HomeMy WebLinkAboutCT 02-28; LA COSTA CONDOMINIUMS; LANDSLIDE STABILIZATION RECOMMENDATIONS; 2007-02-27American GeotechnicaUnc.
SOIL, FOUNDATION AND GEOLOGIC STUDIES
March 27, 2007 File No. 23080.02
Law Offices of Patrick E. Catalano
550 W. C Street, Suite 530
San Diego, CA 92101-3544
Attention: Mr. Patrick E. Catalano, Attorney at Law
Subject: LANDSLIDE STABILIZATION RECOMMENDATIONS
Banich, Powers, Calso Landslides
2416 Sacada Circle
Carlsbad, Califomia 92009
Dear Mr. Catalano:
In accordance with your request, we have prepared this report presenting our landslide stability analyses
and stabilization recommendations for the project referenced above. Our recommendations for repair are
based on .subsurface exploration, laboratory testing, geologic analyses, and engineering calculations.
We appreciate the opportunity to be of service. If you should have any questions or concems, please do
not hesitate to contact our office.
Respectfully submitted,
AMERICAN GEOTECI
Gregd
Principal
G.E. 103
GWA/KR: kb/ad (with revisions/corrections)
Enclosures: Figures 1-3
Appendices A-G
Distribution: 6 - Mr. Patrick E. Catalano
wpdata/20000/23080.02.gwa.kr.acl.march.2007.landslidestablization
Reviewed By:
Kevin R. Rogers
Project Geologist
C.E.G. 2425
22725 Old Canal Road, Yorba Linda, CA 92887 • (714) 685-3900 • FAX (714) 685-3909
5600 Spring Mountain Road, Suite 201, Las Vegas, NV 89146 • (702) 562-5046 • FAX (702) 562-2457
5764 Pacific Center Blvd., Suite 112, San Diego, CA 92121 • (858) 450-4040 • FAX (858) 457-0814
712 Fifth Street, Suite #B, Davis, CA 95616 • (530) 758-2088 • FAX (530) 758-3288
File No. 23080.02 llAmerican Geotechnical, Inc.
March 27, 2007
TABLE OF CONTENTS
Page
1.0 INTRODUCTION 1
2.0 SCOPE OF SERVICES ., 1
3.0 GEOLOGIC CONDITIONS 2
4.0 LANDSIDE STABILIZATION RECOMMENDATIONS 5
4.1 Removal Of Landslide 5
4.2 Slope Stabilization, Banich & Powers' Properties 5
4.3 Temporary Slope Support 7
4.4 Surface Drainage System & Erosion Control 7
4.5 Compaction & Grading Specifications 7
4.6 Monitoring 7
5.0 CLOSURE 7
6.0 REFERENCES 8
APPENDIX A Boring & Test Pit Logs
APPENDIX B Laboratory Testing
APPENDIX C Landslide Stability Analyses
APPENDIX D Surficial Slope Stability Calculations
APPENDIX E Temporary Slope Support Calculations
APPENDIX F Tieback Anchor Block Design Calculations
APPENDIX G Compaction & Grading Specifications
raAmerican Geotechnical, Inc. File No. 23080.02
March 27, 2007
Page 1
1.0 INTRODUCTION
The purpose of this report is to present our recommendations for stabilization of the slope.
Figure 1 shows the locations of the Banich, Powers, and Calso properties. The area of repair only
addresses the area of the recent failures affecting the Banich, Powers, and Calso properties, and as
such, does not provide stability for other areas or failures affecting other adjacent properties.
Although there is not a landslide within the Cerra property^ the existing drainage system at the
Cerra property will be tied into the new drainage system of the landslide repair.
Some background information on this project is provided below:
1. Original Construction: According to the San Diego County Assessor's Map, the Cerra
residence is known as Lot 152 and the Banich-Powers residences are known as Lot 153 of La
Costa South, Unit No. 1. The assessor's map also indicates that the street was originally
known as Sevilla Way but the name was subsequently changed to Sacada Circle. These
properties were graded and developed around 1976. For example, we have obtained a Benton
Engineering, Inc. report (see References, Section 6.0) that deals with the development of Lots
152 and 153 on Sevilla Way. According to the Benton Engineering, Inc. report, the building
pads for Lots 152 and 153 were constructed during the period between May 20,1976 to June
23, 1976. We believe the residences were constructed shortly thereafter.
2. Slope Failure: The slope failure occurred in February 2005. The failure was during a period
of record-breaking rainfall in southem Califomia. In our opinion, the effects of the rainfall
and subsequent runoff were to raise the groundwater table and reduce the shear strength of
the slide materials, resulting in the observed failure.
3. Prior Work by Leighton and Associates: In our report, we have referenced borings performed
by Leighton and Associates, who were the soil engineer for the project located directly
beneath the Banich, Powers, and Calso properties. This property has not yet been developed
and is known as Lot 185 of La Costa Avenue South, Unit No. 1. In Section 6.0 (References)
we have referenced the pertinent reports by Leighton and Associates.
2.0 SCOPE OF SERVICES
Our scope of services for this project has included the following:
• Subsurface exploration, consisting of the excavation of two borings and three test pits.
The logs of the borings and test pits are presented in Appendix A. The location of the
borings and test pits are shown on Figure 1.
• Geologic analyses, including the preparation of a geologic cross-section down the center
of the slope, as shown in Figure 2. This cross section was used in the slope stability
analyses.
• Laboratory testing, consisting of various laboratory tests. The soil samples recovered
from the subsurface exploration were retumed to our laboratory for testing. Results of
the laboratory testing are presented in Appendix B and include shear strength testing
(direct shear tests).
File No. 23080.02
March 27, 2007
Page 2
raAmerican Geotechnical, Inc.
• Engineering analyses, including the development of stabilization measures as outlined in
this report.
• Grading plans, which were prepared in conjunction with our soil report.
3.0 GEOLOGIC CONDITIONS
As previously mentioned, our geologic cross-section is presented in Figure 2. This geologic
cross-section was developed from our subsurface exploration consisting of two borings and three
test pits. The borings were large diameter and were dovrahole logged by our engineering
geologist (see Appendix A for logs).
As shown on Figure 2, we have identified two formational materials at the site, the Santiago
Formation, which underlies the upper portion of the slope, and an underlying mudstone/clayey
siltstone tentatively identified as the Delmar Formation. The Santiago Formation consists of
alternating layers of variably oxidized, moderately indurated, yellow-orange to white sandstone
and siltstone. The underlying Delmar Formation consists of relatively non-oxidized, dark green-
brown fractured mudstone cmd clayey siltstone. The landslide shown on Figure 2 appears to have
developed primarily within the Delmar Formation mudstone. Groundwater seepage was observed
emanating from a cemented zone near the top of the Delmar Formation in both borings (see
boring logs. Appendix A).
Geologic references are provided in Section 6.0.
Slope Failure Outside Limit Of Work
To Be Repaired By Calso Per Grading
Plan Drawing No. 422 - 4a
Legend
Pre-slide location of road cut by Leighton
Calso Property
Corrugated metal drain pipe
(surface drain closed) disrupted
by road cut and landslide.
H5 I TP-3
^ I LGB-2
Approximate location of Recent Test Pit
Approximate location of Recent Boring
Approximate location of Cross Section
Approximate location of Drain Pipes
Approximate location of slope access road-cut
for Leighton large diameter boring (1998)
Estimated location of original slope access
road-cut by Leighton
Approximate limits of slope repair grading
Approximate limits of land slide
VICINITY MAP
CITY OF ENCINITAS
Approx. Scale: 1" =40'
REVISIONS
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File No.
23080.02
Date:
Mar 2007
Figure 1
I
I
I
:
I
I
I
A'
300
280 -
260 -
240 -
220 -
200 -
180
160 -
140
LGB-1
LGB-2
Topo from
recent landslide
(10/11/05)
Access road
cut for Leighton
investigation(1998)
Banich Residence
Sacada Circle
56ft. R.O.W
Fill
Santiago
Sandgtooe'
Siltst(
Sandsti
San Diego County
topography (9/18/75) Siitstdis^nr::
1'thick cemented
Sandstone layer
seepage^
Cut / fill benches
observed in sidescarp
of recent landslide
Sandstone^
Delmar Frn'
mudstorre.
120
100
Probable Basal
Slip Shear
300
280
- 260
- 240 I
- 220 B
m
200
180
^ 160
- 140
- 120
100
20 40 60 80 100 120 140 160 180 200 220 240 260 280 300 320 340 360
Ooss-aection ArA"
Approximate Scale: 1" = 40'
REVISIONS
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File No.
23080.02
Date:
Mar 2007
Figure:
File No. 23080.02 raAmeNcan Geotechnical, Inc.
March 27, 2007
Page 5
4.0 LANDSLIDE STABILIZATION RECOMMENDATIONS
This report and the grading plans should be provided to the contiractors to obtain construction
bids. If at all possible, the work should be started this summer and completed before the next
rainy season begins. If the conti-actors have any questions about our recommendations for repak,
they should contact this office. Our recommendations for stabihzation of the landslide are as
follows:
4.1 Removal Of Landslide
The landslide on the Calso property (see Figure 2) will be completely removed and the slope
re-constiiicted so that it has a 2:1 (horizontal: vertical) slope inclination on the lower section of
the slope, and 1.5:1 geogrid reinforced slope inclination on the upper section of the slope.
Cross-section A-A' (see Figure 3) shows the elements of the repair. As indicated on Figure 3, a
key will be constructed at the toe-of-slope and a backdrain will be installed at the rear of the key.
The actual depth of the key and extent of removals will be determined in the field at the time of
the repair. Benches will be excavated as the backcut proceeds and geocomposite drains
horizontally spaced at 12 feet on center will be placed on the benches.
Based on our laboratory testing (direct shear testing) and subsurface exploration, we modeled the
landslide failure and obtained a factor-of-safety of approximately 1.0 (failure condition) as shown
on the first sheet in Appendix C. Gross slope stability analyses were then performed for the
proposed repair assuming that the buttress soil will have shear sti-ength parameters of at least
c' = 100 psf and ^' = 33 degrees. The gross slope stability analyses using the Bishop, Janbu, and
ordinary method of slices are also presented in Appendix C. As these analyses show, the re-built
slope will have a factor-of-safety in excess of 1.5.
It is likely that some of the more clayey areas excavated during the slope repair may not have a
shear sti-ength that meets the requirement (i.e. c' = 100 psf and (j)' = 33 degrees). We propose to
perfonn shear sti-ength tests during construction to determine the shear strength of the compacted
fill. If the clayey soil does not meet the shear sti-ength requirements, then the grading conti-actor
will need to exclude this material from the slope repair or mix the clayey soil with the on-site
granular soil. If any import soil is required, it should be predominately granular in nature and
meet the required shear strength parameters (i.e. c' = 100 psf and (])' = 33 degrees).
4.2 Slope Stabilization. Banich & Powers' Properties
As shown on Figure 3, the slope on the Banich and Powers' properties will be re-constructed such
that it has a 1.5:1 (horizontal: vertical) slope inclination. In order to attain a factor-of-safety of
1.5 for surficial stability, we recommend the installation of geogrid (Synteen SF35 or equivalent
such as Mirafi 3XT) at a vertical spacing of 2 feet. Our surficial slope stability calculations are
presented in Appendix D.
I
I
I
I
I A A'
I
I
300 -
280 -
260 -
240 -
220 -
200 -
180 -
160 -
140 -
120
100 -
For 1.5 H : 1V portion ofthe slope, place
geogrid (Synteen SF35) in between fill
layers at a 24" vertical spacing. Each
layer should start at the slope face and extend
inward to the backcut a min. of 25 feet.
Geogrid layers should be tipped back into
the slope at approx. 10%. Geogrid should
be rolled along slope and all splices should be
overlapped a minimum of 24 in. stagger laps
between layers. (No Geogrid in 2:1 slope area).
Import granular fill to be compacted to
90% relative compaction per ASTM D15S7
(Soil from Calso property can be utilized
as compacted fill soi
F^moveand replace,
as necessary, top of
slope wall and patio
(like, kind, and quality)
Overfill slope at least one foot
and cut back to compacted core
exposing edge of geogrid.
Sacada Circle
56ft. R.O.W
key width
-Typical backdrain: 15ft max. vertical spacing; tip out
of slope at as low an elevation as possible to allow for
outletting (*approximateloc^ion of horizontal drains
at 15" max. vertical spacing).
- 300
- 280
- 260
- 240
220
200
180
- 160
140
- 120
- 100
I Cross-section A-A'
Approximate Scale: 1" = 40'
REVISIONS
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03 CD
File No.
23080.02
Date:
Mar 2007
Figure 3
File No. 23080.02 HAmerican Geotechnical, Inc.
March 27, 2007
Page 7
43 Temporarv Slope Support
A steep excavation is anticipated below the structiire in the uppermost portion of the repair
(i.e. upper 40 feeO- A restraint system is recommended for the upper portion of die excavation to
provide adequate temporary support for the residence. As shown on Figure 3, the proposed
resti-aint system will consist of three rows of tiebacks consisting of 8-inch diameter by 125, 140,
and 155 feet long tiebacks that have a minimum bonded length of 50 feet. Details for the anchor
block and tieback anchor construction are presented on the grading plans. A fiill-time
geotechnical review should be provided during the installation and testing of the restraint system.
The recommended tieback service load capacity is 280 kips per tieback.
The temporary backcut supported by the restrain system will have a factor-of-safety of at least
1.25 as indicated by our slope stability analyses presented in Appendix E. Calculations for the
tieback anchor block system are presented in Appendix F.
4.4 Surface Drainage System & Erosion Control
At the completion of the repair as described above, a surface drainage system will be installed
(see Figure 3). For erosion control, the slope face will also need to be landscaped in accordance
with the recommendations on the grading plans.
4.5 Compaction & Grading Specifications
Our compaction and grading specifications are presented in Appendix G. The compaction and
grading at the project should be performed in accordance with these specifications. If there is a
conflict between recommendations in the main body of this report and the specifications in
Appendix G, then the recommendations in the main body of this report shall govern. Prior to the
start of the project, a meeting should be held between the owner, the soil engineer, the grading
contactor, and the city inspector.
At the completion of the repair, a final compaction report must be prepared. This report will
describe the repair process and provide compaction test resuhs.
4.6 Monitoring
Prior to the start of the repair process, we recommend that one inclinometer be installed at the top
of the slope above the repair area. American Geotechnical will monitor this inclinometer during
the entire repair process.
5.0 CLOSURE
The grading work as described in this report is intended to stabiUze the slope at the area described
in this report. No repair work is proposed for areas outside the hmits as defined in this report. As
such, no warranty in any respect is made as to the performance of the slope outside the area of
repair. If any slope movement or other types of damage occur to areas outside the area of repair,
the geotechnical consultant should be contacted for review.
The contents of this report have been prepared using standard geotechnical engineering principles
and practices. The work has been performed in accordance with the standard of practice for
geotechnical engineers practicing in this or similar areas. No warranty is expressed or implied.
File No. 23080.02 llAmeNcan Geotechnical, Inc.
March 27, 2007
Page 8
6.0 REFERENCES
1. Assessor's Map:
"San Diego County Assessor's Map." Map number BX 216, page 19.
2. Report Bv Benton Engineering. Inc.:
"Project No. 76-5-14D, Final Report on Compacted Filled Ground, Lots 152 and 153, La Costa
South Unit No. 1, Rancho L Costa, Carlsbad, Califomia." Dated June 28,1976.
3. Reports By Leighton and Associates:
"Preliminary Geotechnical Investigation, Lot 185, La Costa Avenue South, Unit 1, Carlsbad,
Califomia." Dated September 24,1999.
"Update Preliminary Geotechnical Report, Lot 185, La Costa Avenue South Unit 1, Carlsbad,
Califomia." Dated October 30, 2002.
4. Geologic References:
"Geology of Califomia", second edition, prepared by Robert M. Morris and Robert W. Webb,
dated 1990
"Geology of the San Diego Metropolitan Area, Califomia, Bulletin 200," prepared by Michael P.
Kennedy, dated 1975.
HAmerican Geotechnical, Inc.
File No. 23080.02
March 27, 2007
APPENDIX A
Boring & Test Pit Logs
Boring No. LGB-i
Project Name: ^^"'^1^
File No. 23080.01
Sheet:
Start Date
End Date Location: 2416 Sacada Circle (Front of house in the street)
Total Depth: 80.0' Rjg jype: Est. Surface Elevation
8/24/06
8/24/06
Location Profile
See Site Plan
Depth
In
Feet
Sample
Type
Blow
Count
Field Description By: KR
Surface Conditions:
Subsurface Conditions:
0.0 -zs
2.0
4.0
6.0 ^
8.0 ^
10.0 ^
12.0 -i
14.0 ^
16.0
18.0 ^
20.0 -
22.0
24.0
26.0 ^
28.0
30.0
32.0
34.0
36.0 ^
38.0 -E
40.0 ^
42.0
,0
48.0 ^
48.0
50.0 —
ASPHALT CONCRETE
0.0" - 3.0"(Street) 3" mininnum and 3 'A" maximum thickness
ROAD BASE
3.0"-7.0"
FIU
7.0"- 12.0'
Fine gravelly silty SAND, mottled white, dark gray and tan, slightly moist,
dense fo very dense, mica flakes and fine gravel size fragments of granitic rocks
Slity SAND, mottled light tan and white, damp to slightly moist, very dense
SANTIAGO FORMATION
1.0' -7.0'
7.0'-13.0'
13.0' - 16.0'
16.0' -29.0'
16.0' -23.4'
20,5'-22.0'
Oxidized silty fine SANDSTONE, mottled light yellow tan and white with
orange rust oxidation-stained bedding and nodules, damp to slightly moist
moderately indurated, moderately strong, low angle to near horizontal
bedding in upper 5.0', becomes less oxidized white, weakly fo moderately
indurated, friable, silty fine SANDSTONE below approximately 4.0'
Massive white to light tan silty SANDSTONE, damp, moderately indurated and
strong, some oxidized yellow and yellow-orange laminations that are low
angle (less than 10°) with variable strikes (near horizontal)
Zone of silty SANDSTONE mottled with abundant orange rust oxidation-
staining, grades into oxidized tan sandy SILTSTONE
Slightly sandy SILTSTONE, light fan with orange-rust oxidation stains
Near vertical vein-filled fracture 1/8-1" wide, rust and black-colored (Fn &Mn
oxides) widens with depth where at 20.0' it intercepts oval vug coated
with iron and manganese oxides, fhe vertical vein-filled fracture narrows to
approximately 1/8 wide belov/ the void and ends at approximately 23.4'
Numerous near-horizontal gypsum veins approximately 1 /8" wide
NOTE:
Heath Afief 20.0' each expert took turns sampling every 5.0' ;tarting v/ith
erington of 25.0' Stoney Miller at 30.0' and American Geotechnical at 35,0'
American
Geotechnica]
wtM Large Sag
P^'"! Ring Sampler
LGB-1 Boring No. _
Project Name: Banich
File No. 23080.01
Sheet:
Start Date
End Date Location: 2416 Sacada Circle (Front of house in the street)
Total Depth: 80.0' Rjg Type: Est. Surface Elevation
8/24/06
8/24/06
Location Profile
See Site Plan
Depth
in
Feet
Sample
Type
Blow
Count
Field Description By: KR
Surface Conditions:
Subsurface Conditions:
50.0
52.0
54.0
56.0
58.0
60.0
62.0
64.0
66.0
68.0 -3
70.0
72.0
74.0
76.0
78.0
80.0 ^
82.0
84.0
1.0 ^
88.0
90.0
92.0
94.0
96.0
98.0 ^
JIOO.O
@ 23.0' SILTSTONE laminations: N10E/5W, below 20.0' the SILTSTONE is light brown to tan,
mottled with closely spaced yellow oxidized laminations with some approximately
1 /8" wide gypsum oriented veins approximately parallel fo bedding
@ 25.8' Several near-horizontal gypsum veins oriented approximately '.u - 3/8" wide
@ 26.6' Concretion - elliptical - disc shaped with ven/ hard cemented core encased with
soft highly oxidized orange and black stained SILTSTONE beds
26.0' - 28.0' Moist cuttings, below 26.6' laminations are oxidized orange-rust
@ 29.0' Grades into light tan silty SANDSTONE, moderately indurated and strong, moist with
orange oxidation stains
@ 34.0' Bedding; N15E/13SW, cuttings are moderately indurated, moderately strong white
silty fine SANDSTONE, damp with paper-thin tan fo light brown clay coated
laminations spaced VV apart at near-horizontal orientation
35.0' - 36.0' White to light gray silty fine SANDSTONE, well indurated and strong, mottled with
some orange to brown oxidation stains, approximately %" thick layer of orange
oxidized silty very fine SANDSTONE in sample tip
@40.0' Bedding: N18E/9SE
@45.4' Bedding: N31E/7SE
@ 46.0' Cemented zone approximately 6,0" thick continuous around borehole
46.0' - 49.0' Intensely oxidized
46.0' - 47.0' Cuttings are orange to brown, intensely oxidized, moist, silty SANDSTONE with
fragments of ver/ hard concreted SANDSTONE
@ 49.0' Seepage along approximately '.-A wide sub horizontal gypsum vein intensely
oxidized, hard, well-cemenfed zone
49.0' - 54,8' Becomes slightly sandy SILTSTONE, light brown moftied with /ellow and orange
oxidized lar-ninations, slightly moisf fo moist
54.3' - 55.6' iH34£/4VV, very hard cemented zone of concreted smoke +o gray SILTSTONE .vith
abundani tiny white bi-valvg fossil shells, very difficult drilling underlain
apofoxirnafely 1 laver of orange oxidized very fine 5AMuSrOr-it
lencan
Geotechnical
Large Bag
Ring Sampler
Boring No.
Project Name:
LGB-1
Banich
File No. 23080.01
Sheet;
Start Date
End Date Location: 2416 Sacada Circle (Front of house in the street)
Total Depth: 80.0' Rig Type: Est. Surface Elevation
8/24/06
8/24/06
Location
See Site Plan
Profile
Depth
In
Feet
Sample
Type
Blow
Count
Field Description By: KR
Surface Conditions:
Subsurface Conditions:
50.0
52.0
54.0 -B
56.0
58.0
60.0 ^
62.0
64.0 ~
66.0
68.0
70.0 ^
72.0 ^
74.0 ^
76.0 ^
78.0 ^
80.0 ^
82.0
84.0
86.0
88.0
90.0
92.0
94.0
96.0 ^
i.O ^
100.0
'S56.5'
@ 60.0'
Dark snnoke gray silty very fine Sandstone, moderately indurated and strong
Drilling suspended at 5:00 to be resumed at 8:00 the following day, drilling
resumed at 8:00, approximately 4.0" of water has accumulated overnight
in bottom of hole
@ 60.4' Contact between smoke to gray SANDSTONE above and dark gray
mudstone below: N12E/5VV
60.4' - 76.0' Very dark gray to green mudstone or SILTSTONE hard and well indurated but
with many low and high angle polished shears (tectonic shears) at various
orientations, number of shears decreases with depth
DELMAR FORMATION
65.0' - 65.85' Mudstone, dark gray to green, damp, well indurated, hard and strong, non
-oxidized subparcllel paper thin polished surfaces (tectonic shear?) with
out gouge or breccia halo about 3/8 apart that dip at approximately 2P
and 55°
@ 76.0'
@ 80.0'
Downhole log terminated, approximately 0.5' - 1.0' of water accumulated
in bottom of borehole, the hole was backfilled with a lean concrete to sand
slurry delivered by Superior Mix with 2 sack sand/yd^
Boring terminated, no caving, seepage at 49.0'
American
Geotechnical
Large Bag
Wl Ring Sampler
LGB-2 Boring No. _
Project Name: Banich
File No. 23080.01
Sheet:
Location: On slope within landslide graben below 2416 Sacada Circle
Total Depth: 37.0' Rjg jype:
Start Date
End Date
Est. Surface Elevation
8/29/06
8/29/06
Location Profile
See Site Plan
Depth
in
Feet
Sample
Type
Blow
Count
Field Description By: KR
Surface Conditions:
Subsurface Conditions:
ANCIENT LANDSLIDE DEBRIS7/FILL
0.0' - 3.5' Silty SAND with gravel, mottled white to light gray with orange to brown
oxidation stains, moist
3.5' - 5.75' Silty SANDSTONE, highly weathered and oxidized, disturbed relict bedding
5.75' - 7.0' SILTSTONE, medium to dark brown, firm to medium
stiff, moist to very moist, abundant roots, grades downward into
weathered Delmar Formation mudstone? Several subparallel polished
clay seams in weathered siltstone - possible ancient landslide shears
RECENT LANDSUDE DEBRIS/INTENSELY FRACTURED DELMAR FORMATION
7.0' - 22.5' MUDSTONE, medium dark gray green, highly fractured (fresh), closely
spaced with numerous polished surfaces in various orientations,
light oxidation on some fractures but many are not oxidized,
fractures are discontinuous except for some as noted below
@ 12.75' Paper thin fracture old continuous around borehole, oxidized and with
rootlets, orientation - N10E/26W
15.0' - 20.0' Cobble size concretions in cuttings
American
Geotechnica]
• Large Bag
Ring Sampler
Boring No.
Project Name:
LGB-2
Banich
File Nn 23080.01
Sheet:
Start Date
Location: slope within landslide graben below 2416 Sacada Circle End Date
Total Depth: 37.0' Rjg Type: Est. Surface Elevation
8/29/06
8/29/06
Location Profile
See Site Plan
Depth
in
Feet
Sample
Type
Blow
Count
Field Description By: KR
Surface Conditions:
Subsurface Conditions:
0.0
2.0 ^
4.0
6.0
8.0 -£
10.0
12.0 ^
14.0
16.0
18.0
20.0 ^
22.0 ^
24.0
26.0 -E
28.0
30.0
32.0
34.0
36.0 ^
38.0
40.0
42.0
44.0
46.0
48.0 ^
50.0
22.5' Possible base of landslide, no distinct basal shear, several coalescing,
lightly oxidized polished shears N80W/13N, bottom of zone of closely
spaced fractures, becomes relatively intact, hard SILTSTONE below with
fewer and more widely spaced fractures
DELMAR FORMATION
22.5' - 25.25' Hard intact relatively unfractured SILTSTONE with some concretions
@ ~ 24.0' Drilling becomes difficult, 10" diameter bucket core installed on rig, core
cuttings are medium to dark green SILTSTONE, well indurated and strong,
with very few fractures, coated with light oxidation
@ 25.25' Seepage from within fractured, very hard cemented zone, approximately
3-4" thick with orientation N50W/4N
25.25' - 34.0' Delmar formation mudstone, dark gray-green some fractures coated with
light oxidation, at various orientations
@ 30.0' Drill cuttings are Delmar formation mudstone, well indurated, moderately
strong, damp to slightly moist, medium to dark green, fractured with
numerous polished surfaces with various orientations (tectonic?)
@ 34.0' Downhole log terminated - bottom of hole filled with sidewall spoils from
downhole logging
'3' 35.0' Drill cuttings change to light tan, sandy and clayey SILTSTONE
'§ 37,0' Drilling termindated. Some seepage into bottom of boring
American
Geotechnical
• Large Bag
• Ring Sampler
Test Pit Nn, AGTP-1 File No. 23080.01
Project Name: Banich Residence
Location: 2416 Sacada Circle
Start Date
End Date
Total Depth: 4.8' Rig Type: Hand Excavation Est. Surface Elevation
8/03/06
8/03/06
Location Profile
See Site Plan
Depth
in Intact
Feet
Sample
Type
Bulk
Field Description By: KR
Surface Conditions:
Subsurface Conditions:
0.0
1.0
2.0 —
3.0
4.0
5.0
6.0
7.0 -
8.0 ^
9.0
10.0 H
11.0
12.0 -d
13.0
14.0
15.0
18.0
17.0
18.0
19.0 -|
20.0 J
FILL
0.0' - 1.2'
1.2'-1.5'
i.5'-4.8'
Silty SAND mottled with pebble to gravel size fragments of white,
yellow and orange silty sand, medium dense to very dense,
some roots
1-3" thick dipping layer of dense to very dense silty SAND with
abundant pebble to gravel size fragments of yellow, white and
orange sandstone and green siltstone and mudstone, dips
downslope approximately 36°
Silty SAND with pebble to gravel size fragments of green
formation claystone, tan, very moist, medium dense to loose,
rootlets
TUBES® 2.5'-3.8'
@ 4.0' - 4.8'
LB @ 2.5'-4.0'
American
Gaotechnicai
Test Pit Nn. AGTP-2 File No. 23080.01
Project Name: Banich Residence
Location: 2416 Sacada Circle
Start Date
End Date
Total Depth: 5.0' Rig Type: Hand Excavation Est. Surface Elevation
8/04/06
8/04/06
Location Profile
See Site Plan
Depth
in
Feet
Sample
Type
Intact Bulk
Field Description By: KR
Surface Conditions:
Subsurface Conditions:
0.0
1.0
2.0
3.0
4.0 -
5.0 -z
6.0 -r
7.0
8.0
9.0 -
10.0 ^
11.0
12.0
13.0
14.0
15.0
16.0
17.0 ^
18.0
13.0
20.0
RECENT LANDSUDE DEBRIS
0.0' - 1.6' Recent landslide debris, light tan silty SAND, mottled with
pebble and small gravel size fragments of green clayey
SILTSTONE Formation
@ 1.6' Basal shear dips downslope at 27° approximately Va" to 1" thick
mottled zone of smeared green clay and brown and white
sand
FILL
1.6' 5.0' Gravelly and clayey SILT with light green and dark green
round sand to gravel size fragments of Formation clayey
SILTSTONE, green, moist to very moist, soft to firm, roots,
mottled with orange oxidized sand grains
TUBES @ 2.0' -2.9'
L8@2.0' -3.0'
American
Geotechnical
Test Pit Nn. AGTP-3 File No. 23080.01
Project Name: Banich Residence
Location: 2416 Sacada Circle
Start Date: 8/04/06
End Date: 8/04/06
Total Depth: 2.4' Rig Type: Hand Excavation Est. Surface Elevation:
Location
See Site Plan
Profile
Depth
in
Feet
Sample
Type
Intact Bulk
Field Description By: KR
Surface Conditions:
Subsurface Conditions:
0.0
1.0
2.0
3.0
4.0
5.0
6.0
7.0 —
8.0
9.0
10.0 —
11.0
12.0 -zi
13.0
14.0 —
15.0 -E
16.0 ^
17.0
18.0 ^
19.0 ^
20.0
FILL
0.0'-1.7'
1.7'-2.4'
Silty SAND with pebble and gravel size fragments of white
SANDSTONE and green SILTSTONE, slightly moist to moist,
dense to very dense, roots
Green gravelly and clayey SILT mixed with medium brown
silty sand, moist, stiff to very stiff with roots and some cobbles
TUBES @ 1.5' -2.4'
American
Geotechnical
iraAmerican Geotechnical, Inc.
File No. 23080.02
March 27, 2007
APPENDIX B
Laboratory Testing
liAnnerican Geotechnical, Inc.
File No. 23080.02
March 27, 2007
LABORATORY TEST PROCEDURES
Moisture Content Determinations
Moisture content determinations were made in accordance with ASTM method of test D2216.
Particle Size Analvsis
Particle size analyses were performed in accordance with ASTM method of test D422. Both mechanical
and hydrometer procedures were utilized.
Atterberg Limits
The Uquid limit and the plastic Umit were performed in accordance with ASTM method of test D4318.
Direct Shear
Direct shear tests were performed on samples remolded to in-place moisture and density. Soil samples
were allowed to soak for about 24 hours while under the confining pressure specified for testing.
ConsoUdated drained conditions were approximated by using a slow, strain-controUed approach, similar
to that outlined in ASTM method of test D3080.
In-Situ
In-Situ
Moisture Degree of* Grain Size Distribution
Exca.
No.
Depth
(feet)
Dry Density
(Lbs/cu. ft.)
Content
(%)
Saturation
(%)
Sand
(%)
Silt
(%)
Clay
(%)
LL
(%)
LGB-1 5-6 106.9 12.8 60
LGB-1 10-11 111.8 13.6 72 _ _
LGB-1 15-16 108.9 19.1 94 _ _
LGB-1 20-21 109.3 17.9 89 _ _
LGB-1 35-36 112.0 13.0 70 _ _
LGB-1 50-51 111.9 18.0 96 _ _ _
LGB-1 65-65.9 108.5 18.3 89 ----
LGB-2 5-6 97.1 16.8 62
LGB-2 10-11 105.1 19.1 86 _ _ _
LGB-2 15-16 102.6 20.1 85 _ _
LGB-2 20-21 98.4 21.1 80 _ _ _
LGB-2 21.5-22.5 ---3 52 46 43
LGB-2 25-26 105.8 15.9 72 ----
AGTP-1 4-4.8 103.6 16.2 70
AGTP-1 7.5-8.8 94.8 15.1 52 ----
AGTP-2 2-2.9 102.2 19.0 79 ----
AGTP-3 1.5-2.4 95.4 15.6 55
Atterberg Limits
PL
%
Passing
PI #200
23 20 43
Note: * Degree of saturation was calculated using specific gravity of 2.70
SUMMARY OF LABORATORY TESTING DATA TABLE
Bl AMERICAN GEOTECHNCIAL F.N. 23080.02 MAR. 2007
<;=• in
I 1-O
z
LU
CH
h-w a: <
UJ
X
w
LU >
I-
o
LU U. U. HI
• ' ' • 1 • • • • 1 • • • • —1—1—I—1—
o RESIDUAL STRESS
—1—1—I—1—
• LGB-2@21.5-22.5 FT
—1—1—I—1—
•
• • • • c = 4 60 psf, (|) = 10 a
• • • • • 1
Samples
and CM
testing 1'
—1 1 1 1 1
were remolde
C. and satura
cycles shear
•dtoM.D.D. •
ted prior to
llll
1 2 3
NORMAL PRESSURE (Ksf)
DIRECT SHEAR TEST PLOT
AMERICAN GEOTECHNICAL F.N. 23080.02 MAR. 2007
FIGURE
Bl
liAmerican Geotechnical, Inc.
File No. 23080.02
March 27, 2007
APPENDIX C
Landslide Stability Analyses
liAmencan Geotechnical, Inc.
File No. 23080.02
March 27, 2007
Sheet 1: Failure Condition
Sheet 1: Cross-section of the failure condition with a factor of safety of approximately 1.0
Sheets 2 through 4; Re-Built Slope
Sheet 2: Bishop method of slices for the re-built slope (F.S. = 1.612)
Sheet 3: Janbu method of slices for the re-built slope (F.S. = 1.524)
Sheet 4: Ordinary method of slices for the re-built slope (F.S. = 1.533)
150
120 .—
90 -
ro o
CO
o
60 —
>
Description: Banich
Comments: Topograph prior to failure - with groundwater
File Name: Banich - 3.sip
Last Saved Date: 9/21/06
Last Saved Time: 12:13:32 PM
Analysis iVIethod: Janbu
Direction of Slip Movement: Right to Left
Slip Surface Option: Grid and Radius
P.W.P. Option: Piezometric Lines / Ru
Soil: 1
Description: Fill
Soil Model: Mohr-Coulomb
Unit Weight: 125
Cohesion: 250 /' "
Phi: 33 , - • "
150
Soil: 3
Description: Slide Material
Soil Model: Mohr-Coulomb
Unit Weight: 125
Cohesion: 460
Phi: 10
Soil: 2 _ ,... -
—Descnption: SanclSitq)f{^
Soil Mode!: Mohr-cJoulomI
Unit Weight: 125
Cohesion: 1000
Phi: 40
Soil: 4
Descnption: Mudstone
Soil Model: Mohr-Coulomb
Unit Weight: 125
Cohesion: 1000
Phi: 33
30 .
50
30
30 60 90 120 150 18t
Horizontal Scale (feet)
210 240 270
- 0
300
1.50 -
120 —
(D •0)
I*—
0)
ro o
05
ro o
•.g 60
>
90 -
Description: Banich
Comments: Slide Removal with Buttress and groundwater cont
File Name: Banich - 4.sip
Last Saved Date: 9/21/06
Last Saved Time: 12:40:18 PM
Analysis Method: Bishop
Direction of Slip Movement: Right to Left
Slip Surface Option: Grid and Radius
P.W.P. Option: Piezometric Unes / Ru
^ - 150
Soil: 1
Description: Fill
Soil Model: Mohr-Coulomb
Unit Weight: 125 j Sotf:-2- -
Cohesion: 250 -Description: Sandst^^e
Phi- 33 - - Soil Model: Mohr-Coulomb
, . " Unit Weight; 125
Cohesion 1000 i
• • • •
Soil: 3
Description: Buttress
Soil Model: Mohr-Coulomb
Unit Weight: 125
Cohesion: 100
Phi: 33
Phi; 40
Soil: 4
Description: Mudstone
Soil Model: Mohr-Coulomb
Unit Weight: 125
Cohesion: 1000
Phi. 33
30
90
• 60
30
0 -
0 30 60 90 120 150 180
Horizontal Scale (feet)
210 240 270 300
150 —
120 -
90 -
ii2
2
CO ro o
•.g 60
>
Soil: 3
Description: Buttress
Soil Model: Mohr-Coulomb
Unit Weight: 125
Cohesion: 100
Phi: 33
Description: Banich
Comments: Slide Removal with Buttress and groundwater con
File Name: Banich - 4.sip
Last Saved Date: 9/21/06
Last Saved Time: 12:40:18 PM
Analysis Method: Janbu
Direction of Slip Movement; Right to Left
Slip Surface Option: Grid and Radius
P.W.P. Option: Piezometric Lines / Ru
— 150
Soil: 1
Description: Fill
Soil Model: Mohr-Coulomb
Unit Weight: 125 Soil: 2 j
Cohesion; 250 Descnption: Sandst^fi^
Phi: 33 - " Soil Model: Mohr-Goulomb
^.z " ^ ' • '' Unit Weight: 125
/ Cohesion: 1000
Phi: 40
90
Soil: 4
Description- Mudstone
Soil Model: Mohr-Coulomb
Unit Weight 125
Cohesion: 1000
Phi: 33
30
60
30
30 SQ 90 120 150 180
Horizontal Scale (feet)
210 240 270 300
'•DO
120 - •
90 --
ro
o
CO
8
60 —
>
Description: Banich
Comments: Slide Removal with Buttress and groundwater coni
File Name: Banich - 4.sip
Last Saved Date: 9/21/06
Last Saved Time: 12:40:18 PM
Analysis Method: Ordinary
Direction of Slip Movement: Right to Left
Slip Surface Option: Grid and Radius
P.W.P. Option: Piezometric Lines / Ru
Soil: 1
Description: Fill
Soil Model: Mohr-Coulomb
Unit Weight: 125
Cohesion: 250 /'
Phi: 33
150
Soil: 3
Description: Buttress
Soil Model: Mohr-Coulomb
Unit Weight: 125
Cohesion: 100
Phi: 33
Goil^2___,,-^
— De'scription: Sandst^
Soil Model: Mohr-Coulomb
Unit Weight: 125
Cohesion: 1000
Phi; 40
1 90
Soil: 4
Description: Mudstone
Soil Model: Mohr-Coulomb
Unit Weight; 125
Cohesion: 1000
Phi: 33
30 .. -
60
30
30 60 90 120 150 180
Horizontal Scale (feet)
210 240 270 300
liiAmencan Geotechnical, Inc.
File No. 23080.02
March 27, 2007
APPENDIX D
Surficial Slope Stability Calculations
70
GEOGRID SPACING CHART FOR FS = 1.50
(d=4')
65 -
60
55
50
BX1200
GEOGRID
VERTICAL 45
SPACING
(inches)
40
35
30
25 •
20
0 5 10 15 20 25 31
SLOPE (degrees)
» 3 5 4 9 4 5 50
GEOGRID CALCULATIONS
BANICH
CARLSBAD, CALIFORNIA
STABILITY ANALYSIS INPUT & OUTPUT
a d c «l) F Yt Xof F e X
(slope) (depth) (C) (<t>') existing (sat soil) XH:1V desjgn e/dy„
degrees feet psf degrees pcf slope ratio psf psf
output input input input output input input input output output
45.0 4.0 100 33 0.73 125.0 1.00 1.5 180.2 0.72
38.7 4.0 100 33 0.82 125.0 1.25 1.5 169.2 0.68
33.7 4.0 100 33 0.92 125.0 1.50 I.S 149.7 0.60
29.7 4.0 100 33 1.03 125.0 1.75 1.5 124.7 0.50
26.6 4.0 100 33 1.15 125.0 2.00 1.5 95.8 0.38
24.0 4.0 100 33 1.27 125.0 2.25 1.5 64.1 0.26
21.8 4.0 100 33 1.39 125.0 2.50 1.5 30.4 0.00
BASIC PARAMETERS VERTICAL GEOGRID SPACING
a d c F Soil USCS Td Ci S=Ta/e S=T„/e
(slope) (depth) (C) (<!>') existing (Coarse to (BX1200) (soil) (BX1200) (BX1200)
degrees feet psf degrees ...Fine) lb/ft feet inches
input output output output output
45.0 4.0 100 33 0.73 SC 350.00 0.80 1.94 23.3
38.7 4.0 100 33 0.82 SC 350.00 0.80 2.07 24.8
33.7 4.0 100 33 0.92 sc 350.00 0.80 2.34 28.1
29.7 4.0 100 33 1.03 SC 350.00 0.80 2.81 33.7
26.6 4.0 100 33 1.15 SC 350.00 0.80 3.65 43.8
24.0 4.0 100 33 1.27 sc 350.00 0.80 5.46 65.5
21.8 4.0 100 33 1.39 SC 350.00 m/A 11.52 138.2
BASIC PARAMETERS ANCHORAGE LENGTH & FS
a d c * F Lg L. L w. T. F
(slope) (depth) (C) existing (grid) (anchor) F=T./Tj
degrees feet psf degrees meters feet feet psf lb/ft lb/ft
input output output output output output
45.0 4.0 100 33 0.73 4.00 9.12 13.12 1070 10139 28.97
38.7 4.0 100 33 0.82 4.00 8.12 10.50 906 7644 21.84
33.7 4.0 100 33 0.92 4.00 7.12 8.75 797 5894 16.84
29.7 4.0 100 33 1.03 4.00 6.12 7.50 719 4569 13.06
26.6 4.0 100 33 1.15 4.00 5.12 6.56 660 3511 10.03
24.0 4.0 100 33 1.27 4.00 4.12 5.83 614 2630 7.52
21.8 4.0 100 33 1.39 4.00 #N/A #N/A m/A #N/A #N/A
BASIC PARAMETERS BOND LENGTH & FS
a d c <t> F Lb U W Taub Tb F
(slope) (depth) (C) (*•) existing (bond) (avg.) (avg.)
degrees feet psf degrees feet psf psf psf lb/ft
output output output output output output
45.0 4.0 100 33 0.73 4.00 62 188 195 780 2.23
38.7 4.0 100 33 0.82 5.00 76 174 181 903 2.58
.i.V7 4.1) KH) M 0,''2 O.I.MJ 86 164 171) lOiO 2.91
29.7 4.0 100 33 1.03 7.00 94 156 162 1134 3.24
26.6 4.0 100 33 1.15 8.00 100 150 156 1248 3.57
24.0 4.0 100 33 1.27 9.00 104 146 151 1363 3.90
21.8 4.0 100 33 1.39 #N/A #N/A #N/A m/A #N/A #N/A
SURFICIAL STABILITY ANALYSIS & GEOGRID DESIGN by William S. McCann; SEP 25, '91
Slope and Soil Strength Data:
Slope angle, a = 33.69 deg.
Cohesion, c = 100 psf
Friction angle, (j) = 33 deg.
Total saturated unit weight, -yj = 125 pcf
Depth, d = 4 ft
Soil Type (USCS Symbol) = SC
1. Check existing unreinforced slope (FQ = 0)
c + (YT - Yw)dcos^atan(|)
F.S. = 0,92 NG
yjdsinacosa
2. Design slope reinforced with geogrids
FS required = 1.5
FG = Geogrid force
e = Force required by geogrids to achieve designed F.S.
N = (YT - Yw)dLcosa + Fosina
S = cL/cosa + [(Yr-YjdLcosa + FGsina]tan(t)
= L/cosa[c + (YT- Yw)dcos^atan(|)] + FGsinatan(t)
FS = S/P =
L/cosa[c + (YT-yw)dcos^atan<t>| + Fcsinatancj)
(dLYxSina - Fccosa)
FoLFScosa + sinatancf)] =FSdLyTsina - L/cosa[c + (YT - Yw)dcos^atan(|)]
L/cosa[FSYTdsinacosa - c - (YT - Y„)dcos^atan(|>]
Fr.=
FScosa + sinatan(|)
Let e = force required per unit vertical height of slope = FofLtana
FSyrdcosa =
c/sina =
(YT - Yw)d(cos^a/sina)tan(|) =
FScosa + sinatancj) =
624.04
180.28
202.95
1.61
Hence, e= (1/sina)
[FSyxdsinacosa - c- (yT-Yw)dcos^atan(j)]
FScosa + sinatan(|) 149.73
GEOGRID DESIGN
AMERICAN GEOTECHNICAL |F.N. 23080.02 I MAR. 2007
TABLE
Dl
Consider: Tensar BX1200 Geogrid;
Td = Long term allowable design strength for geogrids =
Vertical spacing of geogrids required, s = T^/e =
Use TH =
530
350
lb/ft
lb/ft
Use Lo = m ••
3. Check Anchorage Length
LB = d/tana = 6.00
Anchorage length, L^ = LQ - LB =
L = LGtana =
Normal stress, = YT((d + L)/2) =
Ci = 0.8
TA = Ic-Wfjtan^ = 827.92
TA = 'CALA= 5897.57
FSA = TA/TJ = 16.85
Use s =
13.12 ft Geogrid
7.12 ft
8.75 ft
2.34 ft
28.05 inch
inch spacing 24
796.81
a
OK
/LB w
1 .
LA —w
—w
163.60
4. Calculate Bond Length and Factor of Safety
w' = ((0 + d)/2)yT - ((0 + dcos^a)/2>y„ =
TB = 2CiW'tan(t) = 169.99
TB = TBLB= 1019.9353
FSB = TB/TJ = 2.91 OK
END OF DESIGN
NOTE:
1) Altemative geogrid products (such as Mirafi 3XT or Synteen SF35) may be considered subject to
review by project geotechnical engineer.
2) Near top-of-slope where width narrows, extend geogrid up backcut and onto succeeding layer
3 feet except that total grid length need not exceed 13 feet.
GEOGRID DESIGN
AMERICAN GEOTECHNICAL F.N. 23080.02 MAR. 2007
TABLE
Dl
IHAmencan Geotechnical, Inc.
File No. 23080.02
March 27,2007
APPENDIX E
Temporary Slope Support Calculations
250
F.N. 23080.01 Banich Section A-A'
u:\gstabl7data\23080.01 banich\23080.01 banich_b_5.pl2 RunBy:JH 2/15/2007 04:29PM
200
FS
1.262
1.262
1.270
1.276
1.276
1.281
1.282
1.282
1.283
=F Soil Soil Total Saturated Cohesion Friction
Desc. Type Unit Wt. Unit Wt. Intercept Angle
; No. (pcf) (pcf): (psf) (deg)
Fill ; 1 125.0 125.0 250.0 33.0
SndStne 2 125.0 125.0 250.0 33.0
Bed pin. 3 125.0 125.6 100.0 18.0
MudStne 4 125.0 125.0 1000.0 33.0
Pore Pressure Plez.
Pressure Constant Surface
Param.
0.00
0.00
0.00
0.00
150
(psf)
0.0
0.0
0.0
0.0
No.
Wl
W1
Wl
Wl
Load
Ll
L2
I
Value
250 psf
250 psf
/•-JC (qr, .. /
or 2^o ^'
100
50
4f- *
&T2@1ft
GT1@1 t
GSTABL7i
50 100 150 200 250 300 350
GSTABL7V.2 FSmin=1.262
Safety Factors Are Calculated By The Simplified Janbu Method
*** GSTABL7 ***
** GSTABL7 by Garry H. Gregory, P.E. **
** Original Version 1.0, January 1996; Current Version 2.004, June 2003 **
(All Rights Reserved-Unauthorized Use Prohibited)
SLOPE STABILITY ANALYSIS SYSTEM
Modified Bishop, Simplified Janbu, or GLE Method of Slices.
(Includes Spencer & Morgenstern-Price Type Analysis)
Including Pier/Pile, Reinforcement, Soil Nail, Tieback,
Nonlinear Undrained Shear Strength, Curved Phi Envelope,
Anisotropic Soil, Fiber-Reinforced Soil, Boundary Loads, Water
Surfaces, Pseudo-Static s Newmark Earthquake, and Applied Forces.
Analysis Run Date:
Time of Run:
Run By:
Input Data Filename:
Output Filename:
Unit System:
2/15/2007
04:29PM
JH
U:\GStabl7 Data\23080.01 Banich\23080.01 banich_b_5.in
U:\GStabl7 Data\23080.01 Banich\23080.01 banich_b_5.OUT
English
Plotted Output Filename: U:\GStabl7 Data\23080.01 Banich\23080.01 banich b 5.PLT
PROBLEM DESCRIPTION: F.N. 23080.01 Banich
Section A-A'
BOUNDARY COORDINATES
20 Top Boundaries
26 Total Boundaries
Boundary X-Left Y-Left X-Right Y-Right Soil
No. (ft) (ft) (ft) (ft) Below
1 0 .00 28 .00 28 .00 30 .00 4
2 28 .00 30 .00 28 .10 26 .00 4
3 28 .10 26 .00 72 .00 26 .00 4
4 72 .00 26 00 72 10 30 .00 4
5 72 10 30 00 122 00 39 .00 4
6 122 00 39 00 131 00 47 00 4
7 131 00 47 00 132 00 48 00 4
8 132 00 48 00 176 00 85 00 2
9 176 00 85 00 188 00 101 00 2
10 188 00 101 00 199 90 119 00 1
11 199 90 119 00 200 00 121 00 1
12 200 00 121 00 202 00 121 00 1
13 202 00 121 00 228 00 121 00 1
14 228 00 121 00 228 10 126 00 1
15 228 10 126 00 266 00 126 00 1
16 266 00 126 00 294 00 126 00 1
17 294 00 126 00 313 00 127 00 2
18 313 00 127 00 329 00 126 00 2
19 329 00 126 00 329 10 127 00 2
20 329 10 127 00 332 00 127 00 2
21 188 00 101 00 238. 00 120 00 2
22 238 00 120. 00 253. 00 123. 00 2
23 253. 00 123. 00 273. 00 125. 00 2
24 273. 00 125. 00 294 . 00 126. 00 2
25
26
132.00
131.00
48.00
47.00
332.00
332.00
75.00
74.00
Default Y-Origin = 0.00(ft)
Default X-Plus Value = 0.00(ft)
Default Y-Plus Value = 0.00(ft)
ISOTROPIC SOIL PARAMETERS
4 Type(s) of Soil
Soil Total Saturated Cohesion Friction Pore Pressure Piez.
Type Unit Wt Unit Wt. Intercept Angle Pressure Constant Surface
No. (pcf) (pcf) (psf) (deg) Param. (psf) No.
1 125.0 125.0 250.0 33.0 0.00 0.0 1 2 125.0 125.0 250.0 33.0 0.00 0.0 1
3 125.0 125.0 100.0 18.0 0.00 0.0 1
4 125.0 125.0 1000.0 33.0 0.00 0.0 1
BOUNDARY LOAD(S)
2 Load(s) Specified
Load
No.
X-Left
(ft)
X-Right
(ft)
Intensity
(psf)
Deflection
(deg)
202.00
228.10
228.00
266.00
250.0
250.0
0.0
0.0
NOTE - Intensity Is Specified As A Uniformly Distributed
Force Acting On A Horizontally Projected Surface.
TIEBACK LOAD(S)
3 Tieback Load(s) Specified
Tieback X-Pos Y-Pos Load Spacing Inclination Length Force
No. (ft) (ft) (lbs) (ft) (deg) (ft) Method
1 196.59 114.00 35000.0 1.0
2 189.98 104.00 35000.0 1.0
3 182.75 94.00 35000.0 1.0
20.00
20.00
20.00
150.0
135.0
120.0
NOTE An Equivalent Line Load Is Calculated For Each Row Of Tiebacks
Assuming A Uniform Distribution Of Load Horizontally Between Individual
Tiebacks. Force Method 1 Considers Only Tangential Tieback Forces.
Force Method 2 Considers Both Tangential and Normal Tieback Forces.
Force Method 3 Considers Only Normal Tieback Forces.
Force Method 4 Limits Normal and Tangential Tieback-Force Distribution
to 1.5 Times the Tieback Inclination, or to 30 Degrees Below (Left of)
the Tieback-Failure Surface Intersection, Whichever is Greater.
A Critical Failure Surface Searching Method, Using A Random
Technique For Generating Sliding Block Surfaces, Has Been
Specified.
600 Trial Surfaces Have Been Generated.
2 Boxes Specified For Generation Of Central Block Base
Length Of Line Segments For Active And Passive Portions Of
Sliding Block Is 20.0
Box X-Left Y-Left X-Right Y-Right Height
No. (ft) (ft) (ft) (ft) (ft)
1 132.00 47.50 132.00 47.50 1.00
2 175.00 53.50 300.00 69.50 1.00
WARNING! The factor of safety calculation did not converge in 20 iterations.
The Trial Failure Surface In Question Is Defined
By The Following 7 Coordinate Points
Point X-Surf Y-Surf
No. (ft) (ft)
1 131.49 47.49
2 132.00 47.37
3 199.50 56.38
4 201.84 76.24
5 205.82 95.84
6 219.96 109.98
7 220.04 121.00
Factor of Safety for the Preceding Surface is Between-4.712 and25.279
WARNING! The factor of safety calculation did not converge in 20 iterations.
The Trial Failure Surface In Question Is Defined
By The Following 7 Coordinate Points
Point X-Surf Y-Surf
No. (ft) (ft)
1 131.50 47.50
2 132.00 47.36
3 186.71 54.95
4 200.23 69.69
5 200.26 89.69
6 202.15 109.60
7 209.86 121.00
Factor of Safety for the Preceding Surface is Between 8.458 and 8.442
The Factor Of Safety For The Trial Failure Surface Defined
By The Coordinates Listed Below Is Misleading..
Failure Surface Defined By 7 Coordinate Points
Point X-Surf Y-Surf
No. (ft) (ft)
1 131.58 47.58
2 132.00 47.17
3 181.92 54.80
4 193.42 71.16
5 204.88 87.55
6 216.85 103.58
7 217.40 121.00
Factor Of Safety For The Preceding Specified Surface =*******
WARNING! The factor of safety calculation did not converge in 20 iterations.
The Trial Failure Surface In Question Is Defined
By The Following 7 Coordinate Points
Point X-Surf Y-Surf
No. (ft) (ft)
1 131.46 47.46
2 132.00 47.15
3 185.89 54.86
4 186.04 74.86
5 192.51 93.78
6 202.43 111.15
7 208.21 121.00
Factor of Safety for the Preceding Surface is Between 8.842 and 8.833
WARNING! The factor of safety calculation did not converge in 20 iterations.
The Trial Failure Surface In Question Is Defined
By The Following 7 Coordinate Points
Point X-Surf Y-Surf
No. (ft) (ft)
1 131.81 47.81
2 132.00 47.64
3 186.07 55.32
4 195.64 72.89
5 209.77 87.04
6 222.66 102.33
7 222.75 121.00
Factor of Safety for the Preceding Surface is Between-0.094 and 0.154
The Factor Of Safety For The Trial Failure Surface Defined
By The Coordinates Listed Below Is Misleading.
Failure Surface Defined By 7 Coordinate Points
Point
No.
X-Surf
(ft)
Y-Surf
(ft)
131.60
132.00
272.68
282.19
296.29
296.30
305.04
47.60
47.22
65.96
83.56
97.75
117.75
126.58
Factor Of Safety For The Preceding Specified Surface = -2.612
The Factor Of Safety For The Trial Failure Surface Defined
By The Coordinates Listed Below Is Misleading.
Failure Surface Defined By 7 Coordinate Points
Point
No.
X-Surf
(ft)
Y-Surf
(ft)
131.54
132.00
179.20
192.51
199.73
212.29
212.97
47.54
47.21
53.91
68.84
87.50
103.06
121.00
Factor Of Safety For The Preceding Specified Surface =-71.481
WARNING! The factor of safety calculation did not converge in 20 iterations.
The Trial Failure Surface In Question Is Defined
By The Following 7 Coordinate Points
Point
No.
1
2
3
4
5
6
7
X-Surf
(ft)
131.28
132.00
199.99
203.53
205.67
205.85
209.24
Y-Surf
(ft)
47.28
47.01
56.62
76.30
96.18
116.18
121.00
Factor of Safety for the Preceding Surface is Between-0.429 and-0.121
WAGING! The factor of safety calculation did not converge in 20 iterations.
The Trial Failure Surface In Question Is Defined
By The Following 7 Coordinate Points
Point X-Surf Y-Surf
No. (ft) (ft)
1 131.29 47.29
2 132.00 47.13
3 179.05 53.52
4 188.74 71.02
5 193.52 90.44
6 200.34 109.24
7 201.19 121.00
Factor of Safety for the Preceding Surface is Between-4.053 and 9.179
WARNING! The factor of safety calculation did not converge in 20 iterations.
The Trial Failure Surface In Question Is Defined
By The Following 7 Coordinate Points
Point X-Surf Y-Surf
No. (ft) (ft)
1 131.07 47.07
2 132.00 47.05
3 215.64 58.32
4 227.49 74.43
5 239.40 90.50
6 246.28 109.28
7 246.35 126.00
Factor of Safety for the Preceding Surface is Between-0.183 and******
The Factor Of Safety For The Trial Failure Surface Defined
By The Coordinates Listed Below Is Misleading.
Failure Surface Defined By 6 Coordinate Points
Point X-Surf Y-Surf
No. (ft) (ft)
1 131.76 47.76
2 132.00 47.69
3 199.74 57.00
4 211.99 72.81
5 215.07 92.57
6 215.07 121.00
Factor Of Safety For The Preceding Specified Surface = 0.000
WARNING! The factor of safety calculation did not converge in 20 iterations.
The Trial Failure Surface In Question Is Defined
The Following 7 Coordinate
Point X-Surf Y-Surf
No. (ft) (ft)
1 131.85 47.85
2 132.00 47.80
3 175.21 53.77
4 180.54 73.05
5 194.65 87.23
6 208.70 101.46
7 209.29 121.00
Factor of Safety for the Preceding Surface is Between-1.710 and-0.907
WARNING! The factor of safety calculation did not converge in 20 iterations.
The Trial Failure Surface In Question Is Defined
By The Following 7 Coordinate Points
Point X-Surf Y-Surf
No. (ft) (ft)
1 131.49 47.49
2 132.00 47.37
3 199.50 56.38
4 201.84 76.24
5 205.82 95.84
6 219.96 109.98
7 220.04 121.00
Factor of Safety for the Preceding Surface is Between-4.712 and25.279
WARNING! The factor of safety calculation did not converge in 20 iterations.
The Trial Failure Surface In Question Is Defined
By The Following 7 Coordinate Points
Point X-Surf Y-Surf
No. (ft) (ft)
1 131.50 47.50
2 132.00 47.36
3 186.71 54.95
4 200.23 69.69
5 200.26 89.69
6 202.15 109.60
7 209.86 121.00
Factor of Safety for the Preceding Surface is Between 8.458 and 8.442
The Factor Of Safety For The Trial Failure Surface Defined
By The Coordinates Listed Below Is Misleading.
Failure Surface Defined By 7 Coordinate Points
Point X-Surf Y-Surf
No. (ft) (ft)
1 131.58 47.58
2 132.00 47.17
3 181.92 54.80
4 193.42 71.16
5 204.88 87.55
6 216.85 103.58
7 217.40 121.00
Factor Of Safety For The Preceding Specified Surface =*******
WARNING! The factor of safety calculation did not converge in 20 iterations.
The Trial Failure Surface In Question Is Defined
By The Following 7 Coordinate Points
Point X-Surf Y-Surf
No. (ft) (ft)
1 131.46 47.46
2 132.00 47.15
3 185.89 54.86
4 186.04 74.86
5 192.51 93.78
6 202.43 111.15
7 208.21 121.00
Factor of Safety for the Preceding Surface is Between 8.842 and 8.833
Following Are Displayed The Ten Most Critical Of The Trial
Failure Surfaces Evaluated. They Are
Ordered - Most Critical First.
* * Safety Factors Are Calculated By The Simplified Janbu Method * *
Total Number of Trial Surfaces Attempted = 600
WARNING! The Factor of Safety Calculation for one or More Trial Surfaces
Did Not Converge in 20 Iterations.
Number of Trial Surfaces with Non-Converged FS = 11
Number of Trial Surfaces with Misleading FS = 5
Number of Trial Surfaces With Valid FS - 584
Percentage of Trial Surfaces With Non-Valid FS Solutions
of the Total Attempted = 2.7 %
Statistical Data On All Valid FS Values:
FS Max = 72.014 FS Min = 1.262 FS Ave = 2.573
Standard Deviation = 4.382 Coefficient of Variation 170.30 %
Failure Surface Specified By 8 Coordinate Points
Point
No.
X-Surf
(ft)
Y-Surf
(ft)
131.404
132.000
197.942
211.391
222.148
230.572
243.171
244.819
47.404
47.189
56.430
71.232
88.093
106.232
121.765
126.000
Factor of Safety
"** 1.262 ***
Individual data on the 17 slices
Water Water Tie Tie Earthquake
Force Force Force Force Force Surcharge
Slice Width Weight Top Bot Norm Tan Hor Ver Load
No. (ft) (lbs) (lbs) (lbs) (lbs) (lbs) (lbs) (lbs) (lbs)
1 0 .6 30 2 0 0 0 0 0. 0. 0 .0 0 0 0 0
2 44 .0 89253 4 0 0 0 0 0. 0. 0 .0 0 0 0 0
3 12 .0 58206 2 0 0 0 0 0. 0. 0 0 0 0 0 0
4 9 9 65596 5 0 0 0 0 0. 376. 0 0 0 0 0 0
5 0 5 3650 5 0 0 0 0 0. 0. 0 0 0 0 0 0
6 1 5 11040 3 0 0 0 0 0. 0. 0 0 0 0 0 0 7 0 1 767 0 0 0 0 0 0. 0. 0 0 0 0 0 0
8 2 0 15301. 1 0 0 0 0 0. 0. 0 0 0 0 0 0
9 9 4 64491. 0 0. 0 0 0 0. 0. 0 0 0 0 2347 9
10 10 8 55579. 8 0. 0 0 0 0. 1940. 0 0 0 0 2689 1
11 5 9 19463. 2 0. 0 0 0 0. 4221. 0 0 0 0 1463 1
12 0 1 283. 7 0. 0 0 0 0. 105. 0 0 0 0 0 0
13 2 5 6930. 3 0. 0 0 0 0. 3125. 0 0 0 0 618 0
14 7 4 14103. 0 0. 0 0 0 0. 10863. 0 0 0 0 1857 0
15 4 5 4384. 7 0. 0 0 0 0. 5988. 0 0 0 0 1115 9
16 0 7 413. 1 0. 0 0. 0 0. 898. 0 0 0 0 176 9
17 1 6 436. 2 0. 0 0. 0 0. 2642. 0 0 0 0 412 0
Failure Surface Specified By 8 Coordinate Points
Point
No.
X-Surf
(ft)
Y-Surf
(ft)
131.404
132.000
197.942
211.391
222.148
230.572
243.171
244.819
47.404
47.189
56.430
71.232
88.093
106.232
121.765
126.000
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Factor of Safety
*** 1.262 ***
Failure Surface Specified By 8 Coordinate Points
Point X-Surf Y-Surf
No. (ft) (ft)
1 131 .552 47.552
2 132 .000 47.176
3 192 723 56.196
4 205 045 71.949
5 213 013 90.293
6 225 083 106.240
7 238 831 120.766
8 241 736 126.000
Factor of Safety
* * * 1.270 ***
Failure Surface Specified By 8 Coordinate Points
Point X-Surf Y-Surf
No. (ft) (ft)
1 131.473 47.473
2 132.000 47.275
3 190.526 55.623
4 204.584 69.849
5 216.913 85.597
6 228.388 101.978
7 242.490 116.160
8 250.291 126.000
Factor of Safety
••** 1.276 ***
Failure Surface Specified By 8 Coordinate Points
Point X-Surf Y-Surf
No. (ft) (ft)
1 131 473 47.473
2 132 000 47.275
3 190 526 55.623
4 204 584 69.849
5 216 913 85.597
6 228 388 101.978
7 242 490 116.160
8 250 291 126.000
Factor of Safety
1.276
Failure Surface Specified By 8 Coordinate Points
Point
No.
X-Surf
(ft)
Y-Surf
(ft)
131.952
132.000
194.981
205.100
211.866
221.263
235.235
236.931
47.952
47.907
55.923
73.175
91.995
109.650
123.960
126.000
Factor of Safety
*** 1.281 ***
Failure Surface Specified By 7 Coordinate Points
^oint X-Surf Y-Surf
No. (ft) (ft)
1 131 605 47.605
2 132 000 47.574
3 183 934 54.907
4 197 763 69.355
5 208 923 85.952
6 218 058 103.744
7 225 824 121.000
Factor of Safety
* * * 1.282 ***
Failure Surface Specified By 7 Coordinate Points
Point
No.
X-Surf
(ft)
Y-Surf
(ft)
131.605
132.000
183.934
197.763
208.923
218.058
225.824
47.605
47.574
54.907
69.355
85.952
103.744
121.000
Factor of Safety
*** 1.282 ***
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Failure Surface Specified By 8 Coordinate Points
Point X-Surf Y-Surf
No. (ft) (ft)
1 131.719 47.719
2 132.000 47.598
3 190.770 55.243
4 200.956 72.455
5 212.946 88.462
6 224.491 104.793
7 237.623 119.878
8 241.592 126.000
Factor of Safety
*** 1.283 ***
Failure Surface Specified By 8 Coordinate Points
Point X-Surf Y-Surf
No. (ft) (ft)
1 131.659 47.659
2 132.000 47.348
3 187.077 54.878
4 198.769 71.105
5 209.203 88.167
6 221.162 104.198
7 233.905 119.613
8 236.366 126.000
Factor of Safety
"*•" 1.283 ***
END OF GSTABL7 OUTPUT ****
liAmencan Geotechnical, Inc.
File No. 23080.02
March 27, 2007
APPENDIX F
Tieback Anchor Block Design Calculations
TIEBACK ANCHOR BLOCK DESIGN
File Number:
File Name:
23080.01
Banich
DESIGN SUMMARY
Anchor Block Length = 8 feet
Anchor Block Width = 8 feet
Anchor Block Thickness = 22 inch
Lognitudinal Reinforcement = #8 bars @ 12 inch @ top & bottom
Transverse Reinforcement = #8 bars @ 12 inch o.c. at bottom
#4 bars @, 12 inch o.c. at top
DESIGN CRITERIA
Tieback load per foot =
Tieback Spacmg, s =
Service Load per Tieback, P
CHECK BEARING PRESSURE
Allowable Bearing Pressure =
Anchor Block Width, w =
Bearing pressure, a = /'(10V[(w)(j )] =
<
ANCHOR BLOCK DESIGN
Check for Wide Beam Shear (One-Way Shear)
^„ = 1.7/'= 476 kips
qu=PJ{{yv)is)\= 7.44 ksf
Size of bearing plate (square), b =
4500
60000
psi
psi
35
8
kips/ft
ft on cener
280 kips
6000 psf
ft
4375 psf
6000 psf [OK]
12 mch
The critical section for wide beam shear occurs at a distance d fi-om the face ofthe bearmg plate.
So shear at critical sectiorij
Txyd = I 1.091 [ft = 13.09 mch
F„ = [(s 12 -b/2)- d]iw )q „ = 143.34 ksf
(l>V,= [a85g)sqrt^e)(144)/10'](rf)(w) = 143.33 ksf
Use d = I 7J1 inch
American Geotechnical Page 1 of 3 February 14, 2007
By: JH
Check for Diagonal Tension (Two-way shear)
Shear stress for two-way action = 4^sqTt(f^) = 228.08 psi =
l=b+ 2(d/2) =
V„ = ?„-(/Vl44)q„
Shear stress = VJA
Check for d =
i\2
25 inch
443.72 kips
24.58 ksf
16.615|inch
a.2 A = (b+d)7144 = 5.69 ft^
Perhneter = 4(b+d) = 9.54 ft
Shear force, V = P„ - A(q„) = 433.71 kips
Shear stress = 32.84 kips
V(aio = 4 (j) sqrt(/'e') = 228.08 psi = 32.84 ksf
Used
Total
USE
17 inch thick (effective) anchor block
Total anchor block thickness = 21 inch (assume #8 bar)
inch thickness anchor block 22
DESIGN FOR REINFORCEMENT
Longitudinal Direction (Long way)
Assume simply supported conditions between tiebacks
and consider
w=Pls 35.00 kips/ft
M™ax = W5VlO =
12 inch wide section
M„=1.7M„„
M„ = (|)A/y(d - a/2)
A =
224 kips-ft
380.8 kips-ft^ 47.60 kips-ft/ft
0.674
a = A/y/(0.85/'eb) =
Mu = <t)A/y(d - a/2) -
m^
0.88
50.22 kips-ft/ft
32.84 ksf
b
d/2
1.
[OK]
Check for mmimum remforcement
As(nun) = Pbd = 0.673 <
Use 22 inch thick anchor block
bars@
(As = 0.79 in^)
> 47.60 kips-ft/ft OK
0.674 [OK]
12 inch @ top & bottom
Transverse Direction (Short way)
q=PIA= 4.38 kips/ft
/ = w/2 - b/2 =
M = ql^l2 =
M„ = \.1M =
Mu = <|)A/v(d - a^2)
A,= 0.674 m
3.5 ft
26.80 kips-ft
45.55 kips-ft/ft
i T
w
i
American Geotechnical Page 2 of 3 February 14, 2007
By: JH
a = A/y/(0.85/,b) =
Mu = (t)A/y(d - a/2) =
0.88
50.22 kips-ft/ft 45.55 kips-ft/ft OK
Check for minimum reinforcement
*^s(min) pbd = 0.673 < 0.674 [OK]
Use #8 bars@ 12
Use #4 bars@ 12
inch o.c. at bottom
inch o.c. at top
(A,
(A,
0.79 in')
0.20 in^)
I
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I American Geotechnical Page 3 of 3 February 14, 2007
By: JH
^American Geotechnical, Inc.
File No. 23080.02
March 27, 2007
APPENDIX G
Compaction & Grading Specifications
liAmerican Geotechnical, Inc.
File No. 23080.02
March 27, 2007
A. GENERAL
I
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Al This document presents our grading recommendations. This information should be
considered to be a part of the project specifications.
A2 The contractor should not vary from these specifications without prior recommendation
by the geotechnical engineer and the approval of the client or the authorized
representative. Recommendations by the geotechnical engineer and/or client should not
be considered to preclude requirements issued by the local building department.
A3 These grading specifications may be modified and/or superseded by recommendations
contained in the text of the preliminary geotechnical report and/or subsequent reports.
A4 If disputes arise out of the interpretation of these gradmg specifications, the geotechnical
engineer shall provide the goveming interpretation.
B. OBLIGATIONS OF PARTIES
B1 The geotechnical engineer should provide observation and testing services and should
make evaluations to advise the client on geotechnical matters. The geotechnical engineer
should report the findings and recommendations to the client or the authorized
representative.
B2 The client should be chiefly responsible for all aspects ofthe project. The client or
authorized representative and the contractor(s) performing the repair have the
responsibility of reviewing the findings and recommendations of the geotechnical
engineer contained in this report and the project grading plans. The client shall authorize
or cause to have authorized the contractor and/or other consuhants to perform work
and/or provide services. During grading the client or the authorized representative should
remain on-site or should remain reasonably accessible to all concerned parties in order to
make decisions necessary to maintain the flow of the project.
B3 The contractor should be responsible for the safety of the project and satisfactory
completion of all grading and other associated operations on construction projects,
including, but not limited to, earthwork in accordance with the project plans,
specifications and controlling agency requirements. During grading, the contractor or the
authorized representative should remain on-site. Overnight and on days off, the
contractor should remain accessible.
C. SITE PREPARATION
C1 The cUent, prior to any site preparation or grading, should arrange and attend a meeting
among the grading contractor, the design structural engineer, the geotechnical engineer,
representatives of the local building department, as well as any other concerned parties.
M\ parties should be given at least 48 hours notice.
liAmerican Geotechnical, Inc.
File No. 23080.02
March 27, 2007
C2 Clearing and grubbing should consist of the removal of vegetation such as brush, grass,
woods, stumps, trees, roots of trees and otherwise deleterious natural materials fi-om the
areas to be graded. Clearing and grubbing should extend to the outside of all proposed
excavation and fill areas.
C3 Demolition should include removal of buildings, structures, foimdations reservoirs,
utilities (including underground pipelines, septic tanks, leach fields, seepage pits,
cisterns, mining shafts, tunnels, etc.) and other man made surface and subsurface
improvements fi-om the areas to be graded. Demolition of utilities should include proper
capping and/or rerouting pipelines at the project perimeter and cutoff and capping of
wells in accordance with the requirements of the local building department and the
recommendations of the geotechnical engineer at the time of demolition.
C4 Trees, plants or man-made improvements not planned to be removed or demolished
should be protected by the contractor from damage or injury.
C5 Debris generated diuing clearing, grubbing and/or demolition operations should be
wasted from areas to be graded and disposed off-site. Clearing, grubbmg and demolition
operations should be performed imder the observation of the geotechnical engineer.
C6 The client or contractor should obtain the required approvals from the local building
department for the project prior, during and/or after demolition, site preparation and
removals. The appropriate approvals should be obtained prior to proceeding with grading
operations.
D. SITE PROTECTION
Dl Protection of the site during the period of grading should be the responsibility of the
contractor. Unless other provisions are made in writing and agreed upon among the
concerned parties, completion of a portion ofthe project should not be considered to
preclude that portion or adjacent areas from the requirements for site protection until such
time as the entire project is complete as identified by the geotechnical engineer, the client
and the local building department.
D2 The contractor should be responsible for the stabihty of all temporary excavations.
Recommendations by the geoteclmical engineer pertaining to temporary excavations
(e.g., back-cuts) are made m consideration of stability of the completed project and,
therefore, should not be considered to preclude the responsibilities of the contractor.
D3 Precautions should be taken during the performance of site clearing, excavations, and
grading to protect the work site from flooding, ponding, or mundation by poor or
improper surface drainage. Temporary provisions should be made to adequately direct
surface drainage away from and off the work site, which includes re-routing of existing
drainage lines. Additional protection may be required if rainy conditions develop during
the repair work. Where low areas cannot be avoided, pimips should be kept on hand to
continually remove water during periods of rainfall.
D4 During periods of rainfall, plastic sheeting should be kept reasonably accessible to
prevent unprotected slopes from becoming saturated. Where necessary during periods of
rainfall, the contractor should install check-dams, desilting basins, rip-rap, sand bags or
other devices or methods necessary to control erosion and provide safe conditions.
liAmencan Geotechnical, Inc.
File No. 23080.02
March 27, 2007
D5 During periods of rainfall, the geotechnical engineer should be kept informed by the
contractor as to the nature of remedial or preventative work being performed (e.g.,
pumping, placement of sandbags or plastic sheeting, other labor, dozing, etc.).
D6 Following periods of rainfall, the confractor should contact the geotechnical engmeer and
arrange a walkover of the site in order to visually assess rain related damage. The
geotechnical engineer may also recommend excavations and testing in order to aid in the
assessments. At the request of the geotechnical engineer, the contractor shall make
excavations in order to evaluate the extent of rain related-damage.
D7 Rain-related damage should be considered to include, but may not be limited to, erosion,
silting, saturation, swelling, structural distress and other adverse conditions identified by
the geotechnical engineer. Soil adversely affected should be classified as unsuitable
materials and should be subject to overexcavation and replacement with compacted fill or
other remedial grading as recommended by the geotechnical engineer.
D8 Relatively level areas, where saturated soils and/or erosion gullies exist to depths of
greater than 1.0 foot, should be over-excavated to unaffected, competent material. Where
less than 1.0 foot in depth, unsuitable materials may be processed in-place to achieve
near-optimum moisture conditions, then thoroughly recompacted in accordance with the
applicable specifications. If the desired results are not achieved, the affected materials
should be over-excavated, then replaced in accordance with the applicable specifications.
D9 In slope areas, where saturated soil and/or erosion gullies exist to depths of greater than
1.0 foot, they should be over-excavated and replaced as compacted fill in accordance
with the applicable specifications. Where affected materials exist to depths of 1.0 foot or
less below proposed finished grade, remedial grading by moisture conchtioning in-place,
followed by thorough recompaction in accordance with these grading specifications, may
be attempted. If the desired results are not achieved, all affected materials should be
over-excavated and replaced as compacted fill in accordance with the slope repair
recommendations herein. As field conditions dictate, other slope repair procedures may
be recommended by the geotechnical engineer.
E. EXCAVATIONS
El UNSUITABLE MATERIALS
El. 1 Materials that are unsuitable should be excavated under observation and
recommendations ofthe geotechnical engineer or engineering geologist.
Unsuitable materials include, but may not be limited to: (1) dry, loose, soft, wet,
organic, or compressible natural soils, (2) fi-actured, weathered, or soft bedrock,
(3) nonengineered fill, and (4) other deleterious fill materials.
El .2 Material identified by the geotechnical engineer or engineering geologist as
unsatisfactory due to its moisture conditions should be over-excavated, watered
or dried, as needed, and thoroughly blended to a uniform near optimum moisture
condition prior to placement as compacted fill.
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March 27,2007
E2 CUT SLOPES
E2.1 Unless otherwise recommended by the geotechnical engineer and approved by
the local building department, permanent cut slopes should not be steeper than
2:1 (horizontal: vertical).
E2.2 If excavations for cut slopes expose loose, cohesionless, significantly fi-actured or
otherwise unsuitable material, overexcavation and replacement of the unsuitable
materials with a compacted stabilization fill should be accomplished as
recommended by the geotechnical engineer.
E2.3 The geotechnical engineer or engineering geologist should review cut slopes
during excavation. The geotechnical engineer should be notified by the
contractor prior to begiiming slope excavations.
E2.4 If during the course of grading, adverse or potentially adverse geotechnical or
geologic conditions are encoimtered which were not anticipated in the
preliminary report, the geotechnical engineer or engineering geologist should
explore, analyze and make recommendations to treat these problems.
E2.5 When cut slopes are made in the direction of the prevailing drainage, a non-
erodible diversion swale (brow ditch) should be provided at the top-of-cut.
F. COMPACTED FILL
All fill materials should be compacted as specified below or by other methods specifically
recommended by the geotechnical engineer. Unless otherwise specified, the minimum degree of
compaction (relative compaction) should be 90 percent ofthe laboratory maximum density
(Modified Proctor).
Fl PLACEMENT
Fl. 1 Prior to placement of compacted fill, the contractor should request a review by
the geotechnical engineer of the exposed ground surface. Unless otherwise
recommended, the exposed ground surface should then be scarified (six inches
minimum), watered or dried as needed, thoroughly blended to achieve near
optimum moisture conditions, then thoroughly compacted to a nunimum of 90
percent ofthe maximum density (Modified Proctor). The review by the
geotechnical engineer should not be considered to preclude requirement of
inspection and approval by the local building department.
F1.2 Compacted fill should be placed in thin horizontal lifts not exceeding eight
inches in loose thickness prior to compaction. Each lift should be watered or
dried as needed, thoroughly blended to achieve near optimum moisture
conditions then thoroughly compacted by mechanical methods to a minimum of
90 percent of laboratory maximum dry density (Modified Proctor). Each lift
should be treated in a like maimer until the desired finished grades are achieved.
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F1.3 The contractor should have suitable and sufficient mechanical compaction
equipment and watering apparatus on the job site to handle the amount of fill
being placed in consideration of moisture retention properties of the materials. If
necessary, excavation equipment should be "shut down" temporarily in order to
permit proper compaction of fills. Earth moving equipment should only be
considered a supplement and not substituted for conventional compaction
equipment.
Fl.4 When placing fill in horizontal Hfts adjacent to areas sloping steeper than 5:1
(horizontal: vertical), horizontal keys and vertical benches should be excavated
into the adjacent slope area. Keying and benching should be sufficient to provide
at least six-foot wide benches and a minimum of four feet of vertical bench
height withm the firm natural ground, firm bedrock, or engineered compacted
fill.
No compacted fill should be placed in an area subsequent to keying and benching
until the area has been reviewed by the geotechnical engineer. Material
generated by the benching operation should be moved sufficiently away from the
bench area to allow for the recommended review of the horizontal bench prior to
placement of fill.
Fl .5 Within a single fill area where grading procedures dictate two or more separate
fills, temporary slopes (false slopes) may be created. When placing fill adjacent
to a false slope, benchmg should be conducted in the same maimer as above
described. At least a 3-foot vertical bench should be established within the firm
core of adjacent approved compacted fill prior to placement of additional fill.
Benching should proceed in at least 3-foot vertical increments until the desired
finished grades are achieved.
Fl .6 Fill should be tested for compliance with the recommended relative compaction
and moisture conditions. Field density testing should conform to ASTM Method
of Test D 1556 (Sand Cone), D 2922 (Nuclear Metiiod), and D 2937 (Drive-
Cylinder). Tests should be provided for about every two vertical feet or 1,000
cubic yards of fill placed. Actual test intervals may vary as field conditions
dictate. Fill found not to be in conformance with the grading recommendations
should be removed or otherwise handled as recommended by the geotechnical
engineer.
Fl .7 The contractor should assist the geotechnical engineer or field technician by
digging test pits for removal determinations or for testing compacted fill.
Fl .8 As recommended by the geotechnical engineer, the contractor should "shut
down" or remove grading equipment from an area being tested.
F1.9 The geotechnical engineer should maintain a plan with estimated locations of
field tests. Unless the client provides for actual surveying of test locations, the
estimated locations by the geotechnical engineer should only be considered rough
estimates and should not be utilized for the purpose of preparing cross sections
showing test locations or in any case for the purpose of after-the-fact evaluating
of the sequence of fill placement.
liAmerican Geotechnical, Inc.
File No. 23080.02
March 27, 2007
F2 MOISTURE
F2.1 For field-testing purposes, "near optimum" moisture vsdll vary wdth material type
and other factors including compaction procedure. "Near optimum" may be
specifically recommended in Preliminary Investigation Reports and/or may be
evaluated during grading. As a preliminary guideline, "near optimum" should be
considered from one percent below to three percent above optimum.
F2.2 Prior to placement of additional compacted fill following an overnight or other
grading delay, the exposed surface or previously compacted fill should be
processed by scarification, watered or dried as needed, thoroughly blended to
near-optimum moisture conditions, then recompacted to a minimum of 90
percent of laboratory maximum dry density (Modified Proctor). Where wet or
other dry or other unsuitable materials exist to depths of greater than one foot, the
unsuitable materials should be over-excavated.
F2.3 Follovvdng a period of flooding, rainfall or over-watering by other means, no
additional fill should be placed until damage assessments have been made and
remedial grading has been performed.
F3 FILL MATERIAL
F3.1 Excavated on-site materials, which are acceptable to the geotechnical engineer,
may be utilized as compacted fill, provided trash, vegetation and other
deleterious materials are removed prior to placement.
F3.2 Where import materials are required for use on-site, the geotechnical engineer
should be notified at least 72 hours in advance of importing, in order to sample
and test materials from proposed borrow sites. No import materials should be
delivered for use on-site without prior sampling and testing by the geotechnical
engineer.
F3.3 Where oversized rock or similar irreducible material is generated during grading,
it is recommended, where practical, to waste such material off-site or on-
site in areas designated as "nonstructural rock disposal areas." Rock placed in
disposal areas should be placed with sufficient fines to fill voids. The rock
should be compacted in lifts to an unyielding condition. The disposal area should
be covered with at least three feet of compacted fill that is free of oversized
material. The upper three feet should be placed in accordance with these
specifications for compacted fill.
F3.4 Rocks 12 inches in maximum dimension and smaller may be utilized within the
compacted fill, provided they are placed in such manner that nestmg of the rock
is avoided. Fill should be placed and thoroughly compacted over and around all
rock. The amount of rock should not exceed 40 percent by dry weight passing
the 3/4-inch sieve size. The 12-inch and 40 percent recommendations herein
may vary as field conditions dictate.
F3.5 During the course of grading operations, rocks or similar irreducible materials
greater than 12 inches maximum dimension (oversized material), may be
liAmerican Geotechnical, Inc.
File No. 23080.02
March 27, 2007
generated. These rocks should not be placed within the compacted fill unless
placed as recommended by the geotechnical engineer.
F3.6 Where rocks or similar irreducible materials of greater than 12 inches but less
than four feet of maximum dimension are generated during grading, or otherwise
desired to be placed within an engineered fill, special handling is recommended.
Rocks greater than four feet should be broken dovra or disposed off-site. Rocks
up to four feet maxunum dimension should be placed below the upper 10 feet of
any fill and should not be closer than 20 feet to any slope face. These
recommendations could vary as locations of improvements dictate.
Where practical, the rocks should not be placed below areas where structures or
deep utilities are proposed. The rocks should be placed in windrows on a clean,
over-excavated or unyielding compacted fill or firm natural groimd surface.
Select native or imported granular soil (SE = 30 or higher) should be placed and
thoroughly flooded over and around all wdndrowed rock, such that voids are
filled. Windrows of large rocks should be staggered so that successive strata of
the large rocks are not in the same vertical plane.
The contractor should be aware that the placement of rock in windrows will
significantly slow the grading operation and may require additional equipment or
special equipment.
F3.7 It may be possible to dispose of individual larger rock as field conditions dictate
and as recommended by the geotechnical engineer at the time of placement.
F3.8 Material that is considered unsuitable by the geoteclmical engineer should not be
utilized in the compacted fill.
F3.9 During grading operations, placing and mixing the materials from the cut or
borrow areas may result in soil mixtures which possess unique physical
properties. Testing may be required of samples obtained directly from the fill
areas in order to verify conformance with the specifications. Processing of these
additional samples may take two or more working days. The contractor may
elect to move the operation to other areas wdthin the project, or may continue
placing compacted fill, pending laboratory and field test results.
Should the contractor use the second altemative, the fill may need to be removed
and recompacted depending on the outcome of the laboratory and field tests.
F3.10 Any fill placed in areas not previously reviewed and evaluated by the
geotechnical engineer may require removal and recompaction at the contractor's
expense. Determination of over-excavation should be made upon review of field
conditions by the geotechnical engineer.
F4 FILL SLOPES
Fl Unless otherwise recommended by the geotechnical engineer and approved by the local
building department, permanent fill slopes should not be steeper than 2:1 (Horizontal:
Vertical).
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File No. 23080.02
March 27, 2007
F2 Except as specifically recommended otherwise or as otherwise provided for in these
grading specifications, compacted fill slopes should be overbuilt and cut back to grade,
exposing the firm, compacted fill inner core. The actual amount of overbuilding may
vary as field conditions dictate. If the desired results are not achieved, the existing slopes
should be over-excavated and reconstmcted per the recommendation of the geotechnical
engineer.
The degree of overbuilding shall be increased until the desired compacted slope surface
condition is achieved. Care should be taken by the contractor to provide thorough
mechanical compaction to the outer edge of the overbuilt slope surface.
F3 Although no constmction procedure produces a slope free from risk of future movement,
overfilling and cutting back of slope to a compacted iimer core is, given no other
constraints, the most desirable procedure. Other consfraints, however, must often be
considered. These constraints may include property line situations, access, the critical
nature of the development and cost. Where such constraints are identified, slope face
compaction on slopes of 2:1 or flatter may be attempted as a second best altemative by
conventional constmction procedures including back-rolling techniques upon specific
recommendation by the geotechnical engineer.
Fill placement should proceed in thin lifts, (i.e., six to eight inch loose thickness). Each
lift should be moisture conditioned and thoroughly compacted. The desired moisture
condition should be maintained or re-established, where necessary, during the period
between successive hfts. Selected lifts should be tested to ascertain that desired
compaction is being achieved. Care should be taken to extend compactive effort to the
outer edge of the slope.
Each lift should extend horizontally to the desired finished slope surface or more as
needed to ultunately establish desired grades. Grade during constmction should not be
allowed to roll off at the edge of the slope. It may be helpfiil to elevate slightly the outer
edge ofthe slope. Slough resuUing from the placement of individual hfts should not be
allowed to drift down over previous lifts. At intervals not exceeding four feet in vertical
slope height or the capability of available equipment, whichever is less, fill slopes should
be thoroughly back-rolled utilizing a conventional sheepsfoot-type roller. Care should be
taken to maintain the desired moisture conditions and/or reestablishing same as needed
prior to back-rolling. Upon achieving final grade, the slopes should again be moisture
conditioned and thoroughly back-rolled. The use of a side-boom roller will probably be
necessary and vibratory methods are sfrongly recommended. Without delay, so as to
avoid (if possible) further moisture conditioning, the slopes should then be grid-rolled to
achieve a relatively smooth surface and uniformly compact condition.
hi order to monitor slope constmction procedures, moisture and density tests should be
taken at regular intervals. Failure to achieve the desired resuhs will Ukely result in a
recommendation by the geotechnical engineer to over-excavate the slope surfaces
followed by reconstmction of the slopes utihzing over-filling and cutting back procedures
or further attempts at the conventional back-rolling approach. Other recommendations
may also be provided which would be commensurate with field conditions.
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File No. 23080.02
March 27, 2007
G STAKING
Gl In all fill areas, the fill should be compacted prior to the placement of the stakes.
This particularly is important on fill slopes. Slope stakes should not be placed until the
slope is thoroughly compacted (back-rolled). If stakes must be placed prior to the
completion of compaction procedures, it must be recognized that they will be removed
and/or demolished at such time as compaction procedures resume.
G2 In order to allow for remedial grading operations, which could include over-excavations
or slope stabilization, appropriate staking offsets should be provided. For finished slope
and stabilization backcut areas, at least a 10-foot setback is recommended from proposed
toes and tops-of-cut.
H. MAINTENANCE
HI LANDSCAPE PLANTS
In order to enhance surficial slope stability, slope planting should be accomplished at the
completion of grading. Slope planting should consist of deep-rooting vegetation. Plants
native to the area of grading are generally desirable. A landscape architect would be the
best party to consult regarding actual types of plants and planting configuration.
H2 IRRIGATION
H2.1 Irrigation pipes should be anchored to slope faces, not placed in frenches
excavated into slope faces.
H2.2 Slope irrigation should be minimized. If automatic timing devices are utilized on
irrigation systems, provisions should be made for intermpting normal irrigation
during periods of rainfall.
H2.3 Though not a requirement, consideration should be given to the installation of
near-surface moisture monitoring control devices. Such devices can aid in the
maintenance of relatively uniform and reasonably constant moisture conditions.
H2.4 Property ovraers should be made aware that over-watering of slopes is
detrimental to slope stability.
MAINTENANCE
11 Periodic inspections of landscaped slope areas should be planned and appropriate
measures should be taken to control weeds and enhance growth ofthe landscape plants.
Some areas may require occasional replanting or reseeding.
12 Terrace drains and downdrains should be periodically inspected and maintained free of
debris. Damage to drainage improvements should be repaired immediately.
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File No. 23080.02
March 27, 2007
13 Property owners should be made aware that burrowing animals could be detrimental to
slope stability. A preventative program should be established to confrol burrowing
animals.
14 As a precautionary measure, plastic sheeting should be readily available, or kept on hand,
to protect all slope areas from saturation by periods of heavy or prolonged rainfall. This
measure is strongly recommended, begiiming with the period of time prior to landscape
planting.
STATUS OF GRADING
Prior to proceeding with any grading operation, the geotechnical engineer should be notified at
least two working days in advance in order to schedule the necessary observation and testing
services.
JI Prior to any significant expansion or cut back in the grading operation, the geotechnical
engineer should be provided with adequate notice (i.e., two days) in order to make
appropriate adjustments in observation and testing services.
32 Following completion of grading operations or between phases of a grading operation,
the geotechnical engineer should be provided with at least two working days notice in
advance of commencement of additional grading operations.