä

SITE"

1_10

8232

002_

SL.m

xd 6

/29/20

17 J

DL

NOTE: DIRECTIONS, DIMENSIONS AND LOCATIONS ARE APPROXIMATE. | SOURCE: ESRI WORLD TOPO, 2017

SITE LOCATIONSKYLINE HILLS COMMUNITY PARK

8285 SKYLINE DRIVE, SAN DIEGO, CALIFORNIA108232002 | 6/17

FIGURE 1

!o 0 1,500 3,000

FEET

§̈¦15

§̈¦5

§̈¦8§̈¦805

MAP INDEX

San Dieg oCoun ty

@?&

@?&

IT-1TD=6

IT-2TD=5

SKYLINE DRIVE

!o

2_10

8232

002_

BL.m

xd 6

/29/20

17 J

DL

NOTE: DIRECTIONS, DIMENSIONS AND LOCATIONS ARE APPROXIMATE. | SOURCE: ESRI WORLD TOPO, 2017

BORING/INFILTRATION TEST LOCATIONSSKYLINE HILLS COMMUNITY PARK


FIGURE 2

0 60 120

FEET

BORING/INFILTRATION TESTTD=TOTAL DEPTH IN FEET@?&

IT-2TD=5

LEGEND

LIMITS OF WORK

LEGEND

Qvop

!o

3_10

8232

002_

G.mx

d 6/2

9/201

7 JD

L

NOTE: DIRECTIONS, DIMENSIONS AND LOCATIONS ARE APPROXIMATE. |SOURCE: KENNEDY, M.P., AND TAN, S.S., 2008, GEOLOGIC MAP OF THE SAN DIEGO 30' X 60' QUADRANGLE, CALIFORNIA

FIGURE 3

0 2,000 4,000

FEET

GEOLOGYSKYLINE HILLS COMMUNITY PARK


SITE"

M E X I C OU S A

P a c i f i c O c e a n

NEVADACALIFORN IA

!

SAN

J A C IN T O

E L S I N O R E

IMPE R I AL

W H I T T I E R

N EWPO RT - I NG L E WO OD

CORONADOBANK

SAN DIEGOTROUGH

SAN CLEMENTE

SANTA CRUZ-SANTA CATALINA RIDGEPALOS VERDES

OFFSHORE ZONE

OF DEFORMATION

GARLOCK

CLEARWATERSAN

GABRIEL

SIERRA MADRE

B A N N I N G

M I S S I O N C R E E KBLACKWATERHARPER

LOCKHART

LENWOOD

CAMP ROCKCALICO

LUDLOW

PISGAH

BULLION MOUNTAIN

JOHNSON VALLEY

EMERSON

PINTO MOUNTAIN

MANIX

MIRAGE VALLEY

NORTH

HELENDALE

FRONTAL

CHINO

SAN JOSECUCAMONGA

MALIBU COAST SANTA MONICA

SANCAYETANO

SANTASUSANASANTA

ROSA

NORTHRIDGE

CHARNOCK

SAWPITCANYON

SUPERSTITION HILLS

RO SECANY ON

PINE MOUNTAIN

WHITE WOLF

SAN ANDREAS FAULT ZONE

PLEITOWHEELER

POSO CREEK

BLUE CUT

SALTON CREEK

SAN ANDREAS FAULT ZONECOYOTE CREEK

CLARK

G L E NI V Y

E A RT H Q U A K EVA LL E Y

ELMO

RERA

NCH

LA GUNASA LADA

BRAWLEY SEISMIC

ZONE

San Bernardino County

Kern County

Riverside County

San Diego County

Imperial County

Los Angeles County

Inyo County

Tulare County

Ventura County

Orange County

CAL I F ORN IA

LEGEND

HOLOCENE ACTIVE

CALIFORNIA FAULT ACTIVITY HISTORICALLY ACTIVE

LATE QUATERNARY (POTENTIALLY ACTIVE)

STATE/COUNTY BOUNDARY

QUATERNARY (POTENTIALLY ACTIVE)

SITE

"

!o

4_10

8232

002_

FL.m

xd 6

/15/20

17 J

DL

NOTE: DIRECTIONS, DIMENSIONS AND LOCATIONS ARE APPROXIMATE. |SOURCE: U.S. GEOLOGICAL SURVEY AND CALIFORNIA GEOLOGICAL SURVEY, 2013, QUATERNARY FAULT AND FOLD DATABASE FOR THE UNITED STATES.

FIGURE 4FAULT LOCATIONS

SKYLINE HILLS COMMUNITY PARK8285 SKYLINE DRIVE, SAN DIEGO, CALIFORNIA

108232002 | 6/17

0 30 60

MILES

JAMACHA RD

IMPERIAL

AV

WOODROW AV

S WORTHINGTON ST

MASSACHUSETTS AV

HELIX

ST

BLOSSOM LN

S MEADOWBROOK DR

SWEETWATER RD

CANTON DR

SKYLINE DR

LISBON ST

69TH ST

MEADOWBROOK DR

CARLSBAD ST

JAMACHA BL

BRIARWOOD RD

ALSACIA ST

SAN VICENTE ST

WORT

HING

TON

ST

S WOODMAN ST

SR-54

WB

LEMON GROVE

AV

PARADISE VALLEY RD

CARDIFF ST

SR-54 EB

SR-125 SBSR-125 NB

POTO

MAC

ST

27

53

52

52 27

52

2753

27

22

52

53

LEGEND

12 POTENTIALLY ACTIVE, INACTIVE, PRESUMED INACTIVE, OR ACTIVITY UNKNOWN

!

! !

!

!

FAULTINFERRED FAULTCONCEALED FAULT11 ACTIVE, ALQUIST PRIOLO EARTHQUAKE FAULT ZONE

52 OTHER LEVEL AREAS, GENTLY SLOPING TO STEEP TERRAIN, FAVORABLE GEOLOGIC STRUCTURE, LOW RISK53 LEVEL OR SLOPING TERRAIN, UNFAVORABLE GEOLOGIC STRUCTURE, LOW TO MODERATE RISK

OTHER TERRAIN

52

53

SLIDE-PRONE FORMATIONS27 OTAY, SWEETWATER, AND OTHERS27

AREA NOT MAPPED

Aä

SITE"

!o

5_10

8232

002_

GH.m

xd 6

/29/20

17 J

DL

NOTE: DIRECTIONS, DIMENSIONS AND LOCATIONS ARE APPROXIMATE. |SOURCE: SANGIS, 2008, CITY OF SAN DIEGO SEISMIC SAFETY STUDY GEOLOGIC HAZARDS AND FAULTS.

GEOLOGIC HAZARDSSKYLINE HILLS COMMUNITY PARK


FIGURE 5

0 2,000 4,000

FEET

?pE

22 POSSIBLE OR CONJECTURED22LANDSLIDES

aPpP

D

PASSIVEPRESSURE

ACTIVEPRESSURE

H/3RESULTANT

D/3

NOTES:

ASSUMES NO HYDROSTATIC PRESSURE BUILD-UP BEHIND THE RETAINING WALL

1.

2.

BEHIND THE RETAINING WALLWALL DRAINAGE DETAIL SHOULD BE INSTALLEDDRAINS AS RECOMMENDED IN THE RETAINING3.

5.

RECOMMENDED GEOTECHNICAL DESIGN PARAMETERS

Equivalent Fluid Pressure (lb/ft /ft)LateralEarth

Pressure

Level Backfillwith Granular Soils

2 (1)

(2) with Granular Soils2H:1V Sloping Backfill

(2)

aP

pP300 D 115 D

40 H 64 H

Level Ground 2H:1V Descending Ground

H AND D ARE IN FEET (H IS LESS THAN 12 FEET)

6. SETBACK SHOULD BE IN ACCORDANCE WITHTHE CBC

HRESULTANT

RETAININGWALL

4. SURCHARGE PRESSURES CAUSED BY VEHICLESOR NEARBY STRUCTURES ARE NOT INCLUDED

SKYLINE HILLS COMMUNITY PARK

8285 SKYLINE DRIVE, SAN DIEGO, CALIFORNIA

LATERAL EARTH PRESSURES FOR YIELDING RETAINING WALLS

108232002 I 6/17

FIGURE 6

6 10

82

32

00

2 D

-Y

RW

.D

WG

STRUCTURAL, GRANULAR BACKFILL MATERIALSSHOULD BE USED FOR RETAINING WALL BACKFILL

SOIL BACKFILL COMPACTED TO 90%RELATIVE COMPACTION *

OUTLET

4-INCH-DIAMETER PERFORATED SCHEDULE 40 PVC PIPE OR EQUIVALENT INSTALLED WITH PERFORATIONS DOWN;1% GRADIENT OR MORE TO A SUITABLE

3/4-INCH OPEN-GRADED GRAVEL WRAPPEDIN AN APPROVED GEOFABRIC.

3 INCHES

WALL FOOTING

FINISHED GRADE

RETAINING WALL

12 INCHES

12 INCHES

VA

RIE

SGEOFABRIC

*BASED ON ASTM D1557

RETAINING WALL DRAINAGE DETAIL

FIGURE 7

7 10

82

32

00

2 D

-R

W.D

WG

SKYLINE HILLS COMMUNITY PARK

8285 SKYLINE DRIVE, SAN DIEGO, CALIFORNIA

108232002 I 6/17


APPENDIX A

Boring Logs


APPENDIX A

BORING LOGS

Field Procedure for the Collection of Disturbed Samples Disturbed soil samples were obtained in the field using the following method.

Bulk Samples Bulk samples of representative earth materials were obtained from the exploratory borings. The samples were bagged and transported to the laboratory for testing.

Field Procedure for the Collection of Relatively Undisturbed Samples Relatively undisturbed soil samples were obtained in the field using the following method.

The Split Barrel Knocker Bar Sampler The sampler, with an external diameter of 3.0 inches, was lined with 1 inch long, thin brass rings with inside diameters of approximately 2.4 inches. The sampler was manually driven into the ground with a hammer weighing approximately 35 pounds. The samples were removed from the sample barrel in the brass rings, sealed, and transported to the laboratory for testing.

Soil Classification Chart Per ASTM D 2488

Primary DivisionsSecondary Divisions

Group Symbol Group Name

COARSE- GRAINED

SOILS more than

50% retained on No. 200

sieve

GRAVEL more than

50% of coarse fraction

retained on No. 4 sieve

CLEAN GRAVELless than 5% fines

GW well-graded GRAVEL

GP poorly graded GRAVEL

GRAVEL with DUAL

CLASSIFICATIONS 5% to 12% fines

GW-GM well-graded GRAVEL with silt

GP-GM poorly graded GRAVEL with silt

GW-GC well-graded GRAVEL with clay

GP-GC poorly graded GRAVEL with

GRAVEL with FINES

more than 12% fines

GM silty GRAVEL

GC clayey GRAVEL

GC-GM silty, clayey GRAVEL

SAND 50% or more

of coarse fraction passes

No. 4 sieve

CLEAN SAND less than 5% fines

SW well-graded SAND

SP poorly graded SAND

SAND with DUAL

CLASSIFICATIONS 5% to 12% fines

SW-SM well-graded SAND with silt

SP-SM poorly graded SAND with silt

SW-SC well-graded SAND with clay

SP-SC poorly graded SAND with clay

SAND with FINES more than 12% fines

SM silty SAND

SC clayey SAND

SC-SM silty, clayey SAND

FINE- GRAINED

SOILS 50% or

more passes No. 200 sieve

SILT and CLAY

liquid limit less than 50%

INORGANIC

CL lean CLAY

ML SILT

CL-ML silty CLAY

ORGANICOL (PI > 4) organic CLAY

OL (PI < 4) organic SILT

SILT and CLAY

liquid limit 50% or more

INORGANICCH fat CLAY

MH elastic SILT

ORGANICOH (plots on or above “A”-line) organic CLAY

OH (plots below “A”-line) organic SILT

Highly Organic Soils PT Peat

USCS METHOD OF SOIL CLASSIFICATION

Apparent Density - Coarse-Grained Soil

Apparent Density

Spooling Cable or Cathead Automatic Trip Hammer

SPT (blows/foot)

Modified Split Barrel (blows/foot)

SPT (blows/foot)


Very Loose < 4 < 8 < 3 < 5

Loose 5 - 10 9 - 21 4 - 7 6 - 14

Medium Dense 11 - 30 22 - 63 8 - 20 15 - 42

Dense 31 - 50 64 - 105 21 - 33 43 - 70

Very Dense > 50 > 105 > 33 > 70

Consistency - Fine-Grained Soil

Consis-tency

Spooling Cable or Cathead Automatic Trip Hammer

SPT (blows/foot)


SPT (blows/foot)


Very Soft < 2 < 3 < 1 < 2

Soft 2 - 4 3 - 5 1 - 3 2 - 3

Firm 5 - 8 6 - 10 4 - 5 4 - 6

Stiff 9 - 15 11 - 20 6 - 10 7 - 13

Very Stiff 16 - 30 21 - 39 11 - 20 14 - 26

Hard > 30 > 39 > 20 > 26

LIQUID LIMIT (LL), %

PLA

STI

CIT

Y IN

DE

X (

PI)

, %

0 10

1074

20

30

40

50

60

70

020 30 40 50 60 70 80 90 100

MH or OH

ML or OLCL - ML

Plasticity Chart

Grain Size

Description Sieve Size Grain Size Approximate

Size

Boulders > 12” > 12” Larger than basketball-sized

Cobbles 3 - 12” 3 - 12” Fist-sized to basketball-sized

Gravel

Coarse 3/4 - 3” 3/4 - 3” Thumb-sized to fist-sized

Fine #4 - 3/4” 0.19 - 0.75” Pea-sized to thumb-sized

Sand

Coarse #10 - #4 0.079 - 0.19” Rock-salt-sized to pea-sized

Medium #40 - #10 0.017 - 0.079” Sugar-sized to rock-salt-sized

Fine #200 - #40 0.0029 - 0.017”

Flour-sized to sugar-sized

Fines Passing #200 < 0.0029” Flour-sized and

smaller

CH or OH

CL or OL

0

5

10

15

20

XX/XX

SM

CL

Bulk sample.

Modified split-barrel drive sampler.

No recovery with modified split-barrel drive sampler.

Sample retained by others.

Standard Penetration Test (SPT).

No recovery with a SPT.

Shelby tube sample. Distance pushed in inches/length of sample recovered in inches.

No recovery with Shelby tube sampler.

Continuous Push Sample.

Seepage.Groundwater encountered during drilling. Groundwater measured after drilling.

MAJOR MATERIAL TYPE (SOIL):Solid line denotes unit change.Dashed line denotes material change.

Attitudes: Strike/Dipb: Beddingc: Contactj: Jointf: FractureF: Faultcs: Clay Seams: Shearbss: Basal Slide Surfacesf: Shear Fracturesz: Shear Zonesbs: Shear Bedding Surface

The total depth line is a solid line that is drawn at the bottom of the boring.

BORING LOG

Explanation of Boring Log Symbols

PROJECT NO. DATE FIGURE

DE

PT

H (

feet)

Bu

lkS

AM

PLE

SD

rive

n

BLO

WS

/FO

OT

MO

IST

UR

E (

%)

DR

Y D

EN

SIT

Y (

PC

F)

SY

MB

OL

CLA

SS

IFIC

AT

ION

U.S

.C.S

.

BORING LOG EXPLANATION SHEET

Updated Nov. 2011BORING LOG

20

0

5

10

15

20

SM

SM

ML

FILL:Brown, dry, medium dense, silty SAND with trace gravel and roots.VERY OLD PARALIC DEPOSITS:Gray to brown, moist, weakly to moderately cemented, fine- to medium-grainedsilty SANDSTONE with trace gravel and cobbles.

Yellowish brown, moist, moderately indurated, sandy SILTSTONE; iron-oxidestaining present.

Total Depth = 5 feet.Groundwater not encountered during excavation.Backfilled shortly after excavation on 6/09/17.

Note: Groundwater, though not encountered at the time of excavation, may rise toa higher level due to seasonal variations in precipitation and several other factorsas discussed in the report.

The ground elevation shown above is an estimation only. It is based on ourinterpretations of published maps and other documents reviewed for the purposesof this evaluation. It is not sufficiently accurate for preparing construction bids anddesign documents.

FIGURE A- 2


108232002 | 6/17

DE

PT

H (

fee

t)

Bu

lkS

AM

PL

ES

Dri

ven

BL

OW

S/F

OO

T

MO

IST

UR

E (

%)

DR

Y D

EN

SIT

Y (

PC

F)

SY

MB

OL

CL

AS

SIF

ICA

TIO

NU

.S.C

.S.

DESCRIPTION/INTERPRETATION

DATE DRILLED 6/08/17 BORING NO. IT-2 (North)

GROUND ELEVATION 444'± MSL SHEET 1 OF

METHOD OF DRILLING Manual

DRIVE WEIGHT N/A DROP N/A

SAMPLED BY GSW LOGGED BY GSW REVIEWED BY CAT

1

0

5

10

15

20

16.5 94.2

SM

ML

ML

FILL:Dark brown, moist, medium dense, silty SAND; trace gravel.VERY OLD PARALIC DEPOSITS:Yellowish brown, moist, moderately indurated, clayey SILTSTONE; trace cobblesup to approximately 6 inches in diameter; trace roots.

Yellowish brown, moist, moderately indurated, clayey SILTSTONE.

Total Depth = 6 feet.Groundwater not encountered during excavation.Backfilled shortly after excavation on 6/09/17.

Note: Groundwater, though not encountered at the time of excavation, may rise toa higher level due to seasonal variations in precipitation and several other factorsas discussed in the report.

The ground elevation shown above is an estimation only. It is based on ourinterpretations of published maps and other documents reviewed for the purposesof this evaluation. It is not sufficiently accurate for preparing construction bids anddesign documents.

FIGURE A- 1


108232002 | 6/17

DE

PT

H (

fee

t)

Bu

lkS

AM

PL

ES

Dri

ven

BL

OW

S/F

OO

T

MO

IST

UR

E (

%)

DR

Y D

EN

SIT

Y (

PC

F)

SY

MB

OL

CL

AS

SIF

ICA

TIO

NU

.S.C

.S.

DESCRIPTION/INTERPRETATION

DATE DRILLED 6/08/17 BORING NO. IT-1 (South)

GROUND ELEVATION 453'± MSL SHEET 1 OF

METHOD OF DRILLING Manual

DRIVE WEIGHT N/A DROP N/A

SAMPLED BY GSW LOGGED BY GSW REVIEWED BY CAT

1


APPENDIX B

Laboratory Testing


APPENDIX B

LABORATORY TESTING

Classification Soils were visually and texturally classified in accordance with the Unified Soil Classification System (USCS) in general accordance with ASTM D 2488-00. Soil classifications are indicated on the logs of the exploratory borings in Appendix B.

In-Place Moisture and Density Tests The moisture content and dry density of relatively undisturbed samples obtained from the exploratory borings were evaluated in general accordance with ASTM D 2937-04. The test results are presented on the logs of the exploratory borings in Appendix B.

Direct Shear Tests Direct shear tests were performed on relatively undisturbed and remolded samples in general accordance with ASTM D 3080 to evaluate the shear strength characteristics of selected materials. The samples were inundated during shearing to represent adverse field conditions. The results are shown on Figure B-2.

Soil Corrosivity Tests Soil pH, and minimum resistivity tests were performed on representative samples in general accordance with CT 643. The sulfate and chloride contents of the selected samples were evaluated in general accordance with CT 417 and 422, respectively.

1 PERFORMED IN GENERAL ACCORDANCE WITH CALIFORNIA TEST METHOD 6432 PERFORMED IN GENERAL ACCORDANCE WITH CALIFORNIA TEST METHOD 4173 PERFORMED IN GENERAL ACCORDANCE WITH CALIFORNIA TEST METHOD 422

CHLORIDE

CONTENT 3

(ppm)pH 1

SAMPLEDEPTH (ft)

SAMPLE LOCATION RESISTIVITY 1 SULFATE CONTENT 2

6.8 315660 2460 0.246IT-1 0.5-3.0

CORROSIVITY TEST RESULTS


108232002 6/17

FIGURE B-2

CORROSIVITY IT-1 @ 0.5-3.0.xlsx

PERFORMED IN GENERAL ACCORDANCE WITH ASTM D 3080

Silty SAND X Ultimate5.0-6.0IT-1

Cohesion(psf)

Friction Angle(degrees)

Soil Type

Formation29

29

130

Formation

Description SymbolSample Location

250

Depth(ft)

Shear Strength

5.0-6.0Silty SAND IT-1 Peak

0

1000

2000

3000

0 1000 2000 3000

SH

EA

R S

TR

ES

S (

PS

F)

NORMAL STRESS (PSF)

FIGURE B-1

DIRECT SHEAR TEST RESULTS


108232002 6/17

DIRECT SHEAR IT-1 @ 5.0-6.0.xlsx


APPENDIX C

Infiltration Test Results

Test Date: Infiltration Test No.: IT-1 (South)

Test Hole Diameter, D (inches): 6.0 Excavation Depth (feet): 6.0

Test performed and recorded by: GSW Pipe Length (feet): 6.00

(min/in) (in/hr)

6:50 4.20 7:15 4.22 25 0.02 104 1.79 0.04

7:15 4.20 7:40 4.21 25 0.01 208 1.80 0.02

7:40 4.20 8:10 4.21 30 0.01 250 1.80 0.02

8:10 4.20 8:40 4.21 30 0.01 250 1.80 0.02

8:40 4.20 9:10 4.21 30 0.01 250 1.80 0.02

9:10 4.20 9:40 4.21 30 0.01 250 1.80 0.02

9:40 4.20 10:10 4.21 30 0.01 250 1.80 0.02

10:10 4.20 10:40 4.21 30 0.01 250 1.80 0.02

10:40 4.20 11:10 4.21 30 0.01 250 1.80 0.02

11:10 4.20 11:40 4.21 30 0.01 250 1.80 0.02

11:40 4.20 12:10 4.21 30 0.01 250 1.80 0.02

12:10 4.20 12:40 4.21 30 0.01 250 1.80 0.02

Test Date: Infiltration Test No.: IT-2 (North)

Test Hole Diameter, D (inches): 6.0 Excavation Depth (feet): 5.0

Test performed and recorded by: GSW Pipe Length (feet): 5.00

(min/in) (in/hr)6:55 3.65 7:20 3.68 25 0.03 69 1.34 0.077:20 3.65 7:45 3.67 25 0.02 104 1.34 0.057:45 3.65 8:15 3.69 30 0.04 62 1.33 0.08

8:15 3.65 8:45 3.68 30 0.03 83 1.34 0.06

8:45 3.65 9:15 3.67 30 0.02 125 1.34 0.04

9:15 3.65 9:45 3.67 30 0.02 125 1.34 0.04

9:45 3.65 10:15 3.67 30 0.02 125 1.34 0.04

10:15 3.65 10:45 3.68 30 0.03 83 1.34 0.06

10:45 3.65 11:15 3.67 30 0.02 125 1.34 0.04

11:15 3.65 11:45 3.67 30 0.02 125 1.34 0.04

11:45 3.65 12:15 3.67 30 0.02 125 1.34 0.04

12:15 3.65 12:45 3.67 30 0.02 125 1.34 0.04

Notes:

t1 = initial time when filling or refilling is completed

d1 = initial depth to water in hole at t1

t2 = final time when incremental water level reading is taken

d2 = final depth to water in hole at t2

∆t = change in time between initial and final water level readings

∆H = change in depth to water or change in height of water column (i.e., d2 - d1) It = tested infiltration rate, inches/hour

H0 = Initial height of water column ∆H = change in head over the time interval, inches

in/hr = inches per hour ∆t = time interval, minutes

r = effective radius of test hole

Havg = average head over the time interval, inches

Havg

(feet)

Infiltration Rate

6/9/2017

∆H(feet)

Percolation Rate

Havg

(feet)

Percolation Rate to Infiltration Rate Conversion 1

1 Based on the "Porchet Method" as presented in: Riverside County Flood Control, 2011, Design Handbook for Low Impact Development Best Management Practices: dated September.

t1d1

(feet)t2

d2

(feet)∆t

(min)Infiltration Rate∆H

(feet)

Percolation Rate

6/9/2017

t1d1

(feet)t2

d2

(feet)∆t

(min)

∆ 60

∆ 2

Ninyo & Moore | 8285 Skyline Drive, San Diego, California | 108232002 Appendix C | June 29, 2017 1 of 1

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