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UPDATE
GEOTECHNICAL INVESTIGATION
BUERGER PROPERTY
CARLSBAD, CALIFORNIA
PREPARED FOR
NU WEST COMMUNITIES
SAN DIEGO, CALIFORNIA
MAY 23, 2001
Or 9Q-/0
GEOCON
INCORPORATED
GEOTECHNICAL CONSULTANTS
Project No. 06143-52-03
May 23, 2001
NU West Communities
% Civcom & Associates
3665 Ruffin Road, Suite 230
San Diego, California 92123
Attention: Mr. Roger Bhatia
Subject: BUERGER PROPERTY
CARLSBAD, CALIFORNIA
UPDATE GEOTECHNICAL INVESTIGATION
Gentlemen:
In accordance with your request and our proposal dated April 23, 2001 (Proposal No. LG-0121 1), we
have performed an update geotechnical investigation for the proposed development of the Buerger
Property in Carlsbad, California. The accompanying report presents the results of the investigation
and conclusions and recommendations relative to the geotechnical aspects of developing the property
as proposed.
If you have any questions regarding this report, or if we may be of further service, please contact the
undersigned at your convenience.
Very truly yours,
GEOCON INCORPORATED
3atrick A. Thomas
CEG 2024
PAT:JH:MSC:dlj
(6/del) Addressee
oobs
1524
cernma
lichael S. Chapi
CEG 1149
GE 2248
NO. 2024
CERTIRED
ENGINEERING
GEOLOGIST
CERTIFIED
ENGINEERINGGEOLOGIST
6960 Flanders Drive • San Diego, California 92121-2974 • Telephone (858) 558-6900 • Fax (858) 558-6159
TABLE OF CONTENTS
1. PURPOSE AND SCOPE 1
2. SITE AND PROJECT DESCRIPTION 1
3. SOIL AND GEOLOGIC CONDITIONS 2
3.1 Undocumented Fill (Qudf) 2
3.2 Topsoil (Unmapped) 2
3.3 Alluvium (Unmapped) 2
3.4 Lindavista Formation (Qln) 2
4. GROUNDWATER/SEEPAGE 3
5. GEOLOGIC HAZARDS 3
5.1 Ancient Landslides 3
5.2 Faulting 3
5.3 Seismicity-Deterministic Analysis 3
5.4 Liquefaction 4
6. CONCLUSIONS AND RECOMMENDATIONS 5
6.1 General 5
6.2 Soil and Excavation Characteristics 5
6.3 Seismic Design Criteria 5
6.4 Corrosive Potential 6
6.5 Grading 7
6.6 Slope Stability 8
6.7 Foundations 8
6.8 Retaining Walls and Lateral Loads 11
6.9 Preliminary Pavement Recommendations 13
6.10 Drainage and Maintenance 13
6.11 Grading and Foundation Plan Review 14
LIMITATIONS AND UNIFORMITY OF CONDITIONS
MAPS AND ILLUSTRATIONS
Figure 1, Vicinity Map
Figure 2, Geologic Map (Map Pocket)
Figure 3, Cut Slope Stability Analysis
Figure 4, Fill Slope Stability Analysis
Figure 5, Surficial Slope Stability Analysis
Figure 6, Retaining Wall Drainage Detail
APPENDIX A
FIELD INVESTIGATION
Figures A-l to A-18, Logs of Trenches
TABLE OF CONTENTS (Continued)
APPENDIX B
LABORATORY TESTING
Table B-I, Summary of Laboratory Maximum Dry Density and Optimum Moisture
Content Test Results
Table B-H, Summary of Laboratory Direct Shear Test Results
Table B-III, Summary of Laboratory Expansion Index Test Results
Table B-FV, Summary of Laboratory Potential of Hydrogen (pH) and Resistivity Test Results
Table B-V, Summary of Laboratory Water Soluble Sulfate Test Results
Table B-VI, Summary of Laboratory Chloride Test Results
Table B-VII, Summary of Laboratory TKN (Organic Nitrogen) Test Results
APPENDIX C
RECOMMENDED GRADING SPECIFICATIONS
GEOTECHNICAL INVESTIGATION
1. PURPOSE AND SCOPE
This report presents the results of an update geotechnical investigation of the Buerger Property
located in Carlsbad, California (see Vicinity Map, Figure 1). The purpose of the investigation was to
update our previous report, entitled Geotechnical Investigation for Buerger Property, Carlsbad,
California, dated November 20, 1998. Additional subsurface exploration was performed to evaluate
the limits and thickness of undocumented fill in the southeast portion of the property.
Recommendations relative to the geotechnical engineering aspects of developing the proposed
residential subdivision have been updated as well.
The scope of this study consisted of excavating 10 shallow exploratory trenches. Details of the field
investigation and logs of the current and previous exploratory trenches are presented in Appendix A.
Laboratory test results from the previous investigation are presented in Appendix B. The approximate
locations of the current and previous exploratory trenches are shown on Figure 2. The conclusions
and recommendations that follow are based on the findings of this study and experience with similar
soil and geologic conditions.
2. SITE AND PROJECT DESCRIPTION
The site consists of approximately 5 acres of undeveloped land located east of Black Rail Road and
north of Aviara Parkway in Carlsbad, California (see Vicinity Map, Figure 1). The rectangular
property is bounded by Black Rail Road on the west, open space and the Aviara master-planned
community on the east, a nursery on the south, and an undeveloped property on the north.
Topographically, the property is characterized by gently sloping terrain on the north and west and a
flat-graded pad to the southeast. Elevations vary from a high of approximately 380 feet above Mean
Sea Level (MSL) along the northern property boundary to a low of approximately 340 feet MSL at
the southwest comer of the site.
The property is currently vacant with two abandoned buildings and several areas of non-irrigated
plant material and trees. A roughly 15-foot-high, south-facing cut slope exists on the central portion
of the site, and a San Diego Gas and Electric (SDG&E) easement and transmission tower are present
on the southwest portion. It is understood that a 12-lot, single-family residential subdivision is
planned for the property.
It is anticipated that cut and fill slopes having a maximum height of 20 feet at an inclination of 2:1
(horizontahvertical) will be planned. In general, development and grading will consist of maximum
Project No. 06143-52-03 -1 - May 23, 2001
cut and fill depths of roughly 12 feet to create individual pads and two access streets. In addition, five
retaining walls up to six feet high are proposed.
3. SOIL AND GEOLOGIC CONDITIONS
One geologic formation and three surficial units were observed at the site. The surficial material
consists of undocumented fill, topsoil, and alluvium. The geologic formation consists of the
Quaternary-aged Lindavista Formation. Each of the soil and geologic units encountered is discussed
below in order of increasing age. The areal extent of the Lindavista Formation and undocumented fill
is shown on the Geologic Map, Figure 2.
3.1 Undocumented Fill (Qudf)
The southeastern portion of the site is underlain by undocumented fill soil placed during the
construction of previously existing green houses. The maximum thickness of the undocumented fill is
estimated to be on the order of 10 feet. Undocumented fill deposits will require removal and
compaction in areas of proposed development.
3.2 Topsoil (Unmapped)
Topsoil was encountered across the majority of the site and is estimated to be 3 to 4 feet thick. The
topsoil typically consists of silty to clayey, fine- to medium-grained sand. Removal and compaction
of the topsoil will be necessary in areas to receive fill and/or structures.
3.3 Alluvium (Unmapped)
Alluvium was encountered beneath the undocumented fill within the southeast portion of the site. The
alluvium consists of loose, dry to damp, dark brown, silty, fine sand and sandy clay. The maximum
thickness of the alluvium is estimated to be on the order of 8 feet. Alluvial deposits will require
removal and compaction in areas of proposed development.
3.4 Lindavista Formation (Qln)
Dense, partially cemented, reddish brown sandstone of the Lindavista Formation was observed in
most of the exploratory trenches. Excavations within this unit typically can be accomplished with
conventional heavy-duty grading equipment with moderate to heavy effort. Heavy ripping may be
required for excavations within localized areas of highly cemented sandstone and/or conglomerate.
Based on laboratory test results, these materials have a "low" expansion potential and adequate
bearing characteristics. Occasional areas of "medium" expansive soils have been encountered within
this unit on adjacent projects.
Project No. 06143-52-03 -2- May 23, 2001
4. GROUNDWATER/SEEPAGE
No groundwater or seepage was observed at the time of the investigation. Groundwater conditions
can be highly variable due to geologic conditions and seasonal rainfall.
5. GEOLOGIC HAZARDS
5.1 Ancient Landslides
No geomorphic features suggestive of ancient landslides were observed at the site during the
investigation or during the review of aerial photographs.
5.2 Faulting
It is our opinion, based on geologic mapping for this report and a review of published geologic maps
and reports, that the site is not located on an active or potentially active fault trace.
The Rose Canyon Fault (Offshore Zone of Deformation), located approximately 5 miles west of the
site, is the closest known active fault. An active fault is defined by the California Division of Mines
and Geology (CDMG) as a fault with evidence for Holocene activity (approximately 11,000 years
before present).
5.3 Seismicity-Deterministic Analysis
Earthquakes that might occur on the Rose Canyon, Coronado Bank, Elsinore, and other faults within
the southern California/northern Baja California area are potential generators of significant ground
motion at the site. To determine the distance of known faults from the site, the computer program
EQFAULT, Blake (1989, revised 1994 and 1997), was utilized. The results of the deterministic
analysis indicate that the Rose Canyon Fault is the most significant potential source of ground motion
at the site due to its proximity to the site. The Rose Canyon Fault is postulated as having the potential
to generate a maximum earthquake of magnitude 6.9.
Presented on the following table are the maximum earthquake events and calculated peak site
accelerations for the faults considered most likely to subject the site to ground shaking.
Project No. 06143-52-03 - 3 - May 23, 2001
TABLE 5.3
DETERMINISTIC SITE PARAMETERS FOR SELECTED ACTIVE FAULTS
Fault Name
Rose Canyon
Coronado Bank
Newport Inglewood
Elsinore-Julian
Elsinore-Temecula
Distance
from Site
(miles)
5
21
9
24
24
Maximum
Earthquake
Magnitude
6.9
7.4
6.9
7.1
6.8
Peak Site
Acceleration (g)
0.34
0.16
0.25
0.12
0.10
A review of the above information indicates that the site could be subjected to moderate to severe
ground shaking in the event of an earthquake on any of the above-tabulated faults or other faults in
the Southern California area. However, the seismic risk at the site is not considered significantly
different from that of the surrounding developments. While listing of 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 soil conditions underlying the
site. We recommend that seismic design of the structures be performed in accordance with the 1997
Uniform Building Code (UBC) guidelines.
5.4 Liquefaction
The potential for liquefaction during a strong earthquake is limited to those soils that are in a
relatively loose, unconsolidated condition and located below the water table. Due to the absence of a
permanent water table, and the recommended removal and recompaction of surficial loose soils, the
risk of seismically induced soil liquefaction occurring at the property is considered very low.
Project No. 06143-52-03 -4-May23, 2001
6. CONCLUSIONS AND RECOMMENDATIONS
6.1 General
6.1.1 No soil or geologic conditions were encountered at the site that would preclude the
development of the property as planned, provided the recommendations of this report are
followed.
6.1.2 The surficial deposits (undocumented fill, topsoil, and alluvium) are not considered suitable
for the support of fill or structural loads in their present condition and will require remedial
grading.
6.2 Soil and Excavation Characteristics
6.2.1 The soil conditions at the site are anticipated to consist of low to medium expansive, silty
sand to sandy clay derived from excavations within formational material and surficial soils.
6.2.2 Excavations within the Lindavista Formation will generally vary in difficulty with the
depth of excavation. Oversized rock generated during excavation within cemented portions
of the Lindavista Formation should be placed in accordance with Recommended Grading
Specifications (Appendix C) and the requirements of the City of Carlsbad. Since proposed
fill areas and depths are relatively limited, oversize rock may require breakage to smaller
than 6 inches or exportation from the property.
6.3 Seismic Design Criteria
6.3.1 According to UBC 1997 Figure 16-2, the site is located within Seismic Zone 4. For seismic
design, the site is characterized as Soil Type Sc- The nearest Type A fault is the Elsinore-
Julian Fault, located approximately 24 miles from the site. The nearest Type B fault is the
Rose Canyon Fault, located approximately 5 miles from the site. The following table
summarizes the site design criteria. The values listed below are for the more dominant
Rose Canyon Fault.
Project No. 06143-52-03 - 5 - May 23, 2001
TABLE 6.3
SEISMIC DESIGN PARAMETERS
Parameter
Seismic Zone Factor
Soil Profile Type
Seismic Coefficient, Ca
Seismic Coefficient Cv
Near Source Factor, Na
Near Source Factor Nv
Seismic Source
Value
0.40
Sc
0.40
0.63
1.0
1.1
B
UBC Reference
Table 16-1
Table 16-J
Table 16-Q
Table 16-R
Table 16-S
Table 16T
Table 16-U
6.4 Corrosive Potential
6.4.1 Potential of Hydrogen (pH) and resistivity tests were performed to evaluate the corrosion
potential to subsurface metal structures. The tests were performed in accordance with
California Test Method No. 643, and indicate a "mildly corrosive" condition may exist on
the site. The test results are presented in Appendix B and should be considered for the
design of underground metal structures. This information should be provided to the project
civil and corrosion engineers in preparation of improvement and plumbing plans.
6.4.2 Laboratory tests were performed to determine the percentage of water soluble sulfate and
chloride. Results of the laboratory soluble sulfate and chloride tests are presented in
Appendix B, Tables V and VI, and indicate that the on-site materials possess "moderate"
sulfate exposure and "negligible" chloride exposure to steel reinforced concrete structures
as defined by UBC Table 19-A-4. Recommendations for concrete mix design when
exposed to "moderate" sulfate conditions include using Type II cement, limiting the water-
cement ratio to a maximum of 0.50, and designing with a minimum concrete compressive
strength of 4000 psi.
6.4.3 Laboratory tests were performed to determine the percentage of TKN or organic nitrogen
which is potentially corrosive to buried copper pipes. The laboratory test results presented
in Appendix B, Table VII indicate a high potential of exposure for copper pipes. Geocon
Incorporated does not practice in the field of corrosion engineering. Therefore, due to the
potentially corrosive environment for copper pipes it is recommended that further
evaluation by a corrosion engineer be performed to incorporate the necessary precautions
to avoid premature corrosion of underground copper pipes in direct contact with the on-site
soils. This will require corrosion protection design during plumbing plan preparation.
Project No. 06143-52-03 -6-May23,2001
6.5 Grading
6.5.1 All grading should be performed in accordance with the attached Recommended Grading
Specifications (Appendix C). Where the recommendations of this section conflict with
Appendix C, the recommendations of this section take precedence. All earthwork should be
observed and all fills tested for proper compaction by Geocon Incorporated.
6.5.2 Prior to commencing grading, a preconstruction conference should be held at the site with
the owner or developer, grading contractor, civil engineer, and geotechnical engineer in
attendance. Special soil handling requirements can be discussed at that time.
6.5.3 Site preparation should begin with the removal of all deleterious material and vegetation.
The depth of removal should be such that material exposed in cut areas and soil to be used
as fill are relatively free of organic matter. Material generated during stripping and/or site
demolition should be exported from the site.
6.5.4 All potentially compressible surficial soils within areas of planned grading should be
removed to firm natural ground and be properly compacted prior to placing additional fill
and/or structural loads. The maximum depth of removal is estimated to be on the order of
16 feet below existing grade. We understand that remedial grading cannot extend beyond
the property boundaries. The minimum lateral extent of removal should encompass the area
below a 1:1 plane extending down and out from the edge of a building pad. Specialized
earth moving techniques such as "top loading" by large tracked excavators may be required
to accomplish removals of undocumented fill and surficial deposits near the subdivision
boundaries in the southeast portion of the site. Overly wet surficial materials, if
encountered, will require drying and/or mixing with drier soils to facilitate proper
compaction.
6.5.5 The site should then be brought to final subgrade elevations with structural fill compacted
in layers. In general, soils native to the site are suitable for re-use as fill if free from
vegetation, debris and other deleterious material. Layers of fill should be no thicker than
will allow for adequate bonding and compaction. All fill, including backfill and scarified
ground surfaces, should be compacted to at least 90 percent of maximum dry density at or
slightly above optimum moisture content, as determined in accordance with ASTM Test
Procedure D 1557-91.
6.5.6 To reduce the potential for differential settlement, it is recommended that the cut portion of
cut-fill transition building pads be undercut at least 3 feet and replaced with properly
compacted "very low" to "low" expansive fill soils.
Project No. 06143-52-03 - 7 - May 23, 2001
6.5.7 Where practical, the upper 3 feet of all building pads (cut or fill) and 12 inches in pavement
areas should be composed of properly compacted or undisturbed formational "very low" to
"low" expansive soils. Medium expansive soils, if encountered, should be placed in the
deeper fill areas greater than 3 feet and properly compacted. "Very low" to "low"
expansive soils are defined as those soils that have an Expansion Index of 50 or less in
accordance with UBC Table 18-I-B. Rock greater than 12 inches in maximum dimension
are typically not placed within 10 feet of finish grade or 3 feet from the deepest utility.
Rock greater than 6 inches in maximum dimension should not be placed within 3 feet of
finish grade in building pad areas.
6.6 Slope Stability
6.6.1 The results of the slope stability analysis, using soil strength parameters based on
laboratory tests and experience with similar soil materials in nearby areas indicate that the
proposed cut and fill slopes will have calculated factors-of-safety in excess of 1.5 under
static conditions for both deep-seated and shallow sloughing conditions. The stability of the
slopes was analyzed for cut and fill slopes constructed at 2:1. Slope stability calculations
for surficial stability and deep seated stability are presented on Figures 3 through 5.
6.6.2 It is recommended that all cut slope excavations be observed during grading by an
engineering geologist to verify that soil and geologic conditions do not differ significantly
from those anticipated.
6.6.3 The fill slopes should either be over built a minimum of 3 feet and cut back to final grade
or, as a minimum, backrolled with a sheepsfoot compactor at maximum 4-foot-high
intervals and track-walked upon completion so that a dozer track covers the entire slope at
least twice to achieve the required compaction.
6.6.4 The use of terrace drains on cut or fill slopes proposed for the project is not considered
necessary to maintain the gross stability of the slope.
6.6.5 All slopes should be planted, drained and properly maintained to reduce erosion. Slope
planting should generally consist of drought tolerant plants having a variable root depth.
Slope watering should be kept to a minimum to just support the plant growth.
6.7 Foundations
6.7.1 The following preliminary foundation recommendations apply to one- and two-story
structures and are separated into categories dependent on depth and geometry of fill soils
Project No. 06143-52-03 - 8 - May 23, 2001
for a particular pad, as well as the expansive characteristics of the soil within
approximately four feet of finished pad grade.
6.7.2 Foundations for either Category I, II, or III may be designed for an allowable soil bearing
pressure of 2,000 pounds per square foot (psf) (dead plus live load). This bearing pressure
may be increased by one-third for transient loads such as wind or seismic forces.
TABLE 6.7.1
FOUNDATION RECOMMENDATIONS BY CATEGORY
Foundation
Category
I
II
III
Minimum
Footing Depth
(inches)
12
18
24
Continuous Footing
Reinforcement
Two No. 4 bars, one top and
one bottom
Four No. 4 bars, two top and
two bottom
Four No. 5 bars, two top and
two bottom
Interior Slab
Reinforcement
6x6- 10/10 welded wire
mesh at slab mid-point
No. 3 bars at 24 inches on
center, both directions
No. 3 bars at 18 inches on
center, both directions
CATEGORY CRITERIA
Category I Maximum fill thickness is less than 20 feet and Expansion Index is less than or
equal to 50.
Category II Maximum fill thickness is less than 50 feet and Expansion Index is less than or
equal to 90, or variation in fill thickness is between 10 feet and 20 feet.
Category III: Fill thickness exceeds 50 feet, or variation hi fill thickness exceeds 20 feet, or
Expansion Index exceeds 90, but is less than 130.
Notes:
1.
2.
3.
4.
5.
All footings should have a minimum width of 12 inches.
Footing depth measured from lowest adjacent subgrade.
All interior living area concrete slabs should be at least four inches thick for Categories I and II
and 5 inches thick for Category III.
All interior concrete slabs should be underlain by at least 4 inches (3 inches for 5-inch slabs) of
clean sand or crushed rock.
All slabs expected to receive moisture sensitive floor coverings or used to store moisture
sensitive materials should be underlain by a vapor barrier covered with at least 2 inches of the
clean sand recommended in No. 4 above.
Project No. 06143-52-03 -9-May 23, 2001
6.7.3 No special subgrade preparation is deemed necessary prior to placing concrete, however,
the exposed foundation and slab subgrade soils should be sprinkled, as necessary, to
maintain a moist soil condition as would be expected in any such concrete placement.
6.7.4 Where buildings or other improvements are planned near the top of a slope steeper
than 3:1, special foundations and/or design considerations are recommended due to the
tendency for lateral soil movement to occur.
• Building footings should be deepened such that the bottom outside edge of the
building footing is at least 7 feet horizontally from the face of the slope.
• Swimming pools located within 7 feet of the top of cut or fill slopes are not
recommended. Where such a condition cannot be avoided, it is recommended that
the portion of the swimming pool wall within 7 feet of the slope face be designed
assuming that the adjacent soil provides no lateral support. It should be noted that
difficult excavation with very heavy effort or possibly blasting should be
anticipated during swimming pool construction operations that encounter
formational material.
• Although other improvements that are relatively rigid or brittle, such as concrete
flatwork or masonry walls may experience some distress if located near the top of a
slope, it is generally not economical to mitigate this potential. It may be possible,
however, to incorporate design measures that would permit some lateral soil
movement without causing extensive distress. Geocon Incorporated should be
consulted for specific recommendations.
6.7.5 Although the previously discussed foundation recommendations are considered adequate,
consideration should be given to the use of post-tensioned concrete slab and foundation
systems for the support of the proposed structures. The post-tensioned systems should be
designed by a structural engineer experienced in post-tensioned slab design and design
criteria of the Post-Tensioning Institute (UBC Standard No. 29-4, Part II). Although this
procedure was developed for expansive soils, it can also be used to reduce the potential for
foundation distress due to differential fill settlement. The post-tensioned design should
incorporate the geotechnical parameters presented on the following table entitled Post-
Tensioned Foundation System Design Parameters for the particular Foundation Category
designated.
Project No. 06143-52-03 -10 - May 23, 2001
TABLE 6.72
POST-TENSIONED FOUNDATION SYSTEM DESIGN PARAMETERS
Post-Tensioning Institute (PTI)
Design Parameters
1. Thornthwaite Index
2. Clay Type-Montmorillonite
3 . Clay Portion (Maximum)
4. Depth to Constant Soil Suction
5. Soil Suction
6. Moisture Velocity
7. Edge Lift Moisture Variation Distance
8. Edge Lift
9. Center Lift Moisture Variation Distance
10. Center Lift
Foundation Category
I
-20
Yes
30%
7.0ft.
3.6ft.
0.7 in./mo.
2.6ft.
0.41 in.
5.3ft.
2.12 in.
II
-20
Yes
50%
7.0ft.
3.6ft.
0.7 in./mo.
2.6ft.
0.78 in.
5.3ft.
3.21 in.
HI
-20
Yes
70%
7.0ft.
3.6ft.
0.7 in./mo.
2.6ft.
1.15 in.
5.3ft.
4.74 in.
6.7.6 UBC Standard No. 29-4 Part II uses interior stiffener beams in its structural design
procedures. If the structural engineer proposes a post-tensioned foundation design method
other than UBC Standard No. 29-4, Part II, it is recommended that interior stiffener beams
be used for Foundation Categories II and III. The depth of the perimeter foundation should
be at least 12 inches for Foundation Category I. Where the Expansion Index for a
particular building pad exceeds 50 but is less than 91, the perimeter footing depth should be
at least 18 inches; and where it exceeds 90 but is less than 130, the perimeter footing depth
should be at least 24 inches. All interior concrete slabs should be underlain by at least 4
inches (3 inches for 5-inch slabs) of clean sand or crushed rock. Geocon Incorporated
should be consulted to provide additional design parameters as required by the structural
engineer.
6.8 Retaining Walls and Lateral Loads
6.8.1 The following recommendations for retaining walls are provided based on our experience
with similar site and soil conditions. Modifications may be required depending on actual
site conditions.
6.8.2 Retaining walls not restrained at the top and having a level backfill surface should be
designed for an active soil pressure equivalent to the pressure exerted by a fluid density
of 35 pounds per cubic foot (pcf). Where the backfill will be inclined at no steeper than 2:1,
an active soil pressure of 50 pcf is recommended. These soil pressures assume that the
backfill materials within an area bounded by the wall and a 1:1 plane extending upward
from the base of the wall possess an Expansion Index of less than 50. For those pads where
Project No. 06143-52-03 -11-May23, 2001
backfill materials do not conform to the above criteria, Geocon Incorporated should be
consulted for additional recommendations.
6.8.3 Unrestrained walls are those that are allowed to rotate more than 0.001H (where H equals
the height of the retaining portion of the wall in feet) at the top of the wall. Where walls are
restrained from movement at the top, an additional uniform pressure of 7H psf should be
added to the above active soil pressure.
6.8.4 All retaining walls should be provided with a drainage system adequate to prevent the
buildup of hydrostatic forces and should be waterproofed if required by the project
architect. The use of drainage openings through the base of the wall (weep holes) is not
recommended where the seepage could be a nuisance or otherwise adversely impact the
property adjacent to the base of the wall. A typical wall drain detail is provided as Figure 6.
The above recommendations assume a properly compacted granular (Expansion Index less
than 50) backfill material with no hydrostatic forces or imposed surcharge load. If
conditions different than those described are anticipated, or if specific drainage details are
desired, Geocon Incorporated should be contacted for additional recommendations.
6.8.5 In general, wall foundations having a minimum depth and width of one foot may be
designed for an allowable soil bearing pressure of 2,000 psf, provided the soil within 3 feet
below the base of the wall has an Expansion Index of less than 90. The proximity of the
foundation to the top of a slope steeper than 3:1 could impact the allowable soil bearing
pressure. Therefore, Geocon Incorporated should be consulted where such a condition is
anticipated.
6.8.6 For resistance to lateral loads, an allowable passive earth pressure equivalent to a fluid
density of 300 pcf is recommended for footings or shear keys poured neat against properly
compacted granular fill soils or undisturbed natural soils. The allowable passive pressure
assumes a horizontal surface extending away from the base of the wall at least 5 feet or
three times the height of the surface generating the passive pressure, whichever is greater.
The upper 12 inches of material not protected by floor slabs or pavement should not be
included in the design for lateral resistance. An allowable friction coefficient of 0.4 may be
used for resistance to sliding between soil and concrete. This friction coefficient may be
combined with the allowable passive earth pressure when determining resistance to lateral
loads.
6.8.7 The recommendations presented above are generally applicable to the design of rigid
concrete or masonry retaining walls having a maximum height of 8 feet. In the event that
Project No. 06143-52-03 -12- May 23, 2001
walls higher than 8 feet or other types of walls are planned, such as crib-type walls, Geocon
Incorporated should be consulted for additional recommendations.
6.9 Preliminary Pavement Recommendations
6.9.1 Pavement sections should be designed based on the Resistance Value (R-Value) of the
subgrade soils when final grading of the site is complete. For preliminary design, a Traffic
Index of 5.5 was used and an R-Value of 30 was assumed. These assumptions result in a
4-inch asphalt concrete section over 5 inches of aggregate base.
6.9.2 Subgrade soil should be compacted to a minimum of 95 percent relative compaction to a
depth of 12 inches below rough grade.
6.9.3 Class 2 base should conform to Section 26-1.028 of the Standard Specifications for The
State of California Department of Transportation (Caltrans) with a %-inch maximum size
aggregate and should be compacted to a minimum of 95 percent of the maximum dry
density at near optimum moisture content. The asphalt concrete should conform to Section
203-6 of the Standard Specifications for Public Works Construction (Green Book).
6.9.4 The performance of asphalt concrete pavement is highly dependent upon providing positive
surface drainage away from the edge of the pavement. Ponding of water on or adjacent to
the pavement will likely result in pavement distress and subgrade failure. If planter islands
are proposed, the perimeter curb should extend at least 6 inches below the subgrade
elevation of the adjacent pavement. In addition, the surface drainage within planters should
be such that ponding will not occur. Our experience indicates that even with these
provisions, groundwater conditions can develop as a result of increased irrigation,
landscaping and surface runoff.
6.10 Drainage and Maintenance
6.10.1 Establishing proper drainage is critical to reduce the potential for differential soil
movement, erosion and subsurface seepage. Positive measures should be taken to properly
finish grade the building pads after structures and other improvements are in place, so that
drainage water from the building pads and adjacent properties is directed away from
foundations and tops of slopes to controlled drainage devices. Under no circumstances
should water be allowed to pond adjacent to footings. Experience has shown that even with
these provisions, a shallow groundwater or subsurface condition can and may develop in
areas where no such condition existed prior to site development. This is particularly true
Project No. 06143-52-03 - 13 - May 23, 2001
where a substantial increase in surface water infiltration results from an increase in
landscape irrigation.
6.11 Grading and Foundation Plan Review
6.11.1 It is recommended that Geocon Incorporated review proposed grading and/or foundation
plans prior to finalizing. The need for additional analysis or comments can be determined
at that time.
Project No. 06143-52-03 -14 - May 23, 2001
LIMITATIONS AND UNIFORMITY OF CONDITIONS
1. 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.
2. This report is issued with the understanding that it is the responsibility of the owner, or of his
representative, to ensure that the information and recommendations contained herein are
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.
3. 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.
Project No. 06143-52-03 May 23, 2001
', A/J/R4
SOtf
COURSE
SOURCE : 2001 THOMAS BROTHERS MAP
SAN DIEGO COUNTY, CALIFORNIA
REPRODUCED WITH PERMISSION GRANTED BY THOMAS BROTHERS MAPS.
THIS MAP IS COPYRIGHTED BY THOMAS BROS. MAPS. IT IS UNLAWFUL TO COPY
OR REPRODUCE ALL OR ANY PART THEREOF, WHETHER FOR PERSONAL USE OR
RESALE, WITHOUT PERMISSION NO SCALE
GEOCON
INCORPORATED
GEOTECHNICAL CONSULTANTS
6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92121-2974
PHONE 858 558-6900 - FAX 858 558-6159
VICINITY MAP
BUERGER PROPERTY
CARLSBAD, CALIFORNIA
PT/JMW DSK/EOOOD DATE 05-23-2001 PROJECT NCX 06143 - 52-03 | FIG. 1
1VICMAP
PROJECT NO. 06143-52-03
20 feet
(Horizontal :Vertical)
130 pounds per cubic foot
28 degrees
550 pounds per square foot
ASSUMED CONDITIONS:
Slope Height H =
Slope Inclination 2:1
Total Unit Weight of Soil Yt =
Angle of Internal Friction <1> =
Apparent Cohesion C =
No Seepage Forces
ANALYSIS:
YC(|) = YHtan(l> Equation (3-3), Reference 1
C
FS = NcfC Equation (3-2), Reference 1
YH
Yoj) = 2.5 Calculated Using Eq. (3-3)
Ncf = 11.5 Determined Using Figure 10, Reference 2
FS = 2.4 Factor of Safety Calculated Using Eq. (3-2)
REFERENCES:
(1) Janbu, N., Stability Analysis of Slopes with Dimensionless Parameters, Harvard Soil Mechanics,
Series No. 46, 1954.
(2) Janbu, N., Discussion of J.M. Bell, Dimensionless Parameters for Homogeneous Earth Slopes,
Journal of Soil Mechanics and Foundation Design, No. SM6, November 1967.
CUT SLOPE STABILITY ANALYSIS
BUERGER PROPERTY
CARLSBAD, CALIFORNIA
FIGURE 3
PROJECT NO. 06143-52-03
ASSUMED CONDITIONS:
Slope Height
Slope Inclination
Total Unit Weight of Soil
Angle of Internal Friction
Apparent Cohesion
No Seepage Forces
H =
2:1
Yt =
C =
20 feet
(Horizontal :Vertical)
125 pounds per cubic foot
28 degrees
550 pounds per square foot
ANALYSIS:
Equation (3-3), Reference 1
Equation (3-2), Reference 1
Calculated Using Eq. (3-3)
Determined Using Figure 10, Reference 2
Factor of Safety Calculated Using Eq. (3-2)
REFERENCES:
(1) Janbu, N., Stability Analysis of Slopes with Dimensionless Parameters, Harvard Soil Mechanics,
Series No. 46, 1954.
(2) Janbu, N., Discussion of J.M. Bell, Dimensionless Parameters for Homogeneous Earth Slopes,
Journal of Soil Mechanics and Foundation Design, No. SM6, November 1967.
FILL SLOPE STABILITY ANALYSIS
BUERGER PROPERTY
CARLSBAD, CALIFORNIA
FIGURE 4
PROJECT NO. 06143-52-03
ASSUMED CONDITIONS:
Slope Height H = Infinite
Depth of Saturation Z = 3 feet
Slope Inclination 2:1 (Horizontal :Vertical)
Slope Angle I = 27 degrees
Unit Weight of Water Yw = 62.4 pounds per cubic foot
Total Unit Weight of Soil Yt = 125 pounds per cubic foot
Angle of Internal Friction 4» = 28 degrees
Apparent Cohesion C = 200 pounds per square foot
Slope saturated to vertical depth Z below slope face.
Seepage forces parallel to slope face
ANALYSIS:
_ _
r o — — 2.. 2.
Yt Z sin / cos /'
REFERENCES:
(1) Haefeli, R. The Stability of Slopes Acted Upon by Parallel Seepage, Proc. Second International
Conference, SMFE, Rotterdam, 1948, 1, 57-62.
(2) Skempton, A. W., and F. A. Delory, Stability of Natural Slopes in London Clay, Proc. Fourth
International Conference, SMFE, London, 1957,2, 378-81.
SURFICIAL SLOPE STABILITY ANALYSIS
BUERGER PROPERTY
CARLSBAD, CALIFORNIA
FIGURES
RETAINING
WALL
12" MIN.
' •' .<>.'. o. •' •* .<*.'. c. '•' •* ,j
o • ' • '«o ' ' • '«<
FIf fj1^:—/mm,iS
GROUND
SURFACE
]_ „
3/4" CRUSHED
GRAVEL
MIRAFI 140
FILTER FABRIC
4" DIA. PERFORATED
ABS OR ADS PIPE
TO DAYLIGHT
NO SCALE
RETAINING WALL DRAINAGE DETAIL
GEOCON
INCORPORATED
GEOTECHNICAL CONSULTANTS
6960 FLANDERS DRIVE • SAN DIEGO, CALIFORNIA 92121-2974
PHONE 858 558-6900 - FAX 858 558-6159
BUERGER PROPERTY
CARLSBAD, CALIFORNIA
PT/JMW DSK/GTYPD DATE 05 - 23 - 2001 PROJECT NO. 06143-52-03 FIG. 6
RETWALL / JMW
I
I
I
E
C
I
I
I
C
I
I
C
I
I
I
I
i
E
APPENDIX A
FIELD INVESTIGATION
The field exploration was performed by Geocon Incorporated on October 29, 1998 and May 4, 2001,
and consisted of excavating and logging a total of 18 shallow exploratory trenches.
Bulk samples of representative soils were obtained from the exploratory trenches. The soils
encountered were examined, visually classified, and logged in general accordance with American
Society for Testing and Materials (ASTM) practice for Description and Identifications of Soils
(Visual-Manual Procedure D 2844). Logs of the exploratory trenches are presented as Figures A-l
through A-l8. The logs indicate the general soil types encountered and the depth at which samples
were obtained. Figures A-l through A-8 pertain to the field investigation performed on October 29,
1998. Figures A-9 through A-18 pertain to the field investigation performed on May 4, 2001.
Project No. 06143-52-03 May 23, 2001
PROJECT NO. 06143-52-02
DEPTH
IN
FEET
AU
z
SAMPLE
NO.FHOLOGYH_l
#•
V/*
'//•
•/ :/-
n-JNDWATEoQLCD
SOIL
CLASS
(USCS)
SM
CO5>C
CL
TRENCH T 1
ELEV. (MSL.) 372 DATE COMPLETED 10/29/98
EQUIPMENT HAND EXCAVATED
MATERIAL DESCRIPTION
TOPSOIL
Medium dense, dry, light brown, Silty, fine SAND,
^ numerous pinholes /
Dense, slightly moist, medium brown, Clayey, fine
~\ SAND f
\ LINDAVISTA FORMATION /
\ Stiff, moist, dark red-brown, fine Sandy CLAY /
TRENCH TERMINATED AT 2.5 FEET 'RATIONSTANCEIS/FT.)LUS°z[2_jLUfficOQ_ "-v./JENSITYC.F.)&Q
^%uj-5ct^(-
COJHHE!otEoCJ
Figure A-l, Log of Trench T 1 BUERP
SAMPLE SYMBOLS D ... SAMPLING UNSUCCESSFUL
H ... DISTURBED OR BAG SAMPLE
E ... STANDARD PENETRATION TEST • ... DRIVE SAMPLE (UNDISTURBED)
B ... CHUNK SAMPLE JE ... WATER TABLE OR SEEPAGE
NOTE: 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.
PROJECT NO. 06143-52-02
DEPTH
IN
FEET
0
- 2 ~
-
SAMPLE
NO.fHOLOGYH
'/- ^
'Y/''/- ',-,
%
W
rr
JNDWATEoceCD
SOIL
CLASS
(USCS)
SC
SC
SC
TRENCH T 2
ELEV. (MSL.) 380 DATE COMPLETED 10/29/98
EQUIPMENT HAND EXCAVATED
MATERIAL DESCRIPTION
TOPSOIL
Loose, wet, dark brown, Clayey, fine SAND ^
Loose to medium dense, wet, brown, Clayey, fine
SAND, numerous pinholes
LINDAVISTA FORMATION
— \ Dense, wet, red brown, Clayey, fine to medium /— •
\ SAND /
TRENCH TERMINATED AT 3.5 FEET •RATIONSTANCEJS/FT.)uK°^— 1 il ^UI^CQQ."-^
-JENSITYC.F.)"-• .
5_OL
OL~Q
LUS
gh-
Wmgi-SzEoCJ
Figure A-2, Log of Trench T 2 BUERP
SAMPLE SYMBOLS D... SAMPLING UNSUCCESSFUL
^ ... DISTURBED OR BAG SAMPLE
C... STANDARD PENETRATION TEST
K ... CHUNK SAMPLE
... DRIVE SAMPLE (UNDISTURBED)
... WATER TABLE OR SEEPAGE
NOTE: 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.
PROJECT NO. 06143-52-02
DEPTH
IN
FEET
SAMPLE
NO.
CDO
O
|—H_J
j
^•/•y.
fV
JNDWATEoQLCD
SOIL
CLASS
(USCS)
SC
SC
TRENCH T 3
ELEV. (MSL.) 355 DATE COMPLETED 10/29/98
EQUIPMENT HAND EXCAVATED
MATERIAL DESCRIPTION
TOPSOBL
Loose to medium dense, very moist, brown,
Clayey, fine SAND (numerous roots in top 6")
LINDAVISTA FORMATION
\ Very dense, moist, red-brown, Clayey, fine SAND /
TRENCH TERMINATED AT 2.5 FEET "RATIONSTANCEJS/FT.)LU^COQ_ tt>^
-JENSITYC.F.)^^ •
a
|S
||
(_>
Figure A-3, Log of Trench T 3 BUERP
SAMPLE SYMBOLS D... SAMPLING UNSUCCESSFUL C... STANDARD PENETRATION TEST •... DRIVE SAMPLE (UNDISTURBED)
ii ... DISTURBED OR BAG SAMPLE K ... CHUNK SAMPLE T. ... WATER TABLE OR SEEPAGE
NOTE: 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.
PROJECT NO. 06143-52-02
DEPTH
IN
FEET
°
_
- 2 -
SAMPLE
NO.LITHOL06Y'/. S
^-/////_•/
'%,
/?'/•'/-GROUNDUATER |SOIL
CLASS
(USCS)
sc
SC
TRENCH T 4
ELEV. (MSL.) 343 DATE COMPLETED 10/29/98
EQUIPMENT HAND EXCAVATED
MATERIAL DESCRIPTION
TOPSOIL
Loose, wet, brown, Clayey, fine SAND, numerous
roots in top 6"
LINDAVISTA FORMATION
\ Very dense, moist, red-brown, Clayey, fine to /
\ medium SAND /
TRENCH TERMINATED AT 3 FEET ENETRATIONRESISTANCEBLOWS/FT. >Q_"-^
_
-
fc
go
a MOISTUREONTENT COo
Figure A-4, Log of Trench T 4 BUERP
SAMPLE SYMBOLS D ... SAMPLING UNSUCCESSFUL
S ... DISTURBED OR BAG SAMPLE
C... STANDARD PENETRATION TEST •... DRIVE SAMPLE (UNDISTURBED)
K ... CHUNK SAMPLE I ... WATER TABLE OR SEEPAGE
NOTE: 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.
PROJECT NO. 06143-52-02
DEPTH
IN
FEET
I)
- 2 -
- 4 -
SAMPLE
NO.LITHOL06Y//"?
f-//'//•/
8n
^'./-X GROUNDUATER |SOIL
CLASS
(USCS)
SC
sc
TRENCH T 5
ELEV. (MSL.) 351 DATE COMPLETED 10/29/98
EQUIPMENT HAND EXCAVATED
MATERIAL DESCRIPTION
TOPSOIL
Loose, wet, brown, Clayey, fine to medium SAND,
numerous roots in top 6", pinholes
LINDAVISTA FORMATION
~\ Moderately dense to dense, very moist, red-brown, f~
\ Clayey, fine to medium SAND, indistinct layering, /
\ trace mica /
TRENCH TERMINATED AT 5 FEET ENETRATIONRESISTANCEBLOWS/FT.)Q. ^
_
"
-
ih
|cJ
a MOISTUREONTENT (JOo
Figure A-5, Log of Trench T 5 BUERP
SAMPLE SYMBOLS D... SAMPLING UNSUCCESSFUL C... STANDARD PENETRATION TEST •... DRIVE SAMPLE (UNDISTURBED)
DISTURBED OR BAG SAMPLE CHUNK SAMPLE T. . . . WATER TABLE OR SEEPAGE
NOTE: 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.
PROJECT NO. 06143-52-02
DEPTH
IN
FEET
SAMPLE
NO.LITHOL06Y%GROUNDUATER |SOIL
CLASS
(USCS)
SC
TRENCH T 6
ELEV. (MSL.) 359 DATE COMPLETED 10/29/98
EQUIPMENT HAND EXCAVATED
MATERIAL DESCRIPTION
LINDAVISTA FORMATION
SAND /
TRENCH TERMINATED AT 1 FOOT PENETRATIONRESISTANCE(BLOWS/FT.),G~
^gu
>btza MOISTURECONTENT (JOFigure A-6, Log of Trench T 6 BUERP
SAMPLE SYMBOLS D... SAMPLING UNSUCCESSFUL C... STANDARD PENETRATION TEST •... DRIVE SAMPLE (UNDISTURBED)
II ... DISTURBED OR BAG SAMPLE E ... CHUNK SAMPLE 3C ... WATER TABLE OR SEEPAGE
NOTE: 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.
PROJECT NO. 06143-52-02
DEPTH
IN
FEET
SAMPLE
NO.FHOLOGYH
-/- '.y
/-//-
fa
fV
JNDWATEoctCD
SOIL
CLASS
(USCS)
SC
TRENCH T 7
ELEV. (MSL.) 359 DATE COMPLETED 10/29/98
EQUIPMENT HAND EXCAVATED
MATERIAL DESCRIPTION
UNDOCUMENTED FILL
Dense, very moist to wet, orange brown, Clayey
_^ SAND ^_
TRENCH TERMINATED AT 1.5 FEET 'RATIONSTANCEIS/FT.)LUf^Ozffi-JLU£<QQ_"-^/
-
E~gul
^0
>bo:Q
/~s
LU£ce
gHtfl£.HtiotEo0
Figure A-7, Log of Trench T 7 BUERP
SAMPLE SYMBOLS D... SAMPLING UNSUCCESSFUL
H ... DISTURBED OR BAG SAMPLE
C... STANDARD PENETRATION TEST
B ... CHUNK SAMPLE
... DRIVE SAMPLE (UNDISTURBED)
... WATER TABLE OR SEEPAGE
NOTE: 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.
PROJECT NO. 06143-52-02
DEPTH
IN
FEET
nU
SAMPLE
NO.FHOLOGYH
/• '/'/
'$&
rv
JNDUATEoQLCO
SOIL
CLASS
(USCS)
SC
TRENCH T 8
ELEV. (MSL.) 356 DATE COMPLETED 10/29/98
EQUIPMENT HAND EXCAVATED
MATERIAL DESCRIPTION
UNDOCUMENTED FILL
Dense, very moist to wet, orange brown, Clayey
SAND J
TRENCH TERMINATED AT 1.5 FEET "RATIONSTANCEJS/FT. )LUKOzf3_iLLJ^CQ0.°"^
-
isz1*-gcJQ .&Q
UjS
= 1-
COJflH£ot
^0CJ
Figure A-8, Log of Trench T 8 BUERP
SAMPLE SYMBOLS D... SAMPLING UNSUCCESSFUL C... STANDARD PENETRATION TEST •... DRIVE SAMPLE (UNDISTURBED)
Hi ... DISTURBED OR BAG SAMPLE K ... CHUNK SAMPLE JE ... WATER TABLE OR SEEPAGE
NOTE: 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.
PROJECT NO. 06143-52-02
DEPTH
IN
FEET
A
U
—
- 2 -
-
- 4 -
- 6 -
- 10 -
-
- 12 -
- 14 -
-
1 <ID
-
- 18 -
SAMPLE
NO.ITHOL06Y_i
r'-b-\ •A\'I1- •
-V";.
'•)•-4!-1':-\l"-•!-.•-
I}-
fc
" r"j- 1 ~
"•i "'- --i i-* 1. r i
J" "
%r.%%
* L J *.* t J *.f* [. <* *.f
\[lv;t«.*^*j*+r OUNDUATERCfl
SOIL
CLASS
(USCS)
SM
SM-SC
SM
TRENCH T 9
ELEV. (MSL.) 354 DATE COMPLETED 5/4/01
EQUIPMENT JD 310 W/24" BUCKET
MATERIAL DESCRIPTION
UNDOCUMENTED FELL
Loose to medium dense, dry, reddish-brown, Silty,
fine SAND
ALLUVIUM
Loose to medium dense, damp, dark brown, Silty,
fine SAND, some clay
LENDAVISTA FORMATION
Dense, damp, reddish-brown, Silty, fine
SANDSTONE
TRENCH TERMINATED AT 18 FEET
No groundwater encountered
Backfilled 05-04-2001 ETRATIONISTANCEDWS/FT.)z[Jj_i
Q.^^
—
-
-
-
-
-
-
-
-DENSITY.C.F.)>w
a
Qi^
,\ ^J
^^ ^_
u
Figure A-9, Log of Trench T 9 BUERP
SAMPLE SYMBOLS D... SAMPLING UNSUCCESSFUL C... STANDARD PENETRATION TEST
H ... DISTURBED OR BAG SAMPLE B ... CHUNK SAMPLE
.. DRIVE SAMPLE (UNDISTURBED)
.. WATER TABLE OR SEEPAGE
NOTE: 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.
PROJECT NO. 06143-52-02
DEPTH
IN
FEET
- o -
- 2 -
-
- 4 -
- 6 -
- 8 -
—
- 10 -1
-
- 12 -
14
SAMPLE
NO.LITHOLOGY-.1 'I/.
r".'I {- -
•i-|i-
I1- -
if-'] ' - -•i- -•-
•:< •"-i . -" i
i *
'' • ' "•b: i
••M-
•n--:1--!/
vl-"GROUNDWATERSOIL
CLASS
(USCS)
SM
SM-SC
TRENCH T 10
ELEV. (MSL.) 356 DATE COMPLETED 5/4/01
EQUIPMENT JD 310 W/24" BUCKET
MATERIAL DESCRIPTION
UNDOCUMENTED FILL
Loose, dry, reddish-brown, Silty, fine SAND
ALLUVIUM
Loose, moist, dark brown, Silty, fine SAND, some
clay
TRENCH TERMINATED AT 14 FEET
No groundwater encountered
Backfilled 05-04-2001 ENETRATIONRESISTANCEBLOWS/FT.)-
-
-
-
_
_
-
-
fego;
a MOISTUREONTENT (X)u
Figure A-10, Log of Trench T 10 BUERP
SAMPLE SYMBOLS EH... SAMPLING UNSUCCESSFUL B ... STANDARD PENETRATION TEST •... DRIVE SAMPLE (UNDISTURBED)
ii ... DISTURBED OR BAG SAMPLE K ... CHUNK SAMPLE 1! ... WATER TABLE OR SEEPAGE
NOTE: 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.
PROJECT NO. 06143-52-02
DEPTH
IN
FEET
"
- 2 -
- 6 -
—
10
SAMPLE
NO.
CD
LITHOLOr-';jt. .
1
t-.-1- - -
]'-)'
:ir»fc»*«j\ *»t*> *>* r *l*
Ivlv!
QLUl
GROUNDUASOIL
CLASS
(USCS)
SM
SM-SC
SM
TRENCH T 11
ELEV. (MSL.) 357 DATE COMPLETED 5/4/01
EQUIPMENT JD 310 W/24" BUCKET
MATERIAL DESCRIPTION
UNDOCUMENTED FILL
Loose, dry, reddish-brown, Silty, fine SAND
ALLUVIUM
Loose, damp, dark brown, Silty, fine SAND, some
clay
LINDAVISTA FORMATION
Dense, damp, reddish-brown, Silty, fine
SANDSTONE
TRENCH TERMINATED AT 10 FEET
No groundwater encountered
Backfilled 05-04-2001
^UJ~ENETRATKJESISTANCBLOWS/FTQ. w
-
-
-
i12
go
a
~MOISTUREONTENT 0o
Figure A-ll, Log of Trench T 11 BUERP
SAMPLE SYMBOLS D... SAMPLING UNSUCCESSFUL C... STANDARD PENETRATION TEST •... DRIVE SAMPLE (UNDISTURBED)
... DISTURBED OR BAG SAMPLE CHUNK SAMPLE I ... WATER TABLE OR SEEPAGE
NOTE: 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.
PROJECT NO. 06143-52-02
DEPTH
IN
FEET
- 2 -
- 6 -
10
SAMPLE
NO.
CDn
LITHOL-.]•!.-.
_VL•1.J--
•\'
;]-!•
.-1- ,-"-
I"1 !-:!}.-
*L*J* f
•t[tvt*.vKr.
Ulh-<r
6ROUNDUSOIL
CLASS
(USCS)
SM
SM-SC
SM
TRENCH T 12
ELEV. (MSL.) 358 DATE COMPLETED 5/4/01
EQUIPMENT JD 310 W/24" BUCKET
MATERIAL DESCRIPTION
UNDOCUMENTED FILL
Loose, dry, reddish-brown, Silty, fine SAND
ALLUVIUM
Loose, damp, dark brown, Silty, fine SAND
LINDAVISTA FORMATION
Dense, damp, reddish-brown, Silty, fine
SANDSTONE
TRENCH TERMINATED AT 10 FEET
No groundwater encountered
Backfilled 04-05-20001
ZUJ~
^^ f ^ I *ENETRAT]iESISTANBLOUS/F1Q- ^
-
-
-
>•
^^ S*\
|o
Q
~||| *\MOISTURONTENT <u
Figure A-12, Log of Trench T 12 BUERP
SAMPLE SYMBOLS D ... SAMPLING UNSUCCESSFUL C ... STANDARD PENETRATION TEST
El ... DISTURBED OR BAG SAMPLE K ... CHUNK SAMPLE
... DRIVE SAMPLE, (UNDISTURBED)
... WATER TABLE OR SEEPAGE
NOTE: 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.
PROJECT NO. 06143-52-02
DEPTH
IN
FEET
nU
"
- 2 -
—
- 4 -
_ —
- 6 -
SAMPLE
NO.LITHOLOGY--U-"
- "1 .
:4r
•U'"i '••"!• ' "bf
•i. i •
':•:]:••**i* ,**r GROUNDUATER |SOIL
CLASS
(USCS)
SM
SM-SC
SM
TRENCH T 13
ELEV. (MSL.) 359 DATE COMPLETED 5/4/01
EQUIPMENT JD 310 W/24" BUCKET
MATERIAL DESCRIPTION
UNDOCUMENTED FILL
Loose, dry, reddish-brown, Silty, fine SAND
ALLUVIUM
Loose, dry, dark brown, Silty, fine SAND, some
clay, some roots
LINDAVISTA FORMATION
SANDSTONE /
TRENCH TERMINATED AT 7 FEET
No groundwater encountered
Backfilled 05-04-2001 ENETRATIONRESISTANCEBLOWS/FT.)Q_"-^
"
-
-
-
~~
|o
ce^a MOISTUREONTENT <y.y(j
Figure A-13, Log of Trench T 13 BUERP
SAMPLE SYMBOLS D... SAMPLING UNSUCCESSFUL C ... STANDARD PENETRATION TEST •... DRIVE SAMPLE (UNDISTURBED)
H ... DISTURBED OR BAG SAMPLE B ... CHUNK SAMPLE f. ... WATER TABLE OR SEEPAGE
NOTE: 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.
PROJECT NO. 06143-52-02
DEPTH
IN
FEET
—
- 2 -
SAMPLE
NO.LITHOLOGY::j:]::|:
» r 4 »[»* *J* *
**M*>**»M»V» f 4 *r»
* r 1 *L*
* r *L*
» r <] »•(»GROUNDUATER |SOIL
CLASS
(USCS)
SM
TRENCH T 14
ELEV. (MSL.) 359 DATE COMPLETED 5/4/01
EQUIPMENT JD 310 W/24" BUCKET
MATERIAL DESCRIPTION
LINDAVISTA FORMATION
Dense, damp, reddish-brown, Silty, fine
SANDSTONE
TRENCH TERMINATED AT 3.5 FEET
No groundwater encountered
Backfilled 05-04-2001 ENETRATIONRESISTANCEBLOWS/FT.)Q_"-^
~
|2
go
Q MOISTUREONTENT (^)o
Figure A-14, Log of Trench T 14 BUERP
SAMPLE SYMBOLS D ... SAMPLING UNSUCCESSFUL C ... STANDARD PENETRATION TEST • ... DRIVE SAMPLE (UNDISTURBED)
H ... DISTURBED OR BAG SAMPLE B ... CHUNK SAMPLE 3C ... WATER TABLE OR SEEPAGE
NOTE: 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.
PROJECT NO. 06143-52-02
DEPTH
IN
FEET
"
- 2 -
-
- 4 -
- 6 -
SAMPLE
NO.
5.LITHOLOGr':';]'!..
'.}.(-.
•j- •
.[{-
}i.
•:':-''"
If.":ifi:
_»[»J*_f
LU
GROUNDUATSOIL
CLASS
(USCS)
SM
SM
SM
TRENCH T15
ELEV. (MSL.) 357 DATE COMPLETED 5/4/01
EQUIPMENT JD 310 W/24" BUCKET
MATERIAL DESCRIPTION
UNDOCUMENTED FILL
Loose, dry, reddish-brown, Silty, fine SAND
ALLUVIUM
Loose, damp, dark brown, Silty, fine SAND
LINDAVISTA FORMATION
SANDSTONE /
TRENCH TERMINATED AT 8 FEET
No groundwater encountered
Backfilled 05-04-2001
"2. s-\ENETRATIOJESISTANCEBLOWS/FT.-
-
-
>.
H-^
^
go
Q MOISTUREONTENT (Xo
Figure A-15, Log of Trench T 15 BUERP
SAMPLE SYMBOLS D... SAMPLING UNSUCCESSFUL C... STANDARD PENETRATION TEST •... DRIVE SAMPLE (UNDISTURBED)
^ ... DISTURBED OR BAG SAMPLE B ... CHUNK SAMPLE T. ... WATER TABLE OR SEEPAGE
NOTE: 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.
PROJECT NO. 06143-52-02
DEPTH
IN
FEET
-
- 2 -
.
-
SAMPLE
NO.LITHOLOGY".1 ' .• .
•i. 1 -
I1 -: t1" "
!< -
I1'. 1-
-1 •'-. i- i
I". }'
1 ' ' '
"1 "I -* f n »i »•A-}4:
*!*]* t» r * *!'»[*.* f GROUNDUATER |SOIL
CLASS
(USCS)
SM
SM
SM
TRENCH T16
ELEV. (MSL.) 359 DATE COMPLETED 5/4/01
EQUIPMENT JD 310 W/24" BUCKET
MATERIAL DESCRIPTION
UNDOCUMENTED FILL
Loose, dry, reddish-brown, Silty, fine SAND
ALLUVIUM
Loose, damp, dark brown, Silty, fine SAND
LINDAVISTA FORMATION
SANDSTONE /
TRENCH TERMINATED AT 7 FEET
No groundwater encountered
Backfilled 05-04-2001 ENETRATIONRESISTANCEBLOWS/FT. )O- ^
~
~
_
-
fc
>-°-
a MOISTUREONTENT CX)o
Figure A-16, Log of Trench T 16 BUERP
SAMPLE SYMBOLS D... SAMPLING UNSUCCESSFUL C... STANDARD PENETRATION TEST •... DRIVE SAMPLE (UNDISTURBED)
E§ ... DISTURBED OR BAG SAMPLE B ... CHUNK SAMPLE T. ... WATER TABLE OR SEEPAGE
NOTE: 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.
PROJECT NO. 06143-52-02
DEPTH
IN
FEET
nU
—
- 2 -
"
- 4 -
-
- 6 -
SAMPLE
NO.
CD
LITHOLO'J- '
"' -
\l
r1'.i-
1*•j- -j .*.r.1,*L*%Kvt;
»L*j* r
QLLU
GROUNDUASOIL
CLASS
(USCS)
SM
SM
SM
TRENCH T17
ELEV. (MSL.) 359 DATE COMPLETED 5/4/01
EQUIPMENT JD 310 W/24" BUCKET
MATERIAL DESCRIPTION
UNDOCUMENTED FILL
Loose, dry, reddish-brown, Silty, fine SAND
ALLUVIUM
LINDAVISTA FORMATION
T\ A AA\ J-» K C"1* fw+f±
SANDSTONE /
TRENCH TERMINATED AT 6 FEET
No groundwater encountered
Backfilled 05-04-2001
SuJ^ENETRATKJESISTANCBLOWS/FTQ. ^/
—
>
|o
ofa
~MOISTUREONTENT (Jo
Figure A-17, Log of Trench T 17 BUERP
SAMPLE SYMBOLS D... SAMPLING UNSUCCESSFUL C... STANDARD PENETRATION TEST •... DRIVE SAMPLE (UNDISTURBED)
^ ... DISTURBED OR BAG SAMPLE K ... CHUNK SAMPLE f. ... WATER TABLE OR SEEPAGE
NOTE: 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.
PROJECT NO. 06143-52-02
DEPTH
IN
FEET
nU
—
- 2 -
SAMPLE
NO.LITHOLOGY:£&:
* f 1 *L*H'K%
» V J » »GROUNDWATER |SOIL
CLASS
(USCS)
SM
TRENCH T18
ELEV. (MSL.) 360 DATE COMPLETED 5/4/01
EQUIPMENT JD 310 W/24" BUCKET
MATERIAL DESCRIPTION
LINDAVISTA FORMATION
Dense, damp, reddish-brown, Silty, fine
SANDSTONE
TRENCH TERMINATED AT 3 FEET
No groundwater encountered
Backfilled 05-04-2001 ENETRATIONRESISTANCEBLOWS/FT.)Q- ^
~
>
|2
go
cfQ MOISTUREONTENT (^)o
Figure A-18, Log of Trench T 18 BUERP
SAMPLE SYMBOLS D... SAMPLING UNSUCCESSFUL C ... STANDARD PENETRATION TEST •... DRIVE SAMPLE (UNDISTURBED)
H ... DISTURBED OR BAG SAMPLE B ... CHUNK SAMPLE JL ... WATER TABLE OR SEEPAGE
NOTE: 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.
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APPENDIX
i
APPENDIX B
LABORATORY TESTING
Laboratory tests were performed in accordance with generally accepted test methods of the American
Society for Testing and Materials (ASTM) or other suggested procedures. Selected soil samples were
tested for their maximum dry density and optimum moisture content, expansion potential, and shear
strength characteristics. Selected soils samples were also tested, as part of an earlier study, for pH,
resistivity, sulfate, chloride, and TKN.
The results of the laboratory tests are presented in Tables B-I through B-VII.
TABLE B-I
SUMMARY OF LABORATORY MAXIMUM DRY DENSITY
AND OPTIMUM MOISTURE CONTENT TEST RESULTS
ASTM D 1557-91
Sample
No.
TP1-1
Description
Orange-brown, Clayey, fine to coarse
SAND
Maximum Dry
Density (pcf)
119.8
Optimum Moisture
Content (% dry wt.)
13.7
TABLE B-ll
SUMMARY OF LABORATORY DIRECT SHEAR TEST RESULTS
ASTM D 3080-98
Sample No.
TP1-1
Dry Density
(pcf)
107.5
Moisture Content
(%)
14.1
Unit Cohesion
(psf)
550
Angle of Shear
Resistance (degrees)
28
Soil sample remolded to 90 percent relative density at near optimum moisture content.
TABLE B-lll
SUMMARY OF LABORATORY EXPANSION INDEX TEST RESULTS
ASTM D 4829-95
Sample No.
TP1-1
TP2-1
Moisture Content
Before Test
(%)
11.0
8.2
After Test
(%)
29.4
14.2
Dry
Density
(pcf)
107.7
117.3
Expansion
Index
7
0
Classification
Very Low
Very Low
Project No. 06143-52-03 -B-l-May 23, 2001
TABLE B-IV
SUMMARY OF LABORATORY POTENTIAL OF
HYDROGEN (pH) AND RESISTIVITY TEST RESULTS
CALIFORNIA TEST NO. 643
Sample No.
1
2
pH
6.8
6.6
Resistivity
(ohm centimeters)
2150
3320
TABLE B-V
SUMMARY OF LABORATORY WATER SOLUBLE SULFATE TEST RESULTS
CALIFORNIA TEST METHOD 417
Sample No.
1
2
Water Soluble Sulfate Content
(percent)
0.114
0.081
Exposure
Moderate
Negligible
TABLE VI
SUMMARY OF LABORATORY CHLORIDE TEST RESULTS
EPA 300 TEST METHOD
Sample No.
1
2
Chloride Present
0.035
0.023
Exposure
Negligible
Negligible
TABLE VII
SUMMARY OF LABORATORY TKN (ORGANIC NITROGEN) TEST RESULTS
EPA 351.3 TEST METHOD
Sample No.
1
2
TKN Percent
0.521
0.088
Exposure
High
Low
Project No. 06143-52-03 -B-2-May23,2001
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APPENDIX
APPENDIX C
RECOMMENDED GRADING SPECIFICATIONS
for
BUERGER PROPERTY
CARLSBAD, CALIFORNIA
PROJECT NO. 06143-52-03
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 Incorporated. The recom-
mendations 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. It will be necessary that the Consultant provide adequate testing and
observation services so that he may determine that, in his 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 him 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, adverse weather, and so forth, 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 construction 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.
GI rev. 8/98
2.4. Consultant shall refer to the soil engineering and engineering geology consulting firm
retained to provide geotechnical services for the project.
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 3/4 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 3/4 inch in maximum dimension. The quantity of fines shall
be less than approximately 20 percent of the rock fill quantity.
GI rev. 8/98
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
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. Representative samples of soil materials to be used for fill shall 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 1-1/2 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.
GI rev. 8/98
4.2. Any asphalt pavement material removed during clearing operations should be properly
disposed at an approved off-site facility. Concrete fragments which 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.
4.3. After clearing and grubbing of organic matter or other unsuitable material, loose or porous
soils shall be removed to the depth recommended in the Geotechnical Report. The depth of
removal and compaction shall 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 6:1 (horizontal:vertical), or
where recommended by the Consultant, the original ground should be benched in
accordance with the following illustration.
TYPICAL BENCHING DETAIL
Finish Grade Original Ground
Finish Slope Surface
Remove All
Unsuitable Material
As Recommended By
Soil Engineer Slope To Be Such That
Sloughing Or Sliding
Does Not Occur
See Note 1 See Note 2-1
DETAIL NOTES:(1) Key width "B" should be a minimum of 10 feet wide, 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 bottom 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.
GI rev. 8/98
4.5. After areas to receive fill have been cleared, plowed or scarified, the surface should be
disced or bladed by the Contractor until it is uniform and free from large clods. The area
should then be moisture conditioned to achieve the proper moisture content, and compacted
as recommended in Section 6.0 of these specifications.
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 Dl557-91.
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.
GI rev. 8/98
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 D1557-91. 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.
6.1.6. Soils having an Expansion Index of greater than 50 may be used in fills if 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.
GI rev. 8/98
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.
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. All rock placement, fill placement and flooding of approved granular soil in the
windrows must be continuously observed by the Consultant or his representative.
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, maximum slope of 5 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
GI rev. 8/98
required compaction or deflection as recommended in Paragraph 6.3.3 shall be
utilized. The number of passes to be made will 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 D1196-64, may be performed in
both the compacted soil fill and in the rock fill to aid in determining the number of
passes of the compaction equipment to be performed. If performed, a minimum of
three plate bearing tests shall 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 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 shall be present during rock fill operations to
verify 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. In general, at least one test should be performed for each approximately
5,000 to 10,000 cubic yards of rock fill placed.
6.3.5. Test pits shall be excavated by the Contractor so that the Consultant can state that,
in his 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.
GI rev. 8/98
6.3.7. All rock fill placement shall be continuously observed during placement by
representatives of the Consultant.
7. OBSERVATION AND TESTING
7.1. The Consultant shall be the Owners 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 shall be placed without at least one field density
test being performed within that interval. In addition, a minimum of one field density test
shall be performed for every 2,000 cubic yards of soil or soil-rock fill placed and
compacted.
7.2. The Consultant shall perform random field density tests of the compacted soil or soil-rock
fill to provide a basis for expressing an opinion as to 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.
7.3. During placement of rock fill, the Consultant shall verify that the minimum number of
passes have been obtained per the criteria discussed in Section 6.3.3. The Consultant shall
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. If performed, plate bearing tests will be performed randomly on
the surface of the most-recently placed lift. Plate bearing tests will be performed to provide
a basis for expressing an opinion as to whether the rock fill is adequately seated. The
maximum deflection in the rock fill determined in Section 6.3.3 shall be less than the
maximum deflection of the properly compacted soil fill. When any of the above criteria
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.
7.4. 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.
GI rev. 8/98
7.5. The Consultant shall observe the placement of subdrains, to verify that the drainage devices
have been placed and constructed in substantial conformance with project specifications.
7.6. Testing procedures shall conform to the following Standards as appropriate:
7.6.1. Soil and Soil-Rock Fills:
7.6.1.1. Field Density Test, ASTM D1556-82, Density of Soil In-Place By the
Sand-Cone Method.
7.6.1.2. Field Density Test, Nuclear Method, ASTM D2922-81, Density of Soil and
Soil-Aggregate In-Place by Nuclear Methods (Shallow Depth).
7.6.1.3. Laboratory Compaction Test, ASTM D1557-91, Moisture-Density
Relations of Soils and Soil-Aggregate Mixtures Using 10-Pound Hammer
and 18-Inch Drop.
7.6.1.4. Expansion Index Test, Uniform Building Code Standard 29-2, Expansion
Index Test.
7.6.2. Rock Fills
7.6.2.1. Field Plate Bearing Test, ASTM Dl 196-64 (Reapproved 1977) Standard
Method for Nonrepresentative Static Plate Load Tests of Soils and Flexible
Pavement Components, For Use in Evaluation and Design of Airport and
Highway Pavements.
8. PROTECTION OF WORK
8.1. 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.
8.2. 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.
GI rev. 8/98
9. CERTIFICATIONS AND FINAL REPORTS
9.1. 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.
9.2. 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.
GI rev. 8/98