HomeMy WebLinkAbout3478; Park Drive Slope / Drainage Study; Geotechnical Report; 1998-05-04KLEINFELDER
A report prepared for:
City of Carlsbad Engineering Department
2075 Las Palmas Drive
Carlsbad, California 92009-4589
Attn: Mr. Galen N. Peterson, Consulting Project Manager
REPORT OF GEOTECHNICAL EXPLORATION
PARK DRIVE SLOPE/DRAINAGE STUDY
CARLSBAD, CALIFORNIA
CITY OF CARLSBAD PROJECT NO. 34781
Kleinfelder Job No. 51-4659-01
Prepared by:
KLEINFELDER, INC.
9555 Chesapeake Drive, Suite 101
San Diego, California 92123
(619) 541-1 145
May 4,1998
5 1-4659-01/5 1 18R014.DOC
Copyright 1998 Kleinfelder, Inc.
Page ii of iv May 4, I998
KLEINFELDER
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
TABLE OF CONTENTS
Section Page
1.1 GENERAL .......................................................................................................................... 1
1.0 INTRODUCTION .................................................................................................................... 1
1.2 PROJECT DESCRIPTION ................................................................................................ 1
1.3 PURPOSE AND SCOPE OF SERVICES .......................................................................... 2
1.4 AUTHORIZATION ............................................................................................................ 3
2.0 INVESTIGATIVE METHODS .............................................................................................. 4
2.1 GEOLOGIC EVALUATION ............................................................................................. 4
2.2 SUBSURFACE EXPLORATION ...................................................................................... 4
2.3 LABORATORY TESTING ............................................................................................... 5
3.0 SITE AND SUBSURFACE CONDITIONS .......................................................................... 6
3.1 SITE CONDITIONS AND OBSERVATIONS ................................................................. 6
3.2 SUBSURFACE CONDITIONS ......................................................................................... 8
3 2.1 Geologic Setting ....................................................................................................... 8
3.2.2 Geologic Units .......................................................................................................... 9
3.3 SURFACE WATER AND GROUNDWATER ............................................................... 10
3.4 GEOLOGIC STRUCTURE .............................................................................................. 10
4.0 DISCUSSION AND CONCLUSIONS ................................................................................. 11
4.1 GROSS BLUFF STABILITY .......................................................................................... 11
4.2 EROSION AND CLIFF RETREAT ................................................................................ 13
4.2.1 Surface Erosion of Natural Ravine. Station 975 .................................................. 13
4.2.2 Steep Cut Slope Erosion. Station 10+76 to Station 15+15 ..................................... 13
4.2.3 45" Slope. Station 15+15 to Station 17+93 ............................................................ 14
4.3 SEEPAGE FROM TOE OF BLUFF ................................................................................ 15
4.4 CURRENT SAND REMOVAL PROCEDURE .............................................................. 15
4.5 CONCLUSIONS .............................................................................................................. 16
5.0 RECOMMENDATIONS ....................................................................................................... 17
5.1 BLUFF EROSION MONITORING ................................................................................. 17
5.2 REMEDIAL GRADING AND DRAINAGE ................................................................... 17
5.3 NEW RETAINING WALL AND SIDEWALK REPLACEMENT ................................ 19
5.4 DRAIN BEHIND EXISTING RETAINING WALL ....................................................... 20
5.5 EROSION MITIGATION STATION 15+15 TO STATION I7+93 ............................... 21
5.6 NEW BROW DITCHES .................................................................................................. 22
5.7 SURFACE EROSION OF RAVINE AT STATION 9+75 .............................................. 23
6.0 ADDITIONAL SERVICES .................................................................................................. 24
7.0 LIMITATIONS ...................................................................................................................... 25
5 1 -4659-0 1 /5 I 1 8RO 14 .DOC
Copyright 1998 Kleinfelder. Inc . Page iii of iv May 4. 1998
KLEINFELDER
TABLE OF CONTENTS (CONTINUF,D)
FIGURES
Figure 1
Figure 2
Figure 3
Figure 4
Figure 5
Figure 6
Figure 7
Figure 8
Vicinity Map
Site Plan and Geologic Map
Geologic Cross Section
Typical Retaining Wall Section and Limits of Foundation Improvement
Typical Drain for Existing Retaining Wall
Typical Detail of Street Outlets and Cleanouts
Modified Type “B Brow Ditch
Gabion Cage Detention Basin
APPENDICES
Appendix A
Appendix B Laboratory Test Data
Appendix C
Appendix D
Appendix E ASFE Insert
Boring Logs and Cone Soundings
Slope Stability Analyses Data
GeowebCB Slope Protection System Technical Overview
5 1-4659-0 115 I ISR014.DOC
Copyright 1998 Kleinfelder, Inc
Page iv of iv May 4, 1998
-
KLEINFELDER
1.0 INTRODUCTION
1.1 GENERAL
This report presents the results of Kleinfelder’s geotechnical exploration for the Park Drive
Slope/Drainage Study repair project in the City of Carlsbad, California. A vicinity map showing
the general location of the site is presented in Figure 1 at the end of this report.
The objective of this report is to provide the design team with geotechnical findings, conclusions,
and recommendations regarding the stability and drainage of approximately 500 linear feet of the
steep bluff on the east side of Park Drive just north of Marina Drive and the erosion of about 290
linear feet of the lower slope on the northeast side of Park Drive to the east of Marina Drive,
1.2 PROJECT DESCRIPTION
As indicated in the previous paragraph, this project consists of providing geotechnical
recommendations to mitigate the soil sloughing and drainage problems along the easterly and
northerly sides of Park Drive in the City of Carlsbad. For continuity, as well as for convenience,
we have elected to use the stationing established by Willdan Associates for the Improvement
Plan for Park Drive Assessment District, Project Nos. 3192 and 3216.’ For the Willdan project,
the intersections of Park Drive with Cove Drive and Marina Drive were designated as Station
2+30 and Station 14+54, respectively, along the centerline of Park Drive (increasing station
numbers to the south). Using this stationing system, the project study area extends from the east
side of Park Drive at about Station 8+52 to east of Marina Drive along the north side of Park
Drive to about Station 17+93.
The improvements to the study area are likely to consist of the following:
Regrading and the addition of approximately 293 lineal feet of subsurface drainage and low
height retaining wall;
‘Willdan Associates, 1987, Improvement Plan for Park Drive Assessment District, Project Nos. 3192 and 3216,
Drawing No. 272-7, Sheets I, 2, and 3.
5 1-4659-01/5118RO14.WC
Copyright 1998 Kleinfelder, lnc.
Page I of 25 May 4, 1998
-
KLEINFELDER
Addition of about 80 feet of back drain to an existing retaining wall;
Installation of approximately 730 lineal feet of subsurface street drain;
Regrading and establishment of vegetation for approximately % acre of sloping ground;
Installation of approximately 750 lineal feet of new brow ditch; and
Installation of gabion cage retention basin and inlet.
1.3 PURPOSE AND SCOPE OF SERVICES
The purpose ,of our study was to evaluate the general surface and subsurface soil and geologic
conditions at the site to provide recommendations for the design of a new retaining wall,
drainage, and erosion mitigation at the base of the bluff and to evaluate the existing stability of
the bluff. The scope of Kleinfelder’s services were to complete a geologic evaluation of the bluff
and a limited geotechnical study at the bluff toe to evaluate foundation design parameters for the
new retaining wall and subdrain system. The specific services provided to date include:
Two meetings with the City’s Consultant Project Manager, the Engineering Department, and
City Maintenance.
Field reconnaissance and geologic mapping of surficial and bedrock geologic units.
Geotechnical investigation of the upper bluff in the vicinity of the existing desilting basin
(northeast of the intersection of Marina and Park Drives) and portions of the bluff toe
between Stations 9+72 and 13+16. Five test borings and two dynamic cone penetration
soundings were made (Appendix A).
Laboratory testing of a few samples of geologic materials to correlate their pertinent
engineering properties with our previous experience (Appendix B).
Analysis of field data which included evaluation of the existing factor of safety of the steep
bluff against deep seated circular and block failures for static and dynamic conditions (using
5 1-4659-0 l/5 1 18R014.DOC
Copyright 1998 Kleinfelder. Inc.
Page 2 of 25 May 4. 1998
-
KLEINFELDER
- a pseudo-static slope stability analysis with a seismic component of 0.15g). We also
evaluated the need for a new retaining wall, drainage, and erosion mitigation.
Preparation of this report presenting OUT findings, conclusions, and recommendations.
Our scope of services was outlined in OUT Proposal No. 51--7-147 dated July 17, 1997 with
requested additional exploration at the top of the slope. On April I%, 1998, the city requested
that Kleinfelder also address the problem of storm erosion in the vicinity of Station 9+75 which
has become evident since the recent late winter and early spring storms.
The recommendations contained within this report are subject to the limitations presented in
Section 7. An information sheet prepared by ASFE (the Association of Engineering Firms
Practicing in the Geosciences) is also included as Appendix E. We recommend that all
individuals utilizing this report read the limitations along with the attached document.
1.4 AUTHORIZATION
Our work for this project was authorized by the City of Carlsbad agreement for Engineering
Services for Project No. 34781 dated October 21, 1997.
5 1-4659-0 115 I 18RO 14.DOC
Copyright I998 Kleinfelder, Inc.
Page 3 of 25 May 4, 1998
- KLEINFELDER
2.0 INVESTIGATIVE METHODS
2.1 GEOLOGIC EVALUATION
Our geologic evaluation consisted of reviewing aerial photographs, researching geologic reports
and maps reasonably available to our ofice, and observation of the geotechnical conditions in
the field at the time of our subsurface investigation. The local area geology is shown on the Site
Plan, Figure 2. A cross section of the slope and geologic profile is shown on Figure 3.
2.2 SUBSURFACE EXPLORATION
For this investigation, we drilled five borings to depths ranging from 11.5 to 50.5 feet below the
existing pavement or ground surface and advanced two cone soundings to depths up to 3.3 feet
below ground surface. Borings 1 through 4 were drilled along the easterly edge of Park Drive;
Boring 5 was drilled within the desilting basin at the top of the bluff. Borings were made by
means of a truck mounted drill rig using nominal eight inch diameter, hollow-stem augers. The
cone soundings were completed using a portable dynamic cone penetrometer which consisted of
driving a nominal 1.5 inch diameter cone into the soil with a free-falling 35 pound hammer.
Approximate boring and cone sounding locations are shown on the Site Plan, Figure 2.
For the soil borings, the drilling and sampling procedures were in general accordance with
ASTM Method D420 “Standard Recommended Practice for Investigating and Sampling Soils
and Rock for. Engineering Purposes” and more particularly, ASTM Method D1452 “Soil
Investigation and Sampling by Auger Borings.” Our field engineer maintained a log of the
borings, visually classified soils encountered according to the Unified Soil Classification System.
and obtained representative samples of the subsurface materials. Logs for Borings 1 through 5
are included in Appendix A as Figures A3 through A8. A key to the boring logs is included as
Figure AI; a description of physical property criteria for rocWformation is included as
Figure A2.
For the cone soundings, the actual blow counts in four-inch (10 centimeter) increments were
recorded in the field and later converted to dynamic cone resistance by computer program. A
plot of dynamic cone resistance and soil consistency is made for each sounding. The plots for
Cone Soundings 1 and 2 are included in Appendix A as Figures A9 and A 10.
5 1-4659-0 115 1 18R014.DOC
Copyright 1998 Kleinfelder, Inc,
Page 4 of 25 May 4, 1998
-
KLEINFELDER
Soil samples were obtained from the boxings using either a California sampler or a standard
penetration sampler. The standard penetration sampler (2.0-inch O.D.) and California sampler
(3.0 inch O.D.) were generally driven 18 inches into undisturbed soil using a 140-pound hammer
with a 30-inch drop. Blow counts were recorded at six-inch intervals for each sample. Soil
samples obtained from the borings were field classified, sealed in the field to reduce moisture
loss and disturbance, and returned to our San Diego laboratory for further testing. After the
borings were completed, they were backfilled with soil cuttings and capped with concrete that
was dyed black (except for Boring 5 within the desilting basin).
.-
-
-
-
Please note that the blow counts recorded on the borings logs represent the raw field data and
have not been corrected for the effects of overburden pressure or variation in sampler size. -
2.3 LABORATORY TESTING
Laboratory testing was performed on representative bulk and disturbed driven samples to
substantiate field classification and provide engineering parameters for geotechnical design.
Testing consisted of: in-situ rnoisture/density, sieve analyses, Atterberg limits, and direct shear
testing. The test results are presented in Appendix B.
5 1 -4659-0M 1 I8RO 14.DOC
Copyright 1998 Kleinfelder, Inc.
Page 5 of 25 May 4, 1998
-
KLEINFELDER
3.0 SITE AND SUBSURFACE CONDITIONS
- 3.1 SITE CONDITIONS AND OBSERVATIONS
- It is obvious that about 500 feet of the east side of Park Drive just north of Marina Drive is
experiencing some drainage and soil sloughmg problems. Water is percolating through the lower
portion of the slope where it is (a) passing through the existing retaining wall in some locations
to the sidewalk and street; (b) partially ponding adjacent to the sidewalk; or (c) is being picked
up by an existing pipe drain and subsequently deposited in the street. Cattails, bamboo, and
algae growth tend to confirm that this area is probably continuously wet. The drainage for the
existing retaining walls is primarily through open joints in the wall faces which allows drainage
and soil to accumulate on the sidewalk area. The existing pipe drain collection system appears to
be partially silted in and simply conducts the water through the sidewalk area where it tends to
collect on the street, owing to the flat grade of Park Drive in the study area. The sidewalk and
gutter areas that were wet during all our site visits from last July through the present generally
had a growth of algae.
-
.-
-
We also observed that the lower 25 to 45 feet of the west facing sandstone bluff is experiencing
typical bluff erosion similar to sea cliffs adjacent to the Pacific Ocean. The steep portion above
the toe of the bluff represents a cut slope that varies in height up to about 45 feet above Park
Drive with inclinations ranging Som about 1H: 1V (horizontal to vertical) to as steep as MH: 1 V
where more severe erosion has occurred along the top of the'cut. The steeper portions of the cut
face exhibit occasional relatively small erosion gullies and shallow slope failures as evidenced by
near-vertical sc.qs along the top of the cut.
Brush is present along most of the slope from Station 8+52 to Station 14+54. The brush is
somewhat mose dense north of Station 13+16, probably due in part to the abundant moisture.
A brush-filled natural drainage ravine is present at about Station 9+75. This ravine trends
upslope in a northeasterly direction above the elevation of the top of the cut slope to a row of
houses that occupy the level top of the bluff west of Sunnyhill Drive. Last December and
January seepage was not observed at the head of the ravine, but was noted in the lower portion of
the ravine at about the same elevation as observed along the adjacent cut slope south of the
ravine. Shallow surface slumps were also present along the steep side slopes of the upper part of
the ravine.
5 1-4659-0 115 1 I8R014.DOC
Copyright 1998 Kleinfelder, Inc.
Page 6 of 25 May 4, I998
- KLEINFELDER
Following the February and early March storms, a considerable amount of surface erosion
occurred in the vicinity of Station 9+75 which deposited a 30-foot wide fan of sediment across
the sidewalk and into the street. Near the east side of the sidewalk the sediment had a maximum
thickness of about 3 feet. The source of the sediment was from storm water removal (erosion) at
the several pre-existing slumps in the ravine, additional slumping along the sides of the ravine
due to erosion and loss of side support, and an increase in the erosion along the center of the
drainage.
In late April, seepage was not observed at the head of the ravine, but was noted in the lower
portion of the ravine. The seepage appeared to be exiting the lower portion of the ravine at a
slightly higher elevation than previously observed in December and January, probably as a result
of the fresh erosion and a slight increase in the hydrostatic pressure head in the vicinity of the
natural drainage.
A small park is present on the level portion of the bluff between the bluff crest and the backyards
of the residences along the west side of Sunnyhill Drive. The park is located from about Station
10+50 to Station 11+50 between the natural drainage ravine and the desilting basin (Boring 5).
The park is obviously well irrigated as evidenced by the lush, spongy, green grass noted during
our reconnaissance.
Accumulations of eroded material at the base of the bluff are apparently washing further down
the lower section of the bluff, over the existing retaining walls, and are being deposited on the
sidewalk and street. Based on our reconnaissance, we did not note any conditions which would
indicate that the gross stability of the bluff was being impacted other than the continuous erosion
and occasional surface related sloughing as portions of the bluff are undermined by erosion.
Two existing pipelines are visible along the eroded bluff face above the sidewalk area south of
Station 10+76 which are being uncovered by erosion. We understand these pipelines are no
longer in service.
Severe rilling and erosion gullies are present along the 1H:lV south facing portion of the bluff on
the north side of Park Drive just east of Marina Drive. Bare soil and erosion gullies up to 3 feet
deep are present. During our March and April site visits, we also noted that vegetation had
eroded from the crest of the slope in several areas from about Station 8+52 to Station 10+76.
5 1-4659-0115 I 18RO 14.DOC
Copyright 1998 Kleinfelder, Inc.
Page 7 of 25 May 4. 1998
- KLEINFELDER
-
Specific observations with respect to key project stationing are listed below:
%?iQn
2+30
- 8+52
9+63
-
- 9+75
10+23
10+23 to 13+16
10+76
13+16
SLatiQn
14+54
15+15 to 17+93
Intersection of Cove Drive with Park Drive.
End of residential property; stat of retaining wall to south.
Start of observed water seepage problem through retaining wall onto sidewalk;
significant algae growth on sidewalk.
Natural drainage ravine trending upslope towards the northeast.
South end of retaining wall.
No retaining wall; ponded surface water and cattaildlush vegetation; algae.
Start of significant cut slope erosion (bare sandstone, no vegetation across
steep cut slope face). Toe of bluff retains vegetation to about Elevation 15 to
20.
Start of retaining wall to south; some sand is coming over top of wall, but no
obvious drainage problem.
EciWs
Intersection of Marina Drive with Park Drive.
Triangular shaped wedge of slope with significant rill and gully erosion that
spills over to sidewalk. Except for erosion and sediment deposition, no
continuous water and algae problems were noted. Steep bluff erosion starting
from Station 10+76 transitions into this area.
3.2 SUBSURFACE CONDITIONS
3.2.1 Geologic Setting
The project area is within the Peninsular Ranges geomorphic province of California. In general,
this province consists of rugged mountains underlain by Mesozoic metamorphic and crystalline
rock to the east, and a coastal plain underlain by Cenozoic marine and nonmarine sediments.
The subject site lies within the coastal plain section. In this section, low hills are eroded from
marine sediments of Eocene age, with valley bottoms filled by Quaternary alluvium and slope
washkolluvium
5 1-4659-01/5 1 18RO 14.DOC
Copyright 1998 Kleinfelder. Inc.
Page 8 of 25 May 4, 1998
-
KLEINFELDER
The geologic materials found at this site are marine and sedimentary rocks, slope
wasl-dcolluvium, topsoil, and artificial fill. This investigation did not identify any existing
landslides, active or suspected active faults, or other major geologic hazards in the project area or
its immediate vicinity.
3.2.2 Geologic Units
3.2.2.1 Santiago Formation (Tsb)
The Eocene age Santiago Formation underlies the entire site. As observed on the face of the
bluff, this bedrock generally consists of light olive to light yellowish gray, silty fine to coarse-
grained sandstone. The sandstone is typically massive with occasional interbeds and intraclasts
of olive green clayey sandstone and clayey siltstone. Intraclasts of up to 20 feet in diameter have
been encountered in grading projects around the Agua Hedonia Lagoon.
The sandstone is weakly consolidated, moderately weathered, moderately friable, and exhibits a
low to non-expansive potential. The clayey siltstone may exhibit moderate to high
expansiveness. The formation is considered relatively incompressible.
3.2.2.2 TopsoiUColluvium
The base of the bluff from about Station 14+54 to the north is mantled by a variable thickness of
topsoil and colluvium. Colluvial deposits are accumulated by slope wash of weathered bedrock
and topsoil creep. These deposits range from silty or clayey sands to silty clay, and are generally
loose/soft to medium dense. The topsoil is generally less than 4 inches thick. The colluvium
was observed to be as much as 16 feet thick in Boring 1, but is generally on the order of 10 feet
thick or less. The upper two to three feet of the topsoil and colluvium are loose to medium dense
and should be considered compressible.
3.2.2.3 Artificial Fill
Approximately eight feet of artificial fill were found in the upper portion of Boring 5 within the
desilting basin, The fill soil is silty sand and likely represents reworked Santiago Formation.
5 1-4659-0 I15 1 I8RO 14.DOC
Copyright 1998 Kleinfelder, Inc.
Page 9 of 25 May 4, 1998
KLEINFELDER -
3.3 SURFACE WATER AND GROUNDWATER
Surface water and groundwater were encountered during the site reconnaissance and subsurface
investigation. Free water was encountered in Borings 1 and 2 at depths of 9 feet and 3 feet below
the pavement surface, respectively. The water level observed in the two borings (Elevations of
9.5 to 3 feet) is well above the water surface (Elevation off 1.0 foot) of the Agua Hedonia
Lagoon inlet located directly behind the apartments on the west side of Park Drive. This free
water in the two borings is likely water that has seeped out of the bluff toe between Stations
9+63 and 13+16 and is perched on impervious soils below the ground surface. Standing or
ponded seepage water was observed at the surface of Cone Soundings 1 and 2. Seepage water
was also observed in March and late April from the sides of the natural ravine at Station 9+75.
Free water was not encountered in any of our other borings. The water level may change due to
variations in precipitation, site drainage, or other factors that may have not been present at the
time of our investigation and subsequent site reconnaissances.
3.4 GEOLOGIC STRUCTURE
Generally, the structure of the Santiago Formation consists of gently dipping sedimentary
bedrock. As observed in the cut slope, little or no fracturing is apparent, and bedding planes are
indistinct except for faint near-horizontal stratification that dips gently (f 10 degrees) to the
southwest. This structure is consistent with the local attitudes provided in Open-File Report 82-
12 LA". However, the open-file report does show a change in the bedding in the vicinity of
Station 15+15 to Station 17+93 where a bedding attitude was recorded with a northeast strike and
a 2 to 5 degree dip to the southeast.
Large landslides were not detected during this investigation. Systems of small recent slope
failures exist on or near the site which are related to the ongoing cut slope erosion and the
erosion of the natural ravine. As indicated earlier, the late wintedearly spring storms have
resulted in considerable erosion of the existing slumps and steep sides of the natural ravine at
Station 9+75. However, no credible evidence exists for geologically recent major landsliding in
this area.
.. California Department of Conservation Open-File Report 82-12 LA, July I, 1982, Recent Slope Failures, Ancient
Landslides. and Related Geology of the North-Central Coastal Area, San Diego County, California.
5 1-4659-01151 18R014.DOC
Copyright 1998 Kleinfelder, Inc.
Page IO of 25 May 4, 1998
-
KLEINFELDER
4.0 DISCUSSION AND CONCLUSIONS
4.1 GROSS BLUFF STABILITY
Although occasional slabs of sandstone will continue to fail downslope as a result of erosion, the
sandstone is relatively massive without adverse planes of weakness. Therefore, the sandstone is
not likely to experience large rotational or translational slope failures. There is no indication of
landslides, either recent or ancient, at the site, and none are shown on available published
geologic maps.
The gross stability of the existing steep bluff along the assumed critical Section A-A’ (see
Figures 2 and 3) was analyzed using the computer program XSTABL (a modified version of the
STABL Program originally developed at Purdue University). This program generates random
failure surfaces based on specified strength parameters and slope geometry. Typically, the gross
stability of formational bluffs are expected to be controlled primarily by weakened planes such as
bedding and/or fractures. Although little or no apparent fracturing and distinct bedding planes
were observed in the Santiago Formation cut slope, the gross bluff stability was analyzed
assuming that these features could potentially be present. The stability of the bluff was primarily
analyzed using a sliding block generator which searches for a critical failure plane and can be
concentrated along known or anticipated planes of weakness within the profile. This option is
also suitable for analyzing transitional slope failures which often tend to follow soil-rock
interface.
The block surfaces are developed by connecting points that have been randomly selected within
specified search boxes. The generated block surfaces consist of three distinct portions: (1)
passive block, (2) central block, and (3) active block. The central block is generated first and is
then followed by generation of the passive and active wedges. The passive wedge is generated
from the leftmost search box, and the active wedge extends upwards from the rightmost search
box.
In addition to the sliding block generator, we also analyzed the factor of safety using a critical
slip-circle analysis. For each slip-circle analysis, the sliding mass is divided into a series of
vertical slices which are acted upon by the weight of the slice, the lateral (pseudo-static) forces,
and the resisting forces from the slip surface.
5 1-4659-0 l/5 1 I8R014.DOC
Copyright 1998 Kleinfelder, Inc.
Page I I of 25 May 4, 1998
-
KLEINFELDER
Dynamic conditions resulting from seismic forces generated during an earthquake were modeled
using a pseudo-static method. The pseudo-static method introduces a horizontal force at the
center of each slice or block of the sliding segment. The magnitude of the horizontal force is.
equal to the weight of the slice or block multiplied by a selected seismic coefficient. The
selection of the seismic coefficient is based on expected ground accelerations, subsurface
conditions, and geometry. For the pseudo-static analyses performed for this study, a maximum
seismic coefficient of 0.15 was considered appropriate.
The selection of strength parameters within the bedrock materials for slope stability analyses was
based on a combination of: (a) laboratory test results performed for this investigation, (b) our
observations of the materials characteristics in the subsurface, in-place condition, and (c) our
previous experience with similar geotechnical conditions. The following isotropic soil
parameters were assumed:
Friction Angle:
Cohesion:
Moist Density:
Saturated Density:
39.5 degrees
500 psf
135 pcf
120 pcf
The critical geometry was bed on Figure 3. Since no water was encountere within Boring 5,
the groundwater table was assumed to be at the line which connects the bottom of Boring 5 and
the seepage observed at the toe of the bluff.
The results of our analysis are included in Appendix C and indicate a minimum factor of safety
of 1.7 for static conditions and 1.3 for pseudo-static conditions. These calculated factors of
safety are likely lower than actually exist because little or no apparent fracturing or distinct
bedding were actually apparent during OUT field reconnaissance. Minimum factors of safety of
1.5 and 1.1 are normally considered acceptable static and pseudo-static conditions, respectively.
Therefore, the results of our analyses indicate the bluff currently possess acceptable factors of
safety against deep seated failures for static and pseudo-static conditions. However, calculated
factors of safety are essentially point measurements in time and change constantly over the years
as the slope ages due to exposure to the elements and the effects of erosion.
5 1-4659-0 115 1 18R014.DOC
Copyright 1998 Kleinfelder, Inc.
Page 12 of 25 May 4. 1998
4.2 EROSION AND CLIFF RETREAT
4.2.1 Surface Efosion of Natural Ravine. Station 9+75
Severe gully erosion has recently occurred within this ravine due to the season’s heavy rains. As
the existing slump material was removed and the central portion of the drainage was 1owered.by
erosion, continued slumping of the drainage side walls and erosion occurred. The primary water
causing the major erosion is surface water that falls onto the ravine below the sidewalk at its
crest and the surface water that flows to the drainage area from beyond the sidewalk at the crest
of the ravine. A minor source of water within the ravine during the heavy storm surface flows
may be due to a slight increase in the hydrostatic head at the subsurface water which raised the
point of seepage from the time between middle January and late April of this year.
The severe degree of recent erosion is apparently a direct function of the severity of the storm
rainfall. No significant accb-mlations of eroded material were observed at the base of the ravine
during our site visits of last July, December, and January. Furthermore, City Maintenance
personnel did not indicate that routine removal of sediment from the lower sidewalk was an issue
north of about Station 13+16 during our site visit in January.
4.2.2 Steep Cut Slope Erosion, Station 10+76 to Station 15+15
Like other bluffs in the area, the bluff in the study area is experiencing progressive failure. The
friable, but massive, sandstone that comprises the cut slope is erodable. The sandstone is not
cemented or indurated, and is weaker near the top of the slope which is more susceptible to
erosion. The bare, steeply sloping cut face of sandstone is particularly prone to erosion through
mass wasting, primarily in the form of slaking. Slaking is an ongoing process where physical
weathering and animal activity loosen the face of the bluff.
Weathering is the process by which the sandstone is disaggregated in place for erosion to take
over. The common weathering agents are oxygen, carbon dioxide, water, and salt crystal growth
which alter and dissolve the sandstone binding. Direct rainfall and runoff from the crest of the
slope tend to erode the sand particles and cause periodic saturation of the cliff face which
enhances slumping. Although occasional erosion gullies are present, they are relatively small
and most of the erosion is from surface water that sheet flows unchecked from the natural slope
5 1-4659-01/5 I18R014.DOC
Copyright 1998 Kleinfelder, Inc.
Page 13 of25 May 4, 1998
-
KLEINFELDER
- above the cut slope. The loose debris from the erosion process accumulates along the toe of the
bluff.
The rate of cliff retreat is highly variable from place to place and from time to time. Based on
our past experience and the technical literature on cliff retreat rates, we estimate the long term
cliff retreat rate may be on the order of 1 to 4 inches per year. This rate is comparable to other
rates for Southern California coastal bluffs.
The two existing pipelines observed along the bluff face are reportedly abandoned. Portions of
the abandoned pipelines, especially those at the higher elevations, may be conduits of drainage
water and could be locations where concentrated erosion can occur.
Erosion of the steep cut slope does not place any structure or utility in immediate risk of failure.
However, the accumulation of eroded Santiago Formation at the bluff toe is a nuisance that
requires continual removal.
With respect to slowing the process of cut slope erosion, there are methods which may be
successful, but may not be acceptable to the California Coastal Commission. These include
covering of the slope face with lower permeability materials and installation of anchored walls.
Implementing a monitoring program over the next several years may be a more practical
approach. Removing or capping the pipelines on either side of the cut face would also reduce the
potential for concentrated erosion along those conduits.
4.2.3 45' Slope, Station 15+15 to Station 17+93
Severe rill and gully erosion is occurring on this relatively bare, triangular-shaped, south facing
slope. The depth of erosion on this 1H:IV slope reaches about 3 feet in some locations. The
erosion processes are similar to those for the steep cliff area. However, in this immediate area,
the lithology and bedding are such that the rain wash and runoff stay concentrated on the slope to
the extent that deep channels are eroded into the slope.
5 1-4659-0115 1 18R014.DOC
Copyright 1998 Kleinfelder, Inc.
Page 14 of 25 May 4, 1998
-
KLEINFELDER
4.3 SEEPAGE FROM TOE OF BLUFF
The sources of the groundwater seeping from the toe of the bluff between Station 9+63 and
13+16 are likely irrigation water and rainfall that fall on the lawns of the vast residential area
northeast of the study area. It is likely that groundwater is at a low gradient and at an elevation
not much higher than seepage elevation at the mouth of the natural ravine near Station 9+75.
Although the small park located directly at the top of the bluff adjacent to the seepage area has
green, lush vegetation from frequent irrigation, it is unlikely that a large portion of the seepage
water is attributable to this source since:
No evidence of seepage was observed on the cut slope. face directly down slope from the
park; and
The vertical hydraulic conductivity of the Santiago Formation in this area is relatively slow
due to the presence of clay and silt layers, the density, and cementation of the sandstone. The
lateral hydraulic conductivity is anticipated to be several times that of the vertical.
4.4 CURRENT SAND REMOVAL PROCEDURE
Based on our meeting of January 15, 1998 with representatives of the City’s Engineering and
Maintenance Department, City maintenance crews periodically (usually after heavy rain storms)
remove accumulated sand deposits (sediment from cliffklope erosion carried by stormwater
runoff) from the sidewalk on the easterly side of Park Drive from approximately Station 13+16
to about Station 17+93. In addition to removing the accumulated sand from the sidewalks, loose
sand that accumulates at the ground surface behind the low retaining wall from Station 15+15 to
Station 17+93 is excavated with a small backhoe.
The representatives of the City Maintenance Department indicated that sand removal in this
manner has not been a significant burden since some periodic maintenance is already included in
the annual budget. However, the water seepage and algae growth on the sidewalk and street have
been a significant nuisance and safety hazard to pedestrian traffic. The seepage and algae
problem occurs from about Station 9+63 to Station 13+16.
5 1-4659-0115 I 18R014.DOC
Copyright 1998 Kleinfelder, Inc.
Page 15 of25 May 4. 1998
- KLEINFELDER
- The sand that eroded out from the natural ravine at Station 9+75 and was deposited on the
sidewalk and street was both a nuisance and safety hazard since it precluded use of the sidewalk
and part of the street until its clean-up could be completed. Since clean-up crews were busy
throughout the city, it took longer than normal to service this site.
-
-
4.5 CONCLUSIONS -
The following conclusions are based on our field observations, five test borings, two dynamic
cone penetration tests, and our laboratory tests and analysis: .-
- Like other bluffs in the community, the bluff in the study area is experiencing progressive
failure through mass wasting. Although occasional slabs of sandstone will continue to fail as
a result of erosion, the sandstone is relatively massive and not likely to experience large
rotational or translational slope failures. The deposition of eroded materials at the base of the
bluff is a clean-up nuisance.
The bluff presently exhibits static and pseudo-static factors of safety which most practitioners
agree are acceptable for gross stability against landslide. Although the steeper portions of the
cut face and the steeper side slopes of the natural drainage ravine exhibit occasional shallow
slope andor slump failures, no recent or ancient landslides are indicated for the site.
As a result of heavy storms in February and March, severe gully erosion has occurred within
the northeast trending ravine at Station 9+75. The erosion was due primarily to uncontrolled
surface drainage, although increase subsurface drainage may have been involved to a minor
extent. Erosion from this ravine has apparently not been a past periodic maintenance
problem.
The severe rill and gully erosion from Station 15+15 to Station 17+93 leaves sediment
deposits on the sidewalk area which are also a nuisance.
The seepage and algae growth on the sidewalk and street from about Station 9+63 to Station
13+ 16 are both a nuisance and a potential slip hazard for pedestrian traffic.
5 1-4659-0115 I18R014.DOC
Copyright 1998 Kleinfelder, Inc.
Page 16 of25 May 4, 1998
-
KLEINFELDER
5.0 RECOMMENDATIONS
5.1 BLUFF EROSION MONITORING
We recommend that a minimum of three surface monuments be established along the west side
of the sidewalk (at about Stations 10+00, 12+00, 14+00) at the east end of the small park at the
top of the bluff. We recommend that the distance between the monuments and the cut slope face
be monitored on a yearly basis to assess erosion rates and note any significant changes. If
necessary, recommendations for erosion protection and/or specific treatment of localized areas
can be made in the future.
Although they don't pose an immediate problem, consideration should be given to capping
and/or removing the two existing abandoned pipelines to reduce their potential for increasing
local erosion;
5.2 REMEDIAL GRADING AND DRAINAGE
To remedy the major seepage problem from the toe of the bluff we recommend placement of a
new retaining wall and drain from Station 10+23 to Station 13+16. Prior to construction of the
retaining wall and retaining wall drain, some remedial grading and drainage will be required.
Figure 4 shows the general recommendations for the limits and procedures for the remedial
grading and drainage. Based on the two cone soundings and Borings 2, 3, and 4 we anticipate
that relatively stable foundation material should be encountered within three feet of the existing
ground surface. The soils within two to three feet of the existing ground surface are expected to
be relatively loose and saturated.
We recommend the contractor predrain the subgrade prior to starting excavation to reduce
instability and slumping of the existing sandstone cut slope and the adjacent retaining walls.
Temporary sump pits (slotted 55 gallon barrels embedded 4 feet below sidewalk elevation at 75-
foot centers) with pumps are recommended for the drainage system. The barrels should be
wrapped in a geotextile fabric (Mirafi 140N or equivalent) or provided with a six inch wide
sandy gravel filter ('A inch drain rock mixed with washed concrete sand) to reduce the potential
of pumping out fines resulting in potential loss of stability to excavation slopes and subgrade.
5 1-4659-01/5 I 18R014.DOC
Copyright 1998 Kleinfelder, Inc.
Page 17 of 25 May 4, 1998
-
KLEINFELDER
- The Regional Water Quality Control Board is likely to restrict the discharge of water without
proper NPDES permits.
The primary considerations in the remedial grading are that the unstable soil is removed, and
adequate drainage to accept the seepage water is provided. The unstable soil below a nominal
%H:lV downward projection from the base of retaining wall to firm, underlying material should
be removed and replaced with good foundation soils. The bottom of the excavation should be
sloped 2 percent towards the existing cut slope.
-
-
.-
- The existing soils are expected to be saturated. Since the bottom of the excavation is also
expected to be fairly wet due to the on-going seepage, we recommend that the excavated soils be
replaced with Caltrans Class 2 aggregate base compacted to 90% of ASTM D1557 maximum dry
density. If drainage permits, the aggregate base should be placed and compacted in nominal 8-
inch thick lifts. However, to preserve stability of the side slopes, it may be necessary to increase
the lift thickness by a factor of 2 to 3 in some locations.
.-
Details of the geotextile wrapped drains to collect the seepage and outlet to the street drain are
shown on Figures 4 and 6, respectively. The fabric wrapped drain can be modified to adjust to
field conditions, especially with respect to the spacing between the drain and the back edge of the
foundation for the new retaining wall.
All pipe drains should be 6 inches minimum diameter to allow proper cleaning. The pipes
should be constructed of schedule 40 PVC pipe. Pipes completely embedded within geotextile
fabric should be perforated (perforations placed down) and placed 6 inches above the bottom of
the geotextile fabric. All other pipes should not be perforated.
Collection and outlet drains should be placed with a minimum gradient of 0.10 feeU100 feet
where possible. If topography dictates, a flatter gradient may be used, but should not be less than
0.05 feet/100 feet for collection drains; outlet and street drains may have lesser gradients
provided they are positive to some degree.
We are recommending that two outlets to the new street subdrains be constructed at about Station
10+23 and Station 11+70. This spacing is fairly close, but is intended to provide some
redundancy in exit drainage. The outlets and cleanouts should be constructed in general
accordance with the detail shown on Figure 6. Since no subdrains are known to exist in the
vicinity of Station 10+23 or Station 11+70, a new street subdrain will need to be constructed. It
5 1-4659-0 115 I I8RO 14.DOC
Copyright 1998 Kleinfelder, Inc.
Page I8 of 25 May 4, 1998
-
KLEINFELDER
- should be constructed of unperforated 6-inch diameter schedule 40 PVC pipe. The nearest point
of connection to a storm drain appears to be at about Station 4+42 where there is an existing 24
inch diameter reinforced concrete pipe crossing Park Drive. It is likely that additional permits
will be required from the Regional Water Quality Control Board to connect this subdrain to the
existing storm drain since it does appear to drain into the Agua Hedonia Lagoon. Any permitting
for this drainage should be coordinated with temporary dewatering permits to avoid construction
delays and additional permitting costs.
-
-
-
Unless other City of Carlsbad standard details dictate, we recommend the narrow trenching for
the street subdrain follow the details provided on San Diego Regional Drawing Number G-34 for
a Type C resurfacing. The Willdan plans for the Park Drive improvements indicate the existing
pavement section consists of 4 inches of asphalt concrete over 10 inches of aggregate base.
__
_-
To reduce the potential for clogging, we recommend that all trees be removed from within 50
feet of perforated subdrains. Although cleanouts have been recommended in the event drains
become clogged, removal of the root source is recommended if at all possible.
5.3 NEW RETAINING WALL AND SIDEWALK REPLACEMENT
We recommend that a new concrete retaining wall be constructed between Station 10+23 and
Station 13+16 to tie in with the existing retaining walls on either end. The existing retaining
walls are on the order of 18 to 24 inches high; however, it may be desirable to increase the height
by two to three feet to provide additional sediment storage volume. Figure 4 shows the key
design items.
Bearing capacity of the retaining wall foundation soils, after removal of the loose, compressive
soils and replacement with properly compacted aggregate base as described in Section 5.2, can
be assumed as 4,000 pounds per square foot. This value may be increased by one-third for
seismic loading. The depth of embedment should be at least one foot.
For sliding resistance, a friction coefficient of 0.35 may be used at the concrete and soil interface.
Passive pressure resistance against the toe of the retaining wall (and keyway if one is included)
can be calculated assuming an equivalent fluid weight of 300 pounds per cubic foot. The
allowable lateral resistance can be taken as the sum of the frictional resistance and the passive
5 1-4659-Ol/J I 18R014.DOC
Copyright 1998 Kleinfelder, Inc.
Page 19of25 May 4. 1998
- KLEINFELDER
- resistance, provided the passive resistance does not exceed two-thirds of the total allowable
resistance. The passive resistance may be increased by one-third for seismic loading.
The lateral earth pressure value for the cantilever retaining wall should be assumed as an active
equivalent fluid weight of 55 pounds per cubic foot. This value assumes a sloping backfill up to
1.5H to 1V to allow for some temporary accumulation of eroded soil between periodic sediment
removal. This value also assumes that the backfill above the foundation of the wall will be non-
expansive sandy soil classified as SP, SM, or SC and that a suitable wall drain will be
constructed as shown in Figure 4. Wall backfill should be placed in nominal 8-inch thick lifts
and compacted to at least 90 percent relative compaction in accordance with ASTM D1557.
-
.-
-
-
- We recommend that where the existing curb and gutter need to be replaced that they be replaced
with a 6" P.C.C. Type "G curb and gutter. To accommodate occasional traffic loads on the
pavement, we recommend that the sidewalk thickness should be at least 6 inches.
5.4 DRAIN BEHIND EXISTING RETAINING WALL
To pick up the water seeping through the existing retaining wall and to discourage algae growth
on the sidewalk, we recommend that 80 feet of drain be constructed behind the existing retaining
wall from about Station 9+43 to the start of the new wall at Station 10+23. The 80 feet of new
drain extends 20 feet beyond the north end of the observed problem area.
Figure 5 shows details of the proposed drain. To avoid clogging of the drain, we again
recommend that all trees be removed from within 50 feet of the wall backdrains, if possible.
As discussed in the field meeting of January 15", 1998, no drains or improvements to the
retaining walls north of Station 9+43 or south of Station 13+16 are recommended at this time. If
drainage from either wall area proves to be a problem in the future, additional slot drains can be
excavated along the back of the retaining walls and connected to the proposed 6-inch diameter
drain lines recommended in this report.
5 1-4659-0115 I 18R014.DOC
Copyright 1998 Kleinfelder, Inc.
Page 20 of 25 May 4, 1998
I
KLEINFELDER
5.5 EROSION MITIGATION STATION 15+15 TO STATION 17+93
To improve its appearance, but more important, to address the continued erosion of the existing
1H:IV slope, we recommend remedial grading of the slope and establishment of native
vegetation. Since the existing slope has numerous rills and gullies up to 3 feet in depth, simply
filling the rills and gullies on such a steep slope is not practical. The fill would likely fail before
sufficient deep roots could grow to help with its reinforcement.
The slope should be excavated to a uniform depth below the deepest gullies (estimated depth = 3
feet) to firm material. The excavated soil can be used as backfill for the new section of retaining
wall from Station 10+23 to Station 13+16. Some of the existing vegetation may have to be
removed above the eroded area to provide a gradual transition in grade between the two areas.
Once the slope has been excavated to the proper gradient, we recommend installation of a slope
protection system to provide a suitable growing medium and to anchor the vegetation until it is
well established. For the steep slope conditions present in this case we recommend using
Presto’s Geowew System, or equivalent.
The GeowebB System is an open (top and bottom) lattice, cellular confinement that is staked to
the slope and filled with topsoil or other select infill materials. Typical components of the
Geoweb@ System and a technical overview are included in Appendix D. Additional
information, including typical installation drawings, project design support, specifications, and
material ordering is available through Mr. Tom Siverly (phone (209) 383-3296) of the Soil
Stabilization Company, Inc.
Based on our geotechnical knowledge of this project, we provide the following suggestions for
incorporation into the overall drainage, landscaping, and GeowebB System design:
To provide better overall performance and reduce the loss of infill material, a lightweight (4 -
6 odyd2), needle-punched, non-woven geotextile fabric should be placed on the slope prior to
installation of confinement cells. The geotextile fabric should be placed as smooth and
wrinkle-free as possible; the fabric should be unrolled from top to bottom of the slope.
Adjacent rolls of geotextile fabric should be overlapped at least two feet. Pins or nails will be
required to maintain geotextile fabric positions during placement of the Geoweb@ System.
5 l-4659-01/5 I I8RO 14.DOC
Copyright 1998 Kleinfelder, Inc.
Page 21 of 25 May 4. 1998
-
KLEINFELDER
0 Assuming that the regraded slope will be at nearly a 1H:lV slope, an 8-inch Standard
GeowebQ cell should be used. This will allow the use of vegetable topsoil infill with the
lowest acceptable infill angle of repose (19") for the regraded slope.
For preliminary costing, surface anchorage of each 84. wide GeowebQ section should
include at least 4 tendons with 18 inch long clip anchors at 3-foot intervals along each
tendon. Specific anchoring requirements for the selected infill material and slope geometry
should follow the manufacturer's recommendations.
Vegetated topsoil infilling, selected plant species, irrigation requirements, and fertilization
should be established by the design landscape architect for the project. The angle of repose
for the infilling material proposed by the landscape architect should be evaluated by the
geotechnical engineer prior to final design of the GeowebB System so that the stability of the
overall system is consistent with the cell size selected.
The topsoil infilling should proceed from the top of the slope to toe. The infill material
should be processed as required to remove clumps greater than 1 inch in diameter prior to
placement. Air voids should be removed during the placement process by light hand
tamping. The cells should be completely filled, but overfilling should be avoided.
Seeding and the installation of a degradable erosion blanket should follow immediately after
infilling is complete.
The design landscape architect should make provisions for maintenance, repair, and/or
replanting until an adequate vegetation cover is well established.
5.6 NEW BROW DITCHES
New brow ditches and any required down drains are recommended at the approximate locations
shown on Figure 2. The exact location of brow ditches should be established by the civil
designer; however, the general intent is that the brow ditch north of Station 14+54 should
intercept surface water runoff before it enters the natural drainage ravine and should be situated
at least 10 feet from the cut slope crest to allow for some natural erosion of the steep slope face
without impacting the integrity of the ditch.
5 1-4659-0 115 1 18R014.DOC
Copyright 1998 Kleinfelder. Inc.
Page 22 of 25 May 4, 1998
-
KLEINFELDER
The new brow ditch between Station 15+1S and Station 17+93 should be located just above the
eroded portion of the slope in an area that has existing good vegetation cover that can be quickly
reestablished.
Figure 7 shows a typical detail of the brow ditch that has been used in the immediate area in the
past. Since the design has been used successfully on the steep slope areas in the past, its
continued use is recommended, however, the actual details can be amended to fit the site
conditions as recommended by the civil designer.
5.7 SURFACE EROSION OF RAVINE AT STATION 9+75
Correction of the surface water erosion within the ravine due to heavy storm flows requires
additional civil design studies that are beyond the intent and scope of this geotechnical study.
We anticipate subsurface drainage recommended for this project should accommodate most of
the subsurface drainage problems we have observed next to the natural northeast trending ravine
near Station 9+75. The installation of the new brow ditch across the upper end of the drainage
should help reduce the sediment and runoff from typical five year storms. However, we
recommend that a complete surface drainage study be undertaken to evaluate specific drainage
requirements to safely carry surface water through the ravine and into a proper storm water
conveyance system. A gabion cage retention basin, similar to the typical detail shown in Figure
E, can be constructed to collect storm water runoff and sediment deposition. Based on the
drainage study, a separate inlet may be required at the base of the ravine within the ponding area.
The City Maintenance Department should be consulted regarding the configuration of the
retention basin so that it can be properly cleaned on a periodic basis with available equipment.
To repair the eroded steep slopes, we recommend that grass be hydroseeded on the bare spots.
To promote plant growth on the steeply inclined surface, we recommend that the seed be
hydroseeded with a cementitious binder mixed with water and mulch to produce an erosion-
resistant crust. Airtrol Geobinder produced by the United States Gypsum Company (Technical
Department telephone number 1-800-487-443 1) is a nontoxic, noncombustible cementitious
binder produced from gypsum that has been used with seed, fertilizer, and mulch to provide
vegetation coverage on steep slopes.
5 1-4659-0 115 1 I8RO 14.DOC
Copyright 1998 Kleinfelder. Inc.
Page 23 of 25 May 4. 1998
- KLEINFELDER
6.0 ADDITIONAL SERVICES
It has been our experience that civil designers providing project design or contractors bidding on .
the project often contact US to discuss the geotechnical aspects of the project. Informal contacts
between Kleinfelder and an individual designer or contractor could result in incorrect or
incomplete information being provided. Therefore, we recommend that all design questions be
routed through the City’s Engineering Department in writing. We also recommend Kleinfelder
conduct a general review of final plans and specifications to evaluate that our geotechnical
recommendations have been properly interpreted and implemented during design. In the event
Kleinfelder is not retained to perform this recommended review, we will assume no
responsibility for misinterpretation of our recommendations.
We further recommend that a pre-bid meeting be held to answer any questions about the report
prior to submittal of bids. If a pre-bid meeting is not possible, questions or clarifications
regarding this report should be directed to the project owner or his designated representative.
After consultation with Kleinfelder, the project owner (or his representative) should provide
clarifications or additional infomation to all contractors bidding the job.
All drains should be reviewed in the field prior to backfilling and all backfill placement should
be monitored by a representative from Kleinfelder. The purpose of these services would be to
provide Kleinfelder the opportunity to observe the soil conditions encountered during
construction, evaluate the applicability of the recommendations presented in this report to the
soil conditions encountered, and recommend appropriate changes in design or construction
procedures if conditions differ from those described herein.
5 1-4659-0 1/5 i I 8R014.DOC
Copyright 1998 Kleinfelder, Inc.
Page 24 of 25 May 4, 1998
-
KLEINFELDER
7.0 LIMITATIONS
Recommendations contained in this report are based on our field observations, five test borings,
two dynamic cone penetration soundings, data from laboratory tests, and our present knowledge
of the proposed construction. The study was performed using a mutually agreed upon scope of
work. It is our opinion that this study was a cost-effective method to evaluate the subject site and
evaluate some of the potential geotechnical concerns. More detailed, focused, and/or thorough
investigations can be conducted. Further studies will tend to increase the level of assurance;
however, such efforts will result in increased costs. If the client wishes to reduce uncertainties
beyond the level associated with this study, Kleinfelder should be contacted for additional
consultation.
It is possible that subsurface conditions could vary between or beyond the points explored. If
soil and groundwater conditions are encountered during construction which differ from those
described herein, our firm should be notified immediately in order that a review may be made
and any supplemental recommendations provided. If the scope of the proposed construction,
including proposed loads, grades or structural locations change from that described in this report,
our recommendations should also be reviewed.
Our firm has prepared this report for the City of Carlsbad‘s exclusive use on this project in
substantial accordance with the local geotechnical practice as it exists in the site area at the time
of our study. No warranty is expressed or implied. The recommendations provided in this report
are based on the assumption that an adequate program of tests and observations will be
conducted by our firm during the construction phase in order to evaluate compliance with our
recommendations. If we are not retained for these services, the client agrees to assume
Kleinfelder’s responsibility for any potential claims that. may arise during or after construction.
This report is issued with the understanding that the City chooses the risk it wishes to bear by the
expenditures involved with the construction alternatives and scheduling that is chosen. It is the
City’s responsibility to see that all parties to the project, including the civil design engineer,
project landscape architect, contractor, subcontractors, etc., are made aware of this report in its
entirety.
5 1-4659-01151 18R014.DOC
Copyright 1998 Kleinfelder, Inc.
Page 25 of 25 May 4, 1998
SOURCE: ME THOMAS BROS. GUIDE, SAN DIEGO COUNTY. 1995 EDITION. REPRODUCED WITH PERMISSION GRANTED
EROS. MAPS. IT IS UNLAWFUL TO COPY OR REPRODUCE ALL OR ANY PART THEREOF, WHETHER FOR PERSONAL USE OR RESALE,
240C 4800
BY THOMAS BROS. MAPS. mis MAP IS COPYRGHTED BY THOMAS -
APPROXIMATE SRAPHI'3 SCALE
(FEET) WMWT PERMISSIDN.
FIGURE KLEINFELDER VICINITY MAP
1 9555 CHESAPEAKE ORIM. SUITE 101
SAN DIEGO. CALIFORNIA 92123
ECKED BY: A& IFN: VICINITY CITY OF CARLSBAD
OJECT NO. 51-4659-01 IDATE: 12/22/97
PARK DRIVE SLOPE / DRAINAGE STUDY
CARLSBAD, CALIFORNIA
I I i I I I I I I I I I I I I 1 I I I
PROPOSED BROW DITCH
APPROXIMATE LOCATION OF EXISTING DESlLTlNG BASIN
SOUTH END OF EXISTING
NORTH END OF EXISTING
RETAINING WALL
APPROXIMATE LOCATION OF CONE APPROXIMATE LOCATION
AND DOWN DWN APPROXIMATE LOCARON OF GEOLOGIC CROSS SECTION (SEE FIGURE 3) - - - APPROXIMATE LOCATION OF
GEOLOGIC CONTACT
APPROXIMATE LOCATBN OF EXISTING BROW DITCH AND DOWN OWN Tsb WTWO FORMATION
Qsw SLOPE WASH/COLLWIUM
PARK DRIVE SLOPE / DRAINAGE STUDY APPROXIMATE GRAPHIC SCALE
Tsb
1 I I I I 1 I 1 I I I I I I I I I I
KLElNFELDER
9555 CHEWEAKE DRM. SUITE 101
CHECKED BY REL IFN: 4659XSECT
PROJECT NO. 51-4659-01 1 DATE 2/23/98
W DIEGO. ULIFORNU 92123
APPROXIMATE
GEOLOGIC CONTACT BETWEEN Tsb AND Osw
HORIZONTAL DISTANCE FROM ORIGIN (FEET)
FlGURE GEOLOGIC CROSS SECTION
PARK DRIVE SLOPE / DRAINAGE STUDY
CITY OF CARLSBAD CARLSBAD, CALIFORNIA 3
I LEGEND:
~
NOTE:
1. SINCE NO WATER TABLE WAS OBSERVED IN BORING 5 (LOCATED AT TOP OF BLUFF) WITHIN IT'S MAXIMUM
DEPTH OF 50.5 FT.. A WORST CASE WATER TABLE CONDITION WAS ASSUMED. CONDITION IS BASED ON A PROJECTED LINE FROM THE
SEEP ALONG THE SLOPE FACE TO THE BOTTOM OF BORING 5.
THIS WORST CASE
APPROXIMATE LOCATION OF WRINGS (OFFSET TO SECTION A-A')
1 - GROUNDWATER LML OBSERVED
TSb wmo FORMATION
asw SLOPE WAWCOLL~UM
bf PRTlFlClAL FILL
APPROXIMATE GRAPHIC SCALE
0 50
HORIZONTAL: 1 "=50' VERTICAL: 1 "=50'
-
1.
2.
3.
4.
5.
6.
7.
a.
9.
KLEINFELDER
9555 CVESWEAKE DRIVE CUTE 101
SAN SEGO CALIFORNiA 92 23
iECKED BY REL IFN 4659SHTl
?OJECT NO 51-4659-01 /DATE 5/4/98
TEMPORARY STOCKPILE OF ACCUMULATED ERODED SLOPE MATERIAL
REPLACE EXISTI SIDEWALK, CURB, GUrTER AS NECES
DRAIN (SEE NOTE 7)
40 PVC PIPE
6"0 SCHEDULE 40 PVC PIPE
TYPICAL RETAlNlNQ WALL SECTION AND LIMITS OF FOUNDATION IMPROVEMENT STATION -23 TO STATION 13+M
PARK DRIVE SLOPE / DRAINME STUDY CrrYoFCAFU6AD CARLSW CALIFORNIA
FIGURE
4
(11b d' MINI) I 'MIN '
Wall may be of other configuration (ex. San Diego Regional Drawing C-2, C-4, and C-6,
except that drainage shall follow, note 7 below).
H = Height of wall.
volume desired. H mqy extend above level bockfill if additional sediment storage
B = Width of wall foundation
d = 28 or depth to adequate bearing material (aperoximate Elev. 10 from Station 10+23
to Stotion 13t16) whichever is less except that "d should not be less than 2 feet,
Remove and replace existing soil in the zone indicated for the length of the wall. Backfill
below bottom of footing to be Coltrans Closs 2 Aggregate baserock compocted in 8 inch
loose lifts to 90% ASTM 01557.
clossified os SP, SM, or SC, compacted in 8 inch loose lifts to 90% ASTM 01557. Excavated
soils free of excess moisture, vegetation, ond muck ore suitable sandy soils, especially soils
graded from Station 15t15 to Station 17t93. Water was encountered at about Elev. 13.3 on 12/5/97.
Geotextile wrapped bock drain to consist of 3/4" to No. 4 drain rock wrapped in Mirofi
140N or equivalent, 6 inch minimum fabric overlap. Provide 9 cubic feet mimimum of
drain rock per lineal foot of drain. Perforoted 6 0 PVC Schedule 40 pipe (perforations
down) should be ploced 6 inches above bottom.
Station lot23 and Station 11t70. See Figure 6.
Geotextile wrapped wall drain to consist of 3/4" to No. 4 drain rock wrapped in Mirafi
140N or equivalent, 6 inch minimum fabric overlap.
minimum and should extend from top of footing to 2/3 H.
40 pipe (perforations down), should be ploced 6 inches above footing.
outlet to street subdrain at Station 10t23 ond Station 11t70.
Provide suitable waterproofing as designated by the wall designer.
A 1H : 1V back cut is typical, but can be steeDened to near vertical in sandstone to
ovoid undercuttinq bluff.
Backfill above footing bottom to be non-expansive sandy soil
Some predroinoge should be onticipated.
Provide outlet to street subdrain at
Width of drain to be 1.5 feet
Perforoted 6"0 PVC Schedule
Provide suitable
See Figure 6.
1.
2.
3.
4.
5.
6.
TYPICAL DRAIN FOR EXISTING RETAINING WALL STATION 94 TO STATION 10123 181 KLEINFELDER
9555 CHESAPmKE DRIVE SUITE 101
SAN DIEGO. CALIFOPNIA g2123 PARK DRIVE SLOPE / DRUNAQE STUDY ECKED BY REL 1 FN: 4659SHTl CllY OF CARLSBAD
ZOJECT NO. 51-4659-01 I DATE 2/23/98 CARLSBAD, CAUFORNU
CLEANOUT AT STATION 9+43
EXISTING RETAINING WALL
WATERPROOF BACK OF WALL
CLEAN AND SEAL EXISTING
OPEN JOINTS AT BASE OF W COMPACTED AGGRETATE
FIGURE
5
GEOTEXllLE WRAPPED WALL
6-0 SCHEDULE 40 PVC PIPE DRAIN (SEE NOTE 5)
H = Height of woll
From Station 9+43 to Station 10+23 a new drain should be installed directly adjacent
to the existing retaining wall.
top of the footing.
After the drain slot is excavated, the back of the wall should be waterproofed to mitigate
moisture passing through the wall. The type of waterproofing should be specified by the
wail designer.
To mitigate erosion, the upper 12 inches of backfill should be Caltrans Class 2 aggregate
baserock comDacted in two 6 inch level lifts with hand tools.
A nominal 18 inch wide slot should be excavated to the
Geotextile wrapped wall drain to consist of 3/4“ to No. 4 drain rock wrapped in Mirofi
140N or equivalent, 6 inch minimum fabric overlap.
minimum and should extend from top of footing to 2/3 H.
40 pipe (perforations down), should be placed 6 inches above footing.
outlet to street subdrain at Station 10+23. See Figure 6.
A cleanout with protective cover should be added to the surface at the end of the wall drain
Width of drain to be 1.5 feet
Perforated 6”0 PVC Schedule
Provide suitable
rK
/
KLEINFELDER
3555 rHESAPEAKL DRIVE SUITE 101
SAN 3IEGO CALIFORNiA 92123
HECKED BY REL IFN 4659SHT1
ROJECT NO 51-4659-01 !DATE 5/4/98
/
STREET OUTLETS AND CLEANOUTS FIGURE TYPICAL DETAILS
PARK DRIVE SLOPE 1 DRAlNMY 8NDY CrrY OF CARLSBAD CARLSBAD, CALIFORNIA
6 STATION ~k25 AND STATION n+7o
LEVEL FINISHED GROUND SURFACE
CLEANOUT WITH (AFTER CONSTRUCTION)
^-OTECTIVE COVER A
GEOTEXTILE WRAPPED WALL DRAIN
1. If conditions permit, subdrains should have a minimum positive gradient of 0.10 ft/l00 ft.
A flotter gradient may be used if topography dictates, but the gradient should be positive
to some degree.
2. The street subdrain and all outlet/cleanout pipes should be unperforoted.
3. See Figure 4 for other specific items.
MODIFIED TYPE "B" BROW DITCH fr
KLEINFELDER
9555 CHEWWE ORNE. Sum 101 SAN OIECO. CAUFORNIA 92123
iECKED BY: REL
70JECT NO. 51 -4659-01 I DATE: 2/23/98
I FN: BROWDET
7 c2"X12'' CALIFORNIA REDWOOD NO. 1 CHEVRONS,
10' ON CENTER. LENGTH TO EXTEND TO UNDISTURBED EXISTING GROUND OR 5' MIN.
MODIFIED TYPE "B" BROW DITCH WITH
REDWOOD CHEVRONS
PARK DRIVE SLOPE / DRAINAGE STUDY
CITY OF CARLSBAD CARLSBAD, CALIFORNIA
FIGURE
7
PROFILE
NOT TO SCALE f SEE A
MODIFIED TYPE "B" 1
BROW DITCH PER
REG. STD. DWG. D-75
DETAIL A
NOT TO SCALE
CUT 6"X6" NOTCH IN REDWOOD
CHEVRON CAULK BETWEEN CONCRETE AND REDWOOD
-5 t 5'- f - #5 REBAR. 3' IN LENGTH,
DRILL REDWOOD CHEVRON AS REQUIRED TO DRIVE REBAR THROUGH REDWOOD CHEVRON 5' ON CENTER, ONE AT EACH
END WITH A MAXIMUM OF 5' SPACING IN BETWEEN
,--VELOClPl REDUCER r GRAVEL
KLEINFELDER
9555 CHEWWE DRNE. SUE 101 SIW DIECO, CAUFORNU 92123
CKED BY: REL I FN: GABCAGE
JECT NO. 51-4659-01 I DATE 2/23/98
LG,IOPI CAGE (DESIGNED AND INSTALLED IN ACCORDANCE WITH MANUFACTURER'S INSTRUCTIONS)
GABION CAGE RETENTION BASIN FIGURE
PARK DRIVE SLOPE I DRAINAGE STUDY
CITY OF CARLSBAD
CARLSBAD, CALIFORNIA 8
60 SECOND RFTENTION TIME 2 YEAR STORM 7
INLET
LGRAVEL FILTER DESIGNED TO SLOW FLOW, ALLOWING SEDIMENT TO DROP OUT (2"-3"0 GRAVEL) i SEEPAGE CUT OFF
REDUCER
(PLASTIC FILM, CEMENT, ETC.)
SECTION A-A
51 -4659-01
DRILLING EQUIPMEW
B/\CKFIIl.EO: SURFACE CONDmONS
I I
LOG OF BORING LEGEND SHEET 1 OF 1
Loc*TIoN PROJECT WE
PARK DRIVE SLOPE STUDY CARLSBAD, CA
SOIL DESCRIPTION
ELEVAllON
WELL-GRADED GRAVELS AND GRAVEL-SAND MIXTURES. LITTLE OR NO FINES
POORLY GRADED GRAVELS AND GRAVEL-SAND
MIXTURES, LITTLE OR NO FINES
SILTY GRAVELS, GRAVEL- SAND-SILT MlXTU RES
CLAYEY GRAVELS, GRAVEL-SAND-CLAY MIXTURES
g n
......... .......... JWELL-GRADED SANDS AND GRAVELLY SANDS, ........... ....... LITTLE OR NO FINES ........... ......
OAK STARTED: DRILLING AGENCY GROUNOWAER CWAnON
COMPLmD LOGGED BY
SILTY SANDS, SAND-SILT MIXTURES
CLAYEY SANDS, SAND-CLAY MIXTURES
INORGANIC SILTS, VERY FINE SANDS, ROCK FLOUR, SlLM OR CLAYEY FINE SANDS
INORGANIC CLAYS OF LOW TO MEDIUM PLASTICITY, GRAVELLY CLAYS. SANDY CLAYS, SILTY CLAYS, LEAN CLAYS
ORGANIC SILTS AND ORGANIC SILTY CLAYS OF LOW PLASTICITY
INORGANIC SILTS, MICACEOUS OR DIATOMACEOUS FINE SANDS OR SILTS, ELASTIC SILTS
ORGANIC CLAYS OF MEDIUM TO HIGH PLASTICITY
WATER LEVEL AT TIME OF DRILLING
2gd I
CAVED
AREA
NATURAL BACKFILL
BENTONITE PACKER
SAND BACKFILL
SW
SP
SM
SC SAND
VOLCLAY GROUT dL
3L PIPE
SLOllED PIPE JL
NOTES 6
CONTINUOUS SAMPLER
GRAE SAMPLE
CALIFORNIA SAMPLER
MODIFIED CALIFORNIA - SAMPLER * * * - ' :
-
-
NO RECOVERY
-
PITCHER SAMPLER
SHELBY TUBE SAMPLER
STANDARD PENETRATION
-
r SAMPLER
REFER TO FIGURE A2 FOR PHYSICAI
PROPERTIES CRITERIA FOR ROCK/
I FORMATION DESCRIPTIONS. I KLEINFELDER SAN MEGO. WlFORNlA 92123 FIGURE NO. A1
30. '
'N: 4659LOGS 9555 CHEYPEME ORE. SUE 101
CONSOUDATION OF SEDIMENTARY ROCKS: usually obtained from unweathered samples. dependent on cementation. Largely
U = unconsolidated
P = poorly consolidated M = moderately cansalidated
W = well consolidated
BEDDINQ OF SEDIMENTARY ROCKS
Splitting Properly
Massive
Blocky
Slabby
flwy Shaly or platy
Papery
Thickness
Greater than 4.0 ft. 2.0 to 4.0 ft. 0.2 to 2.0 ft. 0.05 ta 0.2 ft.
0.01 to 0.5 ft.
Less than 0.01 ft.
Stratification
very thick bedded
thick-bedded thin-bedded
very thin-bedded
laminated
thinly laminated
FRACTURINQ
Intensity
Very little fractures
Occasionally fractured 1.0 to 4.0 Moderately fractured 0.5 to 1.0
Closely fractured 0.1 to 0.5
Intensely fractured 0.05 to 0.1
Crushed Less than 0.05
Size of Pieces in Feet
Greater than 4.0
HARDNESS
1. Soft - Reserved for plastic material alone
2. Low hardness - can be gauged deeply or carved easily with a knife blade
3. Moderately hard - can be readily scratched by a knife blade; scratch leaves a heavy trace of dust
and is readily visible after the powder has been blown away.
4. Hard - can be scratched with difficulty; scratch produces little powder and is often lainly visible.
5. Very hard - cannot be scratched with knife blade; leaves a metallic streak.
STRENQTH
1. Plastic or very low strength 2. Friable - crumbles easily by rubbing with fingers 3. Weak - An unfractured specimen of such material will crumble under light hammer blows. 4. Moderately strong - Specimen will withstand a few heavy hammer blows before breaking.
5. Strong - Specimen will withstand a few heavy ringing hammer blows and will yield with difficulty only
dust and small lying fragments.
6. very strang - Specimen will resist heavy ringing hammer blows and will yield with difficulty only dust and small flying fragments.
WaTHERIN - The physical and chemical disintegration and decomposition of rocks and minerals by
natural processes such as oxidation, reduction, hydration, solution, carbonation, freezing, and thawing.
0. Deep - Moderate to complete mineral decomposition; extensive disintegration: deep and thorough
discoloration; many fractures. all extensively coated or filled with oxides. carbonates, and/or clay or silt.
M. Moderate - Slight change or partial decomposition of minerals,; little disintegration, cementation-little to unaffected, moderate to occasionally intense discoloration, moderately coated fractures.
L. Little - No megascopic decompasition of minerals, little or no effect on normal cementation, slight ond
intermittent, or localized discoloration, few stains on fracture surfaces.
F. Fresh - Unaffected by weathering agents. No disintegration or discoloration. Fractures usually less numerous than joints.
PHYSICAL PROPERTIES CRITERIA FIGURE E I E E I FOR ROCK/FORMATION DESCRIPTIONS I
.--..-- -.. I I.. I- ?OJECT NO. 51-4659-01 I DATE 2/23/98 CARLSBAD. CALIFORNIA I
PROJECT NO.
51-4659-01 LOG OF BORING 1 SHEET 1 OF 1
LounoN DRILLING PROJECT WE EQUIPMENT CUE 55 (W/AUTOHAMMER)
WE OF BK E" HSA I 12'
2 COMPL~EO: 12-5-97 LOGGW BT GMB P -
PARK DRIVE SLOPE STUDY STATION 9+72
16.5' 1 WMER OAT*: m. 1 40 m. DROP 30 INCHES rnTU Ern OF HOLE
STARTED: 12-5-97 DRILLING AGENCY SCOTT'S DRILLING GROUNDWATER 9.0' ATD MTE 12-5-97 u- WATlON
SURFACE CONDlTlONS 6" AC / 6" GRANULAR BASE BACKFILLED: 12-5-97
I I
LOG OF MATERIAL
I
I 9555 CHESPSEIKE ORM. SUITE 101 SAN DIEGO. WFORNU 92123 I: 4659LOGS I 118 KLEINFELDER
~
NOTES
GURE NO,: A3
PRWECT NO. 51-4659-01
ORlWNG EQUIPMENT CME 55 (W/AUTOHAMMER)
LOG OF MATERIAL
LOG OF BORING 2 SHE0 1 OF 1
PRCJECT WE LOCATION PARK DRIVE SLOPE STUDY STATION 10+23
11.5’ OF HOLE
MEDIUM DENSE, BROWN CLAYFf SAND,
FINE TO MEDIUM-GRAINED, MOIST
VERY DENSE, MOIST, (OUTSIDE OF
NO CAVING OBSERVED
FREE WATER OBSERVED AT 3 FT. ATD
BOREHOLE BACKFILLED WITH SOIL CUTINGS AND CAPPED WITH CONCRETE DYED BLACK 14-
15-
16-
17-
18-
19-
20-
2 1-
22-
23-
!4-
5-
!6-
!7-
!8-
!9-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
7 in I
-
WELL ETA11
- ~ ~
9555 CHESAPEAKE ORM. SUITE 101
SAN DIEGO. WUFORNlA 92123 I 118 KLEINFELDER N 4659LOGS
-
NOTES
4
IGURE NO.: A4
PRDJECT NO. 51 -4659-01
DRILUNG EQUIPMEW CUE 55 (W/AUTOHAMMER)
LOG OF MATERIAL
LOG OF BORING 3 SHEET 1 OF 1
LOUnON PRDJECT WE
PARK DRIVE SLOPE STUDY STATION 1 1 +47
FINE TO MEDIUM-GRAINED, MOIST
VERY DENSE
HARD, OLIVE SlLN CLAY, DRY
NO CAVING OBSERVED
BOREHOLE BACKFILLED WITH SOIL CUnINGS AND CAPPED WITH CONCRETE DYED BLACK
W S n
ID-,
OF HOLE
DATE STARTED 12-5-97 ORILUNG AGENCY SCOTT'S DRILUNG GROUNDWATER ELEVATION
COMPLEXD 12-5-97 LOGGED BY GM~
BACKFILLED: 12-5-97 SURFACE 6~* AC CONDITIONS 1 BASE
9555 CHEYPUKE DRNE SUITE 101 SAN DIEGO. WFORNI~ 9212s N: 4658LOGS m KLEINFELDER 1
NOTES - GURE NO,: A5
‘ROJECT NO. 51 -4659-01
IRIUNG QUIPMENT :ME 55 (W/AUTOHAMMER)
LOG OF MATERIAL
LOG OF BORING 4 SHEET 1 OF 1
LOUTlON PROJECT WE
PARK DRIVE SLOPE STUDY STATION 13+ 1 0
-6” ASPHALT CONCRETE
OLIVE BROWN SILTY SAND, FINE TO
MEDIUM-GRAINED, MOIST
LIGHT BROWN CLAYEY SAND, FINE-GRAINED,
MOIST
BROWN SILTY CLAY. MOIST
15’ OF HOLE
GRAVEL LAYER
d ? 1
SANTIAGO FORMATW
LIGHT BROWN SANDSTONE, POORLY TO MODERATEL
CONSOLIDATED, MASSIVE, MODERATELY HARD, WEAK
MODERATELY WEATHERED, MOIST
HARD DRILLING
LAYER OF HARD BROWN CLAYSTONE AT BOTTOM, DRY
BORING STOPPFO AT 15 FT
DATE STARTED 12-5-97 DRIWNG AGENCY SCOTT’S DRILLING GROUNDWATER
COMPLEED: 12-5-97 LOGGED By GMB
ELEVATION
-
WELL ETA11
: 12-5-97
-.
NO CAVING-OBSERVED
NO FREE WATER OBSERVED
BOREHOLE BACKFILLED WITH SOIL CUTTINGS AND CAPPED WITH CONCRETE DYED BLACK
SURFACE CONDmONS 6” AC / 6” BASE
9555 CHESAPEAKE ORNE. SUITE 101 KLEINFELDER SAN DIEGO. WFORNW 92123
111
101
116
NOTES
GURE NO.: A6
PROJECT NO. 51-4659-01
DRIUNG EQUIPMENT CUE 55 (W/AUTOHAMMER)
- LOG OF BORING 5 SHEET 1 OF 2
LOWilON PROJECT WE
PARK DRIVE SLOPE STUDY DESlLTlNG BASIN
~
SURFACE CONDITIONS 12-5-97 I GRASS / 3" ROOT ZONE
OF HOLE
LOG OF MATERIAL
\POOT ZONE / CONCRETE
BROWN SILTY SAND, VERY FINE-GRAINED,
MOIST
STARTED 12-5-97 ORIUNG AGENCY SCOTT'S DRlLUNG
COMPLETED: 12-5-97 I LOGGm By GMB -
VERY DENSE, MOIST, (OUTSIDE OF
SAMPLER WET)
ME GROUNDWATER ELWAnON
SANTIAGO FORMU
L-
=&
--lL cmo
"3
BROWN SANDSTONE. FINE-GRAINED, MODERATELY TO WELL CONSOLIDATED, MASSIVE, WEAKLY
CEMENTED, MODERATELY HARD, WEAK, FRESH, MOIST
Y f 2 NOTES
WATER ADDED TO COOL AUGERS
5-. -
E-. -
7-.
-
9-
IO-
Il-
12-
13-
4-
5-
6-
7-
8-
9-
O-
!I-
2-
3-
4-
5-
6-
7-
3-
3-
-
-
- -
- -
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
:
MOTLING WITH RED-BROWN. YELLOW-BROWN,
4ND OLIVE
..... - .. .....
.. .. ..... .'. :. .. ..... .. . . . . .. ..... .. ...., :. :. .. -..... .. 0--
1-
4659LOGS
.IGHT OLIVE. MODERATELY CEMENTED
YlTH WELL CEMENTED FRAGMENTS
;LIGHTLY MORE CLAYEY
1)s- CHEYPUKE ORNE. SUlE 101 5AN OIEGO. WFORNU 92123 181 KLEINFELDER
I
-
WELL 1ETAIL -
~~ ~
XJRE NO.: A7
PROJECT NO. 51 -4659-01
ORlLLlNG EQUIPMENT CME 5s (W/AUTOHAMMER)
I: 4859LOGS
LOG OF BORING 5 SHEET 2 OF 2
LOCATION PROJECT NAME
PARK DRIVE SLOPE STUDY DESlLTlNG BASIN
LOG OF MATERIAL
50.5' OF HOLE
"HARD. BROWN TO LIGHT OLIVE SILTY CLAYSTONE.
MODERATELY CONSOLIDATED. MASSIVF I nw
W 2 n
-. -- __ HARDNESS, WEAK, Ll-LE WEATHERING, DRY
DATE STARTED 12-5-97 DRILLING AGENCY SCOTT'S DRILLING GROUNDWATER
COMPLETED: 12-5-97 LOGGEO 6Y GMB
ELNATION
SURFACE CWDmONS
WRY DENSE, DARK OLIVE SILTY FINE-GRAINED
SANDSTONE, MODERATELY TO WELL CONSOLIDATFD
BACKFILLED: 12-5-97
--. ~~ ~. _._.
MASSIVE, MODERATELY HARD, WEAK, FRESH, MOIST
GR~sS 1 3s* ROOT ZONE
LESS SILT, GRADATION CHANGE FROM FINE-
GRAINED TO MEDIUM-GRAINED
VERY DENSE. OLIVE-GRAY CLAYEY SANDSTONE,
MODERATELY TO WELL CONSOLIDATED, MASSIVE,
MODERATELY HARD, WEAK, FRESH, MOIST
BORING STOPPED AT 50.5 FT. ~. YO CAVING OBSERVEO '40 FREE WATER OBSERVED 30REHOLE BACKFILLED WITH SOIL CUiTNGS
0 c
U
-
WELL )ETAIL -
9555 CHEUPE4KE DRM. SUE 101 KLEINFELDER SAN DIEW. WFORNU 92123
NOTES
I FIGURE NO.: A8 -_ I
DATE PERFORMED: 12-0597
CREW: * G. Binger
CONE AREA: 10 SQ. CM
HAMMER WEIGHT: 35 Pounds
hq KLEINFELDER
9555 CHESAPEAKE DRIVE SUITE I01 SAN DIEW, CALIFORNIA 92123
LOJECT NO. 51 4659-01
IECKED BY: C&& IDATE: 01 -28-9a
JEPTH DEPTH
DYNAMIC CONE SOUNDING LOG FIGURE
A9 PARK DRIVE SLOPE / DRAINAGE STUDY
CITY OF CARLSBAD
CARLSBAD. CALIFORNIA
FT
4"
8"
1'
1 '4"
1'8'
2'
2'4"
2'8"
3'
34"
M
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
Notes
DYNAMIC CONE SOUNDING 1
SURFACE ELEVATION: 13 R.
WATER ON COMPLETION: 13 4"
LOCATION: sta. 10 + 76
BLOWS RESISTANCE CONE RESISTANCE TESTED CONSISTENCY
PER 10 CM KG/CM"Z
3 13.3
6 26.6
30 133.2
20 88.8
38 168.7
30 133.2
31 137.6
36 159.8
36 159.8
38 168.7
0 50 100 150 N' SAND SILT CLAY -__- --__ .. ................
3 VERY LOOSE
7 LOOSE
DENSE
If. ..... ..... *....*I*.. "... ..(I. ................ 25 MED. DENSE .... ...*.".*..* .t"-n.....*t.. DENSE
DENSE
DENSE ,
DENSE
DENSE
DENSE
..... t..."."........."..
..*....**...........*....O ......... f."*....,....~..lt.t. ............................... ...............................
1. A "-" in the N' column indicates an equivalent SPT N' value greater than 25.
2. The soil was classified in the field as a brown silty SAND (SM) to clayey SAND (SC).
3. Standing water level was approximately 4 inches above the existing ground surface.
4. Effective cone refusal was encountered at approximately 3'4".
DYNAMIC CONE SOUNDING 2
hq KLEI NFELDER
9555 CHESAPEAKE DRIVE SUITE 101
SAN DIEGO. CALIFORNIA 92123
DATE PERFORMED 12-0597
CREW G. Binger
CONE AREA: 10 SQ. CM
HAMMER WEIGHT 35 Pounds
DYNAMIC CONE SOUNDING LOG FIGURE
AI 0 PARK DRIVE SLOPE I DRAINAGE STUDY
)EPTH DEPTH
FT
4"
8"
1'
1 '4"
1'8"
2'
24"
28"
3'
M
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
Notes
SURFACE ELEVATION: 13 R.
WATER ON COMPLETION: 13'4"
LOCATION: Sta. 12 + 74
BLOWS RESISTANCE CONE RESISTANCE
PERlOCM KGICM"2 0 50 100 150 N'
3 13.3 3
4 17.6 *** 5
6 5 22.2
6 26.6 7
a 7 31.1
8 7 31.1
7 31.1 8
7' 31.1 8
_._~ __ -__-__ ...
.*.. .....
..*I.
*.. f.. ...... ......
532.8 .... .I..*._...._*.. ".l...If.l.... . ...* .... 120
1. A "-'' in the N' column indicates an equivalent SPT N' value greater than 25.
2. The soil was classifed in the feld as a brown silty SAND (SM) lo clayey SAND (SC).
3. Standing water level was approximately 4 inches above the existing ground surface.
4. Effective cane refusal was encountered at approximately 3'4".
TESTED CONSISTENCY
SAND SILT CLAY -.--___ ~ __
VERY LOOSE
LOOSE
LOOSE
LOOSE
LOOSE
LOOSE
LOOSE
LOOSE
VERY DENSE
CITY OF CARLSBAD
CARLSBAD, CALIFORNIA ?OJECT NO. 51-4659-01
iECKED BY: ro/ln& (DATE: 01-28-98
SIEVE ANALYSIS
100
90
80
70
2 60 H lJY lJY a 50 I- z w u
40
J
30 r
20
10
0
HYDROMETER
GRAIN SIZE (mm)
SILT GRAVEL SAND
coarse 1 fine (coarse I medium fine CLAY
a W z H
W LT
I- z W u LT W 0
_1 U +
F
E
r Symbol Boring No. Depth (ft) Description
e 3 6.5 Brown clayey SAND
Classification
sc
Park Drive Slope/Drainage Study kq KLEINFELDER Carlsbad, California
GRAIN SIZE DISTRIBUTION
'ROJECT NO. 5 1-4659-0 1
FIGUFZ
B1
GRAVEL
loC ' n'
SAND
9c
SILT coarse 1 tine lcoarse 1 medium 1. tine
80
CLAY
70
Symbol
e
60 H (0
v) a
50 + z W u
40
Boring No. Depth (ft) Description
5 20.5 Light olive SANDSTONE
a 2 30 I-
-
20
GRAIN SIZE DISTRIBUTION PROJECT NO. 51-4659-01
10
0
10 I 0. I
GRAIN SIZE (mm)
1 I
O.(
c z W u
P #j
0.001
I Park Drive Slope/Drainage Studv 1 FIGURE - kq K L E I N F E L D E R 1 Carlsbad, California I I B2
\ I I
I
100
90
80
70
$ 60
H rn rn U
c z W u
a 50
E 40
-I U + E 30
20
10
0
I Park Drive Slope/Drainage Study I FIGURE
GRRIN SIZE (rnrn)
SIEVE ANALYSIS HYDROMETER
GRAVEL SAND
-
K L E I N F E L D E R 1 Carlsbad, California
SILT coarse I fine lcoarse I medium fine
GRAIN SIZE DISTRIBUTION
PROJECT NO. 5 1-4659-0 1 -
CLAY
~ B3
Symbol
0
Boring No. Depth (ft) Description
5 30.5 Light olive SANDSTONE
LIQUID LIMIT (LL)
0
W
Boring Depth (ft) LL (%) PL (%) PI (9%) LI (-) Description
Brown silty CLAY 4 6.5 36 21 15
5 30.5 36 19 17 Light olive SANDSTONE
LL - Liquid Limit
PL - Plasticity Limit
NP - Nonplastic
kq KLEINFELDER
PI - Plasticity Index
LI - Liquidity Index
Park Drive SlopdDrainage Study FIGURE
Carlsbad, California
Unified Soil Classification
Fine Grained Soil Groups
r
PLASTICITY CHART
ROJECT NO. 51-4659-01 I B4
7
Boring No. 4
Depth - ft 11.0
T
I
1 2
1 Cohesion - ksf I 0.50 !
I
Dry Density - pcf
~ 4 5 6 7 8
118 114 I 116
NORMAL STRESS - ksf
Initial Water Content - %
Final Water Content - %
12 12 12
19 I8 17
DIRECT SHEAR TEST
PROJECT NO. 51-4659-01
B5
1 Friction Angle - deg 1 40
1 Normal Stress - ksf I 1.00 I 2.00 I 3.00 I
1 Maximum Shear - ksf I 1.40 I 2.01 1 3.06 1
[ Park Drive SlopelDrainage Study 1 FIGURE kq K L E I N F E L D E R 1 Carlsbad, California
I i 1 I I I I I I I I I I 1 I I I I I
4659SC 12-30-97 13:Ol
Park Drive (Static)
10 most critical surfaces, MINIMUM JANBU FOS = 1.726 500 ~
01 I I I I I I I I
0 100 200 300 400 500 600 700 800
X-AXIS (feet)
XSTABL File: 4659SC 12-30-97 13 : 01
..........................................
* * * XSTABL *
* Slope Stability Analysis * * using the * * Method of Slices *
* Copyright (C) 1992 a 96 *
* MOSCOW, ID 83843, U.S.A. *
* All Rights Reserved *
* *
* Interactive Software Designs, Inc. *
* *
* * * Ver. 5.200 96 6 1437 * ..........................................
Problem Description : Park Drive (Static) -
12 SURFACE boundary segments
Segment x-left y-left x-right
No. ( ft) (ft) ( ft)
1
2
3
4
5
6
7
8
9
10
11
12
.o
100.0
155.0
190.0
195.0
210.0
245.0
262.0
272.0
290.0
310.0
420.0
111.0
111.0
115.0
120.0
125.0
129.0
175.0
185.0
190.0
200.0 200.0
205.0
100.0
155.0
190.0
195.0
210.0
245.0
262.0
272.0
290.0
310.0
420.0
500.0
y-right
(ft)
111.0
115.0
120.0
125.0
129.0
175.0
185.0
190.0
200.0
200.0
205.0
209.0
Soil Unit
Below Segment
1
1
1
1
1
1
1
1
1
1
1
1
..........................
ISOTROPIC Soil Parameters ..........................
1 Soil unit(s) specified
Soil Unit Weight Cohesion Friction Pore Pressure Water
Unit Moist Sat. Intercept Angle Parameter Constant Surface
NO. (PCf) (pcf) (PSf) (des) Ru (PSf) NO.
1 120.0 135.0 500.0 39.50 .ooo .o 1
1 Water surface(s) have been specified .-
Unit weight of water = 62.40 (pcf)
-
Water Surface No. 1 specified by 5 coordinate points
..................................
PHREATIC SURFACE, - ..................................
- Point x-water y-water
No, (ft) (ft)
1 . 00 107.00
2 100.00 107.00
3 155.00 115.00
4 190.00 120.00
5 500.00 165.00
A critical failure surface searching method, using a random
technique for generating CIRCULAR surfaces has been specified.
100 trial surfaces will be generated and analyzed.
10 Surfaces initiate from each of 10 points equally spaced
along the ground surface between x = 75.0 ft
and x = 155.0 ft
Each surface terminates between x = 290.0 ft
and x = 360.0 ft
Unless further limitations were imposed, the minimum elevation
at which a surface extends is y = .o ft
10.0 ft line segments define each trial failure surface.
.....................
ANGULAR RESTRICTIONS .....................
The first segment of each failure surface will be inclined
within the angular range defined by :
.Lower angular limit := -45.0 degrees
Upper angular limit := (slope angle - 5.0) degrees
Factors of safety have been calculated by the :
* * * * * SIMPLIFIED JANBU METHOD * * * * *
The 10 most critical of all the failure surfaces examined are displayed below - the most critical first
Failure surface No. 1 specified by 19 coordinate points
Point x-surf
No. (ft)
1 155.00
2 164.92
3 174.91
4 184.90
5 194.83
6 204.64
7 214.26
8 223.63
9 232.67
10 241.35
11 249.59
12 257.35
13 264.57
14 271.21
15 277.22
16 282.56
17 287.20
18 291.10
19 293.40
** Corrected JANBU FOS =
y-surf
( ft)
115.00
113.72
113.25
113.59
114.74
116.69
119.43
122.94
127.19
132.17
137.83
144.14
151.06
158.54
166.53
174.99
183.85
193.05
200.00
1.726 ** (Fo factor = 1.069)
Failure surface No. 2 specified by 19 coordinate points
Point x-surf y-surf
No. ( ft) (ft)
1
2
3
4
5 6
7
8
9
10
11
12 13
14
15
16
17
155.00
164.96
174.96
184.94
194.84
204.60 214.17
223.49
232.49
241.13
249.36
257.12
264.36
271.05
277.15
282.61
287.41
115.00
114.07
113.91
114.53
115.93 118.08
120.99
124.62
128.97
134.01
139.69
146.00 152.89
160.33
168.25
176.63
185.40
18 291.51 194.52
19 293.48 200.00
** Corrected JANBU FOS = 1.737 ** (Fo factor = 1.067)
Failure surface No. 3 specified by 21 coordinate points
Point x-surf y-surf
NO. ( ft) ( ft)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
146.11
155.87
165.77
175.75
185.75
195.71
205.56
215.26
224.74
233.95
242.82
251.31
259.36
266.93
273.96
280.43
286.28
291.49
296.01
299.83
301.70
114.35
112.17 110.75
110.10
110.24
111.14
112.82
115.26
118.44
122.35
126.96
132.25
138.18
144.71
151.82
159.45
167.56
176.10
185.01
194.25
200.00
** Corrected JANBU FOS = 1.744 ** (Fo factor = 1.072)
Failure surface No. 4 specified by 21 coordinate points
Point x-surf y-surf
NO. ( ft) (ft)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
155.00
164.66
174.51
184.46
194.46
204.43
214.31
224.02
233.50
242.67
251.48
259.87
267.77
275.13
281.90
288.03
293.48
298.21
302.19
115.00
112.42'
110.66
109.73
109.63
110.37
111.94
114.33
117.53
121.50
126.23
131.68
137.81
144.57
151.93 159.83
168.22
177.03
186.21
20 305.38 195.68
21 306.45 200.00
** Corrected JANBU FOS = 1.751 ** (Fo factor = 1.075)
Failure surface No. 5 specified by 21 coordinate points
Point x-surf y-surf
NO. (ft) ( ft)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
146.11
155.33
164.88
174.68
184.63
194.63
204.58
214.40
223.97
233.22
242.05
250.37
258.10
265.18
271.52
277.07
281.78
285.59
288.48
290.41
291.25
114.35
110.47
107.52
105.52
104.50
104.46
105.40
107.32
110.20
114.01
118.71
124.25
130.59
137.66
145.39
153.71
162.53
171.77
181.35
191.16
200.00
** Corrected JANBU FOS = 1.768 ** (Fo factor = 1.084)
Failure surface No. 6 specified by 24 coordinate points
Point x-surf y-surf
NO. ( ft) (ft)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
137.22
146.39
155.86
165.57
175.44
185.41
195.41
205.37
215.22
224.90
234.32 243.44
252.19
260.50
268.32
275.60
282.28
288.31
293.67
113.71
109.72
106.51
104.10
102.51
101.74
101.80
102.70
104.42
106.96
110.29
114.39
119.24
124.80
131.03
137.89
145.34
153.31
161.75
20 298.30 170.62
21 302.18 179.84
22 305.27 189.34
23 307.57 199.08
24 307.71 200.00
** Corrected JANBU FOS = 1.804 ** (Fo factor = 1.081)
Failure surface No. 7 specified by 23 coordinate points
Point x-surf y-surf
No. ( ft) (ft)
10
11
12
13
14
15
16
17
18
19
20
21
22
23
137.22
146.22
155.56
165.19
175.01
184.97
194.97
204.93
214.79
224.46
233.86
242.92
251.58
259.75
267.38
274.40
280.77
286.42
291.32
295.43
298.71
301.14
302.70
113.71
109.33
105.78
103.06
101.22
100.25
100.17
100.97
102.66
105.22
108.62
112.85
117.86
123.63
130.09
137.21
144.92
153.17
161.89
171.00
180.45
190.15
200.00
** Corrected JANBU FOS = 1.806 ** (Fo factor = 1.083)
Failure surface No. 8 specified by 24 coordinate points
Point x-surf y-surf
NO. ( ft) (ft)
1
2
3
4
5
6 7
8
9
10
11
12 13
14
119.44
128.63
138.10
147.79
157.66
167.62
177.62
187.59
197.47
207.19
216.69
225.92
234.80
243.28
112.41
108.45
105.24
102.80
101.15
100.29
100.24
100.99
102.55
104.89
108.00
111.87 116.47
121.76
15
16
17
18
19
20
21
22
23
24
251.31
258.83
265.80
272.18 277.91
282.96
287.31
290.91
293.76
295.04
127.72
134.31
141.48
149.19
157.38
166.01
175.02
184.34
193.93
200.00
** Corrected JANBU FOS = 1.839 ** (Fo factor = 1.080)
Failure surface No. 9 specified by 23 coordinate points
Point x-surf
No. ( ft)
1 128.33
2 138.26
3 148.24
4 158.24
5 168.23
6 178.18
7 188.07
8 197.85
9 207.51
10 217.02
11 226.34
12 235.45
13 244.33
14 252.94
15 261.25
16 269.26
17 276.92
18 284.22
19 291.14
20 297.66
21 303.75
22 309.40
23 , 312.53
** Corrected JANBU FOS =
y-surf
(ft)
113.06
111.85
111.19
111.07
111.50
112.47
113.99
116.04
118.62
121.72
125.34
129.46
134.07
139.16
144.71
150.71
157.13
163.97
171.19
178.77
186.70
194.95
200.12
1.888 ** (Fo factor = 1.060)
Failure surface No.10 specified by 22 coordinate points
Point x-surf y-surf
No. ( ft) (ft)
137.22
147.21
157.21
167.20
177.15
187.04
196.85
206.54
216.10
113.71
113.15
113.10
113.55
114.51
115.97
117.93
120.39
123.33
10 225.50
11 234.71
12 243.71
13 252.49
14 261.00 15 269.25
16 277.19
17 284.82
18 292.11
19 299.04
20 305.61
21 311.78
22 317.17
** Corrected JANBU FOS =
126.75
130.64
134.99
139.79
145.03
150.69
156.77
163.23
170.08
177.28
184.83
192.69
200.33
1.907 ** (Fo factor = 1.055)
The following is a summary of the TEN most critical surfaces
Problem Description : Park Drive (Static)
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
Modified
JANBU FOS
1.726
1.737
1.744
1.751
1.768
1.804
1.806
1.839
1.888
1.907
Correction
Factor
1.069
1.067
1.072
1.075
1.084
1.081
1.083
1.080
1.060
1.055
Initial
x-coord
( ft)
155.00
155.00
146.11
155.00
146.11
137.22
137.22
119.44
128.33
137.22
Terminal
x-coord
(ft)
293.40
293.48
301.70
306.45
291.25
307.71
302.70
295.04
312.53
317.17
* * * END OF FILE * * *
Available
Strength
(lb)
3.0353+05
2.878E+05
3.917E+05
4.4873+05
4.286E+05
5.522E+05
5.471Ef05
4.7213+05
3.890E+05
3.8053+05
I I ! I I I I I I I I I 1 I I I I I I
4659s 12-30-97 12:40
400
500 I Park Drive (Static)
10 most critical surfaces, MINIMUM JANBU FOS = 1.746
1 n I +
Q, 300
Q)
100
01 I I I I I I I I
0 100 200 300 400 500 600 700 800
X-AXIS (feet)
XSTABL File: 46595 12-30-97 12 : 40
- ..........................................
* * * XSTABL *
* Slope Stability Analysis * * using the * *. Method of Slices *
* Copyright (C) 1992 a 96 *
* Moscow, ID 83843, U.S.A. *
* All Rights Reserved *
* *
* Interactive Software Designs, Inc. *
* *
* * * Ver. 5.200 96 1437 * ..........................................
Problem Description : Park Drive (Static)
12 SURFACE boundary segments
Segment x-left y-left x-right
No. ( ft) ( ft) ( ft)
1
2
3
4
5
6
7
8
9
10
11
12
.o
100.0
155.0
190.0
195.0
210.0
245.0
262.0
272.0
290.0
310.0
420.0
111.0
111.0
115.0
120.0
125.0
129.0
175.0
185.0
190.0
200.0
200.0
205.0
100.0
155.0
190.0
195.0
210.0
245.0
262.0
272.0
290.0
310.0
420.0
500.0
y-right
(ft)
111.0
115.0
120.0
125.0
129.0
175.0
185.0
190.0
200.0
200.0
205.0
209.0
Soil Unit Below Segment
1
1
1
1
1
1
1
1
1
1
1
1
1 Soil unit(s) specified
Soil Unit Weight Cohesion Friction Pore Pressure Water
Unit Moist Sat. Intercept Angle Parameter Constant Surface
NO. (PCf) (PCf) (PSf) (des) Ru (PSf) No.
1 120.0 135.0 500.0 39.50 .ooo .o 1
.
1 Water surface(s) have been specified
Unit weight of water = 62.40 (pcf)
Water Surface No. 1 specified by 5 coordinate points
..................................
PHREATIC SURFACE, ..................................
Point x-water y-water
No. (ft) ( ft)
1 .oo 107.00
2 100.00 107.00
3 155.00 115.00
4 190.00 120.00
5 500.00 165.00
A critical failure surface searching method, using a random
technique for generating sliding BLOCK surfaces, has been specified.
The active and passive portions of the sliding surfaces are generated according to the Rankine theory.
100 trial surfaces will be generated and analyzed.
2 boxes specified for generation of central block base
Length of line segments for active and passive portions of
sliding block is 10.0 ft
Box x-left y-left x-right y-right Width
no. ( ft) ( ft) ( ft) (ft) ( ft)
1 150.0 85.0 220.0 90.0 20.0
2 275.0 160.0 360.0 160.0 40.0
Factors of safety have been calculated by the :
* * * * * SIMPLIFIED JANBU METHOD * * * * *
The 10 most critical of all the failure surfaces examined are displayed below - the most critical first
Failure surface No. 1 specified by 11 coordinate points
Point x-surf y-surf
No. ( ft) ( ft)
1
2
3
4
5
6
7
8
9
10
11
178.58 182.14
191.19
200.23
209.28
218.32
286.79
291.06
295.32
299.59
302.51
118.37
116.68
112.42
108.15
103.89
99.62
166.68
175.72
184.77
193.81
200.00
** Corrected JANBU FOS = 1.746 ** (Fo factor = 1.082)
Failure surface No. 2 specified by 14 coordinate points
Point x-surf y-surf
No. ( ft) ( ft)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
169.78
170.84
179.89
188.93
197.98
207.02
216.06
277.60
281.86
286.13
290.39
294.66
298.92
300.78
117.11
116.61
112.34
108.08
103.81
99.54
95.28
150.83
159.88
168.92
177.97
187.01
196.05
200.00
(Fo factor = 1.085) ** Corrected JANBU FOS = 1.773 **
Failure surface NO. 3 specified by 12 coordinate points
Point x-surf y-surf
No. (ft) ( ft)
1
2
3
4
5
6
7
8
'9
10
11
12
166.53
169.93
178.97
188.02
197.06
206.11
280.93
285.20
289.46
293.73
297.99
301.67
116.65
115.04
110.78
106.51
102.25
97.98
156.03
165.07
174.12
183.16
192.21
200.00
+* Corrected JANBU FOS = 1.788 ** (Fo factor = 1.078)
Failure surface No. 4 specified by 14 coordinate points
Point x-surf y-surf
NO. (ft) (ft)
1
2
3
4
5
6
7
8 9
10
11
12
13
14
170.34
178.23
187.28
196.32
205.36
214.41
276.06
280.32 284.59
288.85
293.12 297.39
301.65
304.25
117.19
113.47
109.21
104.94
100.68
96.41
140.22
149.26
158.31
167.35
176.40
185.44
194.49
200.00
** Corrected JANBU FOS = 1.789 ** (Fo factor = 1.083)
Failure surface No. 5 specified by 15 coordinate points
Point NO.
1
2
3
4
5
6
7
.8
9
10
11
12
13
14
15
x-surf
( ft)
171.68
172.95
181.99
191.04
200.08
209.13
218.17
280.00
284.26
288.53
292.79
297.06
301.33
305.59
307.39
y-surf
(ft)
117.38
116.79
112.52
108.25
103.99
99.72
95.46
141.92
150.97
160.01
169.06
178.10
187.15
196.19
200.00
** Corrected JANBU FOS = 1.804 ** (Fo factor = 1.084)
Failure surface No. 6 specified by 14 coordinate points
Point x-surf y-surf
NO. (ft) (ft)
1 161.44 115.92
2 170.20 111.79
3 179.25 107.52
4 188.29 103.26
5 197.34 98.99
6
7
8
9
10
11
12
13
14
206.38
215.43
275.56
279.83
284.09 288.36
292.62
296.89
299.34
94.72
90.46
149.58
158.62
167.67
176.71
185.76
194.80
200.00
** Corrected JANBU FOS = 1.811 ** (Fo factor = 1.088)
Failure surface No. 7 specified by 12 coordinate points
Point x-surf y-surf
No. ( ft) ( ft)
1
2
3
4
5
6
7
8
9
10
11
12
164.77
165.26
174.30
183.34
192.39
201.43
210.48
219.52
302.10
306.37
310.63
312.94
116.40
116.16
111.90
107.63
103.37
99.10
94.84
90.57
177.14
186.19
195.23
200.13
** Corrected JANBU FOS = 1.821 ** (Fo factor = 1.086)
Failure surface No. 8 specified by 11 coordinate points
Point x-surf
No. (ft)
1 162.83
2 168.24
3 177.29
4 186.33
5 195.38
6 204.42
7 213.47
8 284.83
9 289.09
10 293.36
11 295.83
** Corrected JANBU FOS =
y-surf
( ft)
116.12
113.57
109.30
105.04
100.71
96.51
92.24
176.68
185.72
194.77
200.00
1.832 ** (Fo factor = 1.087)
Failure surface No. 9 specified by 11 coordinate points
Point x-surf y-surf
NO. ( ft) ( ft)
1 167.92 116.85
2
3
4
5
6
7
8
9 10
11
172.55
181.59
190.64
199.68
208.73
217.77
314.61
318.88
323.14
326.05
114.66
110.40
106.13
101.86
97.60
93.33
176.47
185.52
194.56
200.73
** Corrected JANBU FOS = 1.837 ** (Fo factor = 1.081)
Failure surface No.10 specified by 16 coordinate points
Point x-surf
NO. (ft)
1 152.54
2 153.85
3 162.90
4 171.94
5 180.99
6 190.03
8 208.12
9 277.87
10 282.13
11 286.40
12 290.66
13 294.93
14 299.20
15 303.46
16 304.61
7 199- 08
** Corrected JANBU FOS =
y-surf
(ft)
114.82
114.20
109.94
105.67
101.41
97.14
92.87
88.61
143.29
152.34
161.38
170.43
179.47
188.52
197.56
200.00
1.847 ** (Fo factor = 1.086)
The following is a summary of the TEN most critical surfaces
Problem Description : Park Drive (Static)
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
Modified Correction Initial JANBU FOS Factor x-coord
( ft)
1.746
1.773
1.788
1.789
1.804
1.811
1.821
1.832
1.837
1.847
1.082
1.085
1.078
1.083
1.084
1.088
1.086
1.087
1.081
1.086
178.58
169.78
166.53
170.34
171.68
161.44
164.77
162.83
167.92
152.54
Terminal
x-coord
(ft)
302.51
300.78
301.67
304.25
307.39
299.34
312.94
295.83
326.05
304.61
Available
Strength
(lb)
4.216E+05
4.647E+05
4.273E+05
4.957E+05
5.272E+05
4.968E+05
5.490E+05
4.205E+05
5.924E+05
5.527E+05
* * * END OF FILE * * *
I I I I I I I I I I I I I I I I I 1 I
4659D 12-30-97 12:42
500
400
h
t a, 300 a, + v
m
X
Q 200 I >
-
100
0
Park Drive (Dynamic)
10 most critical surfaces, MINIMUM JANBU FOS = 1.386
I I I I I I I I
0 100 200 300 400 500 600 700 800
X-AXIS (feet)
XSTABL File: 4659D 12-30-97 12 : 42
..........................................
* * * XSTABL *
* Slope Stability Analysis * * using the * * Method of Slices *
* Copyright (C) 1992 a 96 *
* Moscow, ID 83843, U.S.A. *
* All Rights Reserved *
* *
* Interactive Software Designs, Inc. *
* *
* * * Ver. 5.200 96 a 1437 * ..........................................
Problem Description : Park Drive (Dynamic)
12 SURFACE boundary segments
Segment x-left y-left x-right
No. ( ft) ( ft) ( ft)
1
2
3
4
5
6
7
8
9
10
11
12
.o 111.0
100.0 111.0
155.0 115.0
190.0 120.0
195.0 125.0
210.0 129.0
245.0 175.0
262.0 185.0
272.0 190.0
290.0 200.0
310.0 200.0
420.0 205.0
100.0
155.0
190.0
195.0
210.0
245.0
262.0
272.0
290.0
310.0
420.0
500.0
y-right
( ft)
111.0
115.0
120.0
125.0
129.0
175.0
185.0
190.0
200.0
200.0
205.0
209.0
Soil Unit
Below Segment
1
1
1
1
1
1
1
1
1
1
1
1
..........................
ISOTROPIC Soil Parameters ..........................
1 Soil unit(s) specified
Soil Unit Weight Cohesion Friction Pore Pressure Water
Unit Moist Sat. Intercept Angle Parameter Constant Surface
NO. (PCf) (PCf) (PSf) (des) RU (PSf) NO.
1 120.0 135.0 500.0 39.50 .ooo .o 1
1 Water surface(s) have been specified
Unit weight of water 5 62.40 (pcf)
Water Surface No. 1 specified by 5 coordinate points
..................................
.................................. PHREATIC SURFACE,
Point x-water y-water
NO. (ft) ( ft)
1 * 00 107.00
2 100.00 107.00
3 155.00 115.00
4 190.00 120.00
5 500.00 165.00
A hotizontal earthquake loading coefficient of .150 has been assigned
A vertical earthquake loading coefficient of .OOO has been assigned
A critical failure surface searching method, using a random technique for generating sliding BLOCK surfaces, has been specified.
The active and passive portions of the sliding surfaces are generated according to the Rankine theory.
100 trial surfaces will be generated and analyzed.
2 boxes specified for generation of central block base
Length of line segments for active and passive portions of sliding block is 10.0 ft
Box x-left y-left x-right y-right Width
no. (ft) ( ft) ( ft) ( ft) (ft)
1 150.0 85.0 220.0 90.0 20.0
2 275.0 160.0 360.0 160.0 40.0
Factors of safety have been calculated by the :
* * * * * SIMPLIFIED JANBU METHOD * * * * *
The 10 most critical of all the failure surfaces examined are displayed below - the most critical first
Failure surface No. 1 specified by 11 coordinate points
Point x-surf y-surf
NO * (ft) ( ft)
1
2
3
4
5
6
7
8
9
10
11
178.58
182.14
191.19
200.23
209.28
218.32
286.79
291.06
295.32
299.59
302.51
118.37
116.68
112.42
108.15
103.89
99.62
166.68
175.72
184.77
193.81
200.00
** Corrected JANBU FOS = 1.386 ** (Fo factor = 1.082)
Failure surface No. 2 specified by 12 coordinate points
Point x-surf y-surf
No. (ft) (ft)
1
2
3
4
5
6
7
8
9
10
11
12
166.53
169.93
178.97
188.02
197.06
206.11
280.93
285.20
289.46
293.73
297.99
301.67
116.65
115.04
110.78
106.51
102.25
97.98
156.03
165.07
174.12
183.16
192.21
200.00
** Corrected JANBU FOS = 1.394 ** (Fo factor = 1.078)
Failure surface No. 3 specified by 14 coordinate points
Point x-surf y-surf
NO. ( ft) (ft)
1 170.34 117.19
2 178.23 113.47
3 187.28 109.21
4 196.32 104.94
5 205.36 100.68
6 214.41 96.41
7 276.06 140.22
8 280.32 149.26
9 284.59 158.31
10 288.85 167.35
11 293.12 176.40
12 297.39 185.44
13 301.65 194.49
14 304.25 200.00
** Corrected JANBU FOS = 1.396 ** (Fo factor = 1.083)
Failure surface No. 4 specified by 14 coordinate points
Point x-surf y-surf
No, (ft) (ft)
10
11
12
13
14
169.78
170.84
179.89
188.93
197.98
207.02
216.06
277.60
281.86
286.13
290.39
294.66
298.92
300.78
117.11
116.61
112.34
108.08
103.81
99.54
95.28
150.83
159.88
168.92
177.97
187.01
196.05
200.00
** Corrected JANBU FOS = 1.400 ** (Fo factor = 1.085)
Failure surface No. 5 specified by 15 coordinate points
Point x-surf y-surf
NO. ( ft) (ft)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
171.68
172.95
181.99
191.04
200.08
209.13
218.17
280.00
284.26
288.53
292.79
297.06
301.33
305.59
307.39
117.38
116.79
112.52
108.25
103.99
99.72
95.46
141.92
150.97
160.01
169.06
178.10
187.15
196.19
200.00
** Corrected JANBU FOS = 1.409 ** (Fo factor = 1.084)
Failure surface No. 6 specified by 11 coordinate points
Point x-surf y-surf
No. (ft) (ft)
1
2
3
4
5
6
7
8
9
10
11
167.92
172.55
181.59
190.64
199.68
208.73
217.77
314.61
318.88
323.14
326.05
116.85
114.66
110.40
106.13
101.86
97.60
93.33
176.47
185.52
194.56
200.73
** Corrected JANBU FOS = 1.417 ** (Fo factor = 1.081)
Failure surface No. 7 specified by 12 coordinate points
Point x-surf
NO. ( ft)
1 174.76
2 180.65
3 189.70
4 198.74
5 207.79
6 216.83
7 303.87
8 308.13
9 312.40
10 316.67
11 320.93
12 323.42
** Corrected JANBU FOS =
y-surf
(ft)
117.82
115.04
110.78
106.51
102.24
97.98
159.16
168.20
177.25
186.29
195.34
200.61
1.423 ** (Fo factor = 1.077)
Failure surface No. 8 specified by 14 coordinate points
Point x-surf
NO. ( ft)
1 161.44
2 170.20
3 179.25
4 188.29
5 197.34
6 206.38
7 215.43
8 275.56
9 279.83
10 284.09
11 288.36
i2 292.62
13 296.89
14 299.34
** Corrected JANBU FOS =
y-surf
( ft)
115.92
111.79
107.52
103.26
98.99
94.72
90.46
149.58
158.62
167.67
176.71
185.76
194.80
200.00
1.430 ** (Fo factor = 1.088)
Failure surface No. 9 specified by 12 coordinate points
Point x-surf y-surf
NO. (ft) ( ft)
1
2
3
4
5
6
7
8
9
10
11
12
164.77
165.26
174.30
183.34
192.39
201.43
210.48
219.52
302.10 306.37
310.63
312.94
116.40
116.16
111.90
107.63
103.37
99.10
94.84
90.57
177.14 186.19
195.23
200.13
** Corrected JANBU FOS = 1.431 ** (Fo factor = 1.086)
Failure surface No.10 specified by 16 coordinate points
Point x-surf y-surf
NO. ( ft) ( ft)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
152.54
153.85
162.90
171.94
180.99
190.03
199.08
208.12
277.87
282.13
286.40
290.66
294.93
299.20
303.46
304.61
114.82
114.20
109.94
105.67
101.41
97.14
92.87
88.61
143.29
152.34
161.38
170.43
179.47
188.52
197.56
200.00
** Corrected JANBU FOS = 1.432 ** (Fo factor = 1.086)
The following is a summary of the TEN most critical surfaces
Problem Description : Park Drive (Dynamic)
Modified correction Initial Terminal Available
JANBU FOS Factor x-coord x-coord Strength
(ft) (ft) (1b)
1. 1.386 1.082 178.58 302.51 4.0313+05
2. 1.394 1.078 166.53 301.67 4.0643+05
3. 1.396 1.083 170.34 304.25 4.724E+05
4. 1.400 1.085 169.78 300.78 4.447E+05
5. 1.409 1.084 171.68 307.39 5.0353+05
6. 1.417 1.081 167.92 326.05 5.661Ec05
7. 1.423 1.077 174.76 323.42 5.4943+05
8. 1.430 1.088 161.44 299.34 4.7723+05
9. 1.431 1.086 164.77 312.94 5.2773+05
10. 1.432 1.086 152.54 304.61 5.2893+05
* * * END OF FILE * * *
I I I I I I I I I I I I I I I I i I I
4659DC 12-30-97 13:OO
400
500 I i
A +
Q, +
W Q,300 i
Park Drive (Dynamic)
10 most critical surfaces, MINIMUM JANBU FOS = 1.322 .
Q 200 I > - w 1
100
- w 1
/--
_/--
01 I I I I I I I
0 100 200 300 400 500 600 700
X-AXIS (feet)
I
800
XSTABL File: 4659DC 12-30-97 13 : 00
- ..........................................
* * * XSTABL *
* Slope Stability Analysis * * using the * * Method of Slices *
* Copyright (C) 1992 a 96 * * Interactive Software Designs, Inc. * * MOSCOW, ID 83843, U.S.A. *
* All Rights Reserved *
* *
* *
* * * Ver. 5.200 96 6 1437 * ..........................................
Problem Description : Park Drive (Dynamic)
12 SURFACE boundary segments
Segment x-left y-left x-right
No. (ft) (ft) (ft)
1
2
3
4
5
6 7
8
9
10
11
12
.o 111.0
100.0 111.0
155.0 115.0
190.0 120.0
195.0 125.0
210.0 129.0
245.0 175.0
262.0 185.0
272.0 190.0
290.0 200.0
310.0 200.0
420.0 205.0
100.0
155.0
190.0
195.0
210.0
245.0
262.0
272.0
290.0
310.0
420.0
500.0
y-right
(ft)
111.0
115.0
120.0
125.0
129.0
175.0
185.0
190.0
200.0
200.0
205.0
209.0
Soil Unit Below Segment
1
1
1
1
1
1
1
1
1
1
1
1
1 Soil unit(s) specified
Soil Unit Weight Cohesion Friction Pore Pressure Water Unit Moist Sat. Intercept Angle Parameter Constant Surface
No. (PCf) (PCf) (PSf) ( deg ) Ru (PSf) NO.
1 120.0 135.0 500.0 39.50 .ooo .o 1
1 Water surface(s) have been specified
Unit weight of water 3 62.40 (pcf)
Water Surface No. 1 specified by 5 coordinate points
..................................
PHREATIC SURFACE, ..................................
Point x-water y-water
No. (ft) ( ft)
1 .oo 107.00
2 100.00 107.00
3 155.00 115.00
4 190.00 120.00 5 500.00 165.00
A horizontal earthquake loading coefficient of .150 has been assigned
A vertical earthquake loading coefficient of .OOO has been assigned
A critical failure surface searching method, using a random technique for generating CIRCULAR surfaces has been specified.
100 trial surfaces will be generated and analyzed.
10 Surfaces initiate from each of 10 points equally spaced along the ground surface between x = 75.0 ft
and x = 155.0 ft
Each surface terminates between x = 290.0 ft and x = 360.0 ft
Unless further limitations were imposed, the minimum elevation at which a surface extends is y = .o ft
10.0 ft line segments define each trial failure surface.
The first segment of each failure surface will be inclined
within the angular range defined by :
Lower angular limit := -45.0 degrees
Upper angular limit := (slope angle - 5.0) degrees
Factors of safety have been calculated by the :
* * * * * SIMPLIFIED JANBU METHOD * * * * *
The 10 most critical of all the failure surfaces examined
are displayed below - the most critical first
Failure surface No. 1 specified by 21 coordinate points
Point x-surf
No. ( ft)
1 155.00
2 164.66
3 174.51
4 184.46
5 194.46
6 204.43
7 214.31
8 224.02
9 233.50
10 242.67
11 251.48
12 259.87
13 267.77
14 275.13
15 281.90
16 288.03
17 293.48
18 298.21
19 302.19
20 305.38
21 306.45
** Corrected JANBU FOS =
y-surf
(ft)
115.00
112.42
110.66
109.73
109.63
110.37
111.94
114.33
117.53
121.50
126.23
131.68
137.81
144.57
151.93
159.83
168.22
177.03
186.21
195.68
200.00
1.322 ** (Fo factor = 1.075)
Failure surface No. 2 specified by 21 coordinate points
Point NO.
1
2
3
4
5
6
7
8
x-surf
( ft)
146.11
155.87
165.77
175.75
185.75
195.71
205.56
215.26
y-surf
(ft)
114.35
112.17
110.75
110.10
110.24
111.14
112.82
115.26
9 224.74
10 233.95
11 242.82
12 251.31
13 259.36 14 266.93
15 273.96
16 280.43 17 286.28
18 291.49
19 296.01
20 299.83
21 301.70
** Corrected JANBU FOS =
118.44
122.35
126.96
132.25
138.18 144.71
151.82
159.45 167.56
176.10
185.01
194.25
200.00
1.327 ** (Fo factor = 1.072)
Failure surface No. 3 specified by 19 coordinate points
Point x-surf
no. ( ft)
1 155.00
2 164.92
3 174.91
4 184.90
5 194.83
6 204.64
7 214.26
8 223.63
9 232.67
10 241.35
11 249.59
12 257.35
13 264.57
14 271.21
15 277.22
16 282.56
17 287.20
18 291.10
19 293.40
** Corrected JANBU FOS =
y-surf
(ft)
115.00
113.72
113.25
113.59
114.74
116.69
119.43
122.94
127.19
132.17
137.83
144.14
151.06
158.54
166.53
174.99
183.85
193.05
200.00
1.333 ** (Fo factor = 1.069)
Failure surface No. 4 specified by 19 coordinate points
Point x-surf y-surf
No. (ft) ( ft)
1
2
3
4
5
6
7
8
9
10
155.00
164.96
174.96
184.94
194.84
204.60
214.17
223.49
232.49
241.13
115.00
114.07
113.91
114.53
115.93
118.08
120.99
124.62
128.97
134.01
11
12
13
14
15
16
17
19 18.
249.36
257.12
264.36
271.05
277.15
282.61
287.41
291.51
293.48
139.69
146.00
152.89
160.33
168.25
176.63
185.40
194.52
200.00
** Corrected JANBU FOS = 1.346 ** (Fo factor = 1.067)
Failure surface No. 5 specified by 24 coordinate points
Point x-surf
No. (ft)
1 137.22
2 146.39
3 155.86
4 165.57
5 175.44
6 185.41
7 195.41
8 ,205.37
9 215.22
10 224.90
11 234.32
12 243.44
13 252.19
14 260.50
15 268.32
16 275.60
17 282.28
18 288.31
19 293.67
20 298.30
21 302.18
22 305.27
23 307.57
24 307.71
** Corrected JANBU FOS =
y-surf
( ft)
113.71
109.72
106.51
104.10
102.51
101.74
101.80
102.70
104.42
106.96
110.29
114.39
119.24 124.80
131.03
137.89
145.34
153.31
161.75
170.62
179.84
189.34
199.08
200.00
1.346 ** (FO factor = 1.081)
Failure surface No. 6 specified by 23 coordinate points
Point x-surf y-surf
No. (ft) (ft)
137.22
146.22
155.56
165.19
175.01
184.97
194.97
204.93
214.79
113.71
109.33
105.78
103.06
101.22
100.25
100.17
100.97
102.66
10
11
12
13
14
15
16
17
18
19
20
21
22
23
224.46
233.86
242.92
251.58
259.75
267.38
274.40
280.77
286.42
291.32
295.43
298.71
301.14
302.70
105.22
108.62
112.85
117.86
123.63
130.09
137.21
144.92
153.17
161.89
171.00
180.45
190.15
200.00
** Corrected JANBU FOS = 1.351 ** (Fo factor = 1.083)
Failure surface No. 7 specified by 24 coordinate points
Point x-surf y-surf
NO. (ft) (ft)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
119.44
128.63
138.10
147.79
157.66
167.62
177.62
187.59
197.47
207.19
216.69
225.92
234.80
243.28
251.31
258.83
265.80
272.18
277.91
282.96
287.31
290.91
293.76
295.04
112.41
108.45
105.24
102.80
101.15
100.29
100.24
100.99
102.55
104.89
108.00
111.87
116.47
121.76
127.72
134.31
141.48
149.19
157.38
166.01
175.02
184.34
193.93
200.00
** Corrected JANBU FOS = 1.381 ** (Fo factor = 1.080)
Failure surface No. 8 specified by 27 coordinate points
Point x-surf y-surf
NO. (ft) ( ft)
1 128.33 113.06
2 137.50 109.07
3 146.92 105.71
4 156.55 102.99
5
6
7
8
9
10
11
12
13
14
15
16
17
18 19
20
21 22
23
24
25
26
27
166.33
176.23
186.21
196.21
206.19 216.10
225.90
235.55 244.99
254.19
263.11 271.69
279.91
287.72
295.10
302.00
308.39
314.25
319.55
324.25
328.36
331.83
332.20
100.94
99.55
98.83
98.79
99.43 100.74
102.73
105.37 108.65
112.57
117.11 122.23
127.93
134.17
140.92
148.16
155.85
163.96
172.44
181.26
190.38
199.76
201.01
** Corrected JANBU FOS = 1.409 ** (Fo factor = 1.077)
Failure surface No. 9 specified by 24 coordinate points
Point x-surf
NO. (ft)
1 155.00
2 164.28
3 173.83
4 183.58
5 193.48
6 203.45
7 213.45
8 223.41
9 233.27
10 242.96
11 252.43
12 261.62
13 270.47
14 278.93
15 286.94
16 294.45
17 301.43
18 307.82
19 313.58
20 318.69
21 323.11
22 326.80
23 329.76
24 330.34
** Corrected JANBU FOS =
y-surf
(ft)
115.00
111.28
108.31
106.09
104.65
103.98
104.11
105.02
106.71
109.17
112.38
116.33
120.98
126.32
132.30
138.90
146.07
153.76
161.93
170.53
179.50
188.79
198.34
200.92
1.417 ** (Fo factor = 1.079)
Failure surface No.10 specified by 24 coordinate points
Point x-surf
No. ( ft)
1 155.00
2 163.75
3 172.91
4 182.39
5 192.13
6 202.03
7 212.02
8 222.01
9 231.92
10 241.66
11 251.14
12 260.30
13 269.05
14 277.32
15 285.03
16 292.13
17 298.56
18 304.25
19 309.16
20 313.26
21 316.49
22 318.85 23 320.31
24 320.50
** Corrected JANBU FOS =
y-surf
( ft)
115.00
110.16
106.14
102.98
100.70
99.32
98.86
99.32
100.70
102.97
106.14
110.16
115.00
120.62
126.99
134.03
141.69
149.91
158.62
167.75
177.21
186.93 196.82
200.48
1.429 ** (Fo factor = 1.085)
The following is a summary of the TEN most critical surfaces
Problem Description : Park Drive (Dynamic)
Modified correction Initial Terminal Available
JANBU FOS Factor x-coord x-coord Strength
(ft) (ft) (lb)
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
1.322
1.327
1.333
1.346
1.346
1.351
1.381
1.409
1.417
1.429
1.075
1.072
1.069
1.067
1.081
1.083
1.080
1.077
1.079
1.085
155.00
146.11
155.00
155.00
137.22
137.22
119.44
128.33
155.00
155.00
306.45
301.70
293.40
293.48
307.71
302.70
295.04
332.20
330.34
320.50
4.1753+05
3.6453+05
2.8233+05
2.6793+05
5.161E+05
5.1213+05
4.4233+05
6.9563+05
6.4593+05
6.701E+05
* * * END OF FILE * * *
THE GEOWEB~ SLOPE PROTECTION SYSTEM
TECHNICAL OVERVIEW
lntroducti on
The Geoweb Cellular Confinement System offers a broad range of su#ace protection treatments lor slopes that are subjected lo erosive forces. The inherent flexibilii of the system, combined with a variety
of simple, yet positive anchoring techniques. permits the application of both vegetated and hard surfacing materials to steep slopes.
By ensuring the long-term stability and effectiveness of slope cover materials, the integrity of underfying
soils can be guaranleed and appropriate aesthetic standards maintained. The Geoweb system can also provide means of fully veqetating slope surfaces that could not otherwise support plant life.
Outlined are common causes of slope surface instability, and recommended design procedures and construction details which relate lo specific structures and conditions.
Examples of Geoweb Slope Surlece Stabiluation
Embankment slopes Cut slopes Shoreline revetments
Containment dikes and levees Dam faces and spillways Landfill caps
Abutment protection Ea* covered structures
L
Surface lnstablllty - Identifying Problems and Deflnlng Caw8 I
General Surface Eroslan Probkms
Rainfall impact and run-off
I
Detachment and ttansportation of soil particles downslope in suspension as run-off flows concentrate. Rills and gulri form and expand as soil loss progresses. Raintan intensity. soil erodibility, slope steepness, and
vegetative mer condition wntrol the rate and extent of such erosion.
~
localized Sudace Instabiltty Problems
Ground-water seepage Drainage of ground-water from the slope can cream high localized seepage pressures that resun in soil piping as panicles are washed out from the slope cover kyer. This action undermines adjacent material
leading to progressive begradation oi the slope surface.
Cyclic freezing and thawing of slope soils can trap lenses of free water or
Soil slurry between frozen cover materials and subsoils producing zones
of low shear resistance. This condition can result in the down-slope
movement of sections of the cover material that would otherwise be
stable.
Hydrodynamic impingement, combined with high velocity up-rush and back-flow, imposes high stress on the slope cover materials. Cyclic
hydraulic-uplift-forces funher destabilize cover materials and allow
displacement and loss of both amoring and underlying soils.
Ffezethaw conditions
Wave imprstandrun-up
/-action
27-SEP-97
Shoreline and dam face revetments can be subjected to severe abrasion
and upli stresses due to movement of adjacent ice fields. Wind- geneated impact and the flotation of adhered ice formations during
water level fluctuations can be particularly damaging.
PAGE 1 OF14
THE GEOWEB@ SLOPE PROTECTION SYSTEM
TECHNICAL OVERVIEW
--
-_.. General Slope Cover Instability Problems
Skp slope cover Addilion of vegetated topsoil or hard armoring to @xisting or reinforced steep slopes requires special slope cover anchorage methods.
Examples include (1) slopes that are steeper than the natural angle of repose of the cover material and (2) slope inclinations that exceed the
interface friction angle of the cover material and subsoil.
Geomembrane and geotexlile slope covers can render a protective soil cover unstable due to the rektively low coefficient-of-friction of many geosynthetics. Stability can be furlher reduced if the cover is saturated,
subjected to warn impact and uplifl forces. or surcharged wilh additional
fill or snow loads.
The stability of a slope cover layer may depend on the end-bearing support at the toe of slope. Scour in the lower sections of the slope can Uesfabilize the entire protective cover. Similarly, crest anchorage in place of toe support can cause protection of the upper part of a long
submerged slope.
Inadequate cmt anchorage Integrated. flexible slope protection can be secured with crest anchors in place of conventional toe support. This is particulatiy advantageous
when protecting only the upper part of a long submerged slope. Inadeauate crest anchoraoe can result in oeneral slooe cover instabilitv.
Geomembnnt proiection
Absence or loss of toe
support
Geoweb Slope Stabilization Systems - 77te Key Components I
Key components of the Geoweb System are indicated in Figure 1. A discussion of the interdependence
of these components and sub-components, where appropriate. follows:
FRONT ELEVATION TYPICAL CROSS-SECTION
Figure 1 Key Components of the Geoweb System
CoPrRffinr 1997 - PRESTO PRODUCTS COMPANY 27-SEP-97
c
THE GEOWEB~ SLOPE PROTECTION SYSTEM
TECHNICAL OVERVIEW
A variety of standard tendons (see Table 1).
covering a range of tensile strengths, is availabte to meet specific anchorage requirements. Spacing
and quantity of individual tendons within each Geoweb section is determined through static
analysis methe available from Presto.
I
STANDARD CELL LARGE CELL
244 mm x 203 mm (9.6 in x8 in) 488 mm x 406 mm (19.2 in x 16 in)
Tab& 1 Typid Tendons
Reference Minimum Namr Break Strength
TPG71 7.12 kN (1600 Ibf)
TP-13 1.33 kN (300 b9
TP-20 2.00 kN (450 IbD
TP-26 267 kN (600 Ibn
TP-32 3.22 kN (725 Ibt)
TP-40 4.00 kN (900 Ibf)
TP-66 6.67 LN (1500 lbf)
CELL DEPTH mm (in) CELL DEPTH mm (in)
C~PYRIGM 1997- PRE~ PROOUCTS COMPANY PAGE 3 OF14
THE GEOWEB~ SLOPE PROTECTION SYSTEM
TECHNICAL OVERVIEW
-
._
Ground anchors .. - I,
Geoweb slope protection Systems can be secured with an array of surface anchors or a crest anchorage system lo suit design requirements and subgrade conditions. The most commonly used types of anchor
are illustrated in Figure 3. Anchor details are determined through static analysis methods availabk from Presto.
-
.-
ATRA Clip SURFACE ANCHORAGE HELICAL CREST ANCHORAGE
DUCKBILL SURFACE ANCHORAGE DEADMAN CREST ANCHORAGE
Figure 3 Typical Geoweb Anchorage Schemes -
,.,, . - 1 Non-wwsri~~~u~ . .. ..,,. ,,.
Installation of a suitable geotextile below worlc. The geotextile underlayer can perform a number of important functions that include:
Geoweb confinement system is typical of slope pmtection
-
Surface treaimmts
Specific solutions to given problems may also require a range of surface treatment materials including: -
Concrete grouts
In-plane drainage of groundwater seepage from the slope Subgrade.
Confinement and filtration of subgrade soil particles. Reinforcement of root-mass with vogetawd infik.
Mechanical protaction of underlying geomambranes.
Tensile reinforcement of stope protection system. -
-
Spray applied polymeric and natural binders
Erosion blankets of all types -
PAGC 4 OF 14 COWRIGUT 1997 * PRESTO PROOKTS COMPANY 27-SEP.97
THE GEOWEB@ SLOPE PROTECTION SYSTEM
TECHNICAL OVERVIEW
-
Geoweb Slope Stabilkttlon Systems - Design Considerations
Analysis of Slope Cover Stability
Figure 4 Stability Analysis of the Ga0w.b Slope Protection System
As slope inclination increases, the down-slope component of the covets selt-weight exceeds the available frictional resistance, thereby necessitating additional anchorage. The integral polymeric
tendons of the.Geoweb system provide an effective means of supplying the required restraint.
Surface anchor pins within the Geoweb cell (see Figure 3) and distributed along each tendon. are tne most common fom of slope cover anchorage. Analysis involves determination of the maximum contributory area of slope cover that can be supported by an individual anchor pin.
Crest anchorage of an entire slope cover can be incorporated when installation of surface anchors is
impractical or when perforation of the underlying geosynthetic layers is unacceptable. A number of crea
anchorage schemes. including deadman anchors and embedment of the tendoned Geoweb system at the
crest of slope. can be emDloved. See Foure 3 and Fiaure 4.
~
Concentnted Sum Flow
Geoweb protected slopes that are subjected lo concentrated surface now require evaluation of maximum potential flow velocities, depths of flow and hydraulic shear stresses. The limiting hydraulic shear resistance of the specified Geoweb infill materiak and the Iota1 tractive force applied to the cover, as a whole, must also be determined. Additional system anchorage may be required in some situations.
17-0CT-97 CWYRffiWT 1997- PRESTO PaOOUCTS COMPANY PAGE5 OF14
THE GEOWEB* SLOPE PROTECTION SYSTEM
- TECHNICAL OVERVIEW
.---.-. (oeoweb*th Vegetated Topsoil infill 1
General ,
I
Weu-established vegetation is recognized as an etiective and anratme form of proteaion for slopes that
are exposed to mild or moderate surface erosion. However, the overall effectiveness of vegetated covers can be compromised if persistent or concentrated surface Nn-Off occurs. Such flows can progressively
remove soil pafWes from the mot zone, creating nlk and gulYies that ultimatety destroy the protectiin.
Benefiis of Cellular Conflnement
The Geoweb cell walls, which contain the topsoil infill, form a series of dreck-dams extending throughout the protected slope. Normal rill development. produced when concentrated llow cuts into
the soil. is prevented since flow is continuously redirected to the surlaca. This mechanism also
retards flow velocity and hence the erosive force of ru-off.
A predetermined depth of topsoil and the developing vegetative mot mass is contained and protected wiihin the individual cells. Roo& readily penetrate through the non-woven geotextils underlayer into
the subsoil, thereby creating an integrated. blanket reinforcement throughout the slope surface.
In arid regions, it has been observed that Geowtb cells can enhance the development of indigenous
vewtation by retaining a higher proportion of available moisture in the near-surface soil zone.
Design Guitblines .I General
Parlial emptying of cells can be expected when infill materials naturally consolidate or become saturated prior to establishment of vegetation.
Vegetated topsoil infill is recommended in situations where surface flows are intermittent. of moderate
intensity. and of relatively shon duration (e 24 hours). Peak velocities of 6 m/s (20 Ws) can be sustained for shon periods when the vegetated cover is well established.
Degradable erosion blankets should be applied to protect exposed topsoil and seed and to promote
rapid establishment of vegetation. Erosion blanKets should be selected and Installed in accordance
with their manufaaurets guidelines.
For Detter overall performance. a lightweight. 150 - 200 g/m’ (4 - 6 o*@. needle-punched. non-
woven geotenik underlayer is a recommended component of the vegetated system. I WI size se/ectiim 1
~
material are the most important factors when selecting cell size. The following cell size recommendations assume that full vegetative cover will be establiished prior to exposure to des& run-off conditions. Large
cell Geoweb is normally sukble with vegetated topsoil infills when slope angles are below 30. and
moderate run-off intensities are anticipated. Slopes steeper than 30. (1.75H:l V) or exposure to severe or
concentrated flow conditions, require standard cell Geoweb. See Figure 2 for standard and large cell Geoweb delails.
Slope steepness, intensity of surface run-off. and the minimum expected angle of repose of the infill
THE GEOWEB" SLOPE PROTECTION SYSTEM
TECHNICAL OVERVIEW
Normal cell depth for vegetated protection is 75 mm (3 in). provided the subsoil will support root development and slope an@es are below 30'. Slopes steeper than 30. require a cell depth of at least
100 mm (4 in). Situations that could require greater cell depths include; revegetation of rock slopes, applications with highly erodible soils and support of vegetated slopes in arid regions.
Hydraulic action prior to full development of vegetation within the Cells can result in loss or settlement or reshaping of infill soils as shown in Figurs 5. The
expressed as:
Mlninwm
lnflli hpm ( d, )
relationship between geometrical variables can be Infill AOk 01
p=~-arctan( F] or
d=Llan( B-$)+d, where:
p = slope angle, d = depth of the cell (mm),
L = lenoth of the cell tmm).
9 =m" inimum angle of repose of the infill material,
de = mi6mum aAp&ie kpth (mm) of inml material. C*n \
D.pth(d) The recommended minimum de is H d. The appropriate
Geoweb cell size and depth based on a de of H d can be
determined using Figure 6.
Figure 5 Dchrmllution of Winlmum Cell Depth I SUkAncftoragc ' .. 1
Typical surface anchorage for revegetation of earlh slopes indudes 3 or 5 tendons per 2.44 m (8 tt) wide Geoweb Section, running down the slope. with 460 mm (18 in) ATRAT* clip anchors spaced at
1000 mm (3 11) intervals along each tendon. Complete anchor detaik are determined through static
analysis methods available from Presto.
Special slope anchonge requirements should be determined in accordam with guidelines presented in the section on Special Anchorage Methods.
svotsm lnsfalllotion
~ ~
On steep slopes. topsoil infilling should generally proceed from top to toe of slope. Excessive over
filling and placement of large clumps of soil in the cells should be avoided. Tamping of infill is
recommended to remove excessive air voids from the topsoil. Ensure that all cells are completely filled after lightly tamping the infill. Over tamping (compaalng) of infill may retard establishment of vegetation.
Seeding and installation of erosion blankets Should immediately follow placement of infill.
17-Om-97 PAGE~OF~~
- THE GEOWEB@ SLOPE PROTECTION SYSTEM
TECHNICAL OVERMEW -
..
Slope Angle (Dogma)
5 10 15 20 25 30 35 40 45 50 55 60 65 70 75
45.00
g 40.00 m a .,
d 6 30.00
a m
3
35.00
e
-
E
0
u a
W
25.00
4 20.00
E z 15.00 E iz
5 10.00
i 5 5.00
- m
c) - -
0.00
Figure 6 Gcoweb Type Selection for Various Slop08 8nd Infills
PAGE 8 OF 14 COPWGMT 1997 - Prism PRODLUS ~oupwv
i
- -_i
i
I
27-SEP-97
As the client of a consulting geotechnical engineer, you
should know that site subsurface conditions cause more
construction problems than any other factor. ASFUThe Association of Engineering Firms Practicing in the
Geosciences offers the following suggestions and observations to help you manage your risks.
A GEOTECHNICAL ENGINEERING REPORT IS BASED
Your geotechnical engineering report is based on a subsurface exploration plan designed to consider a unique set of project-specific factors. These factors typically include. the general nature of the structure involved, its size, and configuration: the location of the
structure on the site; other improvements, such as
access roads, parking lots, and underground utilities;
and the additional risk created by scopeof-service
limitations imposed by the client. To help avoid costly problems, ask your geotechnical engineer to evaluate how factors that change subsequent to the date of the report may affect the report's recommendations.
Unless your geotechnical engineer indicates othetwise, do not use your geotechnical engineering report:
when the nature of the proposed structure is
changed, for example, if an office building will be
erected instead of a parking garage, or a refrigerated
warehouse will be built instead of an unrefrigerated one: when the size, elevation. or configuration of the
proposed structure is altered; when the location or orientation of the proposed
structure is modified; when there is a change of ownership; or
for application to an adjacent site.
Ceotechnical engineers cannot accept responsibility for problems that may occur if they are not consulted after factors considered in their report's development have
changed.
SUBSURFACE CONDITIONS CAN CHANGE
A geotechnical engineering report is based on condi-
tions that existed at the time of subsurface exploration.
Do not base construction decisions on a geotechnical engineering report whose adequacy may have been
affected by time. Speak with your geotechnical consult-
ant to learn if additional tests are advisable before
construction starts.Note. too. that additional tests may
be required when subsurface conditions are affected by construction operations at or adiacent to the site, or by
natural events such as floods, earthquakes, or ground water fluctuations. Keep your geotechnical consultant apprised of any such events.
ON A UNIOUE SET OF PROIECT-SPECIFIC FACTORS
MOST GEOTECHNICAL FINDINGS ARE
PROFESSIONAL JUDGMENTS
Site exploration identifies actual subsurface conditions
only at those points where samples are taken. The data were extrapolated by your geotechnical engineer who then applied judgment to render an opinion about overall subsurface conditions. The actual interface between materials may be far more gradual or abrupt than your report indicates. Actual conditions in areas not sampled may differ from those predicted in your report. While nothing can be done to prevent such situations, you and your geotechnical engineer can work
together to help minimize their impact. Retaining your
geotechnical engineer to observe construction can be
particularly beneficial in this respect.
A REPORTS RECOMMENDATIONS CAN ONLY BE PREUMINARY
The construction recommendations included in your
geotechnical engineefs report are preliminary, because
they must be based on the assumption that conditions
revealed through selective exploratory sampling are
indicative of actual conditions throughout a site. Because actual subsurface conditions can be discerned
only during earthwork. you should retain your geo- technical engineer to observe actual conditions and to finalize recommendations. Only the geotechnical
engineer who prepared the report is fully familiar with
the background information needed to determine
whether or not the report's recommendations are valid
and whether or not the contractor is abiding by appli-
cable recommendations. The geotechnical engineer who developed your report cannot assume responsibility or liability for the adequacy of the report's recommenda- tions if another party is retained to observe construction.
GEOTECHNICAL SERVICES ARE PERFORMED FOR SPECIFIC PURPOSES AND PERSONS
Consulting geotechnical engineers prepare reports to
meet the specific needs of specific individuals. A report
prepared for a civil engineer may not be adequate for a construction contractor or even another civil engineer. Unless indicated othetwise. your geotechnical engineer prepared your report expressly for you and expressly for
purposes you indicated. No one other than you should
apply this report for its intended purpose without first conferring with the geotechnical engineer. No party
should apply this report for any purpose other than that originally contemplated without first conferring with the
geotechnical engineer.
GEOENWRONMENTAL CONCERNS
ARE NOT AT ISSUE
Your geotechnical engineering report is not likely to
relate any findings, conclusions, or recommendations
about the potential for hazardous materials existing at
the site. The equipment. techniques, and personnel used to perform a geoenvironmental exploration differ substantially from those applied in geotechnical engineering. Contamination can create major risks. If you have no information about the potential for your
site being contaminated, you are advised to speak with
your geotechnical consultant for information relating to
geoenvironmental issues
A GEOTECHNICAL ENGINEERING REPORT IS SUBIECT TO MISINTERPRETATION
Costly problems can occur when other design profes- sionals develop their plans based on misinterpretations of a geotechnical engineering report. To help avoid
misinterpretations, retain your geotechnical engineer to
work with other project design professionals who are
affected by the geotechnical report. Have your geotech-
nical engineer explain report implications to design
professionals affected by them, and then review those
design professionals' plans and specifications to see
how they have incorporated geotechnical factors. Although certain other design professionals may be fam-
iliar with geotechnical concerns, none knows as much about them as a competent geotechnical engineer.
BORING LOGS SHOULD NOT BE SEPARATED FROM THE REPORT
Geotechnical engineers develop final boring logs based
upon their interpretation ot the field logs (assembled by
site personnel) and laboratory evaluation of field
samples. Geotechnical engineers customarily include
I
mates was not one of the specific purposes for which it
was prepared. In other words, while a contractoy may gain important knowledge from a report prepared for another party. the contractor would be well-advised to discuss the report with your geotechnical engineer and
to perform the additional or alternative work that the contractor believes may be needed to obtain the data specifically appropriate for construction cost estimating
purposes I Some clients believe that it is unwise or
unnecessary to give contractors access to theirgeo-
technical engineering reports because they hold the
mistaken impression that simply disclaiming responsi-
bility for the accuracy of subsurface information always
insulates them from attendant liability. Providing the
best available information to contractors helps prevent costly construction problems, It also helps reduce the
adversarial attitudes that can aggravate problems to disproportionate scale.
READ RESPONSIBILITY CLAUSES CLOSELY Because geotechnical engineering is based extensively
on iudgment and opinion, it is far less exact than other design disciplines This situation has resulted in wholly
unwarranted claims being lodged against geotechnical
engineers. To help prevent this problem. geotechnical
engineers have developed a number of clauses for use in
their contracts, reports, and other documents. Responsi-
bility clauses are not exculpatory clauses designed to
transfergeotechnical engineers' liabilities to other
parties. Instead. they are definitiveclauses that identify where geotechnical engineers' responsibilities begin and end. Their use helps all parties involved recognize their
individual responsibilities and take appropriate action
Some of these definitive clauses are likely to appear in
your geotechnical engineering report. Read them
closely. Your geotechnical engineer will be pleased to give full and frank answers toanyquestions.
RELY ON THE GEOTECHNIW ENGINEER FOR ADDITIONAL ASSISTANCE
Most ASFE-member consulting geotechnical engineer-
ing firms are familiar with a variety of techniques and
approaches that can be used to help reduce risks for all
parties to a construction project. from design through
construction. Speak with your geotechnical engineer not only about geotechnical issues, but others as well. to learn about approaches that may be of genuine benefit
You may also wish to obtain certain ASFE publications. Contact a member of ASFE or ASFE for a complimentary
directory of ASFE publications.
PROFESSIONAL FIRMS PRACTICING IN THE GEOSCIENCES 881 I COLESVILLE ROAD/SLJITE G106/SILVER SPRING. MD 20910
TELEPHONE 3011565-2733 FACSIMILE 301/589-2017
Copyright 1992 by ASFE Inc Unless ASFE grants SP~CIIIC permission to do 50 duplicarian 01 this document by my means whatsoever 1sexpre5sly prohibited
Re-useofthewording ~nrhlsdocument 8n wholeor in part alsoirexpresslyprohibited andmay bedoneanlywh theexpiessperm~rrionofASFEorloipurDares
01 reww or scholarly research
IIGRO294