HomeMy WebLinkAbout3907; Rancho Santa Fe Road Swr Access Rd; Rancho Santa Fe Road Swr Access Rd; 2002-01-31IP'
pi
h
i
m
i
if
ZHMCA
J.IAM 5
E
GEOTECHNICAL INVESTIGATION
VWD2 SEWER ACCESS ROAD 2
RETAINING WALL
CARLSBAD, CALIFORNIA
PREPARED FOR
DOKKEN ENGINEERING
SAN DIEGO, CALIFORNIA
DECEMBER 31,2002 ' ' '
m
m
m
GEOCON
INCORPORATED
ProjectNo. 07016-22-01
December 31, 2002
Dokken Engineering
9665 Chesapeake Drive, Suite 435
San Diego, Califomia 92123
GEOTECHNICAL CONSULTANTS
Attention:
Subject:
Gentlemen:
Mr. Jason Hubbard
VWD2 SEWER ACCESS ROAD 2 RETAINING WALL
CARLSBAD, CALIFORNIA
GEOTECHNICAL INVESTIGATION
In accordance with your authorization of our proposal No. LG-02544 dated November 13, 2002, we
are submitting the results of our Geotechnical Investigation for the subject site. The accompanying
report presents the findings and conclusions from our study. Based on the results of our study, it is
our opinion that the improvements can be constructed as proposed, provided the recommendations of
this report are followed.
m
m
If you have any questions regarding this investigation, or if we may be of further service, please
contact the undersigned at your convenience.
Very truly yours,
lOCON INCORPORATED
'). Cannon
'kCE^468
CEG 2201
Paul Dunster
RG 6761
PD:GWC:JJV:mms
(6) Addressee
Joseph J. Vettel
GE 2401
6960 Flanders Drive • San Diego, California 92121-2974 • Telephone (858) 558-6900 • Fax (858) 558-6159
m
m
m
TABLE OF CONTENTS
m
1. PURPOSE AND SCOPE 1
2. SITE AND PROJECT DESCRIPTION 1
m 3. SOIL AND GEOLOGIC CONDITIONS 2
3.1 Undocumented Fill (Qudf) 2
^ 3.2 Alluvium (Qal) 2
Ii 3.3 Granitic Rock (Kgr) 3
4. GROUNDWATER 3
m
5. GEOLOGIC HAZARDS 3
• 5.1 Landslides 3
m 5.2 Faulting 3
5.3 Seismicity-Deterministic Analysis 3
5.4 Soil Liquefaction 5
* 5.5 Tsunamis and Seiches 5
* 6. CONCLUSIONS AND RECOMMENDATIONS 6
• 6.1 General 6
6.2 Excavation and Soil Characteristics 6
6.3 Seismic Design Criteria 7
6.4 Grading 7
6.5 Lateral Loading 9
6.6 Retaining Walls 9
6.7 Slopes 10
6.8 Minimum Resistivity, pH and Water Soluble Sulfate 11
6.9 Site Drainage and Moisture Protection 11
6.10 Foundation and Grading Plan Review 11
LIMITATIONS AND UNIFORMITY OF CONDITIONS
to MAPS AND ILLUSTRATIONS
Figure 1, Vicinity Map
* Figure 2, Site Plan
Ii Figure 3, Retaining Wall Drainage Detail
* APPENDIX A
* FIELD INVESTIGATION
Figures A-1 - A-5, Logs of Trenches
m
m
m
4V
Ii
m
m
m
m
TABLE OF CONTENTS (Continued)
APPENDIX B
LABORATORY TESTING
Table B-I, Summary of Laboratory Expansion Index Test Results
Table B-II, Summary of Laboratory Direct Shear Test Results
Table B-m, Summary of Laboratory Potential of Hydrogen (pH) and Resistivity Test Results
Table B-IV, Summary of Laboratory Water-Soluble Sulfate Test Results
Table B-V, Summary of Laboratory Maximum Dry Density and Optimum Moisture Content Test Results
Table B-VI, Summary of Laboratory Resistance Value Test Results
Figures B-1 and B-2, Consolidation Curves
Figure B-3, Gradation Curve
APPENDK C
RECOMMENDED GRADING SPECIFICATIONS
LIST OF REFERENCES
ii
m
MR
HI
ii
m
m
GEOTECHNICAL INVESTIGATION
1. PURPOSE AND SCOPE
This report presents the results of a geotechnical investigation for the proposed retaining wall to be
constructed as part of the Rancho Santa Fe Road Realignment Phase 2 project. The wall will be
located at the former intersection of San Elijo Road and Rancho Santa Fe Road in Carlsbad,
Califomia (see Vicinity Map, Figure 1). The San Elijo Road referred to in this report is currently
closed and traffic uses the new San Elijo Road located several hundred feet to the south. The purpose
of the investigation was to identify the site geology, to observe and sample the prevailing soil
conditions at the site, and to provide recommendations pertinent to the geotechnical aspects of
constructing the proposed retaining. The site was previously investigated and a report was submitted
entitled Geotechnical Design Report, Rancho Santa Fe Road Realignment, Station 252+00 to
Melrose Drive, Carlsbad, Califomia by Geocon hicorporated dated July 17, 2000 revised
November 28, 2000.
The scope of our current investigation included a site reconnaissance, a field investigation,
laboratory testing, engineering analyses, and preparation of this report. The field investigation was
performed on December 6, 2002 and consisted of excavating four exploratory trenches at the
locations indicated on Figure 2. Logs of the exploratory trenches and other details of the field
H investigation are presented in Appendix A. A trench log (T-117) previously reported in the
^ referenced geotechnical investigation is also included.
Laboratory tests were performed on selected soil samples obtained from the field investigation to
^ determine their pertinent physical properties for engineering analyses. A discussion of the laboratory
testing and results is presented in Appendix B. Applicable laboratory results from the previous,
referenced geotechnical investigation are also presented in Appendix B.
The recommendations presented herein are based on analysis of the data obtained from the
exploratory trenches, laboratory tests, the referenced geotechnical investigation, and our experience
with similar soil and geologic conditions.
2. SITE AND PROJECT DESCRIPTION
The proposed project consists of realigning Rancho Santa Fe Road to the west. The current road bed
of Rancho Santa Fe Road will be raised approximately 10 feet and the alignment will be used as an
access road for the Vallecitos Water District. Gas and sewer lines currently within the Rancho Santa
Fe Road alignment will be preserved. An existing water line within the current alignment will be
abandoned.
Project No. 07016-22-01 -1. December 31,2002
In order to raise the road bed for the access road a retaining wall is proposed. The wall will be
approximately 10 feet high and 380 feet long. This investigation focuses exclusively on the design
and construction of the proposed retaining wall. The recommendations for the realignment of Rancho
Santa Fe Road and the proposed access road are presented in the previously referenced geotechnical
report.
3. SOIL AND GEOLOGIC CONDITIONS
Soil and geologic conditions at the site are described from observations made of the exploratory
trenches, our experience with adjacent properties, and review of published geologic literature for the
general area; including our previously published investigation for the Rancho Santa Fe Road
realignment entitled Geotechnical Design Report, Rancho Santa Fe Road Realignment,
Station 252+00 to Melrose Drive, Carlsbad, California dated July 17, 2000 revised November 28,
2000.
• The field investigation indicated that surficial soils composed of undocumented fill and alluvium
overlie granitic rock at the site. These geologic units are described below and on the trench logs in
Appendix A. The surficial soils encountered during our investigation are not suitable in their present
condition for support of the proposed wall, and remedial grading in the form of either complete or
partial removal and recompaction is recommended in later sections of this report.
ii
IM
fl
m
m
m
m
m
m
m
3.1 Undocumented Fill (Qudf)
Undocumented fill soil associated with the previous construction of San Elijo Road and Rancho
Santa Fe Road, and the filling of the small tributary canyon were encountered in 3 of the trenches
excavated during the current investigation. These fills are up to 9 feet thick and are characterized as
loose to medium dense silty sand with gravel and up to 50% cobbles and boulders. The fills
encountered are non-cohesive and readily caved into the trenches.
m
in 3.2 Alluvium (Qal)
Alluvial soils were encountered at the surface and underlying the undocumented fill. The alluvial
soils are characterized as loose, damp, brown silty sand and soft, damp, sandy silt. The alluvium is
highly porous in places. The thickness of the alluvium encountered ranged from approximately 1 to 8
feet.
Project No. 07016-22-01 - 2 - December 31. 2002
3.3 Granitic Rock (Kgr)
Cretaceous-age granitic rock correlated to the Escondido Creek Granodiorite of the Southem
Califomia Batholith comprises the bedrock material underlying the proposed retaining wall. The
weathered granitic rock is characterized as moderately weak to strong, slightly to highly weadiered
rock which excavates as a fine- to coarse-grained sand with gravel, and up to 30% cobble and
boulder-size fragments. The depth to the weathered granitic rock is up to 14 feet from the existing
ground surface. The rock generally becomes less weathered with depth. Rock hardness is highly
variable in the area investigated.
4. GROUNDWATER
Groundwater seepage was encountered at the contact between the alluvium and granitic rock in
trenches T-1 and T-2 during the current investigation, but was not encountered in the referenced
previous geotechnical investigation in trench T-117 in the area of the proposed retaining wall. The
presence of this perched groundwater is likely dependent upon antecedent rainfall. Groundwater is
not anticipated to significantly impact project development as presently proposed. However, it is not
* uncommon for groundwater or seepage conditions to develop where none previously existed. Proper
surface drainage will be critical to future performance of the project.
H 5. GEOLOGIC HAZARDS
m
m
m
m
5.1 Landslides
No landslides were observed at the site or in areas that could affect the site. Landsliding does not
present significant hazard to the project.
5.2 Faulting
A review of geologic literature indicates that there are no known active or potentially active faults
crossing the site. The Rose Canyon Fault, located approximately eight miles south of the site, is the
closest known active fault. An active fault is defined by the Califomia Geological Survey (CGS) as
a fault showing evidence for activity within the last 11,000 years. The CGS has included portions of
the Rose Canyon Fault within an Alquist-Priolo Earthquake Fault Zone, but this site is not located
within such a zone.
5.3 Seismicity-Deterministic Analysis
Earthquakes occurring on the Rose Canyon Fault or other faults within the southem Califomia and
northern Baja Califomia area are potential generators of significant ground motion at the site. In
Project No. 07016-22-01 - 3 - December 31, 2002
il
m
order to determine the distance of known faults to the site, the computer program EQFAULT (Blake,
1996, revised 2000), was utilized. Principal references used within EQFAULT in selecting faults to
be included are Jennings (1975), Anderson (1984) and Wesnousky (1986).
Sixteen known active faults were identified within a search radius of 60 miles from the site. The
results of the deterministic seismic analyses indicate that earthquakes within the Rose Canyon Fault
Zone are the dominant source of potential ground motion at the site. Earthquake magnitudes and site
accelerations based on attenuation relationships of Sadigh et al. (1997) for the faults considered most
likely to subject the site to ground shaking are presented in the following table. The seismic risk at
the site is not considered significantly greater than that of the surrounding developments and the San
Diego area in general.
TABLE 5.3
DETERMINISTIC SITE PARAMETERS FOR SELECTED ACTIVE FAULTS
Fault Name Approximate Distance
From Site (miles)
Estimated Maximum
Magnitude (Mw)
Estimated Peak Site
Acceleration (g)
Rose Canyon Fault 2^ne 8 6.9 0.30
Newport-Inglewood (offshore) 13 6.9 0.20
Elsinore-Julian 22 7.1 0.12
Elsinore-Temecul a 23 6.8 0.10
Coronado Bank 23 7.4 0.14
Earthquake Valley 38 6.5 0.04
Elsinore-Glen Ivy 38 6.8 0.05
Palos Verdes 43 7.1 0.05
San Jacinto-Anza 45 7.2 0.05
San Jacinto- San Jacinto Valley 48 6.9 0.04
San Jacinto-Coyote Creek 48 6.8 0.03
Elsinore-Coyote Mountain 51 6.8 0.03
Newport-Inglewood (L.A. Basin) 54 6.9 0.03
Chino-Central Ave. (Elsinore) 54 6.7 0.03
Whittier 57 6.8 0.02
San Jacinto-Borrego 60 6.6 0.02
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 the soil conditions underlying the site. We recommended that seismic design be
performed in accordance with the California Building Code or other applicable code.
m
Project No. 07016-22-01 -4-December 31,2002
il
m
m
5.4 Soil Liquefaction
Soil liquefaction is a phenomenon where loose, saturated and relatively cohesionless soil deposits
lose strength during strong ground motions. Primary factors controlling the development of
liquefaction include intensity and duration of ground accelerations, characteristics of the subsurface
soil, in situ stress conditions and depth to groundwater. The liquefaction potential within the subject
site is considered to be low due to the lack of permanent near surface groundwater.
5.5 Tsunamis and Seiches
The site is located approximately six miles east of the Pacific Ocean at an average elevation of
approximately 350 feet above Mean Sea Level (MSL). Therefore, the risk of tsunamis affecting the
site is considered low. Lake San Marcos is located less than one mile upstream of the site. Therefore,
in the event of a large earthquake there is a potential for inundation due to seiches.
Project No. 07016-22-01 - 5 - December 31, 2002
6. CONCLUSIONS AND RECOMMENDATIONS
6.1 General
m
6.1.1 From a geotechnical standpoint, it is our opinion that the site is suitable for the proposed
m improvements, provided the recommendations presented herein are implemented in the
W design and construction of the project.
m
^ 6.1.2 The field investigation indicates that the site is underlain by surficial soils composed of
undocumented fill and alluvium that overlie granitic rock. The surficial soils are not
* adequate in their present condition for the support of settlement-sensitive structures;
* however, complete removal of these soils is not possible due to the proximity of live utility
MB lines. Remedial grading in the form of partial removal and recompaction will be required
m as discussed below.
ffl
^ 6.1.3 Perched groundwater was encountered in the current mvestigation. Groundwater is not
anticipated to significantly impact project development as presently proposed. However,
proper surface drainage of irrigation and rain water will be critical to future performance
of the project.
6.1.4 Subsurface conditions observed in the trenches are expected to be generally consistent
across the site; however, variations in subsurface conditions between trench locations
should be expected.
^ 6.1.5 With the exception of possible strong seismic shaking and flooding by seiches, no
significant geologic hazards were observed or are known to exist on the site or other
^ locations that would adversely affect the proposed project.
6.2 Excavation and Soil Characteristics
m
IK 6.2.1 The soil samples tested have a "very low" expansion potential (Expansion Lidex [EI] of 20
or less) as defined by the Uniform Building Code (UBC) Table No. 18-I-B.
Recommendations presented herein assume that soils with an Expansion Index (EI) of less
than 50 will be present to a minimum depth of three feet below bottom of footing grade. If
m soils with an EI greater than 50 are exposed near finish grade, modifications to the
* recommendations presented herein may be required.
m
H
ffl
Project No. 07016-22-01 - 6 - December 31, 2002
6.2.2 The majority of the in-situ soils can be excavated with hght to moderate effort using
conventional heavy-duty equipment. Extra effort may be required if granitic rock is
encountered in footing excavations.
6.2.3 It is the responsibility of the contractor to ensure that all excavations and trenches are
properly shored and maintained in accordance with applicable OSHA rules and regulations
in order to maintain safety and maintain the stability of adjacent existing improvements.
6.3 Seismic Design Criteria
6.3.1 The following table summarizes site design criteria obtained from the 1997 Uniform
Building Code (UBC). The values listed in the table are for the Rose Canyon Fault which
is identified as a Type B fault. The Rose Canyon Fault is located approximately eight
miles south of the site.
TABLE 6.3
SEISMIC DESIGN PARAMETERS
Parameter Value UBC Reference
Seismic Zone Factor 0.40 Table 16-1
Soil Profile Type Sc Table 16-J
Seismic Coefficient, Ca 0.4 Table 16-Q
Seismic Coefficient, Cy 0.56 Table 16-R
Near-Source Factor, Na 1.0 Table 16-S
Near Source Factor, Nv 1.0 Table 16-T
Seismic Source B Table 16-U
m
m
6.4 Grading
6.4.1 Grading should be performed in accordance with the City of Carisbad Grading Ordinance
and the Recommended Grading Specifications in Appendix C. Where the
recommendations of this report conflict with Appendix C, the recommendations of this
section take precedence.
6.4.2 Earthwork should be observed and compacted fill tested by representatives of Geocon
Incorporated.
Project No. 07016-22-01 -7-December 31,2002
m
6.4.3 A preconstruction conference should be held with the project architect, general contractor,
civil engineer, and soil engineer in attendance. Special soil handling requirements can be
discussed at that time.
6.4.4 Grading of the site should commence with the removal of all existing improvements from
the areas to be graded. Deleterious material such as wood, grass, asphalt, and concrete
should be exported from the site and should not be mixed with the fill soils. Disposal of
unsuitable materials should follow relevant environmental and governmental regulations.
Abandoned foundations and buried utilities (if encountered) should be removed and the
subsequent depressions and/or trenches should be filled with properly compacted soil as
part of the remedial grading.
6.4.5 All undocumented fill and alluvium encountered beneath the proposed wall should be
removed to a depth of approximately 3 feet below the bottom of the wall footing. The
removal should extend at least 5 feet beyond the footing limits where practical. Utilities, if
present, should be accurately located within the footing excavation area. Excavated soils
generated from cut operations can be placed and compacted in layers to the design finish
grade elevations. Geocon Incorporated should be retained during overexcavation
operations to identify areas where unsuitable materials may extend deeper than expected.
6.4.6 Soils excavated from the undocumented fill and alluvium will generally be suitable for use
ffl as compacted backfill from a geotechnical engineering standpoint. Soils with an EI greater
• than 50 should not be used as backfill behind the wall. Geocon Incorporated should
observe the excavated materials and determine its suitability as compacted backfill
material.
6.4.7 Imported soil should consist of granular materials with a "low" expansion potential
^ (EI less than 50) firee of deleterious material or cobbles larger than three inches and should
«R be compacted as recommended above. Geocon Incorporated should be notified of the
HI import soil source and should perform laboratory testing of import soil prior to its arrival
at the site to determine its suitability as fill material.
6.4.8 The bottom of the excavation should be scarified to a depth of 8 inches, moisture
conditioned, and compacted to at least 90 percent relative compaction at above optimum
moisture content as determined by ASTM D 1557-00.
^ 6.4.9 Approved backfill material should be placed and compacted in layers to the design finish
grade elevations. All fill and backfill soils should be placed in lifts approximately 8 inches
Project No. 07016-22-01 - 8 - December 31, 2002
*" thick, moisture conditioned to a water content of approximately one to three percent above
optimum moisture content, and compacted to at least 90 percent relative compaction as
^ detennined by ASTM D 1557-00.
m
6.4.10 The upper 12 inches of subgrade soils beneath pavement areas should be compacted to
95 percent relative compaction. The placement of soil should be observed and tested by a
representative of Geocon Incorporated during grading operations.
mm,
6.4.11 Foundation excavations should be observed by a representative of Geocon Incorporated
— prior to the placement of reinforcing steel or concrete to check that the exposed soil
«H conditions are consistent with those anticipated. If unanticipated soil conditions are
encountered, foundation modifications may be required.
6.4.12 No special subgrade presaturation is deemed necessary prior to placing concrete; however,
the exposed foundation soils should be maintained in a moist condition as would be
expected in any such concrete placement.
^ 6.5 Lateral Loading
6.5.1 To resist lateral loads, a passive pressure exerted by an equivalent fluid weight of
300 pounds per cubic foot (pcf) should be used for design of footings or shear keys poured
m neat against properly compacted granular fill soils. The upper 12 inches of material in
I* areas not protected by floor slabs or pavement should not be included in design for passive
resistance.
ffl
•
6.5.2 If friction is to be used to resist lateral loads, an allowable coefficient of friction between
soil and concrete of 0.4 should be used for design.
* 6.6 Retaining Walls
Hit
6.6.1 Retaining walls which are allowed to rotate at the top more than 0.001 H (where H is the
height of the wall) and having a level backfill surface should be designed for an active soil
pressure equivalent to the pressure exerted by a fluid density of 32 pounds per cubic foot
(pcf). Where the backfill will be inclined at 2:1 (horizontal:vertical), an active soil
pressure of 45 pcf is recommended. All soil placed for retaining wall backfill should have
an Expansion Index less than 50.
m
Project No. 07016-22-01 - 9 - December 31, 2002
6.6.2 Where walls are restrained from movement at the top, an additional uniform pressure of
7H pounds per square foot (psf) should be added to the above active soil pressure. For
retaining walls subject to vehicular loads within a horizontal distance equal to two-thirds
the wall height, a surcharge equivalent to two feet of fill soils (240 psf) should be added.
6.6.3 Retaining walls should be founded on granitic rock or properiy compacted fill An
allowable bearing capacity for the retaining wall can be taken as 3,000 psf An associated
settlement of one inch is estimated due to retaining wall footing loads.
6.6.4 Retaining walls should be provided wiUi a drainage system adequate to prevent the buildup
of hydrostatic forces and should be waterproofed as required by the project architect.
Figure 3 presents a recommended retaining wall drainage detail. 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 affect the property adjacent to the base of the
wall. The above recommendations assume a properly compacted granular (EI less than 50)
free-draining 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.
* 6.6.5 The recommendations presented above are generally applicable to the design of rigid
concrete or masonry retaining walls having a maximum height of twelve feet. In the event
!• that walls higher than twelve feet or other types of walls are planned, such as crib-type
walls, Geocon Incorporated should be consulted for additional recommendations.
6.7 Slopes
6.7.1 In general, undocumented fill and alluvium can be considered Type B soils in accordance
with OSHA guidelines. Temporary slopes may generally be excavated no steeper than 1:1
(horizontal to vertical) without shoring provided the top of the excavation is a minimum of
1^ 15 feet from the edge of existing buildings and other improvements. Excavations steeper
than 1:1 or closer than 15 feet from an existing improvement, should be shored in
^ accordance with applicable OSHA codes and regulations.
* 6.7.2 Permanent fill slopes should be no steeper than 2:1 (horizontal: vertical). Anticipated final
• fill slopes have a calculated overall static factor of safety of 1.5. The proposed slopes are
^ expected to perform satisfactorily under both static and earthquake loading conditions.
m
m Project No. 07016-22-01 - 10 - December 31,2002
6.7.3 Fill slopes will be composed of granular soils that are susceptible to surface erosion.
*^ Consideration should be given to the use of jute mesh of other surface treatment to
— minimize transport by runoff until adequate vegetation can take root. All roadway drainage
w should be directed to appropriate collection and discharge facilities so that nm-off does not
flow over the tops of slopes.
^ 6.8 Minimum Resistivity, pH and Water Soluble Sulfate
6.8.1 Potential of Hydrogen (pH) and resistivity tests were performed on a selected sample to
^ evaluate the corrosion potential to subsurface structures. The tests were performed in
^ accordance with California Test Method No. 643 and indicate that a high potential for
corrosion of buried metals exists on site. The results are presented in Appendix B and
* should be considered for design of underground structures.
m
ffl 6.8.2 Laboratory tests were performed on a soil sample of the site materials to determine the
percentage of water-soluble sulfate content. Results from the laboratory water-soluble
sulfate test are presented in Appendix B and indicate that the on-site materials possess
^ "negligible" sulfate exposure to concrete structures as defined by UBC Table 19-A-4.
^ 6.8.3 Geocon Incorporated does not practice in the field of corrosion engineering. If corrosion
sensitive improvements are planned, it is recommended that further evaluations by a
m corrosion engineer be performed to incorporate the necessary precautions to avoid
Iff- premature corrosion on buried metal pipes and concrete stmctures in direct contact with
the soils.
6.9 Site Drainage and Moisture Protection
iff
6.9.1 Adequate drainage is critical to reduce the potential for differential soil movement,
erosion, and subsurface seepage. Under no circumstances should water be allowed to pond
adjacent to footings. The site should be graded and maintained such that surface drainage
is directed away from the wall and the top of slopes into swales or other controlled
drainage devices.
^ 6.10 Foundation and Grading Plan Review
m
6.10.1 Geocon Incorporated should review the grading plans and foundafion plans for the project
^ prior to final design submittal to determine if additional analysis and/or recommendations
are required.
Project No. 07016-22-01 - 11 - December 31. 2002
ffl
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 condidons do not deviate from those disclosed in the
investigation. If any variations or undesirable condidons 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 idendficadon of the potendal presence of hazardous or cortosive
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 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 are 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. 07016-22-01 December 31, 2002
SOURCE: 2002 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
4
NO SCALE
GEOCON O
INCORPORATED
GEOTECHNICAt CONSULTANTS
6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92I2I-2974
PHONE 858 558-6900 - FAX 858 558-6159
VICINITY MAP GEOCON O
INCORPORATED
GEOTECHNICAt CONSULTANTS
6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92I2I-2974
PHONE 858 558-6900 - FAX 858 558-6159
VWD 2 SEWER ACCESS ROAD
2 RETAINING WALL
CARLSBAD, CALIFORNIA
PD / RSS DSK/GOOOO DATE 12-31-2002; PROJECT NO. 07016 - 22 - 01 FIG 1
IGVICMAP
it tl if fl CI 9 § mm ffl ci m § ti ti ii fi ti ii ci ii
360
350
40' VC
-ADJUST EXIST
MANHOLES
iO + 20
VERT P]
?,ELEV = 352.60 .Q
O -AIIJUS" EXIST
MANHOLES
PROJECTED TOE •r SLOPE VITHOUT
ACCESS ROAD
ERNATIVE
PI ANVALLLCITOS WATER DISTRICT ACCESS RDAD 2
LEGEND
kM4 ->PPR0X LOCATION OF EXPLORATORY TRENCHES (CURRENT INVESTIGATION)
T-f 1..JJ>PROX LOCATION OF EXPLORATORY TRENCH {REFERENCED INVESTIGATION)
QUCtf ...UNDOCUMENTED FLL
Qfl/ ....ALLUVIUM (Doltad Whvs Buried)
Kgr QR«4rnC HOCK (ESCONDIDO CREEK GRANODIORITE I Dottad Where Buried))
~^ ,....3URIED CONTACT
GEOTGCHMCAL CONSULTANTS
6960 FLVOBtS ntlVE. SAN CCGO, CAlfORNU 91121-1974
PHONE SSe 558-6900 - FAX BSe 558.6139
fHQIECT NO. 07016.53-01
SITE PLAN DATE 12-31-2001
7016PD.DWG/IISS Geocon- P'-j. It 319D
D6 DOKKEN
IENBINEERINB
Dr.,8ule4% S«iOtagD.CAg2123 (058)514-0377
PROJECT NANACitR R LIPTAK
PSDJECT ENCINECR K BRADBURY
J HUBBARD
Movenber le, gone
RANCHD SANTA FE RDAD
RLALIGNMENT
PHASE 2
PRDPDSED 'VWD2'
SEVER ACCESS RGAD
12" MIN. GROUND
SURFACE
RETAINING
WALL
m
m
W
m
m
m
3/4" CRUSHED
GRAVEL
MIRAFI 140
FILTER FABRIC
4" DIA. PERFORATED
ABS OR ADS PIPE
H
m
m
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
PD / RSS DSK/GTYPD
VWD 2 SEWER ACCESS ROAD
2 RETAINING WALL
CARLSBAD, CALIFORNIA
DATE 12-31-2002 PROJECT NO. 07016 - 22 - 01 FIG 3
RETVWLL/RSS/Vn-IXV
m
m
m
APPENDIX A
FIELD INVESTIGATION
The field investigation was perfomied on December 6, 2002 and consisted of excavating 4
exploratory trenches at the approximate locations shown on Figure 2. The trenches were excavated to
a maximum depth of 16 feet below existing grade using a John Deere 310 rubber-tire backhoe
equipped with 24-inch-wide bucket. Relatively undisturbed chunk, and disturbed bulk samples were
obtained from the excavations.
The soil conditions encountered in the trenches were visually examined, classified, and logged in
general conformance with the American Society for Testing and Materials (ASTM) Practice for
Description and Identification of Soils (Visual-Manual Procedure D 2488). The logs of the
exploratory trenches are presented on Figures A-1 through A-4. A trench log from the previous,
referenced investigation is presented as Figure A-5. The logs depict the various soil types
encountered and indicate the depths at which samples were obtained.
Project No. 07016-22-01 December 31, 2002
PROJECT NO. 07016-22-01
DEPTH
IN
FEET
SAMPLE
MO.
Ci) o _l o
X l-H
SOIL
CLASS
(USCS)
TRENCH T 1
ELEV. (MSL.) 342
EQUIPMENT
DATE COMPLETED
JD310
12/6/02
Hyi-
LU
>-
Q u
- 0
- 2 -
- 4 -
- 6 -
MATERIAL DESCRIPTION
Tl-1
- 10 -
- 12 -
- 14 -
Tl-2
Tl-3
m
SM
ML
FILL
Loose, dry to damp, moderate yellowish brown,
Silty, fme to coarse SAND with angular fme and
coarse gravel, approximately 40% cobbles and
boulders up to 2 feet diameter, non cohesive,
caving
ALLUVIUM
Soft, damp, moderate brown, Sandy SILT, highly
porous
115.2 6.2
ESCONDIDO CREEK GRANGDIORTTE
Slightly to moderately weathered, mottled, fine to
medium grained, weak to moderately strong,
excavates as wet, Silty SAND with gravel,
approximately 30% cobbles up to 12 inches
diameter
-Strong to very strong below 15 feet
TRENCH TERMINATED AT 15 FEET
(REFUSAL)
Figure A-1, Log of Trench T 1 SER1
m
SAMPLE SYMBOLS • ... SAMPLING UNSUCCESSFUL E.. . STANDARD PENETRATION TEST • .. . DRIVE SAMPLE (UNDISTURBED) SAMPLE SYMBOLS • ... SAMPLING UNSUCCESSFUL
B..
SAMPLE (UNDISTURBED)
^ ... DISTURBED OR BAG SAMPLE B.. . CHUNK SAMPLE I .. . WATER TABLE OR SEEPAGE
NOTE: THE LOG OF SUBSURFACE CONDITIONS SHOUN 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. 07016-22-01
DEPTH
IN
FEET
SAMPLE
NO.
SOIL
CLASS
(USCS)
TRENCH T 2
ELEV. (MSL.) 341
EQUIPMENT
DATE COMPLETED
JD310
12/6/02
;UJ' O, H
UJ
tf)!
Si
H .
Q
•
(0 UJ
- 0
MATERIAL DESCRIPTION
- 2 -
- 4 -
- 6 -
T2-1
T2-2
10
12
- 14 H
- 16
T2-3
SM
SM
SM
FELL
Loose, dry to damp, moderate yellowish brown,
Silty, fine to coarse SAND with angular fme and
coarse gravel. Approximately 50% cobbles and
boulders up to 2 feet diameter. Non cohesive,
caving
ALLUVIUM
Soft/loose, dan^, moderate brown, Silty SAND,
highly porous, non cohesive
ESCONDIDO CREEK GRANODIORITE
Moderately to highly weathered, mottled, fme to
medium grained, moderately weak rock. Excavates
as wet Silty SAND with gravel
m
m
m
TRENCH TERMINATED AT 16 FEET
Figure A-2, Log of Trench T 2 SER1
SAMPLE SYMBOLS • ... SAMPLING UNSUCCESSFUL D.. . STANDARD PENETRATION TEST • .. . DRIVE SAMPLE (UNDISTURBED)
^ ... DISTURBED OR BAG SAMPLE E.. . CHUNK SAMPLE ¥ •• . 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. 07016-22-01
DEPTH
IN
FEET
SAMPLE
NO.
> CO o _l o
X
I-
SOIL
CLASS
(USCS)
TRENCH T 3
ELEV. (MSL.) 362
EQUIPMENT
DATE COMPLETED
JD310
12/6/02
Or; •
U
Q.' o
Ul
•o u
- 0
MATERIAL DESCRIPTION
h 2 -
4 -
6 -
10 -
T3-1
T3-2
.1-
•
V
SM
SM
f
FILL
Loose, dry to damp, moderate yellowish brown,
Silty, fine to coarse SAND with angular fine and
coarse gravel. Approximately 20% cobbles and
boulders up to 18 inches diameter. Non cohesive,
caving
ALLUVIUM
Soft/loose, damp, moderate brown, Silty SAND,
highly porous
ESCONDIDO CREEK GRANODIORITE
Highly weathered, dark yellowish orange, fme to
medium grained, weak. Excavates as Silty SAND
with gravel
il
TRENCH TERMINATED AT 11 FEET
m Figure A-3, Log of Trench T 3 SER1
m SAMPLESYMBOLS SAMPLING UNSUCCESSFUL
^ ... DISTURBED OR BAG SAMPLE
D.
B.
. STANDARD PENETRATION TEST DRIVE SAMPLE (UNDISTURBED)
. 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. 07016-22-01
DEPTH
IN
FEET
SAMPLE
NO.
>-CD O _l O X H-H
SOIL
CLASS
(USCS)
TRENCH T 4
ELEV. (MSL.) 362
EQUIPMENT
DATE COMPLETED
JD310
12/6/02
Hyi-
^U.
>-b
Q
UJ
UJ
•o
CJ
MATERIAL DESCRIPTION
- 0
- 2 -
- 4 -T4-1
- 6
ALLUVIUM
Soft/loose, damp, moderate brown, Silty SAND
5M/ML
hi
ESCONDIDO CREEK GRANODIORITE
Highly to moderately weathered, dark yellowish
orange, fme to medium grained, weak, becomes
moderately weathered, strong at 6 feet. Excavates
as Silty SAND with gravel
TRENCH TERMINATED AT 6 FEET
Figure A-4, Log of Trench T 4 SER1
SAMPLESYMBOLS ^ - SAMPLING UNSUCCESSFUL
^ ... DISTURBED OR BAG SAMPLE
E. .. STANDARD PENETRATION TEST DRIVE SAMPLE (UNDISTURBED)
.. 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. 06535-22-01A
DEPTH
IN
FEET
SAMPLE
NO.
>• CD O _l O X
h-
H
SOIL
CLASS
(USCS)
TRENCH T117
ELEV. (MSL.) 341
EQUIPMENT
DATE COMPLETED 6/22/00
JD 555 TRACK HOE ^9
H'
Ul
a
Q; a
UJ
•o
CJ MATERIAL DESCRIPTION
- 0
- 2 -
Mi
- 4 -
SM
- 6 -
rii7-i
rii7-2
- 10
m
m
m
m
m
FILL
Loose to medium dense, damp, dark
yellowish-brown, Silty, fine to coarse SAND
ALLUVIUM
Soft, damp, light and moderate brown, Sandy
SILT, highly porous
ML 104.2 12.6
ESCONDIDO CREEK GRANODIORITE
\ Slightly to moderately weathered, very strong /~
TRENCH TERMINATED AT 10 FEET
m Figure A-5, Log of Trench T 117 RSFRB
aw
SAMPLESYMBOLS ° - '''''''' UNSUCCESSFUL
^ ... DISTURBED OR BAG SAMPLE
E.
B.
.. STANDARD PENETRATION TEST DRIVE SAMPLE (UNDISTURBED)
.. CHUNK SAMPLE ^ ... WATER TABLE OR SEEPAGE
m 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.
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 from
the current investigation were tested for their in-place dry density and moisture content,
consolidation, grain-size distribution, compaction, resistivity, pH and water soluble sulfate content.
Portions of the bulk samples were remolded to selected density and moisture contents and subjected
to shear strength and expansion index tests.
The results of our laboratory tests from the current investigation and pertinent test results from the
previous, referenced investigation are presented in Tables B-I through B-VI and on Figures B-1
through B-3. In-place density and moisture content results are presented on trench logs (Figures A-1
through A-5 in Appendix A).
TABLE B-I
SUMMARY OF LABORATORY EXPANSION INDEX TEST RESULTS
(ASTM D 4829-95)
Sample
No.
Moisture Content Dry Density
(pcf) Expansion Index Sample
No. Before Test (%) After Test (%)
Dry Density
(pcf) Expansion Index
Tl-2 7.8 14.2 119.7 0
T2-1 7.6 15.6 121.3 0
TABLE B-II
SUMMARY OF LABORATORY DIRECT SHEAR TEST RESULTS
(ASTM D 3080-98)
Sample No. Dry Density
(pcf)
Moisture Content
(%)
Unit Cohesion
(psf)
Angle of Shear
Resistance (degrees)
Tl-1 117.0 8.6 100 32
•Remolded to approximately 90 percent of the maximum dry density at near optimum moisture content
Project No. 07016-22-01 -B-1 -December 31. 2002
TABLE B-lll
SUMMARY OF LABORATORY POTENTIAL OF
HYDROGEN (pH) AND RESISTIVITY TEST RESULTS
(CALIFORNIA TEST NO. 643)
Sample No. pH Resistivity (ohm centimeters)
T2-1 6.94 3718
TABLE B-IV
SUMMARY OF LABORATORY WATER-SOLUBLE SULFATE TEST RESULTS
(CALIFORNIA TEST NO. 417)
Sample No. Water Soluble Sulfate (%)
T2-1 0.031
TABLE V
SUMMARY OF LABORATORY MAXIMUM DRY DENSITY
AND OPTIMUM MOISTURE CONTENT TEST RESULTS
ASTM D 1557-00
Sample
No. Description Maximum Dry
Density (pcf)
Optimum Moisture
Content (% dry wt.)
Tl-1 Yellowish Brown, Silty SAND 129.9 8.6
TABLE B-VI
SUMMARY OF LABORATORY RESISTANCE VALUE TEST RESULTS
m (CALIFORNIA TEST METHOD NO. 301)
Sample No. Description R-Value
m T117-2 Brown, Silty SAND to Sandy SILT 54
m
ii
m Project No. 07016-22-01 -B-2-December 31, 2002
PROJECTNO. 07016-22-01
o H H
• H -J O O) z o (J
LU U
LU Q.
SAMPLE NO. Tl-3
-4
-2
10
12 Q.l IQ 100
APPLIED PRESSURE (ksf)
Initial Dry Density (pcf) 102.1
Initial Water Content (%) 13.9
Initial Saturation (%) 58.8
Sample Saturated at (ksf) 0.5
CONSOLIDATION CURVE
VWD 2 SEWER ACCESS ROAD
2 RETAINING WALL
CARLSBAD, CALIFORNIA
SER1 Figure B-1
PROJECTNO. 06535-22-01
z
o
H h-C
a
H _l
a
O) z o o z UJ u
LU
SAMPLE NO. T117-1
-4
-2
10
12
Q.l IQ IQQ
APPLIED PRESSURE (ksf)
Initial Dry Density (pcf) 104.2
hiitiai Water Content (%) 12.6
Initial Samration (%) 56.4
Sample Saturated at (ksf) 0.5
CONSOLIDATION CURVE
RANCHO SANTA FE BRIDGE
CARLSBAD, CALIFORNIA
RSFB1 Figure B-2
PROJECTNO. 07016-22-01
GRAVEL SAND
SILT OR CLAY COARSE FINE :OARSE flEDIUn FINE SILT OR CLAY
U, S. STANDARD SIEVE SIZE
100
90
80
70
60
50
40
30
20
10
0
1-1/2" 3/4" 3/8"
10 1 0.1
GRAIN SIZE IN MILLIMETERS
Q.Ql 0.QQ1
SAMPLE Depth (ft) CLASSIFICATION SAT WC LL PL PI
T2-2 9.0 (SM) Moderate brown, Silty SAND
GRADATION CURVE
VWD 2 SEWER ACCESS ROAD
2 RETAINING WALL
CARLSBAD, CALIFORNIA
SERl Figure B-3
APPENDIX C
RECOMMENDED GRADING SPECIFICATIONS
m VWD2 ACCESS ROAD 2 RETAINING WALL
Ml CARLSBAD, CALIFORNIA
PROJECT NO. 07016-22-01
m
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 appUcable 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 Califomia licensed Civil Engineer
or consulting firm responsible for preparation of the gradmg plans, surveymg and verifying
as-graded topography.
GI rev. 07/02
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 Califomia 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 Califomia 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 recormaissance or geologic investigation that was prepared specifically for the
development of the project for which these Reconmiended 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 m constmction
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 contaming 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.
m
1^ 3.1.3. Rock fills are defined as fills containing no rocks or hard lumps larger than 3 feet
in maximum dimension and contaming little or no fines. Fines are defined as
material smaller than 3/4 mch in maximum dimension. The quantity of fines shall
be less than approximately 20 percent of the rock fill quantity.
m
m
m
m
m
GI rev. 07/02
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 Califomia 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 witiiin tiie affected area. Prior to resummg grading
operations, tiie Owner shall provide a written report to the Consultant indicatmg tiiat the
suspected materials are not hazardous as defined by applicable laws and regulations.
m
m 3.4. The outer 15 feet of soil-rock fill slopes, measured horizontally, should be composed of
properiy compacted soil fill materials approved by the Consultant. Rock fill may extend to
the slope face, provided that tiie slope is not steeper than 2:1 (horizontal: vertical) and a soil
layer no tiiicker tiian 12 inches is track-walked onto the face for landscaping purposes.
m This procedure may be utilized, provided it is acceptable to the goveming agency, Owner
and Consultant.
3.5. Representative samples of soil materials to be used for fill shall be tested in tiie laboratory
by tiie Consultant to determine tiie maximum density, optimum moisture content, and,
where appropriate, shear strength, expansion, and gradation characteristics of the soil.
m
m
mm 3.6. During grading, soil or groundwater conditions other tiian those identified in tiie
m Geotechnical Report may be encountered by the Contractor. The Consultant shall be
notified immediately to evaluate the significance of tiie unanticipated condition
mm
m
4. CLEARING AND PREPARING AREAS TO BE FILLED
m
m 4.1. Areas to be excavated and filled shall be cleared and gmbbed. Clearing shall consist of
complete removal above tiie ground surface of trees, stumps, bmsh, vegetation, man-made
stmctures and similar debris. Gmbbing shall consist of removal of stumps, roots, buried
logs and other unsuitable material and shall be performed in areas to be graded. Roots and
otiier projections exceeding 1-1/2 inches in diameter shall be removed to a depth of 3 feet
iH below tiie surface of the ground. Borrow areas shall be grabbed to the extent necessary to
^ provide suitable fill materials.
m
m
m
GI rev. 07/02
4.2. Any asphalt pavement material removed during clearing operations should be properiy
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 gmbbing of organic matter or otiier unsuitable material, loose or porous
soils shall be removed to tiie depth recommended in tiie Geotechnical Report. The depth of
removal and compaction shall be observed and approved by a representative of tiie
ConsuUant. The exposed surface shall then be plowed or scarified to a mmimum deptii of
6 inches and until tiie 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 tiie original ground is steeper than 6:1 (horizontal:vertical), or
where recommended by tiie Consultant, the original ground should be benched in
accordance with the foUowmg illustration.
m
TYPICAL BENCHING DETAIL
Finish Grade Original Ground
Finish Slope Surface
Remove M\
Unsuitable Material
As Recommended By
Soil Engineer
ii
Slope To Be Such That
Sloughing Or Sliding
Does Not Occur
See Note 1 See Note 2"
m
m
DETAIL NOTES:
No Scale
(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 slightiy into the naUiral 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. 07/02
m
m
4.5. After areas to receive fill have been cleared, plowed or scarified, tiie 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 tiie proper moisture content, and compacted
as recommended m 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-thed rollers, or otiier types of
acceptable compaction equipment. Equipment shall be of such a design tiiat 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 witii
the following recommendations:
6.1.1. Soil fill shall be placed by the Contractor in layers tiiat, when compacted, should
generally not exceed 8 inches. Each layer shall be spread evenly and shall be
tiioroughly mixed during spreading to obtain uniformity of material and moisture
in each layer. The entire fill shall be constmcted as a unit in nearly level Ufts.
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, tiie soil fill shall be compacted at a moisture content at or above the
optimum moisture content as determined by ASTM D1557-00.
6.1.3. When tiie moisture content of soil fill is below that specified by tiie Consultant,
water shall be added by the Contractor until tiie moisture content is in the range
IV specified.
6.1.4. When tiie moisture content of tiie soil fill is above tiie range specified by tiie
Consultant or too wet to achieve proper compaction, tiie soil fill shall be aerated by
the Contractor by bladmg/mixing, or otiier satisfactory methods until tiie moisture
content is within the range specified.
GI rev. 07/02
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 m-place
^ dry density of the compacted fill to the maximum laboratory dry density as
determuied in accordance witii ASTM D1557-00. Compaction shall be continuous
over tiie entire area, and compaction equipment shall make sufficient passes so tiiat
* the specified minimum relative compaction has been achieved throughout tiie
entire fill.
m
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
m 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.
m
* 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 tiien 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 tiian 12 inches but less tiian 4 feet in maximum dimension may be
incorporated into tiie compacted soil fill, but shall be limited to the area measured
" 15 feet minimum horizontally from die slope face and 5 feet below finish grade or
3 feet below the deepest utility, whichever is deeper.
«l
il 6.2.2. Rocks or rock fragments up to 4 feet in maximum dimension may either be
individually placed or placed m wmdrows. Under certain conditions, rocks or rock
2 fragments up to 10 feet in maximum dimension may be placed usmg similar
metiiods. The acceptability of placing rock materials greater tiian 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. 07/02
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, tiie rocks should be placed in trenches excavated in
properiy compacted soil fill. Trenches should be approximately 5 feet wide and 4
feet deep in maximum dimension. The voids around and beneatii rocks should be
filled witii 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 tiie trench procedure, however, tiiis method should
first be approved by the Consultant.
6.2.5. Windrows should generally be parallel to each otiier and may be placed eitiier
parallel to or perpendicular to tiie face of the slope dependmg on tiie 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
overiying course. The minimum vertical spacing between windrow courses shall
be 2 feet from the top of a lower windrow to tiie bottom of the next higher
windrow.
6.2.6. All rock placement, fill placement and flooding of approved granular soil in tiie
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 witii
the following recommendations:
6.3.1. The base of tiie rock fill shall be placed on a sloping surface (minimum slope of 2
percent, maximum slope of 5 percent). The surface shaU slope toward suitable
subdrainage outiet facilities. The rock fills shall be provided with subdrains during
constmction so that a hydrostatic pressure buildup does not develop. The
subdrains shaU be permanently connected to controlled drainage facilities to
control post-constmction infiltration of water.
6.3.2. Rock fills shall be placed in lifts not exceeding 3 feet. Placement shall be by rock
tmcks traversing previously placed lifts and dumping at tiie edge of the currentiy
placed lift. Spreading of tiie 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 tmcks 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 tiian that of a 20-ton steel vibratory
^ roller or other compaction equipment providing suitable energy to achieve the
m
m
GI rev. 07/02
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 Dl 196-93, may be performed in
both the compacted soil fill and in tiie rock fill to aid in determinmg the number of
passes of the compaction equipment to be performed. If performed, a minimum of
three plate bearing tests shall be performed in tiie properiy compacted soil fill
(minimum relative compaction of 90 percent). Plate bearing tests shall tiien be
performed on areas of rock fill having two passes, four passes and six passes of tiie
compaction equipment, respectively. The number of passes required for the rock
fill shall be determuied by comparing the results of tiie plate bearing tests for tiie
soil fill and the rock fill and by evaluating the deflection variation witii number of
passes. The required number of passes of the compaction equipment will be
performed as necessary until tiie plate bearing deflections are equal to or less than
tiiat determined for tiie properly compacted soil fill. In no case will the requhed
number of passes be less than two.
6.3.4. A representative of the Consultant shall be present during rock fill operations to
verify tiiat the minimum number of "passes" have been obtamed. that water is
being properiy applied and that specified procedures are being followed. The
actual number of plate bearing tests will be determuied 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 tiiat tiie Consultant can state that,
in his opinion, sufficient water is present and that voids between large rocks are
properly filled witii smaller rock material. In-place density testmg will not be
required in the rock fills.
^ 6.3.6. To reduce tiie potential for "piping" of fmes into die rock ftil from overiymg soil
il 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 tiie rock
* should be determined by the Consultant prior to commencing grading. The
gradation of tiie graded filter material will be determined at the time the rock fill is
m being excavated. Materials typical of the rock fill should be submitted to the
M Consultant in a timely manner, to allow design of the graded filter prior to the
commencement of rock fill placement.
GI rev. 07/02
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, gmbbmg, filling and compaction operations, hi general, no more than 2 feet in
vertical elevation of soil or soil-rock fill shall be placed witiiout at least one field density
test being performed witiim 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 tiie compacted soil or soil-rock
fill to provide a basis for expressing an opinion as to whether tiie fill material is compacted
as specified. Density tests shall be performed in the compacted materials below any
disturbed surface. When tiiese tests indicate tiiat tiie density of any layer of fill or portion
tiiereof is below tiiat 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 tiiat tiie minimum number of
passes have been obtained per the criteria discussed in Section 6.3.3. The Consultant shall
request tiie excavation of observation pits and may perform plate bearing tests on tiie
placed rock fills. The observation pits will be excavated to provide a basis for expressing
an opinion as to whetiier tiie rock fill is properiy seated and sufficient moisture has been
applied to the material. If performed, plate bearing tests will be performed randomly on
the surface of tiie most-recently placed lift. Plate bearing tests will be performed to provide
a basis for expressing an opinion as to whetiier the rock fill is adequately seated. The
maximum deflection in the rock fill determined in Section 6.3.3 shall be less tiian tiie
maximum deflection of tiie properiy 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 m 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. 07/02
m
7.5. The Consultant shall observe tiie placement of subdrains, to verify that tiie dramage devices
have been placed and constmcted in substantial conformance witii project specifications.
7.6. Testing procedures shall conform to the following Standards as appropriate:
7.6.1. Soil and Soll-Rock Fills:
7.6.1.1. Field Density Test, ASTM D1556-00, Density of Soil In-Place By the
Sand-Cone Method.
7.6.1.2. Field Density Test, Nuclear Metiiod, ASTM D2922-96, Density of Soil and
Soil-Aggregate In-Place by Nuclear Methods (Shallow Depth).
7.6.1.3. Laboratory Compaction Test, ASTM D1557-00, Moisture-Density
Relations of Soils and Soil-Aggregate Mixtures Using 10-Pound Hammer
and 18-Inch Drop.
7.6.1.A. Expansion hidex Test, ASTM D4829-95, Expansion Index Test.
7.6.2. Rock Fills
7.6.2.1. Field Plate Bearing Test, ASTM D1196-93 (Reapproved 1997) Standard
Method for Nonreparative Static Plate Load Tests of Soils and Flexible
Pavement Components. For Use in Evaluation and Design of Airport and
M Highway Pavements.
^ 8. PROTECTION OF WORK
m
8.1. During consti-uction, the Contractor shall properiy 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
1^ Specifications prior to placing additional fill or stmctures.
* 8.2. After completion of gradmg as observed and tested by the Consultant, no further
^ excavation or filling shall be conducted except in conjunction witii tiie services of the
m Consultant.
III
m
m
GI rev. 07/02
9. CERTIFICATIONS AND FINAL REPORTS
9.1. Upon completion of tiie work, Contractor shall fumish Owner a certification by the Civil
Engineer stating that the lots and/or building pads are graded to witiiin 0.1 foot vertically of
elevations shown on the grading plan and tiiat all tops and toes of slopes are within 0.5 foot
horizontally of tiie positions shown on the grading plans. After installation of a section of
subdrain. tiie project Civil Engineer should survey its location and prepare an as-built plan
of the subdrain location. The project Civil Engineer should verify tiie proper outiet for tiie
subdrains and the Contractor should ensure that the drain system is free of obstmctions.
9.2. The Owner is responsible for furnishing a final as-graded soil and geologic report
satisfactory to the appropriate goveming or accepting agencies. The as-graded report
should be prepared and signed by a Califomia licensed Civil Engineer experienced in
geotechnical engineering and by a Califomia Certified Engineering Geologist, indicating
tiiat the geotechnical aspects of the grading were performed in substantial conformance
witii the Specifications or approved changes to the Specifications.
PI
H
m
as
m
IM
GI rev. 07/02
UST OF REFERENCES
1. Blake. T. F., EQFAULT, A Computer Program for the Deterministic Prediction of Peak
Horizontal Acceleration from Digitized Califomia Faults. Users Manual. 1989a, p. 79
(revised 2000).
2. Geocon Incorporated, Geotechnical Design Report, Rancho Santa Fe Road Realignment
Station 252+00 to Melrose Drive Carlsbad, Califomia, July 2000, revised November 28,
^ 2000 (Project No. 06535-22-01).
3. Geologic Map of the Northwestem Part of San Diego County, Califomia. Califomia,
Division of Mines and Geology, DMG Open-File Report 96-02,1996.
m
m
m
m
m
m
M
4. United States Department of Agriculture, Stereoscopic Aerial Photographs, Flight AXN-8M,
Photo Nos. 18 and 19, dated April 11,1953.
5. United States Geological Survey, 7.5 minute Quadrangle Series. Rancho Santa Fe
Quadrangle, 1949 and 1968, photorevised 1983.
6. Unpublished reports, aerial photographs and maps on file with Geocon hicorporated.
Project No. 07016-22-01 December 31, 2002