Item 19 - Attachment A - Exhibit A - Appendix E - Geotech Report
Appendix E
Geologic Reconnaissance Report
GEOLOGIC RECONNAISSANCE
THE FARMS AT POWAY
POWAY, CALIFORNIA
PREPARED FOR
COLLIERS INTERNATIONAL
SAN DIEGO, CALIFORNIA
APRIL 10, 2019
PROJECT NO. G2158-32-04
GROCON
INCORPORATED
GEOTECHNICAL • ENVIRONMENTAL MATERIALSO
6960 Flanders Drive • San Diego, California 92121-2974 • Telephone 858.558.6900 • Fax 858.558.6159
Project No. G2158-32-04
April 10, 2019
Colliers International
4350 La Jolla Village Drive, Suite 500
San Diego, California 92122
Attention: Ms. Erin McKinley
Subject: GEOLOGIC RECONNAISSANCE
THE FARMS AT POWAY
POWAY, CALIFORNIA
Dear Ms. McKinley:
In accordance with your authorization of our Proposal No. LG-18396, dated October 23, 2018, we
have performed a geologic reconnaissance for The Farms at Poway project in Poway, California. The
accompanying report describes the soil and geologic conditions on the property and provides
geotechnical considerations related to future design and construction.
If you have any questions regarding this study, or if we may be of further service, please contact the
undersigned at your convenience.
Very truly yours,
GEOCON INCORPORATED
David B. Evans
CEG 1860
Trevor E. Myers
RCE 63773
Joseph P. Pagnillo
CEG 2679
DBE:TEM:JPP:dmc
(e-mail) Addressee
TABLE OF CONTENTS
1.PURPOSE AND SCOPE ...................................................................................................................... 1
2.SITE AND PROJECT DESCRIPTION ................................................................................................ 1
3.PREVIOUS GEOTECHNICAL STUDIES .......................................................................................... 2
4.SOIL AND GEOLOGIC CONDITIONS ............................................................................................. 2
4.1 Artificial Fill (Qaf) ..................................................................................................................... 2
4.2 Alluvium (Qal) ........................................................................................................................... 2
4.3 Colluvium (unmapped) ............................................................................................................... 3
4.4 Cretaceous-age Granitic Rock (Kgr) .......................................................................................... 3
5.GROUNDWATER ............................................................................................................................... 3
6.GEOLOGIC HAZARDS ...................................................................................................................... 3
6.1 Faulting and Seismicity .............................................................................................................. 3
6.2 Liquefaction ................................................................................................................................ 5
6.3 Landslides ................................................................................................................................... 5
7.CONCLUSIONS AND CONSIDERATIONS...................................................................................... 6
LIMITATIONS AND UNIFORMITY OF CONDITIONS
MAPS AND ILLUSTRATIONS
Figure 1, Vicinity Map
Figures 2 – 3, Geologic Map (Map Pocket)
APPENDIX A – TRENCH LOGS (2017)
APPENDIX B – SEISMIC REFRACTION STUDY (2017)
APPENDIX C – BORING LOGS (1990)
APPENDIX D – BORING LOGS (1987)
APPENDIX E – GRADING SPECIFICATIONS
LIST OF REFERENCES
Project No. G2158-32-04 - 1 - April 10, 2019
GEOLOGIC RECONNAISSANCE
1. PURPOSE AND SCOPE
This report presents the findings of a geologic reconnaissance for The Farms at Poway project located
in Poway, California (see Vicinity Map, Figure 1). The purpose of this study was to perform
reconnaissance-level geologic mapping of the property and identify any known geologic hazards that
may adversely impact the proposed development as presently planned.
The scope of our study included a review of readily available published geologic literature,
geotechnical reports and plans pertinent to the surrounding area (see List of References), performing a
limited field reconnaissance, reviewing stereoscopic aerial photographs of property, and preparing this
report summarizing our findings.
The exhibit used as a base map to depict the geologic conditions consists of a reproducible copy of a
compilation of digital information provided by Hunsaker & Associates (Geologic Map, Figures 2
and 3). The plan depicts the proposed development, existing topography and mapped geologic
contacts based on published information and our reconnaissance. The conclusions and considerations
presented herein are based on an analysis of the data reviewed as part of this study and our experience
with similar soil and geologic conditions.
2. SITE AND PROJECT DESCRIPTION
The site consists of approximately 117-acres of the decommissioned Stoneridge Country Club and
golf course property located north of Espola Road. The property is surrounded on three sides (west,
east and north) by the existing Valle Verde Country Club Estates subdivision. In the northern portion
of the project, an existing condominium community (Stoneridge Chateaus) is surrounded by but is not
part of the planning area.
Based on a review of the plans provided by Hunsaker and Associates, we understand the property will
be developed to create approximately 160 single-family homes with associated underground utilities, a
swim and tennis club, multi-purpose barn, community event space and landscaping improvements.
Maximum cuts and fills during grading are anticipated to be up to approximately 30 feet and 40 feet,
respectively. Maximum 2:1 (horizontal:vertical) cut and fill slopes are planned up to 40 feet and
50 feet, respectively. A backbone roadway will provide ingress and egress to smaller loop roads which
will service the subdivision. A number of detention basins are planned throughout the site.
The locations and descriptions of the project are based on review of published geologic literature, in-
house geotechnical reports pertinent to the general geographic area of the subject property and our
general understanding of the project as presently proposed. If the proposed development details vary
Project No. G2158-32-04 - 2 - April 10, 2019
significantly from those described, Geocon Incorporated should be retained to update and/or modify
this report accordingly.
3. PREVIOUS GEOTECHNICAL STUDIES
A geotechnical investigation was performed by Geocon Incorporated in 2017 as part of a due diligence
study for a portion of the site. In addition, two limited geotechnical investigations were performed in
1987 and 1990 for the pro shop and tennis courts (see List of References). The subsurface information
from these studies, which include exploratory borings, trenches, seismic traverses and as-graded
geologic mapping have been reviewed to provide a general understanding of the soil and geologic
conditions on the property. This information is included in Appendices A, B, C and D. The exploration
locations from these reports has been incorporated onto Figures 2 and 3.
4. SOIL AND GEOLOGIC CONDITIONS
Based on a review of published geologic maps, previous geotechnical reports and observations during
our site reconnaissance, the geology underlying the property consists of surficial soil (Artificial Fill,
Alluvium and Colluvium) over Cretaceous-age granitic rock. The surficial soils and geologic
formation are discussed below in order of increasing age. The estimated extent of these units is shown
on the Geologic Map, Figures 2 and 3, with the exception of colluvium. The composition, extent and
approximate thickness of the surficial deposits will need to be determined during a future geotechnical
investigation.
4.1 Artificial Fill (Qaf)
Artificial fill deposits were observed in the form of embankments created during contour grading for
the golf course. It appears that artificial fill was also placed in the area of the clubhouse, pro shop,
tennis courts and the groundskeeper facilities to create level ground for these structures. The artificial
fill deposits will require remedial grading where they are present within the development footprint. In
addition, mulch was observed at the surface (unmapped) and the thickness is unknown. This material
will require removal and exportation from the site.
4.2 Alluvium (Qal)
Alluvium is present within the existing drainages on the property. These areas generally mimic the
drainage locations indicated on the original topography maps. It is assumed remedial grading was not
performed for the alluvium during previous grading operations for the golf course. The alluvium will
require remedial grading during future development.
Project No. G2158-32-04 - 3 - April 10, 2019
4.3 Colluvium (unmapped)
Our experience in the vicinity of the project indicates that the bedrock is mantled with colluvial
deposits where relatively gently sloping conditions are present. Remedial grading will be necessary
where these soils are present within the development footprint.
4.4 Cretaceous-age Granitic Rock (Kgr)
Cretaceous-age Granitic Rock underlies the property. This formation exhibits a highly variable
weathering profile based upon previous studies. Considering heavy duty grading and excavation
equipment, it appears that the upper approximately 5 to 15 feet of granitic rock below the ground
surface is rippable in the areas studied with the exception of where rock outcroppings are present.
This unit generally exhibits adequate bearing and slope stability characteristics. Cut slopes excavated
at an inclination of 2:1 (horizontal:vertical) should be stable to the proposed heights if free of
adversely oriented joints, fractures or faults. It should be anticipated that excavations within this unit
will generate boulders and oversize materials (rocks greater than 12 inches in length) that will require
special handling and placement procedures.
The rippability characteristics of the granitic rock will be a primary consideration during project
development. A seismic refraction study was performed in 2017. The results of the study are presented
in Appendix B. The study indicates that heavy ripping will be required to achieve the majority of the
proposed excavations for the project and blasting may be required if cuts extend deeper than 5 to 15 feet.
5. GROUNDWATER
No groundwater or seepage was observed on the property during our field reconnaissance. However,
groundwater levels in the man-made ponds and drainage areas can be expected to fluctuate seasonally
and may affect grading if the alluvial areas extend into the development footprint. In this regard,
grading may encounter wet soils causing excavation and compaction difficulty, particularly if
construction is planned during the winter months. Subdrain systems are not anticipated, however, the
need for drains will be evaluated during remedial grading when the bedrock surface can be observed.
6. GEOLOGIC HAZARDS
6.1 Faulting and Seismicity
Based on our observations during mass grading in adjacent areas, previous geotechnical studies, and a
review of published geologic maps and reports, the site is not located on any known “active,”
“potentially active” or “inactive” fault traces as defined by the California Geological Survey (CGS).
Project No. G2158-32-04 - 4 - April 10, 2019
The Newport-Inglewood and Rose Canyon Fault zones, located approximately 16 miles west of the
site, are the closest known active faults. The CGS considers a fault seismically active when evidence
suggests seismic activity within roughly the last 11,000 years. The CGS has included portions of the
Rose Canyon Fault zone within an Alquist-Priolo Earthquake Fault Zone.
We used the computer program EZ-FRISK (Version 7.65) to determine the distance of known faults to
the site and to estimate ground accelerations at the site for the maximum anticipated seismic event.
According to the results, 7 known active faults are located within a search radius of 50 miles from the
property. We used acceleration attenuation relationships developed by Boore-Atkinson (2008) NGA
USGS2008, Campbell-Bozorgnia (2008) NGA USGS, and Chiou-Youngs (2008) NGA in our
analysis. The nearest known active faults are the Newport-Inglewood and Rose Canyon Fault Zones,
located approximately 16 miles west of the site, respectively, and are the dominant sources of potential
ground motion. Table 6.1.1 lists the estimated maximum earthquake magnitudes and PGA’s for the
most dominant faults for the site location calculated for Site Class C as defined by Table 1613.3.2 of
the 2016 California Building Code (CBC).
TABLE 6.1.1
DETERMINISTIC SEISMIC SITE PARAMETERS
Fault Name Distance from
Site (miles)
Maximum
Earthquake
Magnitude (Mw)
Peak Ground Acceleration
Boore-
Atkinson
2008 (g)
Campbell-
Bozorgnia
2008 (g)
Chiou-
Youngs
2008 (g)
Newport-Inglewood 16 7.5 0.19 0.15 0.18
Rose Canyon 16 6.9 0.15 0.13 0.13
Elsinore 21 7.85 0.18 0.13 0.17
Earthquake Valley 29 6.8 0.09 0.07 0.06
Coronado Bank 30 7.4 0.12 0.08 0.09
Palos Verdes 30 7.7 0.13 0.09 0.11
San Jacinto 42 7.88 0.11 0.08 0.09
We performed a site-specific probabilistic seismic hazard analysis using the computer program
EZ-FRISK. Geologic parameters not addressed in the deterministic analysis are included in this
analysis. The program operates under the assumption that the occurrence rate of earthquakes on each
mappable Quaternary fault is proportional to the faults slip rate. The program accounts for fault
rupture length as a function of earthquake magnitude, and site acceleration estimates are made using
the earthquake magnitude and distance from the site to the rupture zone. The program also accounts
for uncertainty in each of following: (1) earthquake magnitude, (2) rupture length for a given
magnitude, (3) location of the rupture zone, (4) maximum possible magnitude of a given earthquake,
Project No. G2158-32-04 - 5 - April 10, 2019
and (5) acceleration at the site from a given earthquake along each fault. By calculating the expected
accelerations from considered earthquake sources, the program calculates the total average annual
expected number of occurrences of site acceleration greater than a specified value. We utilized
acceleration-attenuation relationships suggested by Boore-Atkinson (2008) NGA USGS 2008,
Campbell-Bozorgnia (2008) NGA USGS 2008, and Chiou-Youngs (2008) NGA in the analysis.
Table 6.1.2 presents the site-specific probabilistic seismic hazard parameters including acceleration-
attenuation relationships and the probability of exceedence.
TABLE 6.1.2
PROBABILISTIC SEISMIC HAZARD PARAMETERS
Probability of Exceedence
Peak Ground Acceleration
Boore-Atkinson,
2008 (g)
Campbell-Bozorgnia,
2008 (g)
Chiou-Youngs,
2008 (g)
2% in a 50 Year Period 0.37 0.36 0.41
5% in a 50 Year Period 0.28 0.27 0.29
10% in a 50 Year Period 0.22 0.21 0.21
While listing peak accelerations is useful for comparison of potential effects of fault activity in a
region, other considerations are important in seismic design, including the frequency and duration of
motion and the soil conditions underlying the site. Seismic design of the structures should be evaluated
in accordance with the California Building Code (CBC) guidelines currently adopted by the City of
Poway.
6.2 Liquefaction
Liquefaction typically occurs when a site is located in a zone with seismic activity, onsite soils are
cohesionless, groundwater is encountered within 50 feet of the surface, and soil densities are less than
about 70 percent of the relative density. If all four criteria are met, a seismic event could result in a
rapid increase in pore water pressure from the earthquake-generated ground accelerations. The
potential for liquefaction at the site is considered to be negligible due to the dense formational material
encountered, remedial grading recommended, and lack of a shallow groundwater condition.
6.3 Landslides
No evidence of ancient landslide deposits was observed during our site reconnaissance or geologic
literature review.
Project No. G2158-32-04 - 6 - April 10, 2019
7. CONCLUSIONS AND CONSIDERATIONS
7.1 No soil or geologic conditions were encountered during our reconnaissance or literature
review that would preclude development of the site as presently planned.
7.2 A future geotechnical study that includes a subsurface investigation should be performed to
evaluate the underlying geologic conditions on the property and to provide specific
geotechnical recommendations for the project. This study should include evaluation of
surficial deposits, and a rippability analysis of the granitic rock in areas of planned
development.
7.3 The site is underlain by surficial units that include artificial fill, alluvial, and colluvial
deposits. These deposits are unsuitable in their present condition and will require remedial
grading in the form of removal and compaction where improvements are planned.
7.4 The presence of hard rock at or near the existing ground surface will require special
consideration during site grading. Based on the seismic refraction survey, it is anticipated
that significant portions of the excavations will encounter hard rock conditions and will
require special excavation techniques and possible blasting.
7.5 It is anticipated that excavations within the granitic rock will generate oversize materials
that will require special handling and placement in fills in accordance with the grading
specifications contained in Appendix E. An earthwork analysis should be performed to
determine if there is an adequate volume of fill area available to accommodate the
anticipated volume of blasted/oversize materials. This study should consider the proposed
grading, rippability information contained in this report, rock placement requirements and
include proposed undercutting. Crushing may be necessary to meet the project grading
specifications with respect to capping and particle size restriction zones.
7.6 Cut slopes should be observed by an engineering geologist during grading to verify that the
soil and geologic conditions do not differ significantly from those anticipated. Additional
recommendations will be provided in in event that adverse conditions are encountered.
Scaling of loose rock fragments from proposed cut slopes may be necessary.
Project No. G2158-32-04 April 10, 2019
LIMITATIONS AND UNIFORMITY OF CONDITIONS
1. The firm that performed the geotechnical investigation for the project should be retained to
provide testing and observation services during construction to provide continuity of
geotechnical interpretation and to check that the recommendations presented for geotechnical
aspects of site development are incorporated during site grading, construction of
improvements, and excavation of foundations. If another geotechnical firm is selected to
perform the testing and observation services during construction operations, that firm should
prepare a letter indicating their intent to assume the responsibilities of project geotechnical
engineer of record. A copy of the letter should be provided to the regulatory agency for their
records. In addition, that firm should provide revised recommendations concerning the
geotechnical aspects of the proposed development, or a written acknowledgement of their
concurrence with the recommendations presented in our report. They should also perform
additional analyses deemed necessary to assume the role of Geotechnical Engineer of Record.
2. The recommendations of this report pertain only to the site investigated and are based upon
the assumption that the soil conditions do not deviate from those disclosed in the
investigation. If any variations or undesirable conditions are encountered during construction,
or if the proposed construction will differ from that anticipated herein, Geocon Incorporated
should be notified so that supplemental recommendations can be given. The evaluation or
identification of the potential presence of hazardous or corrosive materials was not part of the
scope of services provided by Geocon Incorporated.
3. This report is issued with the understanding that it is the responsibility of the owner or his
representative to ensure that the information and recommendations contained herein are
brought to the attention of the architect and engineer for the project and incorporated into the
plans, and the necessary steps are taken to see that the contractor and subcontractors carry out
such recommendations in the field.
4. The findings of this report are valid as of the present date. However, changes in the conditions
of a property can occur with the passage of time, whether they be due to natural processes or
the works of man on this or adjacent properties. In addition, changes in applicable or
appropriate standards may occur, whether they result from legislation or the broadening of
knowledge. Accordingly, the findings of this report may be invalidated wholly or partially by
changes outside our control. Therefore, this report is subject to review and should not be relied
upon after a period of three years.
SITESITE
NO SCALE
FIG. 1
THE GEOGRAPHICAL INFORMATION MADE AVAILABLE FOR DISPLAY WAS PROVIDED BY GOOGLE EARTH,
SUBJECT TO A LICENSING AGREEMENT. THE INFORMATION IS FOR ILLUSTRATIVE PURPOSES ONLY; IT IS
NOT INTENDED FOR CLIENT'S USE OR RELIANCE AND SHALL NOT BE REPRODUCED BY CLIENT. CLIENT
SHALL INDEMNIFY, DEFEND AND HOLD HARMLESS GEOCON FROM ANY LIABILITY INCURRED AS A RESULT
OF SUCH USE OR RELIANCE BY CLIENT.
VICINITY MAP
6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92121 - 2974
PHONE 858 558-6900 - FAX 858 558-6159
DSK/GTYPD PROJECT NO. G2158 - 32 - 04JP / RA
THE FARMS AT POWAY
POWAY, CALIFORNIAGEOTECHNICAL ENVIRONMENTAL MATERIALS
Plotted:04/09/2019 9:48AM | By:RUBEN AGUILAR | File Location:Y:\PROJECTS\G2158-32-04 The Farm\DETAILS\G2158-32-04 VicinityMap.dwg
DATE 04 - 10 - 2019
ST. ANDREWS DRIVEESPOLA ROAD
CLOUDCROFT DRIVE
T A M O
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S
H
A
NTER DRIVETAM O'
SHANTER CT.
BOCA RATON CT.ORCHARD BEND ROADMARTINCOIT ROADVALLE VERDE RDALDERWOOD LANE
ST. ANDREWS COURT
VALLE VERDE RDCLOUDCROFT CT .DORSET WAY
2
1
97
98
99
100
101
102
103
104
94
95
96
105
91 92
3
45
67
89
1011
1213
1415
1617
1819
2021
2223
24
33
3431
3229
3027
28
25
26 63
64
65 66
6768
7069
71
72
7473
75
76
7877
79
80
8281
8384
8685
87
88
9089
57
58
56 55
53 54
52 51
49 50
48 47
45 46
44 43
42
41
40
39
38
35
36
37
160
157
155
154
151
106
109
ST. ANDREWS DRIVEESPOLA ROAD
CLOUDCROFT DRIVE TAM
O'SHANT
E
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CT.BOCA RATON CT.ALDERWOODST. ANDREWS COURTVALLE VERDE RDDORSET WAY
CLOUDCROFT DRIVEESPOLA ROAD
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OSR-3
OSR-4
OSR-5
OSR-6
OSR-7
OSR-8
OSC-1
OSC-2
OSC-3
OSC-4
OSC-5
OSC-6
OSC-7
OSC-8
OSC-9
OSC-10
OSC-11
OSC-12
PS-1
PS-2
PS-3
PS-4
PS-5
PS-6
PS-9PS-10PS-11PS-12PS-13PS-14PS-15PS-16PS-17PS-20
P
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P
S
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PS-21
PS-22
PS-23
PS-24
PS-31
PS-25
PS-30
PS-26
PS-29
PS-27
PS-28
··································Qaf
Qaf
Qaf
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T-1
T-2
T-3
T-4
T-5
T-6
T-7
T-8
T-9
T-10
T-11
T-12
T-13
T-14
T-15
T-16
B-1 B-2
B-3
B-4
B-1
B-2
S-2
S-1
S-5
S-6
S-7
S-3
S-4
PROJECT
BOUNDARY
PROJECT
BOUNDARY
6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92121 - 2974
PHONE 858 558-6900 - FAX 858 558-6159 SHEET OF
PROJECT NO.
SCALE DATE
FIGURE
Plotted:04/09/2019 9:49AM | By:RUBEN AGUILAR | File Location:Y:\PROJECTS\G2158-32-04 The Farm\SHEETS\G2158-32-04 GeoMap.dwg
GEOTECHNICAL ENVIRONMENTAL MATERIALS
?
GEOCON LEGEND
........GRANITIC ROCK OVERLAIN BY: Qaf/Qal/QcKgr
........APPROX. LOCATION OF GEOLOGIC CONTACT
(Dotted Where Buried; Queried Where Uncertain)
1" =
GEOLOGIC MAP
THE FARMS AT POWAY
POWAY, CALIFORNIA
100'04 - 10 - 2019
G2158 - 32 - 04
1 2 2
........ALLUVIUMQal
........ARTIFICIAL FILLQaf
T-16
B-4
B-2
S-7
........APPROX. LOCATION OF EXPLORATORY TRENCH (2017, Appendix A)
........APPROX. LOCATION OF EXPLORATORY BORING (1990, Appendix C)
........APPROX. LOCATION OF EXPLORATORY BORING (1987, Appendix D)
........APPROX. LOCATION OF SEISMIC REFRACTION TRAVERSE (2017, Appendix B)
........SEEPAGE/SURFACE WATER
........BOULDERS/ROCK OUTCROPS
........MAN-MADE POND
SEE FIGURE 3
ST. ANDREWS DRIVE
BOCA RATON LANEST. ANDREWS DRIVET A M
BOCA RATON LANE
BOCA RATON CT.BOCA RATON LANEDEL PASO DRIVE
INDIAN CANYON LANE
GLEN ARVEN LANE
ST. ANDREWS PLACE
BURNING HILLS
DRIVE
STARMOUNT WAY
160
157
155
154
151
106
109
149
111
113
115
116
117
118
119
120
121
122
123
124
145
146
147
148
ST. ANDREWS DRIVE
BOCA RATON LANETAM O' SHANTER DR
BOCA RATON CT.TAM O' SHANTER DRDEL PASO DRIVEIND
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133
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136
137
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132ARVENLANE
114
112
110
150
152
108
158
107
153
156
159
OSC-13
OSC-14
OSC-15
OSC-16
OSC-17
OSC-18
OSC-20
OSC-19
OSC-27
OSC-26
OSC-25
OSC-24
OSC-21
OSC-23
OSC-22
PS-6
PS-7
PS-8
Kgr
Kgr
Kgr
Kgr
Kgr
Kgr
Kgr
Qaf
Qaf
Qaf
Qaf
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PROJECT
BOUNDARY
PROJECT
BOUNDARY
PROJECT
BOUNDARY
6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92121 - 2974
PHONE 858 558-6900 - FAX 858 558-6159 SHEET OF
PROJECT NO.
SCALE DATE
FIGURE
Plotted:04/09/2019 9:51AM | By:RUBEN AGUILAR | File Location:Y:\PROJECTS\G2158-32-04 The Farm\SHEETS\G2158-32-04 GeoMap.dwg
GEOTECHNICAL ENVIRONMENTAL MATERIALS
1" =
GEOLOGIC MAP
THE FARMS AT POWAY
POWAY, CALIFORNIA
100'04 - 10 - 2019
G2158 - 32 - 04
2 2 3
?
GEOCON LEGEND
........GRANITIC ROCK OVERLAIN BY: Qaf/Qal/QcKgr
........APPROX. LOCATION OF GEOLOGIC CONTACT
(Dotted Where Buried; Queried Where Uncertain)
........ALLUVIUMQal
........ARTIFICIAL FILLQaf
T-16
B-4
B-2
S-7
........APPROX. LOCATION OF EXPLORATORY TRENCH (2017, Appendix A)
........APPROX. LOCATION OF EXPLORATORY BORING (1990, Appendix C)
........APPROX. LOCATION OF EXPLORATORY BORING (1987, Appendix D)
........APPROX. LOCATION OF SEISMIC REFRACTION TRAVERSE (2017, Appendix B)
........SEEPAGE/SURFACE WATER
........BOULDERS/ROCK OUTCROPS
........MAN-MADE POND
SEE FIGURE 2
APPENDIX A
APPENDIX A
TRENCH LOGS
PREPARED BY GEOCON INCORPORATED,
DATED AUGUST 10, 2017; PROJECT NO. G2158-32-01
FOR
THE FARMS AT POWAY
POWAY, CALIFORNIA
PROJECT NO. G2158-32-04
COLLUVIUM
Medium dense to dense, dry, reddish brown, Silty/Clayey, fine to medium
SAND; pinhole porosity
-Some fresh boulders 24-inch in size or greater, exposed in side wall and
bottom of trench
GRANITIC ROCK
Moderately weak to moderately strong, moderately weathered, yellow, orange,
and gray GRANITIC ROCK; excavates as Silty, fine to coarse SAND
REFUSAL AT 6 FEET
Groundwater not encountered
SM/SC
... DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
0
2
4
6
Figure A-1,
Log of Trench T 1, Page 1 of 1 DRY DENSITY(P.C.F.)... DRIVE SAMPLE (UNDISTURBED)
JD 410G Backhoe PENETRATIONRESISTANCE(BLOWS/FT.)TRENCH T 1
... CHUNK SAMPLE
DATE COMPLETED
... SAMPLING UNSUCCESSFUL
SOIL
CLASS
(USCS)GROUNDWATERT. MYERS CONTENT (%)SAMPLE
NO.07-19-2017
SAMPLE SYMBOLS
... WATER TABLE OR SEEPAGE MOISTUREBY:EQUIPMENT
ELEV. (MSL.)741'
G2158-32-01.GPJ
MATERIAL DESCRIPTIONLITHOLOGY
... STANDARD PENETRATION TEST
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT
IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
G2158-32-01
UNDOCUMENTED FILL
Loose, damp, grayish-brown, Silty, fine to medium SAND
COLLUVIUM
Medium dense, moist, reddish brown, Silty/Clayey, fine to medium SAND;
pinhole porosity
GRANITIC ROCK
Weak, completely weathered, yellow and brown GRANITIC ROCK;
excavates as Silty, fine to coarse SAND with trace clay
TRENCH TERMINATED AT 14.5 FEET
Groundwater not encountered
SM
SM/SC
... DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
0
2
4
6
8
10
12
14
Figure A-2,
Log of Trench T 2, Page 1 of 1 DRY DENSITY(P.C.F.)... DRIVE SAMPLE (UNDISTURBED)
JD 410G Backhoe PENETRATIONRESISTANCE(BLOWS/FT.)TRENCH T 2
... CHUNK SAMPLE
DATE COMPLETED
... SAMPLING UNSUCCESSFUL
SOIL
CLASS
(USCS)GROUNDWATERT. MYERS CONTENT (%)SAMPLE
NO.07-19-2017
SAMPLE SYMBOLS
... WATER TABLE OR SEEPAGE MOISTUREBY:EQUIPMENT
ELEV. (MSL.)707'
G2158-32-01.GPJ
MATERIAL DESCRIPTIONLITHOLOGY
... STANDARD PENETRATION TEST
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT
IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
G2158-32-01
COLLUVIUM
Medium dense, damp, reddish brown, Silty/Clayey, fine to medium SAND;
pinhole porosity
GRANITIC ROCK
Weak, completely weathered, yellow and black GRANITIC ROCK; excavates
as Silty, fine to coarse SAND
TRENCH TERMINATED AT 6 FEET
Groundwater not encountered
SM/SC
T3-1
... DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
0
2
4
6
Figure A-3,
Log of Trench T 3, Page 1 of 1 DRY DENSITY(P.C.F.)... DRIVE SAMPLE (UNDISTURBED)
JD 410G Backhoe PENETRATIONRESISTANCE(BLOWS/FT.)TRENCH T 3
... CHUNK SAMPLE
DATE COMPLETED
... SAMPLING UNSUCCESSFUL
SOIL
CLASS
(USCS)GROUNDWATERT. MYERS CONTENT (%)SAMPLE
NO.07-19-2017
SAMPLE SYMBOLS
... WATER TABLE OR SEEPAGE MOISTUREBY:EQUIPMENT
ELEV. (MSL.)704'
G2158-32-01.GPJ
MATERIAL DESCRIPTIONLITHOLOGY
... STANDARD PENETRATION TEST
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT
IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
G2158-32-01
UNDOCUMENTED FILL
Loose, damp, brown, Silty, fine to medium SAND
-Becomes light brown, Silty/Clayey, fine to medium SAND
COLLUVIUM
Medium dense, moist, reddish brown, Silty/Clayey, fine to medium SAND;
pinhole porosity
GRANITIC ROCK
Weak, completely weathered, orange, brown, and black GRANITIC ROCK;
excavates as Silty, fine to coarse SAND
TRENCH TERMINATED AT 8.5 FEET
Groundwater not encountered
SM
SM/SC
... DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
0
2
4
6
8
Figure A-4,
Log of Trench T 4, Page 1 of 1 DRY DENSITY(P.C.F.)... DRIVE SAMPLE (UNDISTURBED)
JD 410G Backhoe PENETRATIONRESISTANCE(BLOWS/FT.)TRENCH T 4
... CHUNK SAMPLE
DATE COMPLETED
... SAMPLING UNSUCCESSFUL
SOIL
CLASS
(USCS)GROUNDWATERT. MYERS CONTENT (%)SAMPLE
NO.07-19-2017
SAMPLE SYMBOLS
... WATER TABLE OR SEEPAGE MOISTUREBY:EQUIPMENT
ELEV. (MSL.)693'
G2158-32-01.GPJ
MATERIAL DESCRIPTIONLITHOLOGY
... STANDARD PENETRATION TEST
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT
IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
G2158-32-01
UNDOCUMENTED FILL
Loose, damp, grayish brown, Silty, fine to medium SAND
Soft, very moist, light brown, fine to coarse, Sandy CLAY
Loose, moist, grayish-brown, Silty/Clayey, fine to medium SAND
COLLUVIUM
Medium dense, moist, reddish brown, Silty/Clayey fine to medium SAND;
pinhole porosity
GRANITIC ROCK
Weak, completely weathered, gray, yellow, and black GRANITIC ROCK;
excavates as Silty, fine to coarse SAND
TRENCH TERMINATED AT 11.5 FEET
Groundwater not encountered
SM
CL
SM/SC
SM/SC
... DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
0
2
4
6
8
10
Figure A-5,
Log of Trench T 5, Page 1 of 1 DRY DENSITY(P.C.F.)... DRIVE SAMPLE (UNDISTURBED)
JD 410G Backhoe PENETRATIONRESISTANCE(BLOWS/FT.)TRENCH T 5
... CHUNK SAMPLE
DATE COMPLETED
... SAMPLING UNSUCCESSFUL
SOIL
CLASS
(USCS)GROUNDWATERT. MYERS CONTENT (%)SAMPLE
NO.07-19-2017
SAMPLE SYMBOLS
... WATER TABLE OR SEEPAGE MOISTUREBY:EQUIPMENT
ELEV. (MSL.)693'
G2158-32-01.GPJ
MATERIAL DESCRIPTIONLITHOLOGY
... STANDARD PENETRATION TEST
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT
IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
G2158-32-01
UNDOCUMENTED FILL
Loose, damp, dark brown, Silty, fine to medium SAND; heavy roots
COLLUVIUM
Loose, damp to slightly moist, light brown, Silty/Clayey , fine to medium
SAND; porous, roots
Medium dense to dense, damp to slightly moist, brown, Silty/Clayey, fine to
medium SAND
GRANITIC ROCK
Moderately weak, highly weathered, yellow and gray GRANITIC ROCK;
excavates as Silty, fine to coarse SAND
TRENCH TERMINATED AT 9 FEET
Groundwater not encountered
SM
SM/SC
SM/SC
... DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
0
2
4
6
8
Figure A-6,
Log of Trench T 6, Page 1 of 1 DRY DENSITY(P.C.F.)... DRIVE SAMPLE (UNDISTURBED)
JD 410G Backhoe PENETRATIONRESISTANCE(BLOWS/FT.)TRENCH T 6
... CHUNK SAMPLE
DATE COMPLETED
... SAMPLING UNSUCCESSFUL
SOIL
CLASS
(USCS)GROUNDWATERT. MYERS CONTENT (%)SAMPLE
NO.07-19-2017
SAMPLE SYMBOLS
... WATER TABLE OR SEEPAGE MOISTUREBY:EQUIPMENT
ELEV. (MSL.)633'
G2158-32-01.GPJ
MATERIAL DESCRIPTIONLITHOLOGY
... STANDARD PENETRATION TEST
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT
IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
G2158-32-01
UNDOCUMENTED FILL
Loose, dry, brown, Silty, fine to medium SAND; heavy roots, porous
COLLUVIUM
Medium dense, damp, orange brown, Silty/Clayey, fine to medium SAND;
pinhole porosity
GRANITIC ROCK
weak, completely weathered, yellowish brown GRANITIC ROCK; excavates
as Silty, fine to coarse SAND
REFUSAL AT 5 FEET
Groundwater not encountered
SM
SM/SC
... DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
0
2
4
Figure A-7,
Log of Trench T 7, Page 1 of 1 DRY DENSITY(P.C.F.)... DRIVE SAMPLE (UNDISTURBED)
JD 410G Backhoe PENETRATIONRESISTANCE(BLOWS/FT.)TRENCH T 7
... CHUNK SAMPLE
DATE COMPLETED
... SAMPLING UNSUCCESSFUL
SOIL
CLASS
(USCS)GROUNDWATERT. MYERS CONTENT (%)SAMPLE
NO.07-19-2017
SAMPLE SYMBOLS
... WATER TABLE OR SEEPAGE MOISTUREBY:EQUIPMENT
ELEV. (MSL.)618'
G2158-32-01.GPJ
MATERIAL DESCRIPTIONLITHOLOGY
... STANDARD PENETRATION TEST
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT
IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
G2158-32-01
UNDOCUMENTED FILL
Loose, dry, light brown, Silty, fine to medium SAND
COLLUVIUM
Medium dense, damp, orange brown, Clayey/Silty SAND; pinhole porosity
GRANITIC ROCK
Weak, completely weathered, grayish brown GRANITIC ROCK; excavates as
Silty, fine to coarse SAND
TRENCH TERMINATED AT 10 FEET
Groundwater not encountered
SM
SM/SC
... DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
0
2
4
6
8
10
Figure A-8,
Log of Trench T 8, Page 1 of 1 DRY DENSITY(P.C.F.)... DRIVE SAMPLE (UNDISTURBED)
JD 410G Backhoe PENETRATIONRESISTANCE(BLOWS/FT.)TRENCH T 8
... CHUNK SAMPLE
DATE COMPLETED
... SAMPLING UNSUCCESSFUL
SOIL
CLASS
(USCS)GROUNDWATERT. MYERS CONTENT (%)SAMPLE
NO.07-19-2017
SAMPLE SYMBOLS
... WATER TABLE OR SEEPAGE MOISTUREBY:EQUIPMENT
ELEV. (MSL.)606'
G2158-32-01.GPJ
MATERIAL DESCRIPTIONLITHOLOGY
... STANDARD PENETRATION TEST
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT
IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
G2158-32-01
UNDOCUMENTED FILL
Loose, damp, light brown, Silty, fine to medium SAND with some rootlets
GRANITIC ROCK
Moderately weak, highly weathered, orangish-brown, gray and black
GRANITIC ROCK; excavates as Silty, fine to coarse SAND
TRENCH TERMINATED AT 2.5 FEET
Groundwater not encountered
SM
... DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
0
2
Figure A-9,
Log of Trench T 9, Page 1 of 1 DRY DENSITY(P.C.F.)... DRIVE SAMPLE (UNDISTURBED)
JD 410G Backhoe PENETRATIONRESISTANCE(BLOWS/FT.)TRENCH T 9
... CHUNK SAMPLE
DATE COMPLETED
... SAMPLING UNSUCCESSFUL
SOIL
CLASS
(USCS)GROUNDWATERT. MYERS CONTENT (%)SAMPLE
NO.07-19-2017
SAMPLE SYMBOLS
... WATER TABLE OR SEEPAGE MOISTUREBY:EQUIPMENT
ELEV. (MSL.)605'
G2158-32-01.GPJ
MATERIAL DESCRIPTIONLITHOLOGY
... STANDARD PENETRATION TEST
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT
IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
G2158-32-01
UNDOCUMENTED FILL
Loose, damp, brown, Silty, fine to medium SAND with rootlets
COLLUVIUM
Loose to medium dense, moist to very moist, dark brown, Silty/Clayey, fine to
medium SAND; pinhole porosity
GRANITIC ROCK
Weak, completely weathered, orange, yellow and black GRANITIC ROCK;
excavates as Silty, fine to coarse SAND with trace clay
TRENCH TERMINATED AT 13 FEET
Groundwater not encountered
SM
SM/SC
... DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
0
2
4
6
8
10
12
Figure A-10,
Log of Trench T 10, Page 1 of 1 DRY DENSITY(P.C.F.)... DRIVE SAMPLE (UNDISTURBED)
JD 410G Backhoe PENETRATIONRESISTANCE(BLOWS/FT.)TRENCH T 10
... CHUNK SAMPLE
DATE COMPLETED
... SAMPLING UNSUCCESSFUL
SOIL
CLASS
(USCS)GROUNDWATERT. MYERS CONTENT (%)SAMPLE
NO.07-19-2017
SAMPLE SYMBOLS
... WATER TABLE OR SEEPAGE MOISTUREBY:EQUIPMENT
ELEV. (MSL.)594'
G2158-32-01.GPJ
MATERIAL DESCRIPTIONLITHOLOGY
... STANDARD PENETRATION TEST
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT
IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
G2158-32-01
3" ASPHALT CONCRETE
UNDOCUMENTED FILL
Loose, damp, gray, Silty, fine to medium SAND
COLLUVIUM
Loose to medium dense, moist, brown, Silty/Clayey, fine to medium SAND;
pinhole porosity
GRANITIC ROCK
Weak, completely weathered, yellow, orange, and grayish brown GRANITIC
ROCK; excavates as Silty, fine to coarse SAND
TRENCH TERMINATED AT 7 FEET
Groundwater not encountered
SM
SM/SC
... DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
0
2
4
6
Figure A-11,
Log of Trench T 11, Page 1 of 1 DRY DENSITY(P.C.F.)... DRIVE SAMPLE (UNDISTURBED)
JD 410G Backhoe PENETRATIONRESISTANCE(BLOWS/FT.)TRENCH T 11
... CHUNK SAMPLE
DATE COMPLETED
... SAMPLING UNSUCCESSFUL
SOIL
CLASS
(USCS)GROUNDWATERT. MYERS CONTENT (%)SAMPLE
NO.07-19-2017
SAMPLE SYMBOLS
... WATER TABLE OR SEEPAGE MOISTUREBY:EQUIPMENT
ELEV. (MSL.)595'
G2158-32-01.GPJ
MATERIAL DESCRIPTIONLITHOLOGY
... STANDARD PENETRATION TEST
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT
IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
G2158-32-01
UNDOCUMENTED FILL
Loose, dry, light brown, Silty, fine to medium SAND with abundant cobble
and boulders, generally 3-inch to 18-inch in size, and some debris (plastic,
AC, roots)
COLLUVIUM
Loose to medium dense, damp to moist, brown, Silty/Clayey, fine to medium
SAND; porous
GRANITIC ROCK
Weak, completely weathered, orange, black and white GRANITIC ROCK;
excavates as Silty, fine to coarse SAND
TRENCH TERMINATED AT 19.5 FEET
Groundwater not encountered
SM
SM/SC
... DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
0
2
4
6
8
10
12
14
16
18
Figure A-12,
Log of Trench T 12, Page 1 of 1 DRY DENSITY(P.C.F.)... DRIVE SAMPLE (UNDISTURBED)
JD 410G Backhoe PENETRATIONRESISTANCE(BLOWS/FT.)TRENCH T 12
... CHUNK SAMPLE
DATE COMPLETED
... SAMPLING UNSUCCESSFUL
SOIL
CLASS
(USCS)GROUNDWATERT. MYERS CONTENT (%)SAMPLE
NO.07-19-2017
SAMPLE SYMBOLS
... WATER TABLE OR SEEPAGE MOISTUREBY:EQUIPMENT
ELEV. (MSL.)595'
G2158-32-01.GPJ
MATERIAL DESCRIPTIONLITHOLOGY
... STANDARD PENETRATION TEST
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT
IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
G2158-32-01
Mulch/organics, tree trunks/branches
UNDOCUMENTED FILL
Loose, dry, light brown, Silty/Clayey, fine to medium SAND; some debris
(asphalt concrete, plastic, roots)
COLLUVIUM
Loose to medium dense, moist, brown, Silty/Clayey, fine to medium SAND;
porous
GRANITIC ROCK
Weak, completely weathered, brown, orange, gray, and yellow GRANITIC
ROCK; excavates as Silty, fine to coarse SAND
TRENCH TERMINATED AT 18.5 FEET
Groundwater not encountered
SM/SC
SM/SC
T15-1
... DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
0
2
4
6
8
10
12
14
16
18
Figure A-13,
Log of Trench T 13, Page 1 of 1 DRY DENSITY(P.C.F.)... DRIVE SAMPLE (UNDISTURBED)
JD 410G Backhoe PENETRATIONRESISTANCE(BLOWS/FT.)TRENCH T 13
... CHUNK SAMPLE
DATE COMPLETED
... SAMPLING UNSUCCESSFUL
SOIL
CLASS
(USCS)GROUNDWATERT. MYERS CONTENT (%)SAMPLE
NO.07-19-2017
SAMPLE SYMBOLS
... WATER TABLE OR SEEPAGE MOISTUREBY:EQUIPMENT
ELEV. (MSL.)598'
G2158-32-01.GPJ
MATERIAL DESCRIPTIONLITHOLOGY
... STANDARD PENETRATION TEST
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT
IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
G2158-32-01
Mulch/organics
UNDOCUMENTED FILL
Loose, dry, brown gray, Silty, fine to medium SAND with some debris
(plastic, rope, metal, etc)
COLLUVIUM
Loose to medium dense, damp, brown, Silty/Clayey, fine to medium SAND
GRANITIC ROCK
Weak, completely weathered, orangish-brown, gray and black GRANITIC
ROCK; excavates as Silty, fine to coarse SAND
TRENCH TERMINATED AT 17 FEET
Groundwater not encountered
SM
SM/SC
... DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
0
2
4
6
8
10
12
14
16
Figure A-14,
Log of Trench T 14, Page 1 of 1 DRY DENSITY(P.C.F.)... DRIVE SAMPLE (UNDISTURBED)
JD 410G Backhoe PENETRATIONRESISTANCE(BLOWS/FT.)TRENCH T 14
... CHUNK SAMPLE
DATE COMPLETED
... SAMPLING UNSUCCESSFUL
SOIL
CLASS
(USCS)GROUNDWATERT. MYERS CONTENT (%)SAMPLE
NO.07-19-2017
SAMPLE SYMBOLS
... WATER TABLE OR SEEPAGE MOISTUREBY:EQUIPMENT
ELEV. (MSL.)600'
G2158-32-01.GPJ
MATERIAL DESCRIPTIONLITHOLOGY
... STANDARD PENETRATION TEST
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT
IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
G2158-32-01
UNDOCUMENTED FILL
Loose, damp, orangish-brown, Silty, fine to coarse SAND
COLLUVIUM
Loose to medium dense, moist to very moist, dark grayish brown,
Silty/Clayey, fine to medium SAND; pinhole porosity
GRANITIC ROCK
Moderately weak, highly weathered, grayish brown GRANITIC ROCK;
excavates as Silty, fine to coarse SAND
TRENCH TERMINATED AT 14 FEET
Groundwater not encountered
SM
SM/SC
... DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
0
2
4
6
8
10
12
14
Figure A-15,
Log of Trench T 15, Page 1 of 1 DRY DENSITY(P.C.F.)... DRIVE SAMPLE (UNDISTURBED)
JD 410G Backhoe PENETRATIONRESISTANCE(BLOWS/FT.)TRENCH T 15
... CHUNK SAMPLE
DATE COMPLETED
... SAMPLING UNSUCCESSFUL
SOIL
CLASS
(USCS)GROUNDWATERT. MYERS CONTENT (%)SAMPLE
NO.07-19-2017
SAMPLE SYMBOLS
... WATER TABLE OR SEEPAGE MOISTUREBY:EQUIPMENT
ELEV. (MSL.)594'
G2158-32-01.GPJ
MATERIAL DESCRIPTIONLITHOLOGY
... STANDARD PENETRATION TEST
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT
IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
G2158-32-01
UNDOCUMENTED FILL
Loose, damp, brown, Silty, fine to medium SAND
COLLUVIUM
Medium dense, damp, orangish brown, Clayey, fine to medium SAND;
pinhole porosity
GRANITIC ROCK
Moderately weak, highly weathered, grayish brown GRANITIC ROCK;
excavates as Silty, fine to coarse SAND
TRENCH TERMINATED AT 8 FEET
Groundwater not encountered
SM
SC
... DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
0
2
4
6
8
Figure A-16,
Log of Trench T 16, Page 1 of 1 DRY DENSITY(P.C.F.)... DRIVE SAMPLE (UNDISTURBED)
JD 410G Backhoe PENETRATIONRESISTANCE(BLOWS/FT.)TRENCH T 16
... CHUNK SAMPLE
DATE COMPLETED
... SAMPLING UNSUCCESSFUL
SOIL
CLASS
(USCS)GROUNDWATERT. MYERS CONTENT (%)SAMPLE
NO.07-19-2017
SAMPLE SYMBOLS
... WATER TABLE OR SEEPAGE MOISTUREBY:EQUIPMENT
ELEV. (MSL.)596'
G2158-32-01.GPJ
MATERIAL DESCRIPTIONLITHOLOGY
... STANDARD PENETRATION TEST
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT
IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
G2158-32-01
APPENDIX B
APPENDIX B
SEISMIC REFRACTION SURVEY
PREPARED BY SOUTHWEST GEOPHYSICS,
DATED AUGUST 10, 2017; PROJECT NO. 117388
FOR
THE FARMS AT POWAY
POWAY, CALIFORNIA
PROJECT NO. G2158-32-04
SEISMIC REFRACTION SURVEY
STONERIDGE GOLF COURSE
SAN DIEGO, CALIFORNIA
PREPARED FOR:
Geocon Incorporated
6960 Flanders Drive
San Diego, CA 92121
PREPARED BY:
Southwest Geophysics, Inc.
8057 Raytheon Road, Suite 9
San Diego, CA 92111
August 10, 2017
Project No. 117388
August 10, 2017
Project No. 117388
Mr. David Evans
Geocon Incorporated
6960 Flanders Drive
San Diego, CA 92121
Subject: Seismic Refraction Survey
Stoneridge Golf Course
San Diego, California
Dear Mr. Evans:
In accordance with your authorization, we have performed a seismic refraction survey pertaining
to the Stoneridge Golf Course project located in San Diego, California. Specifically, our survey
consisted of performing seven seismic refraction traverses at the project site. The purpose of our
study was to develop subsurface velocity profiles of the areas surveyed, and to assess the appar-
ent rippability of the subsurface materials. This data report presents our survey methodology,
equipment used, analysis, and results.
We appreciate the opportunity to be of service on this project. Should you have any questions
please contact the undersigned at your convenience.
Sincerely,
SOUTHWEST GEOPHYSICS, INC.
PFL/HV/hv
Distribution: Addressee (electronic)
Patrick Lehrmann, P.G., P.Gp.
Principal Geologist/Geophysicist
Hans van de Vrugt, C.E.G., P.Gp.
Principal Geologist/Geophysicist
Stoneridge Golf Course August 10, 2017
San Diego, California Project No. 117388
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TABLE OF CONTENTS
Page
1. INTRODUCTION ....................................................................................................................1
2. SCOPE OF SERVICES ............................................................................................................1
3. SITE DESCRIPTION ...............................................................................................................1
4. SURVEY METHODOLOGY ..................................................................................................1
5. DATA ANALYSIS ..................................................................................................................3
6. RESULTS AND CONCLUSIONS ..........................................................................................3
7. LIMITATIONS .........................................................................................................................4
8. SELECTED REFERENCES ....................................................................................................5
Table
Table 1 – Rippability Classification ................................................................................................3
Figures
Figure 1 – Site Location Map
Figure 2 – Line Location Map
Figure 3 – Site Photographs
Figure 4a – Seismic Profile, SL-1
Figure 4b – Seismic Profile, SL-2
Figure 4c – Seismic Profile, SL-3
Figure 4d – Seismic Profile, SL-4
Figure 4e – Seismic Profile, SL-5
Figure 4f – Seismic Profile, SL-6
Figure 4g – Seismic Profile, SL-7
Stoneridge Golf Course August 10, 2017
San Diego, California Project No. 117388
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1. INTRODUCTION
In accordance with your authorization, we have performed a seismic refraction survey pertaining
to the Stoneridge Golf Course project located in San Diego, California (Figure 1). Specifically,
our survey consisted of performing seven seismic refraction traverses at the project site. The pur-
pose of our study was to develop subsurface velocity profiles of the areas surveyed, and to assess
the apparent rippability of the subsurface materials. This data report presents our survey method-
ology, equipment used, analysis, and results.
2. SCOPE OF SERVICES
Our scope of services included:
Performance of seven seismic P-wave refraction lines at the project site.
Compilation and analysis of the data collected.
Preparation of this data report presenting our results and conclusions.
3. SITE DESCRIPTION
The project site is generally located north of Espola Road between Saint Andrews Drive and
Cloudcroft Drive in San Diego, California (Figure 1). The site is an active golf course and coun-
try club. Vegetation at the site consists of trees, scattered brush and grass. Several granitic
bedrock outcrops are visible at the site. Figures 2, 3a, and 3b depict the site conditions in the area
of the seismic traverses.
4. SURVEY METHODOLOGY
A seismic P-wave (compression wave) refraction survey was conducted at the site to evaluate the
rippability characteristics of the subsurface materials and to develop subsurface velocity profiles
of the areas surveyed. The seismic refraction method uses first-arrival times of refracted seismic
waves to estimate the thicknesses and seismic velocities of subsurface layers. Seismic P-waves
generated at the surface, using a hammer and plate, are refracted at boundaries separating materi-
als of contrasting velocities. These refracted seismic waves are then detected by a series of
surface vertical component 14-Hz geophones and recorded with a 24-channel Geometrics Geode
Stoneridge Golf Course August 10, 2017
San Diego, California Project No. 117388
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seismograph. The travel times of the seismic P-waves are used in conjunction with the shot-to-
geophone distances to obtain thickness and velocity information on the subsurface materials.
Seven seismic lines (SL-1 through SL-7) were conducted in the study area. The general locations
and lengths of the lines were selected by your office. Shot points (signal generation locations)
were conducted along the lines at the ends, midpoint, and intermediate points between the ends
and the midpoint.
The seismic refraction theory requires that subsurface velocities increase with depth. A layer
having a velocity lower than that of the layer above will not generally be detectable by the seis-
mic refraction method and, therefore, could lead to errors in the depth calculations of subsequent
layers. In addition, lateral variations in velocity, such as those caused by core stones, intrusions
or boulders can also result in the misinterpretation of the subsurface conditions. In general, the
effective depth of evaluation for a seismic refraction traverse is approximately one-third to one-
fifth the length of the spread.
In general, the seismic P-wave velocity of a material can be correlated to rippability (see Table 1
below), or to some degree “hardness.” Table 1 is based on published information from the Cater-
pillar Performance Handbook (Caterpillar, 2011) as well as our experience with similar
materials, and assumes that a Caterpillar D-9 dozer ripping with a single shank is used. We em-
phasize that the cutoffs in this classification scheme are approximate and that rock
characteristics, such as fracture spacing and orientation, play a significant role in determining
rock quality or rippability. The rippability of a mass is also dependent on the excavation equip-
ment used and the skill and experience of the equipment operator.
For trenching operations, the rippability values should be scaled downward. For example, veloci-
ties as low as 3,500 feet/second may indicate difficult ripping during trenching operations. In
addition, the presence of boulders, which can be troublesome in a narrow trench, should be antic-
ipated.
Stoneridge Golf Course August 10, 2017
San Diego, California Project No. 117388
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Table 1 – Rippability Classification
Seismic P-wave Velocity Rippability
0 to 2,000 feet/second Easy
2,000 to 4,000 feet/second Moderate
4,000 to 5,500 feet/second Difficult, Possible Blasting
5,500 to 7,000 feet/second Very Difficult, Probable Blasting
Greater than 7,000 feet/second Blasting Generally Required
It should be noted that the rippability cutoffs presented in Table 1 are slightly more conservative
than those published in the Caterpillar Performance Handbook (Caterpillar, 2004). Accordingly,
the above classification scheme should be used with discretion, and contractors should not be
relieved of making their own independent evaluation of the rippability of the on-site materials
prior to submitting their bids.
5. DATA ANALYSIS
The collected data were processed using SIPwin (Rimrock Geophysics, 2003), a seismic inter-
pretation program, and analyzed using SeisOpt Pro (Optim, 2008). SeisOpt Pro uses first arrival
picks and elevation data to produce subsurface velocity models through a nonlinear optimization
technique called adaptive simulated annealing. The resulting velocity model provides a tomogra-
phy image of the estimated geologic conditions. Both vertical and lateral velocity information is
contained in the tomography model. Changes in layer velocity are revealed as gradients rather
than discrete contacts, which typically are more representative of actual conditions.
6. RESULTS AND CONCLUSIONS
As previously indicated, seven seismic traverses were conducted as part of our study. Figures 4a
through 4g present the velocity models generated from our analysis. Based on the results it ap-
pears that the study area is underlain by low velocity materials (e.g., topsoil) in the near surface
and granitic bedrock at depth. Distinct vertical and lateral velocity variations are evident in the
models. Moreover, the degree of bedrock weathering and the depth to bedrock appears to be
highly variable across the study areas. In addition, remnant boulders appear to be present in the
subsurface in some areas.
Stoneridge Golf Course August 10, 2017
San Diego, California Project No. 117388
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Based on the refraction results, variability in the excavatability (including depth of rippability) of
the subsurface materials should be expected across the project area. Furthermore, blasting may
be required depending on the excavation depth, location, equipment used, and desired rate of
production. In addition, oversized materials should be expected. A contractor with excavation
experience in similar difficult conditions should be consulted for expert advice on excavation
methodology, equipment and production rate.
7. LIMITATIONS
The field evaluation and geophysical analyses presented in this report have been conducted in
general accordance with current practice and the standard of care exercised by consultants per-
forming similar tasks in the project area. No warranty, express or implied, is made regarding the
conclusions, recommendations, and opinions presented in this report. There is no evaluation de-
tailed enough to reveal every subsurface condition. Variations may exist and conditions not
observed or described in this report may be present. Uncertainties relative to subsurface condi-
tions can be reduced through additional subsurface exploration. Additional subsurface surveying
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. Southwest Geophys-
ics, Inc. 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 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.
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San Diego, California Project No. 117388
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8. SELECTED REFERENCES
Caterpillar, Inc., 2011, Caterpillar Performance Handbook, Edition 41, Caterpillar, Inc., Peoria,
Illinois.
Mooney, H.M., 1976, Handbook of Engineering Geophysics, dated February.
Optim, Inc., 2008, SeisOpt Pro, V-5.0.
Rimrock Geophysics, 2003, Seismic Refraction Interpretation Program (SIPwin), V-2.76.
Telford, W.M., Geldart, L.P., Sheriff, R.E., and Keys, D.A., 1976, Applied Geophysics,
Cambridge University Press.
SITE LOCATION MAPFigure 1Stoneridge Golf CourseSan Diego, CaliforniaProject No.: 117338Date: 08/17SOUTHWESTGEOPHYSICS INC.Seismic LineLEGENDSL-7SL-3Cloudcroft DrCloudcroft CtSt Andrews Dr
SEISMIC LINE LOCATIONMAPFigure 2Stoneridge Golf CourseSan Diego, CaliforniaSOUTHWESTGEOPHYSICS INC.Project No.: 117338 Date: 08/17Cloudcroft DriveSt Andrews DriveCloudcroftTam O Shanter Drive approximate scale in feet6003000Seismic LineLEGENDSL-71250
SEISMIC PROFILEFigure 4aSOUTHWESTGEOPHYSICS INC.Project No.: 117338Date: 08/17TOMOGRAPHY MODELSL-1Note: Contour Interval = 1,000 feet per secondVelocity (ft/s)Distance (ft)Relative Elevation (ft)Stoneridge Golf CourseSan Diego, California0 102030405060708090100110120-40-30-20-100-40-30-20-10010002000300040005000600070008000900010000
SEISMIC PROFILEFigure 4bSOUTHWESTGEOPHYSICS INC.Project No.: 117338Date: 08/17TOMOGRAPHY MODELSL-2Note: Contour Interval = 1,000 feet per secondVelocity (ft/s)Distance (ft)Relative Elevation (ft)Stoneridge Golf CourseSan Diego, California0 102030405060708090100110120-40-30-20-10010-40-30-20-1001010002000300040005000600070008000900010000
SEISMIC PROFILEFigure 4cSOUTHWESTGEOPHYSICS INC.Project No.: 117338Date: 08/17TOMOGRAPHY MODELSL-3Note: Contour Interval = 1,000 feet per secondVelocity (ft/s)Distance (ft)Relative Elevation (ft)Stoneridge Golf CourseSan Diego, California0 102030405060708090100110120-40-30-20-10010-40-30-20-1001010002000300040005000600070008000900010000
SEISMIC PROFILEFigure 4dSOUTHWESTGEOPHYSICS INC.Project No.: 117338Date: 08/17TOMOGRAPHY MODELSL-4Note: Contour Interval = 1,000 feet per secondVelocity (ft/s)Distance (ft)Relative Elevation (ft)Stoneridge Golf CourseSan Diego, California0 102030405060708090100110120-40-30-20-10010-40-30-20-1001010002000300040005000600070008000900010000
SEISMIC PROFILEFigure 4eSOUTHWESTGEOPHYSICS INC.Project No.: 117338Date: 08/17TOMOGRAPHY MODELSL-5Note: Contour Interval = 1,000 feet per secondVelocity (ft/s)Distance (ft)Relative Elevation (ft)Stoneridge Golf CourseSan Diego, California0 102030405060708090100110120-30-20-100-30-20-10010002000300040005000600070008000900010000
SEISMIC PROFILEFigure 4fSOUTHWESTGEOPHYSICS INC.Project No.: 117338Date: 08/17TOMOGRAPHY MODELSL-6Note: Contour Interval = 1,000 feet per secondVelocity (ft/s)Distance (ft)Relative Elevation (ft)Stoneridge Golf CourseSan Diego, California0 102030405060708090100110120-30-20-10010-30-20-1001010002000300040005000600070008000900010000
SEISMIC PROFILEFigure 4gSOUTHWESTGEOPHYSICS INC.Project No.: 117338Date: 08/17TOMOGRAPHY MODELSL-7Note: Contour Interval = 1,000 feet per secondVelocity (ft/s)Distance (ft)Relative Elevation (ft)Stoneridge Golf CourseSan Diego, California0 102030405060708090100110120-40-30-20-100-40-30-20-10010002000300040005000600070008000900010000
APPENDIX C
APPENDIX C
BORING LOGS
PREPARED BY GEOCON INCORPORATED,
DATED JANUARY 12, 1990; PROJECT NO. D-3543-504
FOR
THE FARMS AT POWAY
POWAY, CALIFORNIA
PROJECT NO. G2158-32-04
APPENDIX D
APPENDIX D
BORING LOGS
PREPARED BY GEOCON INCORPORATED,
DATED OCTOBER 19, 1987; PROJECT NO. D-3543-W02
FOR
THE FARMS AT POWAY
POWAY, CALIFORNIA
PROJECT NO. G2158-32-04
APPENDIX E
APPENDIX E
RECOMMENDED GRADING SPECIFICATIONS
FOR
THE FARMS AT POWAY
POWAY, CALIFORNIA
PROJECT NO. G2158-32-04
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RECOMMENDED GRADING SPECIFICATIONS
1. GENERAL
1.1 These Recommended Grading Specifications shall be used in conjunction with the
Geotechnical Report for the project prepared by Geocon. The recommendations contained
in the text of the Geotechnical Report are a part of the earthwork and grading specifications
and shall supersede the provisions contained hereinafter in the case of conflict.
1.2 Prior to the commencement of grading, a geotechnical consultant (Consultant) shall be
employed for the purpose of observing earthwork procedures and testing the fills for
substantial conformance with the recommendations of the Geotechnical Report and these
specifications. The Consultant should provide adequate testing and observation services so
that they may assess whether, in their opinion, the work was performed in substantial
conformance with these specifications. It shall be the responsibility of the Contractor to
assist the Consultant and keep them apprised of work schedules and changes so that
personnel may be scheduled accordingly.
1.3 It shall be the sole responsibility of the Contractor to provide adequate equipment and
methods to accomplish the work in accordance with applicable grading codes or agency
ordinances, these specifications and the approved grading plans. If, in the opinion of the
Consultant, unsatisfactory conditions such as questionable soil materials, poor moisture
condition, inadequate compaction, and/or adverse weather result in a quality of work not in
conformance with these specifications, the Consultant will be empowered to reject the
work and recommend to the Owner that grading be stopped until the unacceptable
conditions are corrected.
2. DEFINITIONS
2.1 Owner shall refer to the owner of the property or the entity on whose behalf the grading
work is being performed and who has contracted with the Contractor to have grading
performed.
2.2 Contractor shall refer to the Contractor performing the site grading work.
2.3 Civil Engineer or Engineer of Work shall refer to the California licensed Civil Engineer
or consulting firm responsible for preparation of the grading plans, surveying and verifying
as-graded topography.
2.4 Consultant shall refer to the soil engineering and engineering geology consulting firm
retained to provide geotechnical services for the project.
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2.5 Soil Engineer shall refer to a California licensed Civil Engineer retained by the Owner,
who is experienced in the practice of geotechnical engineering. The Soil Engineer shall be
responsible for having qualified representatives on-site to observe and test the Contractor's
work for conformance with these specifications.
2.6 Engineering Geologist shall refer to a California licensed Engineering Geologist retained
by the Owner to provide geologic observations and recommendations during the site
grading.
2.7 Geotechnical Report shall refer to a soil report (including all addenda) which may include
a geologic reconnaissance or geologic investigation that was prepared specifically for the
development of the project for which these Recommended Grading Specifications are
intended to apply.
3. MATERIALS
3.1 Materials for compacted fill shall consist of any soil excavated from the cut areas or
imported to the site that, in the opinion of the Consultant, is suitable for use in construction
of fills. In general, fill materials can be classified as soil fills, soil-rock fills or rock fills, as
defined below.
3.1.1 Soil fills are defined as fills containing no rocks or hard lumps greater than
12 inches in maximum dimension and containing at least 40 percent by weight of
material smaller than ¾ inch in size.
3.1.2 Soil-rock fills are defined as fills containing no rocks or hard lumps larger than
4 feet in maximum dimension and containing a sufficient matrix of soil fill to allow
for proper compaction of soil fill around the rock fragments or hard lumps as
specified in Paragraph 6.2. Oversize rock is defined as material greater than
12 inches.
3.1.3 Rock fills are defined as fills containing no rocks or hard lumps larger than 3 feet
in maximum dimension and containing little or no fines. Fines are defined as
material smaller than ¾ inch in maximum dimension. The quantity of fines shall be
less than approximately 20 percent of the rock fill quantity.
3.2 Material of a perishable, spongy, or otherwise unsuitable nature as determined by the
Consultant shall not be used in fills.
3.3 Materials used for fill, either imported or on-site, shall not contain hazardous materials as
defined by the California Code of Regulations, Title 22, Division 4, Chapter 30, Articles 9
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and 10; 40CFR; and any other applicable local, state or federal laws. The Consultant shall
not be responsible for the identification or analysis of the potential presence of hazardous
materials. However, if observations, odors or soil discoloration cause Consultant to suspect
the presence of hazardous materials, the Consultant may request from the Owner the
termination of grading operations within the affected area. Prior to resuming grading
operations, the Owner shall provide a written report to the Consultant indicating that the
suspected materials are not hazardous as defined by applicable laws and regulations.
3.4 The outer 15 feet of soil-rock fill slopes, measured horizontally, should be composed of
properly compacted soil fill materials approved by the Consultant. Rock fill may extend to
the slope face, provided that the slope is not steeper than 2:1 (horizontal:vertical) and a soil
layer no thicker than 12 inches is track-walked onto the face for landscaping purposes. This
procedure may be utilized provided it is acceptable to the governing agency, Owner and
Consultant.
3.5 Samples of soil materials to be used for fill should be tested in the laboratory by the
Consultant to determine the maximum density, optimum moisture content, and, where
appropriate, shear strength, expansion, and gradation characteristics of the soil.
3.6 During grading, soil or groundwater conditions other than those identified in the
Geotechnical Report may be encountered by the Contractor. The Consultant shall be
notified immediately to evaluate the significance of the unanticipated condition
4. CLEARING AND PREPARING AREAS TO BE FILLED
4.1 Areas to be excavated and filled shall be cleared and grubbed. Clearing shall consist of
complete removal above the ground surface of trees, stumps, brush, vegetation, man-made
structures, and similar debris. Grubbing shall consist of removal of stumps, roots, buried
logs and other unsuitable material and shall be performed in areas to be graded. Roots and
other projections exceeding 1½ inches in diameter shall be removed to a depth of 3 feet
below the surface of the ground. Borrow areas shall be grubbed to the extent necessary to
provide suitable fill materials.
4.2 Asphalt pavement material removed during clearing operations should be properly
disposed at an approved off-site facility or in an acceptable area of the project evaluated by
Geocon and the property owner. Concrete fragments that are free of reinforcing steel may
be placed in fills, provided they are placed in accordance with Section 6.2 or 6.3 of this
document.
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4.3 After clearing and grubbing of organic matter and other unsuitable material, loose or
porous soils shall be removed to the depth recommended in the Geotechnical Report. The
depth of removal and compaction should be observed and approved by a representative of
the Consultant. The exposed surface shall then be plowed or scarified to a minimum depth
of 6 inches and until the surface is free from uneven features that would tend to prevent
uniform compaction by the equipment to be used.
4.4 Where the slope ratio of the original ground is steeper than 5:1 (horizontal:vertical), or
where recommended by the Consultant, the original ground should be benched in
accordance with the following illustration.
TYPICAL BENCHING DETAIL
Remove All
Unsuitable Material
As Recommended By
Consultant
Finish Grade Original Ground
Finish Slope Surface
Slope To Be Such That
Sloughing Or Sliding
Does Not Occur Varies
“B”
See Note 1
No Scale
See Note 2
1
2
DETAIL NOTES: (1) Key width "B" should be a minimum of 10 feet, or sufficiently wide to permit complete coverage with the compaction equipment used. The base of the key should be graded horizontal, or inclined slightly into the natural slope.
(2) The outside of the key should be below the topsoil or unsuitable surficial material and at least 2 feet into dense formational material. Where hard rock is exposed in the bottom of the key, the depth and configuration of the key may be modified as approved by the Consultant.
4.5 After areas to receive fill have been cleared and scarified, the surface should be moisture
conditioned to achieve the proper moisture content, and compacted as recommended in
Section 6 of these specifications.
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5. COMPACTION EQUIPMENT
5.1 Compaction of soil or soil-rock fill shall be accomplished by sheepsfoot or segmented-steel
wheeled rollers, vibratory rollers, multiple-wheel pneumatic-tired rollers, or other types of
acceptable compaction equipment. Equipment shall be of such a design that it will be
capable of compacting the soil or soil-rock fill to the specified relative compaction at the
specified moisture content.
5.2 Compaction of rock fills shall be performed in accordance with Section 6.3.
6. PLACING, SPREADING AND COMPACTION OF FILL MATERIAL
6.1 Soil fill, as defined in Paragraph 3.1.1, shall be placed by the Contractor in accordance with
the following recommendations:
6.1.1 Soil fill shall be placed by the Contractor in layers that, when compacted, should
generally not exceed 8 inches. Each layer shall be spread evenly and shall be
thoroughly mixed during spreading to obtain uniformity of material and moisture
in each layer. The entire fill shall be constructed as a unit in nearly level lifts. Rock
materials greater than 12 inches in maximum dimension shall be placed in
accordance with Section 6.2 or 6.3 of these specifications.
6.1.2 In general, the soil fill shall be compacted at a moisture content at or above the
optimum moisture content as determined by ASTM D 1557.
6.1.3 When the moisture content of soil fill is below that specified by the Consultant,
water shall be added by the Contractor until the moisture content is in the range
specified.
6.1.4 When the moisture content of the soil fill is above the range specified by the
Consultant or too wet to achieve proper compaction, the soil fill shall be aerated by
the Contractor by blading/mixing, or other satisfactory methods until the moisture
content is within the range specified.
6.1.5 After each layer has been placed, mixed, and spread evenly, it shall be thoroughly
compacted by the Contractor to a relative compaction of at least 90 percent.
Relative compaction is defined as the ratio (expressed in percent) of the in-place
dry density of the compacted fill to the maximum laboratory dry density as
determined in accordance with ASTM D 1557. Compaction shall be continuous
over the entire area, and compaction equipment shall make sufficient passes so that
the specified minimum relative compaction has been achieved throughout the
entire fill.
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6.1.6 Where practical, soils having an Expansion Index greater than 50 should be placed
at least 3 feet below finish pad grade and should be compacted at a moisture
content generally 2 to 4 percent greater than the optimum moisture content for the
material.
6.1.7 Properly compacted soil fill shall extend to the design surface of fill slopes. To
achieve proper compaction, it is recommended that fill slopes be over-built by at
least 3 feet and then cut to the design grade. This procedure is considered
preferable to track-walking of slopes, as described in the following paragraph.
6.1.8 As an alternative to over-building of slopes, slope faces may be back-rolled with a
heavy-duty loaded sheepsfoot or vibratory roller at maximum 4-foot fill height
intervals. Upon completion, slopes should then be track-walked with a D-8 dozer
or similar equipment, such that a dozer track covers all slope surfaces at least
twice.
6.2 Soil-rock fill, as defined in Paragraph 3.1.2, shall be placed by the Contractor in accordance
with the following recommendations:
6.2.1 Rocks larger than 12 inches but less than 4 feet in maximum dimension may be
incorporated into the compacted soil fill, but shall be limited to the area measured
15 feet minimum horizontally from the slope face and 5 feet below finish grade or
3 feet below the deepest utility, whichever is deeper.
6.2.2 Rocks or rock fragments up to 4 feet in maximum dimension may either be
individually placed or placed in windrows. Under certain conditions, rocks or rock
fragments up to 10 feet in maximum dimension may be placed using similar
methods. The acceptability of placing rock materials greater than 4 feet in
maximum dimension shall be evaluated during grading as specific cases arise and
shall be approved by the Consultant prior to placement.
6.2.3 For individual placement, sufficient space shall be provided between rocks to allow
for passage of compaction equipment.
6.2.4 For windrow placement, the rocks should be placed in trenches excavated in
properly compacted soil fill. Trenches should be approximately 5 feet wide and
4 feet deep in maximum dimension. The voids around and beneath rocks should be
filled with approved granular soil having a Sand Equivalent of 30 or greater and
should be compacted by flooding. Windrows may also be placed utilizing an
"open-face" method in lieu of the trench procedure, however, this method should
first be approved by the Consultant.
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6.2.5 Windrows should generally be parallel to each other and may be placed either
parallel to or perpendicular to the face of the slope depending on the site geometry.
The minimum horizontal spacing for windrows shall be 12 feet center-to-center
with a 5-foot stagger or offset from lower courses to next overlying course. The
minimum vertical spacing between windrow courses shall be 2 feet from the top of
a lower windrow to the bottom of the next higher windrow.
6.2.6 Rock placement, fill placement and flooding of approved granular soil in the
windrows should be continuously observed by the Consultant.
6.3 Rock fills, as defined in Section 3.1.3, shall be placed by the Contractor in accordance with
the following recommendations:
6.3.1 The base of the rock fill shall be placed on a sloping surface (minimum slope of 2
percent). The surface shall slope toward suitable subdrainage outlet facilities. The
rock fills shall be provided with subdrains during construction so that a hydrostatic
pressure buildup does not develop. The subdrains shall be permanently connected
to controlled drainage facilities to control post-construction infiltration of water.
6.3.2 Rock fills shall be placed in lifts not exceeding 3 feet. Placement shall be by rock
trucks traversing previously placed lifts and dumping at the edge of the currently
placed lift. Spreading of the rock fill shall be by dozer to facilitate seating of the
rock. The rock fill shall be watered heavily during placement. Watering shall
consist of water trucks traversing in front of the current rock lift face and spraying
water continuously during rock placement. Compaction equipment with
compactive energy comparable to or greater than that of a 20-ton steel vibratory
roller or other compaction equipment providing suitable energy to achieve the
required compaction or deflection as recommended in Paragraph 6.3.3 shall be
utilized. The number of passes to be made should be determined as described in
Paragraph 6.3.3. Once a rock fill lift has been covered with soil fill, no additional
rock fill lifts will be permitted over the soil fill.
6.3.3 Plate bearing tests, in accordance with ASTM D 1196, may be performed in both
the compacted soil fill and in the rock fill to aid in determining the required
minimum number of passes of the compaction equipment. If performed, a
minimum of three plate bearing tests should be performed in the properly
compacted soil fill (minimum relative compaction of 90 percent). Plate bearing
tests shall then be performed on areas of rock fill having two passes, four passes
and six passes of the compaction equipment, respectively. The number of passes
required for the rock fill shall be determined by comparing the results of the plate
bearing tests for the soil fill and the rock fill and by evaluating the deflection
GI rev. 07/2015
variation with number of passes. The required number of passes of the compaction
equipment will be performed as necessary until the plate bearing deflections are
equal to or less than that determined for the properly compacted soil fill. In no case
will the required number of passes be less than two.
6.3.4 A representative of the Consultant should be present during rock fill operations to
observe that the minimum number of “passes” have been obtained, that water is
being properly applied and that specified procedures are being followed. The actual
number of plate bearing tests will be determined by the Consultant during grading.
6.3.5 Test pits shall be excavated by the Contractor so that the Consultant can state that,
in their opinion, sufficient water is present and that voids between large rocks are
properly filled with smaller rock material. In-place density testing will not be
required in the rock fills.
6.3.6 To reduce the potential for “piping” of fines into the rock fill from overlying soil
fill material, a 2-foot layer of graded filter material shall be placed above the
uppermost lift of rock fill. The need to place graded filter material below the rock
should be determined by the Consultant prior to commencing grading. The
gradation of the graded filter material will be determined at the time the rock fill is
being excavated. Materials typical of the rock fill should be submitted to the
Consultant in a timely manner, to allow design of the graded filter prior to the
commencement of rock fill placement.
6.3.7 Rock fill placement should be continuously observed during placement by the
Consultant.
7. SUBDRAINS
7.1 The geologic units on the site may have permeability characteristics and/or fracture
systems that could be susceptible under certain conditions to seepage. The use of canyon
subdrains may be necessary to mitigate the potential for adverse impacts associated with
seepage conditions. Canyon subdrains with lengths in excess of 500 feet or extensions of
existing offsite subdrains should use 8-inch-diameter pipes. Canyon subdrains less than 500
feet in length should use 6-inch-diameter pipes.
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TYPICAL CANYON DRAIN DETAIL
7.2 Slope drains within stability fill keyways should use 4-inch-diameter (or lager) pipes.
GI rev. 07/2015
TYPICAL STABILITY FILL DETAIL
7.3 The actual subdrain locations will be evaluated in the field during the remedial grading
operations. Additional drains may be necessary depending on the conditions observed and
the requirements of the local regulatory agencies. Appropriate subdrain outlets should be
evaluated prior to finalizing 40-scale grading plans.
7.4 Rock fill or soil-rock fill areas may require subdrains along their down-slope perimeters to
mitigate the potential for buildup of water from construction or landscape irrigation. The
subdrains should be at least 6-inch-diameter pipes encapsulated in gravel and filter fabric.
Rock fill drains should be constructed using the same requirements as canyon subdrains.
GI rev. 07/2015
7.5 Prior to outletting, the final 20-foot segment of a subdrain that will not be extended during
future development should consist of non-perforated drainpipe. At the non-perforated/
perforated interface, a seepage cutoff wall should be constructed on the downslope side of
the pipe.
TYPICAL CUT OFF WALL DETAIL
7.6 Subdrains that discharge into a natural drainage course or open space area should be
provided with a permanent headwall structure.
GI rev. 07/2015
TYPICAL HEADWALL DETAIL
7.7 The final grading plans should show the location of the proposed subdrains. After
completion of remedial excavations and subdrain installation, the project civil engineer
should survey the drain locations and prepare an “as-built” map showing the drain
locations. The final outlet and connection locations should be determined during grading
operations. Subdrains that will be extended on adjacent projects after grading can be placed
on formational material and a vertical riser should be placed at the end of the subdrain. The
grading contractor should consider videoing the subdrains shortly after burial to check
proper installation and functionality. The contractor is responsible for the performance of
the drains.
GI rev. 07/2015
8. OBSERVATION AND TESTING
8.1 The Consultant shall be the Owner’s representative to observe and perform tests during
clearing, grubbing, filling, and compaction operations. In general, no more than 2 feet in
vertical elevation of soil or soil-rock fill should be placed without at least one field density
test being performed within that interval. In addition, a minimum of one field density test
should be performed for every 2,000 cubic yards of soil or soil-rock fill placed and
compacted.
8.2 The Consultant should perform a sufficient distribution of field density tests of the
compacted soil or soil-rock fill to provide a basis for expressing an opinion whether the fill
material is compacted as specified. Density tests shall be performed in the compacted
materials below any disturbed surface. When these tests indicate that the density of any
layer of fill or portion thereof is below that specified, the particular layer or areas
represented by the test shall be reworked until the specified density has been achieved.
8.3 During placement of rock fill, the Consultant should observe that the minimum number of
passes have been obtained per the criteria discussed in Section 6.3.3. The Consultant
should request the excavation of observation pits and may perform plate bearing tests on
the placed rock fills. The observation pits will be excavated to provide a basis for
expressing an opinion as to whether the rock fill is properly seated and sufficient moisture
has been applied to the material. When observations indicate that a layer of rock fill or any
portion thereof is below that specified, the affected layer or area shall be reworked until the
rock fill has been adequately seated and sufficient moisture applied.
8.4 A settlement monitoring program designed by the Consultant may be conducted in areas of
rock fill placement. The specific design of the monitoring program shall be as
recommended in the Conclusions and Recommendations section of the project
Geotechnical Report or in the final report of testing and observation services performed
during grading.
8.5 We should observe the placement of subdrains, to check that the drainage devices have
been placed and constructed in substantial conformance with project specifications.
8.6 Testing procedures shall conform to the following Standards as appropriate:
8.6.1 Soil and Soil-Rock Fills:
8.6.1.1 Field Density Test, ASTM D 1556, Density of Soil In-Place By the
Sand-Cone Method.
GI rev. 07/2015
8.6.1.2 Field Density Test, Nuclear Method, ASTM D 6938, Density of Soil and
Soil-Aggregate In-Place by Nuclear Methods (Shallow Depth).
8.6.1.3 Laboratory Compaction Test, ASTM D 1557, Moisture-Density Relations of Soils and Soil-Aggregate Mixtures Using 10-Pound
Hammer and 18-Inch Drop.
8.6.1.4. Expansion Index Test, ASTM D 4829, Expansion Index Test.
9. PROTECTION OF WORK
9.1 During construction, the Contractor shall properly grade all excavated surfaces to provide
positive drainage and prevent ponding of water. Drainage of surface water shall be
controlled to avoid damage to adjoining properties or to finished work on the site. The
Contractor shall take remedial measures to prevent erosion of freshly graded areas until
such time as permanent drainage and erosion control features have been installed. Areas
subjected to erosion or sedimentation shall be properly prepared in accordance with the
Specifications prior to placing additional fill or structures.
9.2 After completion of grading as observed and tested by the Consultant, no further
excavation or filling shall be conducted except in conjunction with the services of the
Consultant.
10. CERTIFICATIONS AND FINAL REPORTS
10.1 Upon completion of the work, Contractor shall furnish Owner a certification by the Civil
Engineer stating that the lots and/or building pads are graded to within 0.1 foot vertically of
elevations shown on the grading plan and that all tops and toes of slopes are within 0.5 foot
horizontally of the positions shown on the grading plans. After installation of a section of
subdrain, the project Civil Engineer should survey its location and prepare an as-built plan
of the subdrain location. The project Civil Engineer should verify the proper outlet for the
subdrains and the Contractor should ensure that the drain system is free of obstructions.
10.2 The Owner is responsible for furnishing a final as-graded soil and geologic report
satisfactory to the appropriate governing or accepting agencies. The as-graded report
should be prepared and signed by a California licensed Civil Engineer experienced in
geotechnical engineering and by a California Certified Engineering Geologist, indicating
that the geotechnical aspects of the grading were performed in substantial conformance
with the Specifications or approved changes to the Specifications.
Project No. G2158-32-04 April 10, 2019
LIST OF REFERENCES
1.Boore, D. M., and G. M Atkinson, Ground-Motion Prediction for the Average Horizontal
Component of PGA, PGV, and 5%-Damped PSA at Spectral Periods Between 0.01 and 10.0 S,
Earthquake Spectra, Volume 24, Issue 1, pages 99-138, February 2008.
2.California Department of Conservation, Division of Mines and Geology, Probabilistic Seismic
Hazard Assessment for the State of California, Open File Report 96-08, 1996.
3.California Geological Survey, Seismic Shaking Hazards in California, Based on the
USGS/CGS Probabilistic Seismic Hazards Assessment (PSHA) Model, 2002 (revised April
2003). 10% probability of being exceeded in 50 years.
http://redirect.conservation.ca.gov/cgs/rghm/pshamap/pshamain.html
4.Campbell, K. W., and Y. Bozorgnia, NGA Ground Motion Model for the Geometric Mean
Horizontal Component of PGA, PGV, PGD and 5% Damped Linear Elastic Response Spectra
for Periods Ranging from 0.01 to 10 s, Preprint of version submitted for publication in the NGA
Special Volume of Earthquake Spectra, Volume 24, Issue 1, pages 139-171, February 2008.
5.Chiou, Brian S. J., and Robert R. Youngs, A NGA Model for the Average Horizontal
Component of Peak Ground Motion and Response Spectra, preprint for article to be published
in NGA Special Edition for Earthquake Spectra, Spring 2008.
6.Geocon Incorporated, Geotechnical Engineering Investigation for Stoneridge Country Club
Tennis Court Additions, Poway, California, dated October 18, 1987 (Project No. D-3543-
W02).
7.Geocon Incorporated, Geotechnical Engineering Investigation for Stoneridge Country Club,
Pro Shop and Golf Cart Storage Facilities, Poway, California, dated January 12, 1990
(Project No. D-3543-504).
8.Geocon Incorporated, Transmittal of Preliminary Geotechnical Information, Stoneridge Country
Club Property, Poway, California, dated August 11, 2017 (Project No. G2158-32-01).
9.Jennings, C. W., Fault Activity Map of California and Adjacent Areas, California Geologic
Survey (formerly California Division of Mines and Geology), 1994.
10.Risk Engineering (2015), EZ-FRISK (version 7.65).
11.Tan, S.S. and Kennedy, M.P., Geologic Map of the Escondido 7.5’ Quadrangle, San Diego
County, California, California Department of Conservation Division of Mines and Geology,
Scale 1:24,000, 1999.
12.United States Department of Agriculture, 1953 Stereoscopic Aerial Photographs, Flight AXN-
10M, Photos Nos. 93 and 94 (scale 1:20,000).
13.United States Geological Survey, Topographic Map of the Escondido Quadrangle, San Diego
County, California, 7.5’ Series, Scale 1:24,000, 1968.