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Preliminary Geotechnical Investigation
Storm Drain Reconstruction
North End of Highland Drive
Carlsbad
June 17, 2003
Prepared For:
CITY OF CARLSBAD
Mr. William E. Plummer
Deputy City Engineer
1635 Faraday Avenue
Carlsbad, California 92008
Prepared By:
VINJE & MIDDLETON ENGINEERING, INC.
2450 Vineyard Avenue, Suite 102
Escondido, California 92029
Job #03-262-P
VINJE & MIDDLETON ENQINEERINQ, INC,
^M ••"• — —L - ---- -• - - ••-•
Job #03-262-P
June 17, 2003
City of Carlsbad
Mr. William E. Plummer
Deputy City Engineer
1635 Faraday Avenue
Carlsbad, California 92008
2450 Vineyard Avenue
Escondido, California 92029-1229
Phone (760) 743-1214
Fax (760) 739-0343
PRELIMINARY GEOTECHNICAL INVESTIGATION, STORM DRAIN RECONSTRUCTION,
NORTH END OF HIGHLAND DRIVE, CARLSBAD
Pursuant to your request, Vinje & Middleton Engineering, Inc., has completed the
Preliminary Geotechnical Investigation Report for the storm drain reconstruction at the
above-referenced site.
The following report summarizes the results of our field investigation, laboratory analyses
and conclusions, and provides recommendations for the planned reconstruction as
understood. In our opinion, the reconstruction of the existing failure features are feasible
from a geotechnical engineering standpoint provided the recommendations presented in
this report are incorporated into the final development plans and implemented during the
reconstruction phase of the project.
Thank you for choosing Vinje & Middleton Engineering, Inc. If you have any questions
concerning this report, please do not hesitate to call us. Reference to our Job #03-262-P
will help to expedite our response to your inquiries.
We appreciate this opportunity to be of service to you.
VINJE & MIDDLETON ENGINEERING, INC.
Dennis Middleton
CEG #980
DM/jt
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TABLE OF CONTENTS
PAGE NO.
I. INTRODUCTION 1
II. SITE DESCRIPTION 1
III. SITE INVESTIGATION 1
IV. EXISTING FAILURE FEATURES AND PROPOSED RECONSTRUCTION 2
V. GEOTECHNICAL CONDITIONS 2
A. Earth Materials 2
B. Groundwater 3
C. Slope Stability 3
D. Laboratory Testing / Results 3
VI. CONCLUSIONS 5
VII. RECOMMENDATIONS 6
A. Slope Repairs and Reconstruction 6
B. Storm Drain Replacement 8
C. Soil Design Parameters 10
D. Years to Perforation of Steel Culverts 11
E. Plan Review 11
F. Preconstruction Conference 11
VIII. LIMITATIONS 12
TABLE NO.
Soil Type 1
Maximum Dry Density and Optimum Moisture Content 2
Moisture-Density Tests (Undisturbed Chunk Samples) 3
Direct Shear Test 4
Ph and Resistivity Test 5
Years to Perforation of Steel Culverts 6
Hi
p
TABLE OF CONTENTS (continued)
PLATE NO.
Site Map 1
Geologic Cross-Section 2
Test Trench Logs (with key) 3-4
PRELIMINARY GEOTECHNICAL INVESTIGATION
STORM DRAIN RECONSTRUCTION
NORTH END OF HIGHLAND DRIVE
CARLSBAD
I. INTRODUCTION
The property investigated in this work includes a graded hillside and natural canyon terrain
below the northern terminus of Highland Drive, in the City of Carlsbad. The property
accommodates a 24-inch diameter storm drain pipe which transmits storm waters from
developed areas along Highland Drive down into canyon terrain and the Buena Vista
Lagoon to the north. The existing pipe has failed resulting in high levels of erosion and
sediment transport downstream, as well as uncontrolled run-off within the lower canyon
terrain. We understand that plans for pipe reconstruction are currently underway.
Consequently, the purpose of this work was to determine geotechnical conditions along the
storm drain alignment within the failed segment and their impacts upon the planned
reconstruction. Geologic mapping, test hole digging and soil sampling / testing were
among the activities conducted in connection with the study which have resulted in
reconstruction recommendations presented herein.
II. SITE DESCRIPTION
The project site includes upper graded areas at the north end of Highland Drive. The end
of the road is marked by a large inlet which transmits run-off into a 2-foot diameter
corrugated storm drain pipe buried within a descending fill slope. The slope terminates
nearly 50 feet below in the lower canyon.
A previous failure within the pipe has resulted in high levels of erosion with the lower slope.
Impacted areas are presently marked by a large vertical scarp, soil debris and broken
segments of the pipe throughout. Surrounding hillside areas are characterized by steep,
natural slopes which also evidence recent erosion.
Details of site surface conditions are shown on a Site Plan enclosed with this report as
Plate 1. Subsurface conditions along the alignment are shown on a Geologic Cross-
Section, enclosed with this report as Plate 2. Both graphics have been modified by
approximate physical measurements taken at the site in order to depict recent slope
erosion.
III. SITE INVESTIGATION
Geotechnical conditions along the failed alignment areas were determined from geologic
mapping of existing exposures and from the excavation of 3 test trenches dug with a
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limited access tractor-mounted backhoe. The trenches were logged by our project
geologist who also retained representative soil samples for laboratory testing. Trench
locations and mapped data are shown on Plates 1 and 2. Logs of the trenches are
enclosed with this report as Plates 3 and 4. Laboratory testing and results are summarized
in a following section.
IV. EXISTING FAILURE FEATURES AND PROPOSED RECONSTRUCTION
The existing storm drain has become disjointed and came apart as a result of bedding soil
erosion and subsequent failure of the supporting slope terrain. High flow rates and
velocities, as well as steep invert gradients causing piping (mining) of bedding materials
are suspected causes of the noted failure. Subsequent to the storm drain failure,
accelerated erosion and sediment transport have occurred resulting the existing vertical
scraps. High levels of additional erosion and failures within the impacted canyon terrain
should be anticipated in the event the planned reconstructions and repairs are not carried
prior to the next rainy season.
Details of the planned reconstruction work are presently unknown. We understand that a
new storm drain pipe is proposed along a similar alignment approximately as shown on
Plate 1. Design profile and new inverts are also not known, however, preliminary plans
include the use of a 36-inch diameter pipe designed for 66 cfs flow rate with velocities on
the order of 41 fps. Non-segmented pipe will likely be utilized particularly in steep sloping
portions of the alignment. The pipe will outlet upon a designed structure located at an
unknown point within the lower canyon.
V. GEOTECHNICAL CONDITIONS
The project site consists of graded hillside, and narrow canyon terrain which accommodate
a damaged storm drain pipe. The following geotechnical conditions are apparent at the
property:
A. Earth Materials
Upper hillside terrain at the project site is underlain by fill soils originally placed in
order to expand building areas at the end of Highland Drive. The fill extended into
the lower canyon with a slope gradient of 2:1 (horizontal to vertical). Based upon
noted field exposures, the fill consists of locally derived sandy soils. Grading
records for the fill are not available for review.
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Formational rock units occur at the site beneath the fill and in surface exposures
throughout the lower site canyon areas. The rocks consist of light colored
sandstone units which occur in a weakly cemented and friable condition. Well-
developed examples of site formational rocks were noted in near-vertical
exposures developed from pipe erosion as shown on Plate 2.
Lower canyon areas of the project site are underlain by debris and alluvial soil
resulting from the recent erosion. Alluvial soils at the site consist of sandy deposits
in a loose condition.
The approximate distribution of project earth materials is shown on the enclosed
Plates 1 and 2. Details of the noted deposits are given on the enclosed logs,
Plates 3 and 4.
B. Groundwater
Major groundwater conditions were not encountered at the time of our test trench
excavations to the depths explored; however, slight seepage was encountered
along the base of the sandstone / claystone units in the test trench location T-3.
Groundwater at the site is not expected to impact the project.
C. Slope Stability
Site topographic conditions are depicted on the enclosed Plates 1 and 2. Over-
steepened conditions have resulted in lower site terrain where the recent pipe
failure has occurred. Rotational-type slope failures within the lower near-vertical
slopes can be expected, thus resulting in a progression of failures within remaining
upper sections of the slope and supporting storm drain pipe.
D. Laboratory Testing / Results
Earth deposits encountered in our test trenches were closely examined and
sampled for laboratory testing. Based upon our test data and field exposures, site
soils have been grouped into the following soil types:
TABLE 1
Soil Type
1
2
3
Description
tan to brown silty fine to medium sand (fill/alluvium)
tan to gray fine grain sand (sandstone)
gray fine sandy clay (claystone)
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PAGE 4
JUNE 17, 2003
The following tests were conducted in support of this investigation:
1. Maximum Dry Density and Optimum Moisture Content: The maximum dry
density and optimum moisture content of representative on-site soil samples
were determined in accordance with ASTM D-1557. The test results are
presented in Table 2.
TABLE 2
Location
T-1 @ 2'
T-3@1'
Soil
Type
2
1
Maximum Dry
Density (Ym-pcf)
100.4
103.9
Optimum Moisture
Content (o)opt-%)
15.5
14.0
2. Moisture-Density Tests (Undisturbed Chunk Samples): In-place dry density
and moisture contents of representative soil deposits beneath the site were
determined from relatively undisturbed chunk samples using the water
displacement method. The test results are presented in Table 3.
TABLE 3
Sample
Location
T-1 @ 21
T-2 @ 6'
T-3 @ 4'
Soil
Type
2
2
2
Field
Moisture
Content
(w-%)
21.7
23.1
27.2
Field
Dry
Density
(Yd-pcf)
93.0
91.0
93.8
Maximum
Dry Density
(Ym-pcf)
100.4
100.4
100.4
Ratio of In -Place
Dry Density to
Max. Dry Density*
(Yd/Ymx100)
92.6
90.6
93.4
*Designated as relative compaction for structural fills.
Required relative compaction for structural fill is 90% or greater.
3. Direct Shear Test: Two direct shear tests were performed on representative
samples of Soil Types 1 and 2. The prepared specimens were soaked
overnight, loaded with normal loads of 1, 2, and 4 kips per square foot
respectively, and sheared to failure in an undrained condition. The test results
are presented in Table 4.
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PAGE 5
JUNE 17, 2003
TABLE 4
Sample
Location
T-1 @ 2'
T-3@1'
Soil
Type
2
1
Sample
Condition
remolded to 100% of field Yd & co%
remolded to 90% of Yd @ % coopt
Wet
Density
(Yw-pcf)
118.3
124.3
Angle of
Int. Fric.
(cD-Deg.)
35
31
Apparent
Cohesion
(c-psf)
65
20
4. Ph and Resistivity Test: Ph and resistivity of representative samples of Soil
Type 1 collected at selected locations was determined using "Method for
Estimating the Service Life of Steel Culverts," in accordance with the California
Test 643. The test result is presented in Table 5.
TABLE 5
Sample Location
T-s@r
SoilType
1
Minimum Resistivity (OHM-CM)
3360
Ph
7.19
VI. CONCLUSIONS
Based upon the foregoing investigation, failure in the storm drain pipe within the lower
reaches of the slope has resulted in severe erosion and the destruction of lower pipe
segments. Added slope failure and a continued destruction of remaining segments of the
pipe should be expected, particularly during the forthcoming winter months.
The storm drain pipe may be reconstructed substantially as proposed. The new pipe
should be selected based on the design invert gradients, flow rate and velocity, and placed
within a regarded fill section which extends to the canyon bottom. This will require the
importation of soil or regrading of surrounding terrain in order to generate needed fill soils.
Reconstruction of the lower slopes will also buttress existing near vertical exposures and
impacted surrounding unstable terrain disallowing failure progression towards the upper
unaffected slopes.
Alluvial and debris soils which mark the lower canyon are relatively thin deposits which
should also be regraded in connection with the proposed reconstruction.
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VII. RECOMMENDATIONS
»- A significant failure impacts lower graded fill soils and surrounding natural canyon which
supported the storm drain. Existing eroded features resulted from a high flow rate, high
p~ velocity uncontrolled and concentrated storm water run-off subsequent to the storm pipe
*•• failure. Reconstruction of the eroded slope and ground surfaces to pre-failure
configurations in conjunction with the storm drain replacement is recommended in the
"" following sections. Actual finish grades will also control storm drain pipe invert elevations
*• and should be designed by the project civil engineer, and reflected on the grading and
^ improvement plans.
*• The following preliminary recommendations are based on the site geotechnical conditions
^ and scheme of the project repairs and reconstruction work as understood. Civil drawings
which accurately depict existing site topography, proposed final grades and limits of
m reconstruction work as well as the new storm drain inverts, profile and associated
underground structures should be provided to us for review. More specific
recommendations, if necessary, will be given at that time in a formal Geotechnical Plan
m Review Report.
A. Slope Repairs and Reconstruction
^ J^ |*
pi Repairs to the lower failed portions of the existing slopes and surrounding canyon
to terrain should be undertaken prior to the planned storm drain replacement. Repair
of failed areas may be completed using conventional removal and recompaction
m and grading methods which will require imported soils.
*•* General: The following procedures should be implemented in the repair of the
m affected slope areas in order to construct a safe and stable slope terrain and
m preclude progression failure of the upper slopes. Minor groundwater seeps
encountered during our field work is not expected to significantly impact repair
p grading operations as recommended herein. However, grading repairs and
m storm drain installations completed during the summer months, prior to the
forthcoming rainy seasons, should be considered.
m
M The enclosed Site Plan and Cross-Section provided herein are not surveyed
maps or civil drawings, and have been prepared based on visual observations
^ and approximate physical measurements for the purpose of geotechnical
«• presentations only. These maps and cross-sections may be used for informal
approximate estimates of earthworks and repair grading involved. Detailed civil
*" drawings and surveyed maps prepared by the project civil engineer shall be
*•' considered for accurate repair cost and quantity estimations.
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pn
* Clearing and Grubbing: Remove surface vegetation, trees and other
i* unsuitable / deleterious materials and debris from all areas of slope repairs plus
to a minimum of 10 feet where possible, and as approved in the field by the
project geotechnical engineer or his designated representative.
m
m * Establish a Keyway: Construct a lower keyway at the base of the slope failure
within the unaffected lower formational rock units as approved by the project
"* geotechnical engineer. The keyway should maintain a minimum depth of 3 feet
IM into the competent formational rock with a minimum width of 12 feet. The
bottom oi the keyway should be heeled back a minimum of 2% into the natural
p" hillside and inspected and approved by the project geotechnical engineer.
HH
* Remove Failed and Loose Soil Debris: Loose surface soils and failure scrapp / debris within the affected areas plus 5 feet beyond the failure features (as
"• directed in the field by the project geotechnical engineer), should be removed.
The removal operations should effectively remove all loose bottom deposits and
T unstable side slopes within the failure affected areas, and expose level11 benches (or steps in the steeper side slope areas) within the unaffected
competent formational rocks. The level benches (steps) should be constructed
C in a manner that there is a minimum of 5 feet of compacted fill from the outside
edge (front) of the bench to the finish slope face and keyed into the unaffected
m competent formational rocks. Removed soils are suitable for reuse in
recompacted fill.
p, Imported soils will be required to complete slope repair grading works. Import
soils should be sandy deposits (expansion index less than 51) free of organic
materials, larger than 6-inch rock sizes and trash debris, and approved by the
p project geotechnical engineer prior to delivery to the site.
ttg|
* Recompact Fill Soils: Reconstruct the slope by placing fills in thin, horizontal
p lifts upon lower keyway and level benches that expose firm approved ground
^ to achieve original 2:1 (horizontal to vertical) gradients. Steeper than 2:1
gradient fill slopes (114:1 or flatter), may also be considered; however,
p additional engineering analyses and construction specifications, including
H placement of slope reinforcement Geogrid, will be required and should be given
in the subsequent Geotechnical Plan Review Report as appropriate.
p
m Site fill soils should be moisture conditioned to near optimum levels, thoroughly
processed into a uniform mixture, and mechanically compacted in thin uniform
»• horizontal lifts with heavy construction equipments to a minimum of 90% of the
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laboratory maximum density value in accordance with ASTM D-1557. The fill
should be compacted to a minimum of 90% out to the slope face. Back rolling
at a minimum of 3-foot vertical increments and track walking the completed
slope, or over-building the slope and cutting back to design configurations is
recommended. Field density tests should be performed to confirm adequate
compaction levels within the slope face.
Improve Site Surface Drainage: Surface drainage improvements should be
completed at the site as specified on the project grading and improvement
plans, prepared by the project civil engineer. Overflow of the upper surface
run-off from the top of the slope should not be allowed. Slope drainage should
sheet-flow over the slope face rather than occur in a concentrated flow.
Surface drainage facilities should also be considered. Concentrated run-off
should not be allowed to occur any place over the slope face areas.
m * Engineering Inspection and Testing: The future performance of the
H reconstructed slope depends on correctly implementing the above
recommended procedures. All grading operations should be continuously
H inspected and tested by representatives of this office. A final compaction and
j| slope repair certification report which details grading procedures should then
be prepared at the completion of the work by the project geotechnical
p consultant.
* Plant the Slope Face soon after Reconstruction: The completed slope face
m should be provided with a suitable plant cover. Natural brush is best but difficult
^ to quickly establish. Initially, only broad-leafed, deep rooted vegetation which
requires a minimum of irrigation should be used. Over watering of site
p vegetation should be avoided. Only the amount of water to sustain vegetation
m life should be provided.
p B. Storm Drain Replacement
j^y
We understand that a new 36-inch HOPE storm drain pipe replacement is being
p considered. The following recommendations are appropriate:
m
* Storm drain should be installed in stable compacted fills or natural ground as
P specified herein. All trench excavations should be inspected, tested as
ki necessary and approved by the project geotechnical engineer.
IP
IM
ftH
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NORTH END OF HIGHLAND DRIVE, ESCONDIDO JUNE 17, 2003PP» •
* Bottom of trench and pipe bedding / backfill materials on steeper slope
"" conditions are subject to creep when they become excessively saturated.
«• Erosion and subsequent failures are also common occurrences where
significant flow within the gravel / crushed rock materials, typically used for pipe
m bedding and backfill within the pipe zone, impacts the bottom of the trench and
*• causes trench erosion and subsequent loss of prior support. A well-constructed
and backfilled trench is critical in the future performance of the proposed storm
"" drain constructed on site slopes.
* Storm drains installed on steeper than 4:1 gradient slopes may be encased with
"* concrete slurry within the pipe zone. The concrete slurry may be used for
*" encasing the entire pipe length to a minimum of 1-foot above the top of pipe
m (within the pipe zone). A minimum two-sack concrete slurry should be used.
In this case, provide minimum 4-inch concrete blocks or saddles, securely
111 placed at close intervals to support the storm drain pipe during pipe
m encasement with concrete slurry.
m In the case of 2YzA or steeper invert gradients, provide a minimum of 8 inches
_ wide by 12 inches deep concrete anchors dug into the well-compacted fills, or
•L formational units to assure trench, pipe bedding and backfill stability. The CIP
(Cast In Place) concrete anchors should be constructed perpendicular to the
p, pipe profile, strategically placed at less than 50 feet intervals maximum. The
^ concrete anchors should be provided with a shear key (2-inch X 4-inch wood
board blocked out in concrete) for the subsequent slurry backfill to lock into the
m anchors.
m
* Storm drains or portions thereof installed at flatter that 4:1 invert gradients may
m be provided with %-inch to 1-inch crushed rocks wrapped in filter fabric (Mirafi
^ 140 N), or %-inch crushed rock for pipe bedding and as backfill within the pipe
zone.
m
m * Site or import soils (expansion index less than 51) may be used to backfill
trenches above the pipe zone. Trench backfill soils (above the pipe zone)
P should be moisture conditioned to near optimum levels, placed in thin lifts and
in mechanically compacted to at least 90% of the corresponding maximum dry
density. Field in-place density tests should be performed by the project
P geotechnical consultant to ensure adequate compaction levels within the trench
In backfill materials. Trench backfill compaction test results should be summarized
in a final report.
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m
PRELIMINARY GEOTECHNICAL INVESTIGATION PAGE 10
NORTH END OF HIGHLAND DRIVE, ESCONDIDO JUNE 17, 2003
Storm drains should also be constructed and installed in conformance with the
project civil drawings.
* Temporary trench sidewall excavations less than 5 feet high maximum and
exposing well-compacted fills or competent formational units may be
constructed at near vertical gradients. Recommendations with deeper trench
excavations and sidewall stability will be given in the Geotechnical Plan Review
Report based on the design invert elevations.
C. Soil Design Parameters
The following soil design parameters are based on the tested representative
samples of on-site earth deposits. All parameters should be re-evaluated when the
characteristics of the final as-graded soils have been specifically determined.
Added or modified soil design parameters will be provided in the Geotechnical Plan
Review Report based on actual project design scheme, if necessary:
- Design wet density of soil = 124.3 pcf.
m - Design angle of internal friction of soil = 31 degrees.
- Design active soil pressure for retaining structures = 40 pcf (EFP), level backfill,
m cantilever, unrestrained walls.
p, - Design at-rest soil pressure for retaining structures = 60 pcf (EFP), non-
^ yielding, restrained walls.
- Design passive soil pressure for retaining structures = 388 pcf (EFP), level
m surface at the toe.
10 - Design coefficient of friction for concrete on soils = 0.38.
- Net allowable foundation pressure for certified bearing soils (minimum 12
p inches wide by 12 inches deep footings) = 1500 psf.
fl - Allowable lateral bearing pressure (all structures except retaining walls) for
certified on-site soils = 150 psf/ft.
p
HI Notes:
P - Use a minimum safety factor of 1.5 for wall over-turning and sliding stability.
Mi However, because large movements must take place before maximum passive
resistance can be developed, a safety factor of 2 may be used for sliding
"" stability where sensitive structures and improvements are planned near or on
IM top of retaining walls.
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PAGE 11
JUNE 17, 2003
p
m
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- When combining passive pressure and frictional resistance the passive
component should be reduced by one-third.
- The net allowable foundation pressure provided herein was determined for
footings having a minimum width and depth of 12 inches. This value may be
increased by 20% for each additional foot of depth and 20% for each additional
foot of width to a maximum of 3500 psf if needed. The allowable foundation
pressures provided herein also apply to dead plus live loads and may be
increased by one-third for wind and seismic loading.
- The lateral bearing earth pressures may be increased by the amount of the
designated value for each additional foot of depth to a maximum of 1500
pounds per square foot.
D. Years to Perforation of Steel Culverts
The following are appropriate based on the Ph-Resistivity test result:
TABLE 6
, Sample Location '
T-3@r
" .'•' . • v -• '• _• -,' .'. 'Gage- . • ' . .-•- ': -
Years to Perforation of Steel Culverts
18
28
w '>',?-<«
1$ :
36
'.I*:"
44
-',-12' ;
61
10
78
•: .'a-:.
95
E. Plan Review
Final drainage improvements and slope repair plans should incorporate
recommendations provided in this report and reviewed and approved by this office.
If the final plans vary from conditions used as a basis of our investigation, further
subsoil study may be required and should be anticipated. Additional and / or
modified recommendations will also be provided at that time, as necessary.
F. Preconstruction Conference
A preconstruction meeting between representatives of this office, the property
owner or planner, the city inspector, the project civil engineer, and grading
contractor is recommended in order to discuss repair grading and reconstruction
details.
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VIII. LIMITATIONS
P»
to The conclusions and recommendations provided herein have been based on all available
data obtained from our field observations and laboratory analysis, as well as our
p experience with the soils and formational materials located in the general area. The
it materials encountered on the project site and utilized in our laboratory testing are believed
representative of the total area; however, earth materials may vary in characteristics
P between excavations.
m
Of necessity we must assume a certain degree of continuity between exploratory
*" excavations and / or natural exposures. It is necessary, therefore, that all observations,
i" conclusions, and recommendations be verified during the grading operation. In the event
discrepancies are noted, we should be contacted immediately so that an inspection can
*" be made and additional recommendations issued if required.
m
The recommendations made in this report are applicable to the site at the time this report
* was prepared. It is the responsibility of the owner / developer to ensure that these
* recommendations are carried out in the field.
P It is almost impossible to predict with certainty the future performance of a property. The
*" future behavior of the site is also dependent on numerous unpredictable variables, such
as earthquakes, rainfall, and on-site drainage patterns.p
ta The firm of VINJE & MIDDLETON ENGINEERING, INC., shall not be held responsible for
changes to the physical conditions of the property such as addition of fill soils, added cut
slopes, or changing drainage patterns which occur without our inspection or control.
p This report should be considered valid for a period of one year and is subject to review by
y our firm following that time. If significant modifications are made to your tentative
development plan, especially with respect to the height and location of cut and fill slopes,
p this report must be presented to us for review and possible revision.
m Vinje & Middleton Engineering, Inc., warrants that this report has been prepared within the
p limits prescribed by our client with the usual thoroughness and competence of the
y engineering profession. No other warranty or representation, either expressed or implied,
is included or intended.
p
y Once again, should any questions arise concerning this report, please do not hesitate to
contact this office. Reference to our Job #03-262-P will help to expedite our response to
m your inquiries.
VZNJE & MIDDLETON ENQINEERINQ, INC. 2450 Vineyard Avenue, Escandido, California 92029-1229 .• Phone (760) 743-1214 • fax (760) 739-0343
QEOTECHNICAL INVESTIGATIONS QRADINQ SUPERVISION PERC TESTINq ENVIRONMENTAL INVESTIGATION
pb
p
tt
PRELIMINARY GEOTECHNICAL INVESTIGATION
NORTH END OF HIGHLAND DRIVE, ESCONDIDO
PAGE 13
JUNE 17, 2003
We appreciate this opportunity to be of service to you.
VINJE & MIDDLETON ENGINEERING, INC.
pi
m
p
m
Dennis Middleton
CEG #980 CERTIFIED
ENGINEERING
ehdi S. Shanat
E#46174
RG #6953
DM/SMSS/SJM
Distribution: Addressee (5)
VINJE & MIDDLETON ENQINEERINQ, INC. 2450 Vineyard Avenue, Escondido, California 92029-1229 « Phone (760) 743-1214 • fax (760) 739-0343
QEOTECHN1CAI./NVESTIQATIONS QRADINQ SUPERVISION PERC TESTINQ ENVIRONMENTAL INVESTIGATION
ORMAtlONAL ROCK
FORMATIONAL ROCK
FORMATIONAL
ROCK ^NGLE FAMILY
ESIDENCE
STORM DRAIN PROJECT, NORTH
END OF HIGHLAND DRIVE, CARLSBAD
Base map is modified to depict recent erosion. Not surveyed.
Location of test trench
Geologic cross-section line
PLATE 1
03-262-P
0
iu
I
I
I
I
I
I
I
C
I
I
I
I
I
PLATE 2
wo-
50-
STORM DRAIN PIPE-,.
Original Surface-^/-j/
- 750
-700
T-1
-50
Scale: 1 "=30'
D
Surface profile determined chiefly from physical measurements taken at the site. Not surveyed.
PRIMARY DIVISIONS GROUP
SYMBOL
SECONDARY DIVISIONS
3
8
CD
LUCO5<
0O
ooCM
LL *- LU
0 Z N
U. < CO
<K£
1 CC. LU
I OC
r^cl
O ~
GRAVELS
MORE THAN HALF
OF COARSE
FRACTION IS
LARGER THAN
NO. 4 SIEVE
SANDS
MORE THAN HALF
OF COARSE
FRACTION IS
SMALLER THAN
NO. 4 SIEVE
CLEAN
GRAVELS
(LESS THAN
5% FINES)
GW Well graded gravels, gravel-sand mixtures, little or no fines.
GP Poorly graded gravels or gravel-sand mixtures, little or no fines.
GRAVEL
WITH
FINES
GM Silty gravels, gravel-sand-silt mixtures, non-plastic fines.
GC Clayey gravels, gravel-sand-clay mixtures, plastic fines.
CLEAN
SANDS
(LESS THAN
5% FINES)
sw Well graded sands, gravelly sands, little or no fines.
SP Poorly graded sands or gravelly sands, little or no fines.
SANDS
WITH
FINES
SM Silty sands, sand-silt mixtures, non-plastic fines.
sc Clayey sands, sand-clay mixtures, plastic fines.
to
LU<r Nuj CO SILTS AND CLAYS
LIQUID LIMIT IS
LESS THAN 50%
ML Inorganic silts and very fine sands, rock flour, silty or clayey fine
sands or clayey silts with slight plasticity.
CL Inorganic clays of low to medium plasticity, gravelly clays, sandy
clays, silty clays, lean clays.
OL .Organic silts and organic silty clays of low plasticity.
< ICC I—
0 LULU rrz O
SILTS AND CLAYS
LIQUID LIMIT IS
GREATER THAN 50%
MH Inorganic silts, micaceous or diatomaceous fine sandy or silty
soils, elastic silts.
CH Inorganic clays of high plasticity, fat clays.
OH Organic clays of medium to high plasticity, organic silts.
HIGHLY ORGANIC SOILS PT Peat and other highly organic soils.
GRAIN SIZES U.S. STANDARD SERIES SIEVE
200 40 10
CLEAR SQUARE SIEVE OPENINGS
3/4" 3" 12"
SILTS AND CLAYS
SAND
FINE MEDIUM COARSE
GRAVEL
FINE COARSE
COBBLES BOULDERS
RELATIVE DENSITY CONSISTENCY
SANDS, GRAVELS AND
NON-PLASTIC SILTS
VERY LOOSE
LOOSE
MEDIUM DENSE
DENSE
VERY DENSE
BLOWS/FOOT
0-4
4- 10
10-30
30 - 50
OVER 50
CLAYS AND
PLASTIC SILTS
VERY SOFT
SOFT-
FIRM
STIFF
VERY STIFF
HARD
STRENGTH
0 - </4
'/4 - Vl
'/> ' 1
1 - 2
2-4
OVER 4
BLOWS/FOOT
0 - 2
2-4
4-8
8 - 16
16-32
OVER 32
1. Blow count, 140 pound hammer falling 30 inches on 2 inch O.D. split spoon sampler (ASTM D-1586)
2. Unconfined compressive strength per SOILTEST pocket penetrometer CL-700
Standard Penetration Test (SPT) (ASTM D-1586)
with blow counts per 6 inchesSand Cone Test j§ Bulk Sample | ^6
M Chunk Sample O Driven Rings II 246 = California Sampler with blow counts per 6 inches
VINJE & MIDDLETON
ENGINEERING, INC.
2450 Vineyard Ave., #102
Escondido, CA 92029-1229
KEY TO EXPLORATORY BORING LOGS
Unified Soil Classification System (ASTM D-2487)
PROJECT NO.
KEY
0*
tan
f"
te
to
h.
f"
pi
Ml
PI
Itt
fe*
f"
k.
PI
to
1H
r
Date: 5-14-03
DEPTH
(ft)
•1
- 2 -
- 3 -
- 4 -
- 5 -
c— D —
- 7 -
- 8 -
- 9 -
SAMPLE
\
QH
\
Logged by: SJM
T-1
DESCRIPTION
ALLUVIUM:
Silty fine to medium sand. Brown color. Dry. Loose. Some
cobbles. ST-1
FORMATIONAL ROCK:
Sandstone. Fine grained. Gray color. Slightly micaceous.
Massive. Rust colored staining. Weathered friable. Poorly
cemented.
Color changes to tan at 4'. Unable to obtain chunk samples
below 21/z'.
ST-2
End Test Trench at 6'.
No caving. No groundwater.
uses
SYMBOL
SM
SP
MOISTURE
21.7
DRY
DENSITY
(pcf)
93.0
RELATIVE
COMPACTION
92.6
Date: 3-11-03
DEPTH
(ft)
- 1 -
- 2 -
- 4 -
- 5 -
- 6 -
- 7 -
- 8 -
- 9 -
SAMPLE
Q \
Logged by: SJM
T-2
DESCRIPTION
ALLUVIUM:
Silty fine to medium sand. Tan to rust colored. Some
cobbles. Moist. Loose. Sidewall caving.
ST-1
FORMATIONAL ROCK:
Sandstone. Fine grained. Tan color. Slightly micaceous.
Weathered friable. Massive. Poorly cemented.
ST-2
End Test Trench at 61/2',
Sidewall caving in upper 3'. No groundwater.
VINJE & MIDDLETON ENGINEERING, INC
Escondido, California 92029-1229
Office 760-743-1214 Fax 760-739-0343
T Sand Cone Test • Bulk Sample
uses
SYMBOL
SM
\
SP
MOISTURE
23.1
"• i — ^^—
DRY
DENSITY
(pcf)
91.0
RELATIVE
COMPACTION
90.6
TEST TRENCH LOGS
HIGHLAND DRIVE, CARLSBAD
PROJECT NO. 03-262-P PLATE 3
Q Nuclear Test O Driven Rings
P"
te.
to
P»
il
m
m
p»
IM
f*
Li
P"
III
1*
Date: 5-14-03 Logged by: SJM
DEPTH
(ft)
- 1 -
1
- 3 -
- 4 -
5
- 7 -
- 8 -
- 9 -
SAMPLE
•
Q :
-^
\
T-3
DESCRIPTION
ALLUVIUM:
Silty fine sand. Tan color. Some cobbles. Moist. Loose.
ST-1
FORMATIONAL ROCK:
Sandstone. Fine grained. Gray to tan color. Slightly
micaceous. Weathered friable. Poorly cemented. Massive.
Moist to very moist. ST-2
Fine sandy claystone. Gray color. Rust colored iron
staining. Moist. Very stiff. Weeping at 5'.
ST-3
End Test Trench at 6'.
No caving. Groundwater seeps at 5'.
uses
SYMBOL
SM
SP
CL \
1
MOISTURE
(%)
27.2
DRY
DENSITY
(pcf)
93.8
RELATIVE
COMPACTION
(%)
93.4
P
w
P
P
I
•1
1II
E
m
Date:
DEPTH
(ft)
- 1 -
- 2 -
- 3 -
- 4 -
- 5 -
- 6 -
- 7 -
- 8 -
- 9 -
SAMPLE
Logged by:
DESCRIPTION
VINJE & MIDDLETON ENGINEERING, INC
2450 Vineyard Avenue, Suite 102
Escondido, California 92029-1229
Office 760-743-1214 Fax 760-739-0343
^f~ Groundwater • Bulk Sample
uses
SYMBOL
MOISTURE
DRY
DENSITY
(pcf)
RELATIVE
COMPACTION
TEST TRENCH LOGS
HIGHLAND DRIVE, CARLSBAD
PROJECT NO. 03-262-P PLATE 4
Q Nuclear Test O Driven Rings
F
L