HomeMy WebLinkAboutCDP 03-07; THOMPSON RESIDENCE; GEOTECHNICAL INVESTIGATION; 2001-06-28.I.
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RECEIVED.
JUL 11 2006
ENGINEERiNG
DEPARTMENT
GEOTECHNICAL INVESTIGATION
THOMPSON PROPERTY
CARLSBAD, CALIFORNIA
· . · PREPARED FOR
MR. DAVID THOMPSON
SAN MARCOS, CALIFORNIA
JUNE 28, 2001
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GEOCON
1-NCORPORATED . ~~
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Project No. 06716-32-01
June 28, 2001
Mr. ~avid Thompson
949 Cassou Road
San Marcos, CA 92069
Subject: THOMPSON PROPERTY
CARLSBAD, CALIFORNIA
GEOTECHNICAL INVESTIGATION
Dear Mr. Thompson: ·
In accordance with your authorization and our proposal No. LG-01177, dated April 5, 2001, we are
submitting the results of_ a geotechnical investigatfon for the subject site. The accompanying report
presents the results of the study and our conclusions and recommendations regarding, the
geotechnical aspects of project development.
In our opinion, the site may be developed as proposed provided that the recommendations contained
in this report are followed.
If you have any questions regarding this report, or ifwe may be of further service, please contact the
undersigned at your convenience.
Very truly yours,
GEOCON INCORPORATED £l/!J[___
Davjd B. Evans
CEG 1860
MEE:DBE:dlj
(6/del) Agdressee
Michael E. Embick
GE2462
6960 Flanders Drive • San Diego, California 92121-;1974 • Telephone (858) 558-6900 • Fax ( 858) 558-6159
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TABLE OF CONTENTS
1. PURPOSE AND SCOPE ......................................................................................... -........................ 1
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2. · SIIB AND PROJECT DESCRIPTION ................. · ........................................................................... 2
3'. SOIL AND GEOLOGIC COND1TIONS ......................................................................................... 2
.3.1 Fill (Qud:f, Qpf) ................... : .. _ ................................................................. : .............................. 3
3.2 Alluvium (Qal) ....................................................................................................................... 3
3.3 Colluvium (Qcol).: ........................... :.: ................................................................................... 3
3A Santiago Formation/Torrey Sandstone (Tsa/Tt Undifferentiated) ........................................ 3 .
4. GROUNDWATER ................................................................................................ ; .......................... 4
5. GEOLOGIC HAZARDS· ............................................................................... , ................................... 4
5.1 . Geologic Structure A.i;ld Local Faultjng ......... , ....................................................................... 4
5.2 · Regional Faulting and Seisinicity ........ : .................................................................................. 4
5.3 Ancient Landslides ................................................................................................................ 5
5.4 Liquefaction ................ '. ..... : ..................................................................................................... 6
6. CONCLUSIONS AND RECOMMENDATIONS.' ......................................... · ................................. 7
6.1
6.2
6.3
6.4
6.5
6.6
6.7
6.8.
6.9
6.10
_ 6.11
.. -6.12
General ............................ .' .......... , ....... _ ..................................................................................... ,. 7
Groundwater .................................................................................................... -...................... 7
Soil and Excavation Characteristics ............................................................ : .......................... 7
Grading ............................................................ -...... : ........ _ ....................................................... 8
Slope S-tability ................................................. ., .............................. , ....................................... 9
S . . D . C. · . . 10 e1sm1c es1gn r1tena ···: ............................... ; ................................................................. ..
Foundations ............... : .................. : .... _ ...................................................... : ............................ 10
Conct~te Floor Slabs ............................................. -: ............................................................... 12
Post-Tension Foundation System : .... , .................... : ............................................................. 12
Retaining Walls and· Lateral Loads ....................................................................................... 13
Drainage and Maintenance ................. : ................................................................................ 15
Grading Plan Review ........... : ................................................................................................ 15
LIMITATIONS AND UNIFORMITY OF CONDITIONS
MAPS ANO ILLUSTRATIONS
Figure 1, Vicinity Map
Figure 2, Geologic Map
Figure 3, Slope Stability Analysis
Figure 4, Surffoial Slope Stability Analysis
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TABLE OF CONTENTS (Continued)
APPENDIX A
FIELD INVESTIGATION
Figures A-1-A-4,_Logs of Borings
Figures A-.S-A-12, Logs of Trenches
APPENDIXB
LABORATORY TESTING
Table B-1, Sump1acy of Laboratory Maximl.µli Dry Density and Optimum Moisture
Content Test Results · ·
Table B-11, Summary of Direct Shear Test Results
Figures B-1 Through_B-5, Consolidation Test Results
APPENDIXC
RECOMMENDED GRADING SPECIFICATIONS
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GEOTECHNICAL INVESTIGATION
1. PU~ POSE AND SCOPE
this report presents the results -of a geotechnical investigation for a proposed fill embankment on the
Thompson property within the City of Carlsbad, Califoi:uia (see Vicinity Map, Figure 1). The
purpose of the investigation was to evaluate the soil and geologic cond~tions at the site and to
provide recommendations pertaining to the · geotechnical aspects of developing the property as
proposed. Additional pertinent information relating to the proposed development area include: .
1. Untitled Proposed Fill Slope M3:p by Map,itou Engineering, scale 1 inch = 40 feet, undated.
2. Geologic Maps of the Northwester11 Part of San Diego County, California, California
Division of Mines and Geo fogy, Open File Report 96-02, °1996.
3. . Landslide Hazards in the Northern fart of The San Diego Metropolitan Area, San Diego
· County; California (Encinitas Quadrangle),.CalifomiaDivision of Mines and Geology, Open
File Report 95-04, 1995.
4. Interim As-Graded Geotechnical Report and Maps, Aviara Phase II, Carlsbad, California,
by Irvine Consulting Group, dated February 4, 1993 (Volume I), and February lO, 1993
(Maps).
5. Report of Testing and Observation Services for Spinnaker Hill Unit 3, Carlsbad Tentative
Map No. 73-39, Geoco'n Incorporated, December 1, 1976, revised April 1, 1977 (Project No.
00630-01-03).' -
6. Compaction Report for Portion North Half, SE ¼, NE ¼, Section 28, Tl 28, R4W, S.B.M,
Rancho Santa Fe Engine·ering Company, February 24, 1976.
7. U.S. Geological Survey, 1968, Encinitas, California, 7.5. Minute Quadrangle Map, .
photorevised 1975.
8. 1953 stereoscopic aerial photographs of the site and surrounding areas (AXN-8M-98, 99).
The scope of this.investigation qonsisted of performing a site reconnaiss~nce, reviewing published
geologic literature and previous geotechnical reports pertinent to the site, drilling 2 large-diameter
borings and excavating 8 exploratory trenche$ .. The field investigation was performed on May 15 and
24, 2001. ~he approximate location of the exploratory trenches and borings are depicted on the
Geologic Map, Figur~ 2.
Selected representative soil samples obt~ined-were _subjected to laboratory testing to evaluate
pertinent engineering properties. Details of the field investigation and laboratory testing are
presented in Appendices A and: l3, respectively. The Geologic Map depicts the configuration of the
. property, grading concept, existing topography, and the approximate locations of the exploratory --.
:Project No. 06716-32-01 -1 -June 28, 2001
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excavations. The conclusions and recommenda:tic;ms presented herein are based on an analysis of the
data obtained from the exploratory field investigation, laboratory tests, and our experience with_
similar soil and geplogic conditions.
2. · SITE AND PROJECT DESCRIPTION
The site currently con~ists· of an existing residence that ~s acce~seci by a driveway from Rose Drive in
the City of Carlsbad, California. Immediately behind·( east of) the residence, the driveway extends to
provide access to a detached :garage. Slopes up to approximately 15 feet high extend down from the
east and west margins of the building pad that. supports the residence. The slope to the east is
' landscaped and a large eucalyptus tree is located in the bottom of a depression below the slope.
The depression on the east side of the property is proposed to be filled roughly to the elevation of the
re~ driveway to c_reate a· relativ~ly level pad and increase the area of the back yard. The toe of the
proposed fill slope wjll b~ located within a few feet of the_ eastern property line. Import soil will be
required to fill the· depression. It is understood that the proposed fill area is being considered for
future residential development, and, therefore, recommendations for residential structures are ·
included in this report. Based on a review of the referenced report dated February 24, 2001
(Reference No. 6), the existing slope east of the driveW~y was constructed as compacted fill. The
referenced plan by Manitou Engineering indicates that the new fill slope will have a maximum height
of approximately 25 feet, 'inclined at 2: 1 (horizorttal:vertical). . . ' .
The locations . and descriptions of the · site and proposed development are based upon a site
reconnaissance, a review of the av~ilable plans, ~dour underst~ding of the proposed development.
If project details vary significantly from those described above, Geocon Irtcorporated should be
consulted to provide additional recommendat1ons.and/or analysis.
3. SQIL AND GEOL°OGIC CONDITIONS
One geologic formation and three surficial units were encountered during the investigation. The ·
surficial materials consi~t of fill~ alluvium and colluvium. The geologic formation consists of
undif:(erentiated Santiago Formation/Torrey Sandstone. Each of the soil and geologic units encountered
is discussed below in order of increasing age. Their estimated extent is shown on the Geologic Map,
Figure 2 (Map Pocket). Alluvium and colluvium deposits have not been differentiated on the map.
Landslide deposits have been mapped immediately east of the property (Refereuce No. 4), but none
were observed during this investigation.
Projer:;t No. 06716-32-01. -2-June 28, 2001
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3.1 Fill (Qtfdf, Qpf)
. Undocumented fill (Qudf) associate~ with ~ slope that ascends from the south side of the depression
was encountered along the southern edge of the property. This fill was observed within one trench
and consisted' of loose to medium dense, dry to moist, silty, fme-to medium-grained sand with some
silty clay. This fill is not considered suitable iri: its present condition to support additional fill or
settlement sensitive improvements.
Previously placed compacted fill (Qpf) was identified in Reference No. 6 along the east side of the
residence. Trench T2 indicates that th1s fill is comp9sed of similar materials, namely silty sand, as
the undocumented fill along the south side of the depression. The outer 2 to 4 feet of this slope is
·anticipated to be in a relatively loose .and dty condition aJ:?-d will require heavy benching during the
placement of the new embankment.
3.2 Alluvium (Qal)
Alluvium w:as observed in a majority. of the trenches and within both borings. A review of aerial
photographs and the relatively extensive thickness of alluvium encountered in Boring B 1 suggests
that two deeply incised drainages extending up ,to the· west and north converge along the eastern
property margin. The alluvium ranged in thickness from 5 to 21 feet and typically consisted of moist,
silty and clayey~ fme-to coar~e-grained sand. Some lenses of silty clay and sandy clay were also
observed. The upper portion of the alluvium was typically loose to medium dense and will require
remedial graqing. This was generally supported by .laboratory testing, including density and
consolidation testing of relatively undisturbed samples:
3.3 Colluvium (Qcol)
· Coliuvial deposits were enco:untered in five of tb.e eight trenches overlying either alluvium· or the
geologic fonnation. The colluvium generally consisted of loose, dry to moist, clayey and silty, fme-
grained sand and firm, silty clay. The colluvium is not considered suitable to support fill soil or
settlement sensitive improvements .
3.4 Sa~tiago Formation/Torrey Sandstone (Tsa/Tt Undifferentiated)
The geologic/geotechnical literature reviewed and site observations indicate that the Eocene-age
Santiago Formation underlies the surficial materials throughout the property. Reference No. 4
classified the underlying formation as Torrey Sandstone bas~d on paleontological information
obtained dl)ring grading of the adjacent Avi~a development. For the purpose of this study, the units,
have not been differentiated. The Santiago Formation/Torrey Sandstone encountered during the
Project No. 06716-32-01 -3 -June 28, 2001
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investigation consisted primarily of dense, damp to moist, silty,. fme sandstone and hard, clayey,
siltstone and silty, claystone with varying degrees of cementation. Randomly oriented, clay-filled
fractures were observed wit~ the sandstone and claystone lenses. A relatively deep sheared clay
Seam (bedding parallel shear) was encountered at a depth of 44 feet in Boring_ B 1.
The ~antiago Formation/Torrey Sandstone should provide .adequate foundation and fill support and
generally good slope stability characteristjcs. It should be noted, that the Santiago Formation can be
prone to slope instability in the event that bed<,ling parallel shears or claystones are exposed in cut
. slopes during grading. It is Jike_ly that the presence of bedding parallel shears within this formation
has resulted-in landsliding that was tdentified east of the property. No cut slopes are proposed during
cJevelopment and slope stability analysis performed on the property within the bedding parallel shear
zone indicated factors of safety greater than 2.0.
4. GROUNOWAl'ER
Seepage was observed in both borings within the formational unit. Perched groundwater and/or
seepage conditions -in alluvial,. colluvial and/or the bedrock units likely vary during periods of·
·precipitation. In this regard, remedial grading may encounter wet soils and excavation and
'compaction difficulty, particularly if construction is. planned during the winter months.
5. GEOLOGIC HAZARDS
5.1 Geologic Structure And Local Faulting ·
Due to the limited number of structural features observed cluring the drilling of the two borings, a
consistent structural trend within the prop_osed project area could not be determined. Bedding
attitudes measure~ during grading of the adjacent Aviara development (Reference No. 4).suggest that
. ·the regional bedding within the Santiago F~rmati~n/Tqrr~y Sandstone is dipping 3 to 5 degrees west .
to southwest1 Attitudes measured during this study suggest tl)e bedding is dipping north to northeast.
5.2 Regional Faulting arid Sei·smicity
Based on the site reconm~issalice, evidence obtained in the exploratory excavations, previous work
by others, and a review of published geologic maps ancl reports, ~e site is not located on any known
active or potentially active fault trace. The nearest kno~ .active fault is the Rose Canyon Fault
located approximately 5 milel? to the west. Major earthquakes occurring on the Rose Canyon Fault,
or Other. active faults located in the southern California/northern Baja California area, could subject
the site· to moderate to severe. ground shaking within the life span of the proposed structures.
Project No. 06716-32-01 . -4-June 28, 2001
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The distance of known faults to the site was deten;nined from the computer program EQF AULT
(Bl~e, Ver. 3.00). A search.radius of 62 miles (100 kilometers) was performed and 16 known active
faults were identified. Principle references used by EQFAULT in selecting faults to be included were
Jennings (1975), Anderson (1984) and Wesnousky (1986). The program EQFAULT was also us~d to
estimate ground accelerations at the site for the maximum earthquake magnitude seismic events.
Attenuation relationships developed by-Sadigh et al. (1997) were used to estimate site accelerations.
The results of the seismicity analyses indicate that the Rose Canyon Fault zone, the offshore portion
of the Newport-Inglewood Fault, and the Coronado Bank Fault Zone are the dominant sources of
potential ground motion at the site. The Rose Canyon Fault Zone having a Maximum Earthquake
Magnitude of 6.9 is considered to be the source 01 the greatest seismic ground shaking within the
property. The "maximum earthquake magnitude" is defined as the maximum earthquake that appears
· capable of occurring under the presently knqwn tectonic framework (California Div_ision of Mines
and Geology Note, Number· 43). The estimate~ maximum earthquake magnitude ground acceleration
was calculated to be apP.roxilnately 0.36 g.
Presented on the Table 5.2 are the deterministic earthquake events for selected faults and calculated
peak site accelerations for the faults considered most likely to subject the site to ground shaking.
TABLE5.2
DETERMINISTIC SITE PARAMETERS FOR SELECTED FAULTS
Maximum Earthauake Event
Distance Maximum Peak
Fault Name From Site Earthquake Site
(miles) Magnitude Acceleration
(Mw) (g)
Rose Canyon 4.7 6 .. 9 .36
_ Newport-Inglewood (offshore) 9 . • 6.9 .26
Coronado Bank 20 7.4 .17
Elsinore 25 7.1 .12
· 5,.3 Ancient Landslides
No ancient landslides wei;e obsezyed on the. property during the reconnaissanc~ or aerial photograph
review. However, two confirmed landslides and one suspected landslide exist along the east-facing
natµral slope that abuts the eastern property lint,},. Accordirigto Reference No. 4, the ancient landslide
deposit directly east of the property has been mitigated by conventional remedial grading procedures
{i.e. complete or partial removal, slope buttressing, stability fills, etc.). Slope inclinometers were
PrdJect ~o: 06716-32-01 -5 ~ June 28, 2001
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~stalled adjacent to the subjec~ property to monitor movement during the grading of the Aviara
project. The monitoring indicated that "no significant changes or deep seated progressive movement'~
· occurrecl. It does not appear that the rear portion of the ancient landslide deposit adjacent to the
Thompson property extends into the proposed development area.
·5.4 Liquefaction
Tlie potential for liquefaction during a strong earthquake is limited to those soils which are in a
relatively loose, unconsolidated condition and located below _the water table. Due to the relatively
high density and grain-size distribution characteristics of the surficial and formational materials at
the site, and the absence of a permanent water table · in development areas, the risk qf seis~ically
induced soil liquefaction occurring at the property is considered very low.
Project No. 06716-32-01 -6-June 28, 2001
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6.1.1
6.1.2
6.1.3
6.1.4
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6. CONCLUSIONS AND RECOMMENDATIONS
General
No soil or geologic conditions were encountered which would preclude the development
of the property, as presently planned, provided the recommendations of this ~eport are
followed.
The undocumented fill soils, colluvium, and alluvium within 8 feet of the original ground
surface are not considered suitable for the support of fill or structural loads in their present
condition and will require remedial grading in the form of removal and compaction.
Anticipated depths of remedial grading have been delineated on the Geologic Map,
Figure 2. Further evaluation of the compacted fill east of the driveway should be
performed during grading to determine its ~uitability to support proposed improvements.
However, as discussed previously,. hea.vy benching of the existing compacted fill should be
anticipated during grading.
The alluvium that is .deeper than approximately 8 feet below original ground is considered
suitable to support fill soil and may .be left in-place. Some localized zones may require
deeper removals based on field observations during remedial grading activiti,es.
Complete removals likely will not be possible ~ound project boundaries and in the
vicinity of the large eucalyptus tree within the drainage due to property line constraints.
Where recommended removals can not be accomplished, structural setbacks for settlement
sensitive improvements, if necessary, will be 'provided following grading.
6.2. Groundwater
6.2.1 Perched groundwater and/or seepage was encountered ·m both of the.exploratory borings. It
should be anticipated that remedial grading of surficial deposits in the lowest parts of the
property will encounter wei materials, if remedial grading operations are conducted during
or following the rainy season or periods of precipitation. The wet soils may result in
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possible excavation and fill placement difficulties.
6.3 Soil and Excavation Characteristics
6.3.1 The soil conditions encountered vary from low expansive, silty sands to _potentially
exp~nsive clayey alluvium and colluvium. Remedial. excavations are expected to be
performed with light to moderate effort usmg heavy duty grading equipment.
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6.3.2 The surficial deposits may be very moist to saturated during the winter or early spring
depending on precedin,g precipitation and may require mixing with drier material or drying
prior to their use as compacted fill.
6.4 Grading
6.4.1 · All grading should be performed in ~ccord.ance with the Recommended Grading
Specifications contained in Appendix C and the city of Carlsbad Gra~ing Ordinance. Where
the recommendations of Appendix C conflict with this report, the recommendations of this
report should take ·precedence.
6.4.2. 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
attend.ance. Special soil handling and/or the grading plans can be discussed at that time.
6.4.3 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 or soils to be used
as fill is relatively free of organic matter. Material generated during stripping and/or site
demolition shottld. be exported froin the site,
6.4.4 All potentially compressible surficial soils (u11documented and unsuitable compacted fill,
coliuvium and upper portions of alluvium) within areas of planned grading sh~:mld be
removed to firm natural ground or 8 feet below existing grade and properly compacted
prior to placing additional fill and/or structuraJ loads. The actual extent of unsuitable soil
removals should be determined in the field by the geotechnical engineer and/or
engineering geolo$ist Overly wet, .surficia.l materials will require drying and/or mixing
with drier soils to facilitate proper compaction. Temporary excavations should be inclined
no steeper than .1: 1.
6.4.5 The site should then b_e 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 bop.ding and compaction. AU ·fill, including backfill and scarified
ground surfaces, should be compacted to at least 90 percent of maximum dry density at
near optimum moisture content, as determined in accordance with ASTM Test Procedure
D 1557-91. Fill materials near and/or below optimum moisture content may require
additional moisture conditioning prior to. placing additional fill.
Project No. 06716-32-01 ( -8-June 28, 2001
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6.4.6 Where practical, the upper 3 feet of the fill should be composed of properly compacted or
undisturbed fo;rmational ''very low" to "low" expansive soils. More highly expansive fill
soils should be placed in the. deeper fill areas and properly compacted. "Very low" to
"low" expansive soils are defined as those soils that have an Expansion Index of 50 or less
when tested in accorqance with UBC Table 18-I-B.
6.4.7 fin.port fill soil should possess a t;ninimum angle of internal friction of 30 degrees and .a
"very low" to "low". expansive potential -as previously defined.
6.4.8 Cobbles or concretions greater than 12 inches inma,ximum dimension should not be placed
within 1 () feet of finish grade or 3 feet of the deepest utility. Cobbles and concretions .
greEJ,tet than 6 inches in maximum dimension should not be placed within 3 feet of finish
grade in building pad areas.
6.5 Slope Stability
6.5.1 Slope stability analysis utilizing average drained direct shear strength parameters based on
laboratory tests and experience with similar soil types in nearby areas indicates that fill
slopes up to at least 25 feet high, constructed o{granulai materials should have calculated
factors of safety of at least 1.5 under static conditions for both deep-seated failure and
. .
shallow sloughing conditions. Slope stability and surficial slope stability calculations are
presented on Figures 3 and 4.
6.5 .2 The outer 15 feet ( or_ a distance equal to the height of the slope, whichever is less) of fill
slopes should be composed of properly compacted granular "soil" fill to reduce the
potential for surficial sloughing. In general, soils with an Expansion Index of less than 90
or at least 35 percent sand size particles should be acceptable as "granular" fill. Soils of
· questionable strength to satisfy surficial stability should be tested in the laboratory for
acceptable drained shear strength. Slopes should be compacted by backrolling with a
loaded sheeps:foot roller at vertical intervals-not to exce~d 4 feet and should be . '
track-walked at the completion of each slope . such that the fill soils are uniformly
compacted to at least 90 percent relative compaction to the face of the finished slope ..
6.5.'.3 · Slope stability analysis of the final graded configuration was performed considering the
bedding parallel shear encountered in Boring B 1. An assumption that the shear is
continuous Was used in the analysis. The analyses indicated a factor of safety greater than
2.0 and that this featur~ does not adversely impact project development.
Project No. 06716~32-01 June 28, 2001
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6.5.4 -All slopes should be landscaped with drought-tolerant vegetation, having variable root
depths and requiring minimal landscape irrigation. In addition, all slopes should be 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.
6.6· Seismic Design Criteria
. 6.6. l . The following ~ble summarizes site-specific seismic -design criteria obtained :from the
1-997 Uniform Building Code .(UBC). The values listed in Table 6.6 are for the Rose
Canyon Fault (located approxunately 5 miles west of the site), which is identified as a
Type B fault.
Parameter
Seismic Zone Factor, .Z
Soil Profile Type
Seismic Coefficient, Ca
Seismic Coefficient, Cv
Near-Source Factor, Na
· Near-Source Factor, Nv
Seistµic Source
6.1 foundations
TABLE 6.6 ·
SEISMIC DESIGN PARAMETERS
-.
Design Value
0.40-
Sp
'.
0.44
0.70
1.0 ..
1.1
B
UBC Reference
Table 16-I
Table 16-J
Table 16-Q
Table 16-R
Table 16-S
Table 16-T
Table 16-U
6.7.1 The project is suitable for th!;) use of continuous strip footings, isolated spread footings or
appropriate combinations: thereof if the preceding. grading recommendations are followed .
. The following recommendations are for one-to two-story structures and assume that the
grading will be performed as indicated in this report. Continu01,1s footings for one-and/or
two-story structures should be at least 12 inches wide and should extend at least 24 inches
below lowest adjacent pad grade in(o-prdperly compacted low expansive fill soils. Isolated
' '
spread footings should be at least 2 feet square and extend a minimum of 24 inches below
lowest adjacent pad grade into properly compacted fill soil. Exterior isolated spread
· footings should also be structurally connecterj. to the main building. Minimum continuous
footing reinfor.cement should consist of two No. 5 steel reinforcing bars placed
horizontally in the footings,. one near the top· and one near the bottom. Recommendations
ProjectNo. 06716-32-01 -10 -June 28, 2001
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movement without causing extensive distress. Geocon Incorporated should be
consulted for specific recommendations.
6.8 Concrete Floor. Slabs
6.8.1 Interior concrete slabs-on-grade should. be at least S. inches thick and should be underlain
by at least 3 in,ches of clean sand. ·Where moisture· sensitive floor coverings are planned, a
visqueen moisture barrier should be provided and placed at mid-point within the 3-inch
sand cushion.
6.8.2 Minimum reinforcement of slabs-on-grade should consist of No. 3 reinforcing bars placed
at 18 inches on center in both horizontal directions.
6.8.:3 .The concrete slab-on-grade recommendations are minimums based on soil. support
characteristfos only. It is recommend~d that the project structural engineer evaluate the
structural requirements of the concrete slabs for supporting equipment and storage loads, if
necessary ..
6.9 Post-Tension Foundation System
6.9.1 As an alternative to-the conventional foundation recommendations provided, consideration
should-be _given to the use of post-tensioned concrete slab and foundation systems for the
.support of 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 (tJBC Chap. 18, Div. ill, §1816, 1997). Although this procedure . . .
was developed for expansive soils, it is understood that it can also be used to reduce the
potential for foundation distress due to djfferential fill settlement. The post-te1:1,sioned
design should incorporate the geotechnical parameters presented on the following table -
entitled Post-Tensioned Foundation System Design Parameters.
6.9.2 UBC Chap. 18, Div. UI, §1816, 1997 uses interior stiffener beams in its structural design
procedures. If the structural engineer proposes a post-tensioned foundation design method
·oth~rthan UBC Chap. 18, Div. ill, §181'6, 1997;it is recommended that interior stiffener
beams be used. The depth of the perimeter foundation should be at least 18 inches where
the Expansion Index exceeds· 50 but is less than 90. Geocon Incorporated should be
· consulted to provide additional design parameters as required by the structural engineer.
Projeqt No. 06716-32~01 -12-June 28, 2001
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TABLE6.9
.POST-TENSIONED FOUNDATION SYSTEM DESIGN PARAMETERS
Post-Tensioning Institute (PTI)' Value Design Parameters.
1. Thqmthwaite Index -20
2. Clay Type -: MontQJ.ori]Johite · Yes
3. Clay Portion {Maximum) . . 70%
4. Depth to Constant Soil Suction 7.0 ft.
5. ~oil Suction 3.6 ft.
--
6.· _Moisture Velocity 0.7 in.Imo.
7. Edge Lift Moisture Variation Distance 2.6 ft.
8; Edge Lift 1.15 in.
9. Ce.q.ter Lift Moisture Variation Distance " 5.3 ft.
10. Center Lift 4.74in.
6.9 .3 The recommendations of this· report are intended to reduce the potential for cracking of slabs
due to expansive soils (if present), differential settlement of deep fills or fills of varying
thickness. However, even with the incorporation of the recommendations presented herein,
foundations, ~tucco walls, and slabs-on-grade placed o~ such conditions may still exhibit
· some cracking due to soil movement and/or shrinkage. The occurrence of concrete shrinkage
cracks is independent of the supporting soil characteristics. Their occurrence may be reduced
and/or controlled by limiting the slump of the concrete, proper concrete placement' and
curing, and by the placement of crack control joints at periodic intervals, in particular, where
re-entry slab corners oqcur.
6.10 Retaining WaHs and ~ateral Loads
6.10.1 Retaining walls not restrained at the fop and. having a level backfill surface should be
designed for an active soil pressure equivalent to the pressure exerted by a fluid with a
. density of 30 pounds per cubic foot (pc:(). Where the backfjll will be inclined at no steeper
than 2.0 to 1.0, an active soil pressure of 40 pcf is recommended. These soil pressures
assume that the backfill materials within an area bounded by the wall and a 1 : 1 plane
e?'-tending upward from the base of the wall possess an Expansion Index of less than 50.
F9r those lots with finish grade soils having an Expansion 'Index greater than 50 and/or
where backfill materials do not conform with the above criteria, Geocon Incorporated
should be consulted for additional re99Jlll11endations.
Pr9ject"No. 06716-32-01 · -13'-June 28, 2001
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6.10.2 Umestraip,ed walls are those that are allowed to rotate more than 0.001H at the top of the
. wall. Where walls are restrained from Il;lOVement at the top, an additional uniform pressure
of 7H psf (where H equals the height of th.e ~etaining w~ll portion of the wall in feet)
should be added to the above active soil .pressure.
6.10.3 AU retaining walls should be provided with a drainage system adequate to prevent the
buildup_ of hydrostatic forces and should be wate:tproofed as required·by the project architect.
The use of drainage openings through ~e base of the wall (weep holes, etc.) is not
recomme1).d~d where the seepage could be a nuisance or otherwise adversely impact the
property adjacent to the base of the wall. The above recommendations assume a properly
compacted granular (Expansion Index less than 50) bac~ll material with no hydrostatic
forces or imposed surcharge load. If conditions different than those described are anticipated,
or · if specific dr~inage details are desired, Geocon Incorporated should be contacted for
additional recommendations.
6.10.4 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 E4pansion Index of less than 90. The proximity _of the foundation to
'the top of a slope steeper than J: 1 could impact the allowable soil bearing pressure.
Therefore, Geocon Incorporated should be consulted where such a condition is anticipated.
6.10.5 For resistance to lateral loads, an allow~ble passiv~ earth pressure equivalent to a fluid with a
density of300 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 at least 5 feet or three times the surface generating the
passive pres~ure, whichever is gre~ter. 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 qombined with the allowable passive earth pressure when
determining resistance to lateral loads.
6.10.6 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
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.
Project No. 06716-32-01 -14-June 28, 2001
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6.11 Drainage and Maintenance
6.11. i' Good drainage is .imperative to reduce the potential for differential soil movement, erosion
and ~ubsurface seepage. Positive measures should oe taken to properly finish grade the
building pads after the structures and other improvements are in place, so that the drainage
water from the buildings, iots and adjacent properties is directed off the lots and to the
street away from foundations and the top of the slopes .. Experience has shown that even
with these provisions, a shallow groundwater or subsurface water condition can and may
.develop. in areas where no such water conditions existed prior to the site development; this
is particularly true where a substantial increase in surface water infiltration results from an
increase in landscape irrigation.
6.12 Grading Plan Review
6.12.1 The soils engineer .and engineering geologist should review the Grading Plans prior to
finalization to verify their compliance with the recommendations of this report and determine
the need for additional investigation, comments, recommendations and/or analysis.
' . '
Project No. 06716-32-01 -15-~ June 28, 2001
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LIMITATIONS AND UNIFORMITY OF CONDITIONS
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 anticipate~ herein, Geocon
Incorporated should be notified so that supplemental recommendations can be given. The
evaluation or identification of the potenti~ presence of hazardous or corrosive materials was
not part of the scope of services provided by Geocon Incorporated.
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
pl~s, and the necessary steps are taken to see that the contractor and subcontractors carry
out such recommendations in the field.
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 1egislation or the . . .
broadening of knowledge. Accordingly, the findings of this report may be invalidated wholly
or partially by changes outside our control. Therefore, this rep?rt is subject to review and
should not be relied upon after a period of .three years.
ProjectN:o. 06716-32-01 June 28, 2001
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.·' .. .. ,.·· .. : .· .: ,.-........
SOURCE : 2001 THOMAS BROTHERS MAP · ~AN DIEGO COUNTY, CALIFORNIA
REPRODUCED WTH PERMISSION GRANTED BY THOMAS BROTHERS MAPS.
THIS MAP IS COPYRIGHTED BY THOMAS BROS. MAPS. IT IS UNl.AW'UL TO COPY
OR REPRODUCE ALL OR ANY PART THEREOF, WiETHER FOR PERSONAL USE OR'. RESALE, WTHOUT PERMISSION ' •
GEO-CON
INCORPORATED
GEOTECHNICAL CONSULTANTS
6960 FLANDERS DRIVE • SAN DIEGO, CALIFORNIA 92121· 297 4
PHONE 858 558-6900 • .FAX 858 558-6159
RG./JMW ·1. I DSK/D000D
1_XJ851
• I . \, .. •• 1-••
DATE
j ';,.: ·;r,,1! rt:
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COSMOS er·.
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N
NO SCALE
VICINITY MAP
THOMPSON PROPERTY
CARLSBAD, CALIFORNIA
06-28-2001 I PROJECT NO. 06716 -3~ -01 I· FIG. 1
I
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-. --... -. . :~
-~---
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o--.
"' -~
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X
::::::---,-.... 05:t? . . :::::::-===::::
ls') -~---N:-----_ ~-----. ':~--1?<'?..:, t\i-:---_ ·\J-v.,~---X ..... _ .....,
Q)
lJI :::5 0 .s::.· ,-
Q)
Ill :s 0 .s::. C Q)
Q)
t.. t.:J
GEOCON LEGEND ·
8-2 0 ....... .APPROXIMATE LOCATION OF EXPLORATORY BORING
T-8 .-.., ....... .APPROXIMATE LOCATION OF EXPLORATORY. TRENqH .
@ ....... .ANTICIPATED DEPTH OF REMEDIAL GRADING
Q Udf ....... UNDOCUMEtrrED FILL ,
. Qpf ....... PREVIOUSLY PLACED COMPACTED FILL
Qco//Q;J./ ........ UNDIFFERENTIATED COLLWIUM AND ALLWIUM
Tsa/Tt ........ uNO1FFERENTIATED SANTIAGO FORMATION AND TORREY SANDSTONE . ·
100 200
GRAPHIC SCA.
-..z
-:.~ SCALE 1" = 40'
GEOLOGIC MAP
THOMPSON PROPERTY
CARLSBAD, CAL!FORNIA
GEOCON 0 SCALE 1" ,;,, 40· 10Aos-2s~2001· ·
lNOOl!.POl!.4'l'.D PROJECT NO. 06716 • 32 • 01 FIOURE OIIOIIQNCAI. CCNIULTAHTS 6960 IIAK8S.lllM: • MIi lllEGO, CAU'olW. nm-297, 2 IIION!1515.!l-6900 •PJJC ~-,,, SHEET 1 OF 1
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PROJECT NO .. 06716-32-01
ASSUMED CONDITIONS:
Slope Height
Slope Inclination
H -= 25 feet
2:1 (Horizontal :Vertical)
Total Unit Weight of Soil
Angle of internal Friction
Apparent Cohesion
Yt -"130 pounds per cubic foot
q, = 30 degrees
C = 200 pounds per square foot
No Seepage Forces
ANALYSIS:
Yc4> = ;iHtan!l! Equation _(3-3), Reference 1
C
FS = Ne~ Equation (3-2), Reference 1
yH
Yc4> = 9.4 Calculated U~ing Eq. (3-3)
Ncf = 31 Determined Using Figure 10, Referenc~ 2
FS = 1.91 Factor of Safety .Calculated Using Eq. (3-2)
REFERENCES:
(1) J anbu, N., Stability Analysis of Slopes with Dimensionless Parameters, Harvard Soil Mechanics,
-Series No. 46, 1954.
(2) Jan.bu, N., Discussion of J.M. Bell, Dimensionless Parameters for Homogeneous Earth Slopes,
Journal of Soil Mechanics andFoundatjonDesign, No. SM6, November 1967.
·SLOPE STABILITY ANALYSIS
THOMPSON PROPERTY
CARLSBAD, CALIFORNIA
' . . . ' ...
;"i[ t:•i··~.;-,::,,;;:_L!i,.~'.;,i_."':l..~:~ _.:--~~,..:Jtv~.,,+=...~ ~ ~
FIGURE3
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PROJECTNO 06716-32;01
ASSUMED CONDITIONS:
Slope Height
Dept:11, of Saturation
Slope Inclination-
Slope Angle
Unit Weight of Water
Total Unit Weight of Soil
Angle of Internal Friction
Apparent Cqhesio1J,
if
z
2:1
i
'Yw
'Yt
<l>
C
Slope saturated to vertical depth Z below slope face.
Seepage· forces parallel to sio:pe face ·
ANALYSIS:
REFERENCES:
FS= 9 + (Ye Y w)Zcos2 i tan r/J
YtZ sfui cosi
= Infinite
= 3 feet
(Horizontal : Vertical)
= 27 degrees
= 62.4 pounds per cubic foot
= 130 pounds per cubic foot
= 30 degrees
= 200 pounds per square foot
= 1.88
(1) Haefeli, R. The Stability of Slopes Acted Upon by farallel Seepage, Proc. Second International
Conference, SMFl:t, Rotterdam, 1948, 1, 51-62. ·
(2) Skempton, A. W., and F. A. Delory, Stability of Natural Slopes in London Clay, Proc. Fourth
lniernational Confe~ence, SMFE, London, 1957, 2, 378-81.
S{JRFICIAL SLOPE STABILITY ANALYSIS
THOMPSONPROPERTY
CARLSBAD, CAJ.,IFORNIA
FIGURE4'·
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APPENDIX A
FIELD INVESTIGATION
The field investigation was ·performed on May l5 (Trenches Tl through T8), and May 24 (Borings
B 1 and B2), 2001., and consisted of a visu~l site reconnaissance, the excavation of 2· large-diameter
borings and 8 backhoe trenches. The approximate locations of the exploratory borings and trenches
ar.e shown on Figure 2.
The borings were advanced to depths ranging from 42 to 55 feet below existing grade using an
Easy-bore 120 truck-moµnted drill rig equipped with a 30-inch-diamete_r bucket auger. Relatively
. undisturbed samples were obtained by ·driving a_ 3-inch, split-tube sampler 12 inches into the
undisturbed soil mass with blows from a telescoping K,elly bar varying in weight from 2500 to
4500 poUlids. the sampler was equipped with six 1-inch by 2.5-inch brass sampler rings to facilitate
removal an~ testing. Bulk samples were also obtained .
The backhoe trenches were advanced to depths of 5 to 18 feet using a John Deere 45OC track
mounted extend-a-hoe equipped with a 24-inch-wide bucket. The soils encountered in the borings
and backhoe trenches were visually examined, classified, and logged. Logs of borings and backhoe
trenches a,re presented on Figures A-1 through A-12. The logs depict the soil and geologic conditions
encountered and the depth at which samples Were obtained.
Project No. 06716-32-01 June 28, 2001
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PROJECT NO. 06176-32-0L
. · DEPTH·
IN
FEET
0
2
4
6
8
10
12
14
16
18
SAMPLE
NO.
Bl-1
Bl-3
Bl-4
Bl-5
'Bl-.6
Bl-7
Bl-8
Bl-9
20 . Bl-10
22
24
Bl-11
26
28
ffi ~ l-o (C
.J '3 0 C :c z s I
SOIL
CLASS-
CUSCS)
SM/SC
SM
SM
BORING B 1
ELEV. (MSL.) -249
EQUIPMENT
DATE COMPLE)'ED
30" LARGE DIA. AUGER
MATERIAL DESCRIPTION
ALLUViUM:
5/24/01
Medium dense, moist~ brownish-gray to dark
grayish-brown, Siltyto Clayey, fine SAND, few roots.
Trace clay, mottled light brown,ish-gray to light
brown, friable.
-Very friable.
-Grades to fine to coarse SAND at 16 feet
-Few subr01,mded gravels, charcoal chunks at 19 feet.
Gradational contact approximately I-foot thick zone
be innin · at 20 feet 8 inches.
SANTIAGO FORMATION/fORREY SANDSTONE .
Dense, m()ist, light brownish-gray to light gray, Silty,
fine SANDSTONE, moderately cemented, massive, .
mottled, light reddish-brown, J.ll,ultiple randomly
oriented clay infilied fractures up to 1/4-inch wide
and'.? feet long.
-8-ill_ch thick zone-thinly bedded sands and silts,
mottled orange, few green-gray ripup clasts at
approximately 29 feet 2 inches ·
2 98.7 6.0
2 117.0 13.7
1 110.9 11.3
1 101.4 10.7
1 111.5 .10.9
2 113.3 9.0
3 118.8 9.3
2 111.1 9.0
2 113.9 8.8
6
7
Figure A-1, Log of Boring-B 1 THRES
SAMPLE SYMBOLS 0 ... SAMPLING .UNSUCCESSFUL.
~ • .. DISTURBED OR BAG SAMPLE
IJ ... STANDARD PENETRATION TEST .... DRIVE SAMPLE (UNDISTURBED)
i;I ... CHUNK SAMPLE :J: ... 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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PROJECT NO. 06176--32-01
Jl:: ·>-1.1.J (.!) l-
DEPTH
IN
FEET
SAMPLE
NO.
g ~
0 C :I: z I-. ::::,
~ ~
-30 ·1·r,1·~· Bl-12 ::c:1::~· --.·~·l•.r1
.·~· ~· .r1·
-32 -::f :1::f:
=·t·kf·' -... ·' • 1 ., ., • :r: 1: ·~ • -34 ~ •.r.1 .. ~· · -•• J • t ... -:;t:~:*
Bl-13 I ::f:1::t:
... 36 -:=t=f f: · t -::f :j .. ::t.: ....... -' -38 ""' ~ t :·~-r:[:
(!)
SOIL
CLASS
(USCS)
SM
BORING B 1
ELEV. (MSL.) . -249.
EQUIPMENT
DATE COMPLETED
. 3011 LARGE DIA. AUGER
MATERIAL DESCRIPTION
5/24/01
7 -
-
-
t-
"" 7 -
-
-
ti' : 40 :
: :f: .. j: =t= . . . .. ~. ··r· .·~·~·· ,. .~( ~· .,. . ::;:J::~: ~ -
-
-
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.·,;
--
-42 -
.·~·J·.c, =
.·~· 1· ·~ t ::f;~=:~: , .......... i ..
-Seepage light to moderate at 41 feet 11 inches ...
...
-~~7.Tt--i-,--~--------------------------------------~--+---+--~
Bl-14 I ~-· . CL Hard, moist, greenish-gray, Silty CLAYSTONE,
t-
13
,... 44 -Bl-15 ~ ~ thinly laminated. 95.5 24.8 -------+, --Approximately 1-2-inch thick remolded clay seam, -1----1----t-----1
1 firm, moist, greenish-gray, continuous across boring :
... ..:
• f r ... ... 46 -
--
-48 -
--
:-50 -',
--
.... 52 -
.... ··j·· ~ .. .. ... ·rt ... . r. .... .. .. .. '4 ··f ····t·
... ·~·· 4 ·r·t .... ·~·· ' ·r .T .............
.... ·~·· -. -r~t ...... ' .... ·~· .. ' ·t·r .... '•j•":. ·r·r . . . . . . :• ·~·: : t. t
.. : : : .. I
SM
~ N42W, 12NE at 44 feet 3 inches (bedding parallel 1 ,_
· 1 __ shear) __________ . ____________________ ,' ...
Dense, moist, light gray to light olive-gray, Silty fine
SANDSTONE, massive, moderately cemented. ...
-
-
t-
t-.. :~ ... ... -
11 Ii -----------------· -------.-----------------1----1----t-----1
"" 54 -
--Bl-16
-56 -
""
~
~ ~~~-
t;L/ML· Hard, damp, greenish-gray, Silty CLAYSTONE and
Clayey SILTSTONE, thinly laminated.
BORING TERMINATED AT 57 FEET
Groundwater seepage encountered at 41 feet 11 inches
Backfilled 05-24-2001
Figure A-2, Log of Boring-B 1.
""
-20/2" -
THRES
SAMPLE SYMBOLS ,0 ... SAMPL.ING UNSUCCESSFUL
~ ••• DISTURJ3ED OR BAG SAMPLE.
[] ••• STANDARD PENETRATION TEST •••• DRIVE SAMPLE (UNDISTURBED)
·liiJ . . . 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.
:. -l:..
,,:
/J ,~
I".,
\'
I •
-•~
1:~
. ,~
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......,
I.
,11;·
. . ,· ,~
1:~
1,: :,~ ,,~
\I~ ,~ ,~
,,·,,
.,
PROJECT NO. 06176-32-01 '
~ BORING.B 2 >-I.LI :z UJ'"' >-'"' t!) I-Ou• I-,.._ LlJ~ 0 .(C DEPTH .J ::J: SOIL H:zl-H. ~v
SAMPLE 0 C 1-<CLL Cl>u. =>1-IN I NO. :t: z CLASS ELEV. (MSL.) . -255 DATE COMPLETED 5/24/01 <Ci-" :z • t-z
F~ET I-. ::> ~Cl)(/) LlJu CJ) LlJ
H 0 (USCS) 1-H::J: c. Hi-
.J -~ 30'' LARGE DIA. AUGER
LlJcnO >-0. Oz,
EQUIPMENT :ZLIJ-l (!) ~~e ~v :Co
C (.J
.MATERIAL DESCRIPTION
-0 J 1.-1.
-""' l 1 ·1 ALLUVIUM -
SM Medium dense, moist, light reddish-brown, Silty fine
-2 -."j ~-1· SAND with trace clay. -
. i .
'--J:l ..,
'-4 -l"1l · ., -
."j -~-1· ----
. B2-1 I J i.-i·-1 101.8 . 10.5
'-6 -l 1 ·1
-
--1--1 f_ 1· -
B2-2 1 95.2 9.3
--8 -. -t _. -. .-1-· I· -Becomes grayish-brown at 8.foot
-· -l·I ·1 -
-10 -."j ~-1· -
B2-3 I . -t . 1 110.5 11.5 Jl --· l·l.·1
-
-12 -
="1 t-t·
-
---
B2-4 I -l :1 .. -Gradational contact, approximately 1.5 foot thick t:. 1 (IQ ,, n fl
I :•f ·~·=t· \ I -.......... -
-14 -... j .. -l zone beginning at 12 feet 8 inches.
=r ·=f· SANTIAGO FORMATION/l'ORREY SANDSTONE --J ...... ~ .... -4 -
B2-5 ··( ... , SM . Dense, damp to moist, light brownish-gray ·to light
.. ~ • .. ~ .. ~4 -16 -.. ·~· -4 gray, Silty, fine SANDSTONE, trace clay, moderately -=r~=f .... ·~·· -4 -
~emented, massive, multiple, randomly oriented clay
""' -::f ;.;:~: infilled fractures up to 1/4-inch wide, and 2-feet in -
-18 -' =rj·:f. length. -... .. ~ ... --t :r -. . . -Becomes fine to medium-grained at 19 feet .. ·~· "r ··r 20 -. . .
I-•: :~: .. ~. -
t·T '--.. .. .... .... ·f·· .. -
r · f -22 ...:. :• .... : : -. -~· :·f ·•· :r . ·r . -~ ·r ·r -........... . . .
-24 -... ·~·. -.. -t ·t
-'--· ::t*:r~ -...... ' . r . . . .
--26 -:·r ·.·:t: ... . ·r . :r ·r . ---.. . .. .... -I-
.. ·~· 't ··t .. .. ....
-28 -•: :1:· . -• t t •::,:•"• -..,. :t~·:t: ,.. .. ·~·. ~ ., ... ,
F~gure ~-3, Log. of Boring-B 2 THRES
SAMPLE SYMBOLS
0 .. , SAMPLING UNSUCCESSFUL IJ ... STANDARD PENETRATION TEST •••• DRIVE SAMPLE (UNDISTURBED)
~ ••• DISTURBED OR BAG SAMPLE iiJ' ... 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'SUBSUREACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
,,r~
;
' PROJECT NO
,: ,~ ,~
'DEPTH
IN
FEET
':-30
-
1: ~. : 32 :
-34 -I··. -
/_
,_ 36 --.
-,~ -
1-38 -,~ I-.,.
... 40 -
-
-42 -3
a: : ,,~
... -
44 -
-
... 46 -
... --
1-48 -
1:~ = 50 :
... ,~ ,_ 52 -
.... -
. '
L
SAMPLE
NO.
06176-32-01
Q:: >-LLJ (!) I-0 i SOIL .J 0 C CLASS :c: z I-:::, (USCS) · H 0 .J Q::
(!)
-SM
SM
BORING B 2
ELEV. (MSL.) -255
EQUIPMENT
DATE COMPLETED
.3011 LARGE DIA. AUGER
MATERIAL DESCRIPTION
-36 feet 10'inches to 38 feet 3 inches-thinly bedded
silts and sands to 1/8-inch thick:
-Massive from 41 feet to 44 feet.
-Becomes fine to coarse-grained at 46 feet.
-Light seepage at 47 feet 3 inches.
Hard, damp, greenish-:gray SjLTSTONE bed, up to
approximately 2~inches thick, continuous across
boring at 47 feet 3 inches :N36W, SN .
From 52 to 55 feet multiple <l!'.eas of light seepage
along neat vertical fractures. Fractures up to 1/64
inch wide and 2-feet long.
BORJNG TERMINATED AT 55 FEET
Groundwater seepage encountered at 4 7 feet 3 inches
& 52 to 55 feet
Backfilled 05~24-2001 1:
.,----,
Figure A-4, Log of Boring-B 2
5/24/01
....
-
,_
,_
...
-
....
...
I-
-
-
-
,_
,_
THRES ,~ SAMPLE SYMBOLS 0 .... SAMPLING ~NSUCCESSFUL IJ ... STANDARD PENETRATION TEST •••• DRIVE SAMPLE (UNDISTURBED)
I'
-;~
tl§ ... DISTURBED OR BAG SAMPLE ~ ••• CHUNK SAMPLE J ... 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 1·s NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURfACE CONDIT.IONS AT OTHER LOCATIONS AND TIMES.
,~ ,~ ,\~
-~ ,,
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1:
1:
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~ -. -~
1-:
1:
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1:
1):
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. '
PROJECT NO.
-
'-
-
'-
...
...
...
...
I-
...
'-
DEPTH
IN
FEET
O·
2
4
6
8
-
:..
-
-
-
-
-
-
-'
10
SAMPLE
NO.
Tl-1
Tl-2
06176-32-01
0:: >-UJ (!) .... 0 (C SOIL ..J 2 0 C ·CLASS :x: z .... :J' (USCS) H 0 ..J ' 0:: (.!)
/ Vl/11 ~ 1/Vv vl/11 1//1,-
V/11 1/1/1_;,
CL
TRENCH T 1
ELEV. (MSL.) -257
EQUIPMENT
DATE COMPLETED
JD 450C TRACKHOE
MATERIAL.DESCRIPTION
AILUVIUM
Firm, moist, dark brown, Silty CLAY, abundant
roots. ·
5/15/01
-
t i/.'./1,
.-1-l --------------------------------------------,-
-~--1 T
_"j t.,-
:-1. -t_-j.
·t1 l
_"j .f_ 1· . -t . .-1. ·l r:~ ·r_
:l .f 1 · .-1. l
·1-i ·1· ::[:,::tt :rl·r ... :f ~=:t: • ·1· :•5. ... •:t:
SM
' SM
Medjum dense, moist, reddish-brown, Silty, fme
SAND, trace clay, few roots.
SANTIAGO FO~TION/fORREY
SANDSTONE UNDIFFERENTIATED
Very dense, moist, light gray,_ Siity, fine
'-
I-
,_
...
SANDSTONE, moderately cemented, moderately r~
. fractured, randomly oriented fractures up to
: 1/16-inch wide, infilled with clay. · '--,--'--------'-------''-----------~ TRENCH TERMINATED AT 10 FEET
. No groundwater encountered
Backfilled 05-15-2001
Figure A-5,. Log of Trench T 1
z . '"' >-'"' oUI • .... I"'\ UJ~ HUI-H • o::'"" t-Zu. (J)IJ. (C(C '\. z. :Ji-0:: I-CJ) LI.Ju 1-z 1-Cl>:3' c. (J)UJ
UJHo Hi-Z(J)..J >-e:: -Oz UJUla::i 0:: ::Co a.. o::...., C u
106.3 8.3
THRES
SAMPLE SYMBOLS 0 .. ." SAMPLING UNSUCCESSFUL IJ ... STANDARD PENETRATION TEST .... DRIVE SAMPLE (UNDISTURBED)
~ ... DISTURBED OR BAG SAMPLE liJ ... CHUNK SAMPLE I ... WATER TABLE OR SEEPAGE
NOTE: THE LOG OE 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.
-1~:
1: ,~ ,~
;f,·
' .
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. ,~
11:
1:
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' '
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1:~ ,,~ ,.
1: ,~
,-,.,
1:
I': ,~
PROJECT NO. 06176-32-01 ..
0::: TREN.CH T 2 ->-LIJ zL&J,... >-,... (!)' I-Ou• I-L&JM 0 <I: -H" DEPTH .. ..J 3 SO~L Hzl-a:::'-' SAMPLE 1-<I:LL en •
· IN 0 C CLASS <I:1-' zLL =>1-
NO. :c z ELEV. (MS~.) -258 DATE COMPLETED 5/15/01 o::cncn LIJ • t-z FEET I-:::) cU cnL&J H 0 (USCS) 1-H:I . H1-..,) 0::: .. .ID 450C TRACKHOE UJcnO >-ll.. Oz EQUIPMENT ZLIJ..J ,(!) ~o:::e3 0::y i::o
C u
MATERIAL DESCRIPTION .... 0 . . 11 ·1 ' -:j:_r.1· Fll.,L
I--
."j t. 1-Loose to medium dense, dru:pp to moist, brown to ....
. i _. ' reddish-brown, Silty, fine SAND, abundant ro_ots .
1,-2 -rl-·I" -. T2-1 1·1 ·1 SM
-.,.. . :·1 r 1--
1,-4 .-. J,l -
¾ .ALLUVIUM --Firm to dense; moist, dark brown to light 1,-
0 reddisll-:brown, fine Sandy CLAY and Silty, fine
-6 -SAND, few ,roots. -
½ CL/SM
1,---
1,-8 ... ~ .... (
-Gradational contact approximately 1.5 foot thick ..,. ... .. / zone beginning at 8 feet 11 inches, multiple r .... =·f ., .. :~, . ·~· ' ft:actures up to 1/16-inch wide with clay infill. :rt SANTiAGO FORMATIONffORREY -lO -...... ' I-:• ·~·: . SANDSTONE t. ~ ... ·j·· -• Dense, moist, light gray, Silty, fine SANDSTONE, ·r-r --. . . -... massive. " .... ·~··:. ··f .. ~·:.
12 -:• -~-:t: .... r · f I-:• ·( SM ·r ··t ...
1,--\~\ ...
... .. ~·· ' .. .. .. '
" =·f •.·:i, ' I-14 -··r ~ :•. t d:~:-. .... ~ t·T -:• ·j·:-: -' r · f ...... .,•! • . . . -16 .... .._;l~ ... ;
TRENCH TERMINATED AT 16 FEET
No groun,;hvater encountered
Backfilled 05-15-2001
Figure A-6, Log of Trench T 2 THRES
SAMPLE SYMBOLS
. ~ ••• DISTURBED OR BAG SAMPLE
0 ... SAMPLING UNSUCCE~SFUL IJ ... STANDARD PENETRATION TEST ••.•• DRIVE SAMPLE (UNDISTURBED)
ii.,. 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 ~NDICATED. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
,,','.
. I ' '
I:' ,~
I-~
' ,~ ,,~ ,~
I.·
. . ,~
1: ,~
1: ,~.
1:,~
I; ,:
,. ,:
I~~
I~
PROJECT NO. 06176-32-01 ..
·O:: TRENCH T 3 >-IJJ zlJJ,-,. >-,-,. (!) I-Ou• 1-,-,. UJ~ 0 (I: 'DEPTH ....I 3 SOIL Hzl-H. o::'"' SAMPLE 0 i. CLASS· ~(I:~ ' (J)lL =>1-IN :c ELEV. (MSL.) -251 DATE COMPLETED 5/15/01 0::1-,-(J) z. t-z NO. Wu F~ET I-:::, (USCS) 1-CJ>:;i: c. cn.w ' H 0 LLIHO H1-....I 0:: EQUIPMENT · .JD 450C TRACKHOE z<n....1 >a.. Oz (!) LLIIJJCC 0:: V :Co a.. o::..., C (.)
MATERIAL DESCRIPTION -0 :/"!(/-. ?: ...
COLLUVIUM ,-y/ --/// Loose to firm, moist, dark brown, Clayey, fine I-
l/f SAND and Silty CLAY, abundant roots. '
-2 -/·; I-
~}./ SC/CL
,_ -t,;//. -. /_,1
I-4 ~/0 -. .-1. '·"I-li ., ALLUVIUM --.'j .t_ ,. Loose t<:> medium dense, moist, reddish-brown, I-
. i . .Silty, fine SAND, trace clay .
,_ 6 ·-.-1-l -li .,
--. .t . -T3-1 :l f) ' SM
8 L1: ·I· --· l. i ., t-
99.6 6.7 . { .
--, :l f I · t-
Jl ..
I-10 -·,. i ·, . ---~---------------------------------./· / '.1/: ?/J SC Dense, moist, dark gray, Clayey, fine SAND.
t--(/> -
(//
-12 -·,// ------------------------------------.-1-"'l . l·I ·1 Dense,· nioist, reddish-'brown to grayish-brown, --. .'j .t_ [' Silty, fine SAND. t-
. . -r -14 -.-1-·l -
. l·I ·1 • SM
t--.'j -t. [· -. ·t .-1. l -16 .,. li ·1 I-
--:·l t,1·, '-
.-1. l
'-18 ·,.1-,
TRENCH TERMINATED AT 18 FEET
No groundwater encountered
aackfilled 05.:.15-2001
... Figure A-7, Log of Trench T 3 THRES
SAMPLE SYMBOLS D ... SAMPLING UNSUCCESSFUL I) ... STANDARD PENETRATION TEST •••• DRIVE SAMPLE (UNDISTURBED)
~ ••• DISTURBED OR BAG SAM.PLE . iiJ ... CHUNK SAMPLE !'. ... WATER TABLE OR SEEPAGE
NOTE: THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPEC'IFIC BORING OR TRENCH LOCATION AND AT THE
DATE INDICATED. IT IS NOT WARRANTED TO-~E REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
:I: ,.~ ,\~
1~-
1:
. ,~ ,~. ,,~ ,,~
1: i,~
I;~ ,.~-
i'~
I'
'. ' .
! 1: ,~ ,~
1:
PROJECT NO. 06176-32-01 -
0::: TRENCH T 4 >-UJ ZUJ""' >-,..,, (!) I-Ou• 1-,..,, UJX 0 <C .DEPTH ...J ::J: SOIL Hzl-H. 0:::'"' SAMPLE 0 C 1-<CLL (/)Li. ::::, .... IN :::c z CLASS· ELEV. (MSL.) ---248 DATE COMPLETED 5/15/01 <C1-'\. z • 1-z NO. I-::::, 0::: (J) CJ) LI.Ju (J)UJ FEET H 0 ·(USCS) 1-H:3 c. H1-...J 0::: EQUIPMENT
LLlcnO >-a. Oz JD 450C TRACKHOE ZLLI...J (!) I.LI 0::: al o:::"" :co -. Q. V C u
MATERIAL DESCRIPTION -0 . 1 ·, ·1 \f-1' FilL .--
_"j t. I" Loose to medium dense, dry to moist, light brown . -
. -t . to yellowish-brown, Silty, fine SAND, few
-2· .... .-1-l inclusions· of dark brown, Silty CLAY .. -l~ ·1 SM
--_"j {_ , . -. -t . I
·-4 -.-1:,l -· /.j;rt
·---Pf,i; ALLUVIUM -
{Ytf SM/SC Medium dense, moist, brown to grayish-brown, .. 6 ·-%-G Silty to Clayey, fine SAND. -
T4-1 Vi-K;r ·
--@(-f-..
• 7 j,/1,,-----------.----. -. ·-------------------_-1.1--1-, -8 ..;. l~ ., Dense, moist, rl;lddish-br9Wn, Silty, fme SAND, -'
_"j {_ [· SM trace clay. ---. 1 :1-l -10 -, · li ·1 -
_"j t. 1· --. J-r_.,_ -
-12 ..;. ·i-:!·1 t,··t: .. ;r =rt SM SANTIAGO FOID4;ATION/fO~Y -... SANDSTONE -.-=:r:~==t: .... ·j·· .. D~nse, moist, light gray, Silty, fme SANDSTONE, -14 :•i• •:r: moderately ce:r;nented, massive, vertical fractures r-up to 1/16-inch wide, randomly oriented.
TRENCH TERMINATED AT 14 FEET
No groundwater encountered
Backfilled 05-15-2001
. -Figure A-8, Lo~ of Trench T 4 THRES
SAMPLE SYMBOLS 0 ... SAMPLiNG UNSUCCESSFUL
-~ ••• DISTURBED OR BAG SAMPLE
IJ ... STANDARD PENETRATION TEST •••• DRIVE SAMPLE (UNDISTURBED)
liJ ... 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.
:I: . PROJECT NO 06176-32-01
1,:
1\: ,~
I;~
1:
1:
I'~ ""-
I .
I t ,~
I,',
1:
I .
'. ,,:
,~
,I~ ,.,.
I .. ,,
' . ,~
. ,,'.
' '
j
0:: TRENCH T 5 >-UJ . ZUJ""' >-,...
(,!) I-Ou• 1-,... UJ :-e 0 (C
DEPTH _J :x SOIL Hzl-H. 0:: V
SAMPLE 0 C
1-(CU. U>u. =>1-IN :c z CLASS ELEV. (MSL.) -256 DATE COMPLETED 5/15/01 <C,-'\. z . 1-z
FEET NO. I-::, (USCS)
0:: Cl)(/) Wu (J)UJ
'H-0 ., 1-H:X C • H,-
_J 0:: LIJ(/)0 :,-a.. Oz EQUIPMENT JD 450C-TRACKHOE Zw-1 CJ) ~a::e o::""' :Co
C (.)
. MATERIAL DESCRIPTION .... 0 . ' . 11 .,
-:~:_r.l· SM COILUVIUM .... --:1 t ,-Loos~, dry to moist, reddish-brown, Silty, fine ....
SAND, trace clay, abundant roots. . -t . ... 2 -. '
tf J: ML SANTIAGO FORMATIONtrORREY
--~ SANDSTONE . -• f 't Dense to very dense, moist, brownish-gray, fine , I ... \ ., ' .,,, .. I ·t .. f SM I Sandy SILTSTONE, moderately to highly fractured I :• •(r, \ .... 4 -, • "'., L 4 , __ along cleava_g~ surfaces. . __________________ ,1 ...
::f =ft• Dense, moist, -light gray, Silty, fine SANDSTONE, :·t· •:r: _ .,.. i:p.oderately cemented; massive, near vertical r-fractures with, clay infill, hairline to 1/64-inch
w~de,
TRENCH TERMINATED AT 5 FEET
No groundwater encountered
Backfilled 05-15-2001
Figure A-9, Log of Trench T 5 THRES
0 . . . SAMPLING UNSUCCESSFUL
~ ••• DISTURBED OR BAG SAMPLE
[j ... STANDARD PENETRATION TEST •••• DRIVE SAMPLE (UNDISTURBED) SAMPLE SYMBOLS ~ ••• 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 •
,,,_
J,
' !
-I
• ,~
I
I
,,~-,
I_ • ,~
1.: /,~
I ' '
1;:·
Ir
..
1:
1:
I
·a
,_,·'"',·
' '
1-:
PROJECT NO 06176-32-01 .
0:: TRENCH T -6 >-UI Zw" >-" (!) I-' ·ou. I-" UJ~ o· (C'
DEPTH ..J ,:J: SOIL Hzl-H • o::'"'
SAMPLE 0 C 1-<CU. Cl>u. =>1-IN :c z CLASS ELEV. (MSL.) -254 DATE COMPLETED 5/15/01 <Ci-' z. 1-z NO. I-::::> (USCS)
0:: Cl)CI) Wu Cl>w FEET H 0 1-H:3: c. H1-
...J ,o:: EQUIPMENT
l1looO >-a. Oz JD-450C TRACKHOE Zw..J (!) UI o::CO 0:: V :Co Q. V C u
MATERIAL DESCRIPTION
' ... 0 v'/'/: . v· .. -v/j COILUVIDM ~. -Loose, moist, dark browµ, Clayey, fine SAND -
~j SC abundant roots. ·
-2 -: I-v:// v./.1: ... -:1-'-l
11 ·1 AILUVIUM .... 4 -_"j {_ [· Medium dense, moist, reddish-brown, Silty, fu:1.e I-
. SAND.
.... -·1 1l I-
-:J:_-1\
..., 6 -_ _.j {_ 1-I-
. -t SM
.-1-l --l 1 ·1 -
-8 -_"j t 1· ... -1. ' -Becomes dense at$ feet . .-1---i---li ·1 I-
_"j t 1·
,c-10 ---r I-
T6-1 '. .-1-l 94.8 10.5
I li ·1 --_"j {,. -
--r -12 -.-1-l I-
li ·1
--'--="1 ;-,-I-
:1-l -
>'-14 --r.·l ·1 I-
."j t,. -
>--. -r I-
.-1-l
-16 -li ., >-
."j -t.,. . -t
I--.-1. l -
I-18
r:~ ·1
TRENCH TERMINATED AT 18 FEET
No groundwater encountered
Backfilled 05-15-2001
Figure A-10, Log of Trench T 6 THRES
SAMPLE SYMBdLS 0 ... SAMPLING UNSUCCES$FUL. IJ ... STANDARD PENETRATION TEST •••• DRIVE SAMPLE (UNDISTURBED)
~ ••• DISTURBED OR BAG SAMPLE · ~ ••• 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.
:•: ,.~
.1-. . ,~
·1~ ,~
I' , '
J i-
1:
:1 .. ,,,~
I'>
' '·
-:~ ,.~
:I~~ ,.~
1: .,.,
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I ' ,~
·1·1
l
..
PROIBCT NO. 06176-32:01 ..
Q:: TRENCH T 7 >-UJ z UJ'"' >-'"' (!) I-Ou • l:i'"' UJX 0 (C' DEPTH ..J 3 SOIL Hz!-Q::'-!'
SAMPLE !-(CU. Cl) •
0 C CLASS zLL :JI-IN NO. ::i:: z ELEV. (MSL,) -255 DATE COMPLETED 5/15/01 <C1-' LlJ • 1-z
I-:::J (USCS)
Q::(/)(1) cU CJ)UJ FEET H 0 1-H:I . H1-
..J Q:: EQUIPMENT JD 450C TRACKHOE
LllcnO >-ll.. Oz ZUJ..J (!) ~Q::e
.Q::v l:o
C q -
MATERIAL DESCRIPTION
I-0 v.u-t rf.l SMJSC COLLUVIUM ... -Loose, moist; grayish-brown, Silty tci Clayey, fine -?0J SAND, abundant roots.
I-2 -:1-,.-,.
l~ ·1· ALLUVIUM --
:·1 t-.i-
Loose to medium dern1e, moist, reddish-brown to -
grayish-brown, Silty; fine SAND, massive. .,
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=·ft=t· ....... SANTIAGO FORMATION/l'ORREY =r ·=r· · SM .SANDSTONE . . --' ... -.. ~ ... ... Dense, damp to moist, light gray, Silty, fine :•f • .. ·:t1 .. j .. SANDSTONE, moderately cemented, massive,
,I-14 · :•L• •:f h~rline to 1/64-µich wide near vertic~ fractures. r ...
TRENCH TERMINATED AT 14 FEET
No. groundwater encountered
Backfilled 05-15-2001
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Figure A-11, Log of Trench T 7 THRES
SAMPLE SYMBOLS 0 ... SAMPLING UNSUCCESSFUL IJ ... STANDARD PENETRATION TEST ••••. DRIVE SAMPLE (UNDISTURBED)
illL .. DISTURBE,D OR BAG SAMPLE · ~ ••• 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 WARRANT~D TO·BE REPRESENTATIVE.OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
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DEPTH
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SAMPLE
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~ i CLASS
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TRENCH T 8
ELEV. (MSL.) -255
EQUIPMENT
DATE COMPLETED
JD 450C TRACKHOE
MATERIAL DESCRIPTION
COLLUVIUM
:J.,oose, moist, grayish-brown, Silty to Clayey, fine
SAND, abundant roots.
5/15/01
-
11 P', ·vv, ---------------------------------------------v. ./ ~;~ SM Medium dense, moist, grayish-brown, Silty, fine
ML
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SAND r --------'---'----'--------'--------~ SANTIAGO PORMATIONffORREY -SANDSTONE .
V~ry hard, moist, brownish-gray, fme Sandy
SILTSTONE, moderately to highly fractured along
cleavage surfaces.
Approximately 4-inch thick, thinly laminated,
GLA YSTONE/SILTSTONE b~d at 7 feet; hard,
fractures along cleavage surfaces.
TRENCH TERMINATED AT 9 FEET
No groundwater encountered
B~ck;filled 05:-15-2001
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Figure A-12-, Log of Trench T 8
Zw'"' :>-'"' Cu• I-'"' w~ Hzl-H • o::"-'· 1-<CLL. (l)LL. =>1-<Ci-....... z. 0:: (1)(1) Wu 1-z
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THRES
SAMPLE SYMBOLS -0 ... SAMPLING UNSUCCESSFUL
~ ••• DISTURBED OR BAG SAMPLE
(J ... STANDARD PENETRATION TEST •••• DRIVE SAMPLE (UNDISTURBED)
ii . . . CHUNK SAMPLE I .. .-WATER TAB~E OR SEEPAGE
NOTE: THE LOG OF SUBSUREACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECI-FIC 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_B
LABORATORY TESTING
Laboratory tests were performed in general accordance with the test methods of the American
Society f<?r Testing and Materials (ASTM) or other suggested procedures. Selected, relatively
undisturbed drive samples were tested for their in-place dry density, moisture content, shear strength
and consolidation characteristics. The maximum dry density and optimum moisture content of one
bulk sample was determined in accordance with ASTM Test Procedure D 1557-91. This sample was .
then remolded to 90 percent-of the maximum dry density and subjected to dra~ed direct shear
testing.
The results of our laboratory tests are presente~ .in tabular and graphical forms -hereinafter. The
in-place dry density and moisture characteristics are presented on the boring and trench logs.
Sample
No •.
TAaLl: B-1
SUMMARY OF LABORATORY -MAXIMUM DRY DENSITY
AND OPTIMUM MOISTURE CONTENT TEST RESULTS
ASTM D 1557-91
Description. Maximum Dry Optimum Moisture
Density (pct) Content (% dry wt.)
T4-°1 Silty, fine to medium SAND, trace clay 123.4 10.4
TABLE B-U
SUMMARY OF DIRE:CT SHEAR TEST RESULTS
Sample No. Dry Density Moisture Content Unit Cohesion Angle of Shear
(pct) (%) (psf) Resistance (degrees) ..
;
Bl-4 112.5 10.7 200 35
Bl-6 105.9 8.8 450 31
Bl-10 115.5 10.2 800 26
T4~1* 110:9 10.8 500 ' 30
*Soil S\llllpie· temolded io approximately 90 percent of maximum dry density at near optimum moisture content.
Pro)ect No. 06716-32-01 June 28, 2001
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APPLIED PRESSURE (ksf)
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. Initial Drv Density (ocf) 110.9 Initial Saturation ( % ) 60.4
Initial Water Content ( % ) 11,3 , Sample Saturated at (ksf) 3
CONSOLIDATION ·cURVE
THOMPSON PROPERTY
CARLSBAD, CALIFORNI;A
THRES Figure B-1
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APPLIED PRESSURE (ksf)
Initial Dry DensitV (bet) 101,4 Initial Saturation ( % ) 44.7
Initial Water Content(%) 10.7 Sample Saturated at (lest) 3
•.
CONSOLIDATION CURVE .. .
THOMPSON PROPERTY
CARLSBAD, CALIFORNIA
THRES Figure B-2
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APPLIED PRESSURE (kst)
Initial Dry Densitv (ocf) 111.5 Initial Saturation ( % ) 59.3
Iajtial Water Content(%) 10.9 Sample Saturated at (kst) 4
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CONSOLIDATION CURVE
THOMPSON PROPERTY
· . CARLSBAD, CALIFORNIA
THRES Figure B-3
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Initial Drv Densitv (pct) 113.3 Initial Saturation ( % ) 51.3
-Initial Water Content ( % ) 9.0 Sample Saturated at (ksf) 4
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CARLSBA,D, CALIFORNIA
THRES Figure B-4
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THOMPSON J;>ROPERTY
CARLSBAD, CALIFORNIA
l'HRES Figure B-5
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APPENDIXC
.RECOMMENDED GRADING SPECIFICATIONS
.· for
THOMPSON PROPERTY
CARLSSAD,_ CALIFORNIA
PROJECT NO. 06716-32-01
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2.3. ·
RE:COMMENDED GRADING SPECIFICATIONS
1. GEN~RAL,
. These Recommended Grading Specifications shall be used in conjunction with the
Geotechnical · Report for the project prepared by Geocon Incorporated. The recom-
mendati~ns 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.
Prior to the commencement of grading,· a geotechnical consultant (Consultant) shall be
employed for the purpose of observing earthwork procedµres and testing the fills for
substantial conformance with tlie recommendations of the Geotechnical Report and these
specifications. It will be necessary ·that the Consultant provide adequate testing and
observatj.ort services so that he may det~nnine that, in his opinion, the work was performed
in substantial conformance with these specifications. It shall be the responsibility of the
Contrac;:tor to assist the Consultant anq keep him apprised of work ~chedules and changes . : ' .
so that personnel may be scheduled accordingly.
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 irt 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
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.
CQntractor shall refer to the Contractor performing the site grading work.
Civil Engineer or Engineer of W p;rk shall refer to the California licensed Civil Engineer
or consulting firm responsible for preparation of the grading plans, surveying and verifying
· as-graded topqgraphy ..
GI rev. 8/98
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2.6.
2.7.
3.1.
_ Consultant shall refer to the · soil engineering and engineering geology consulting firm
retained to provide geotechnical services for the project.
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 eonformance with_ these specifications.
Engineering Geologist shall refer to a California licensed Engineering Geologist retained
by the Owner to provide geofogic observations and recommendations during the site
grading.
Geotechnical ~eport shall referto a soil report (including-all addenda) which may include
a geologic reconnais~ance 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
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
9f fills. In general, 'fill materials can be classified as soil fills, soil-rock fills or rock fills, as
defmed below.
3.1.1. Soil fills are defined as fills containing no rocks or hard lumps greater than 12
inches in m!I-Ximum 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. Overs~e rock is defined as material greater than 12
inches.
3 .1.3. Rock fills are defined, as· fills containing ho rocks or hard lumps larger than 3 feet
in max,imum di_inension ap.~ 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
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3.3.
3.4.
3.5.
3.6.
4.1.
Material of a perishable, -spongy, ot otherwise unsuitable nature as determined by the
Consultant shall not be used in fills. '
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 applic~ble 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.
The outer 15 feet of soil-l'ock ·fin 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 iriches is track-walked onto the face for landscaping purposes.
This proc;:edur(? may be utilized, provided it is acceptable to the governing agen_cy, Owner
and Consultant.
Representative samples of soil ~aterials to be used for fill shall be tested in the laboratory
by the. Consultant to determine the maximum density, optimum moisture content, and,
where appropri~te, shear strength, expansion, and gradation characteristics of the soil.
,._
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
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 materi~l and shall be performed in areas to be graded. Roots and
other projections exceeding 1-1/2 in¢hes 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
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4.5. After areas to receive fill ha:ve 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 conditiQned to achieve the p:i,-oper moisture content, and compacted
as recommended irt 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 wili 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 perfor;rned 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 wi~
the following recommendations:
6.1.1. Soil fill shall ~e placed by the Contractor in layers that, when compacted, should
generally not exceed 8 inches. Each .h1.yer 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, ~he soil fill shall be compacted at a moisture content at or above the
optimum moisture content as detemilned by ASTM Dl557-91.
6.1.3. ~en the moisture content of soil fill is below tha,t 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
· Consulta}1t or too ~et to a~N~ve proper co:qipaction, 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
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6.2.
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 ( ei.pressed in percent) of the in-place
. dry density of the comp~cted fill to the maximum iaboratory dry density as
· determined in accordance with ASTM D1557-91. Compaction shall be continuous
-over the entire ar~a, and compaction equipment shall make sufficient passes so that
the specified minimum relativ~ compaction ha~ 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 percept, greater than the optimum moisture content for the material.
6.1.7. Properly compacted soil fill shall ex~end to the design surface of fill slopes. To
achiev,e proper. compaction, it is: recommended that fill slopes be over-built_by at
l~ast 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.
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 borizontally from the slope face and 5 feet below finish grade or
3 feet below the deepest utility, whichever is deeper.
6.2:2. Rocl(s 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
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6.2:3. For individual placement, sufficient space' shall be·provided between rocks to allow
for passage ofcotnpaction equipment. ·
6.2.4. For windrow placement, the rocks should be pl~ced in trenches excavated in
properly compacted soil .fill. Trenches should be approximately 5 feet wide and 4
feet d~ep in maximum dimension. The voids ~ound and beneath rocks should be
filled with approveq. 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" 1:11ethod in lieu of the trench procedure, however, this method should
first be approvec;l 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
wmdrow.
6.2.6. All rock placement, fill placement an~ flooding of approved granular soil in the
windrows must be continuously observed by the Consultant or his representative.
Rock fills, as defined in Section 3.1.3., shall be placed by the Contractor in accordance with
the following recommendat~ons:
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 perrn,anently connected to controlled drainage facilities to
control post-constructi<;m 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
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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 accoJ,'.dance With ASTM D1196-64, inay 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 perfi,:>mied. If performed, a minimum of
three plate bearing tests shl;Jll be performed in the properly compacted soil fill
(minimum relative compactio!1, 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·equipinent, 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 deflec~ons are equal to or less than
that determined for the properly compacted soil fill. fu 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 numbe~ 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 ofrock fill placed.
6.3 .5. Test pits shall be excavated by the Contractor so _that th_e Consultant can state that,
in his opinion, sufficient water is present and that voids between large rocks are
properly filled with smaller rock material. fu-place density testing will hot be
required in the rock fills .
6.3.6. To reduce the potenti~l 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
gra9ation 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 ~f the graded filter prior to the
cotninencement of rock fill placement.
GI rev. 8/98
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7.1.
7.2.
7.3.
7.4.
' 6.3.7. All. rock fill placement shall be·· continuously observed during placement by
representatives of the <;onsu1tant.
7.. OBSERVATION AND TESTING
The Consultant shall be the Owners representative. to observe and perfonn 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 acidition, a minimum of one field density test . '
shall be pe:i;:formed for every 2,000 cubic yards of soil or soil-rock fill placed and
compacted.
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 perfQrmed in. the compacted materials below any
disturbed $urface. 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
i::eworked until the specified density has be·en achieved.
During placement of rock fill, the Consultant shalt verify that the minimum number of
passes have been obtajned per the criteria discussed in Section 6.3.3. The Consultant shall
request t~e 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,.recentlyplaced 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 rill. When any of the above criteria
. indicate that a layer of rock fill or ~my porti_on 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.
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 fiti~l report of testing and observation services performed
during grading.
GI rev. 8/98
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7.5.
7.6.
8.1.
8.2.
the Consultant shall observe the placement of subdrains, to verify that the drainage devices
have been placed and constructed iri substantial confonnance with project specifications. . . .
Testing procedures shall confonn to the following Standards as appropriate:
7 .6.1. S<:>il and Soii-Rock Fills:
. -.
7._6.1.1. Field Density Test, ASTM D1556-82; I)ensity of Soil In-Place By the
Sand-Cone Method.
7 .6.1.2. Field Density Test, Nuclear Method, ASTM D2922-8 l, 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 JO-Pound Hammer
and 18-Inch Drop.
7.6.I.4. Expahsiori Index Test, Unifonn 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 Flexib/e
Pavement Components, For Use in Evaluation and Design of Airport and
· Highway Pavements.
8. PROTECTION OF WORK
During construction; the Contractor s~all properly grade all excavated surfaces to provide
positive dra,inage 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 ~rosion of freshly graded areas until
such time as pennanent 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.
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
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9.1.
9.2.
9. CERTIFICATIONS AND FINAL REPORTS
Upon completion ?f 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 oi:i: the .grading plan and that all tops and toes of slopes are within 0.5 foot
horizontally o~ 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.
· The Owner is respon~ible for furnishing a final as-graded soil and geologic report . .
satis~actory to the appropriate governing or accepting agencies. The as-graded report
should be prepared and signed by a California licensed Civil Engineer experienced in
geotecbnical engineering and by a California Certified Engineering Geologist, indicating
· that the geotechnical aspects of the grading were performed in substantial conformance
with th~ Specification~ or approved changes to the Specifications.
GI rev. 8/98