HomeMy WebLinkAbout3299; Home Plant Lift Station; Home Plant Pump Station Alternate Sloping Plan; 1991-11-11Geotechnical and Environmental Sciences Consultants
November 11, 1991
Project No. 100239-04
„.***• u • n~ * RECEIVEDPaafic Mechanical Corporation
2501 Annalisa Drive .... - <OQ1,
Concord, California 94520 NOV 5 Wli
Attention: Mr. Dave Backman Division of Occupational Safe^ a Hoalth
Subject: Alternate Sloping Plan A--..-.I BU..MU MACAUOSHA Permit Application *W$UOl Permit NO
Home Plant Pumping Station Notification Document R«C8fr«a
Carlsbad, California /") /}" " ' * NOV 51991
m References: Ninyo & Moore, 1987, "Preliminary Geotec!
Pump Station, City of Carlsbad North of the fttWfSlction of
m State Street and Carlsbad Boulevard Carlsbad, California,"
dated April 30
Ninyo & Moore, 1987, "Addendum to Preliminary Geotechnicalm Evaluation," dated October 26.
Gentlemen:
Ig In accordance with your request and authorization we have completed this evaluation of the
proposed excavation slope at the Home Plant Pumping Station in Carlsbad, California.
Previous work by Ninyo & Moore at the site included excavation, logging, and sampling one
small diameter boring within the perimeter of the excavation. The purposes of this letter are
to present our observations from this boring and the results of our slope stability analysis.m
*"" It is our understanding that the proposed excavation will be approximately 29.5 feet deep
m and that the sideslopes will be laid back at an inclination of 1:1. The boring at the
** excavation site encountered approximately 4.5 feet of fill underlain by approximately 11 feet
m of relatively dense beach deposits underlain, in turn, by sandstone and siltstone of the
** Santiago formation. The Santiago formation was very dense to a depth of at least 35.5 feet,
i*1 the full depth of the boring. Ground water was encountered at a depth of approximately
pi 30 feet.
_, Our slope stability analysis was performed using iterative searching algorithms of the
IH computer program PCSTABL-5M. The program uses trial and error methods to identify the
most critical potential failure surface for a given slope. Circular toe and mid-slope circles
10225 Barnes Canyon Road • Suite A-l 12 • San Diego, California 92121 • Phone (619) 457-0400 • Fax (619) 558-1236
• San Diego • Irvine
Pacific Mechanical Corporation November 4, 1991
Project No. 100239-03
*
were considered for this analysis. Strength parameters for the materials comprising the slope
were developed based on correlations between penetration resistance and internal friction
angle. Conservative assumed cohesion intercept values were included where appropriate.
An elevated water table was also assumed outside the excavation, which would act as a
destabilizing force in the analysis. The results of the computer analyses indicates that the
proposed final excavation should have a safety factor against gross instability of
approximately 2.1. Seismic slope stability analyses are generally not performed for temporary
construction slopes. Copies of the computer output have been included with this letter for
reference.
Based on the results of our subsurface evaluation and slope stability analyses, it is our
opinion that the proposed temporary excavation should have an adequate safety factor
against gross instability. We recommend that surcharge loads such as from excavated soil
or stockpiled construction materials not be permitted within 20 feet of the excavation.
Dewatering and slope face protection will be required if the excavation extends below the
ground water table. Slope protection from seepage erosion should consist of sand bags at
least two layers thick covering the entire seepage area. We recommend that the face and
the area near the top of the slope be inspected on a daily basis for ravelling, tension cracks,
or other indicators of potential slope instability. Our office should be contacted immediately
if such features develop and additional recommendations, if required, will be provided.
We appreciate this opportunity to be of service. If you should have any questions regarding
this matter please do not hesitate to call.
Yours sincerely,
NINYO & MOORE
Douglas R. Schwarm, RCE 47819
Project Engineer
Clifford A. Craft, RCE 28832/C?E 243
Chief Geotechnical Engineer
DS/CAC/hs
Distribution:
Attachment:
(4) Addressee
Slope Stability Analyses
-4-J
CO
in
men
oo
in
in
LDin
X o^r un
m
in
CO
0
HOME PLANT PUMP STATION
CUT SLOPE STABILITY
F.S. = 2.0
Fill
Beach Deposits
Santiago Formation
_L
18.75 37.50 56.25 75.00 93.75
X - AXIS (ft)
112.50 131.25 150.00
r i t i i § i t i vi ii r i i i ii n 11 11 •• • i ii ii ii ii
in
en
oo
in
HOME PLANT PUMP STATION
CUT SLOPE STABILITY
C/D
(-H
X<
in
OJ
LDin
m
F.S. = 2.1
Fill
Beach Deposits
Santiago Formation
inr^
CO
o
0 18.75 37.50 56.25
X -
75.00
AXIS
93.75
(ft)
112.50 131.25 150.00
p
m
m
m
PROFIL
HOME PLANT PUMP STATION CUT SLOPE WITH ASSUMED WATER TABLE
75
25. 30. 30. 30. 1
30. 30. 44. 44. 1
44. 44. 55. 55. 2
55. 55. 59.5 59.5 3
* 59.5 59.5 150. 59.5 3
m 55. 55. 150. 55. 2
1 44. 44. 150. 44. 1
SOIL
- 31 131. 135. 500. 41. 0. 0.1
118. 123. 300. 33. 0. 0. 1
_ 121. 125. 100. 31. 0. 0. 1
m WATER
* 165.
- 6
,L 25.30.
30. 30.
p, 35.35.
m 39.39.
59. 39.
m 150.39.
, CIRCLE
" 12
1010
25. 33. 59.5 150.
" 20. 10. 0. 0.
CIRCLE
12
710
42. 54. 59.5 150.
40. 5. 0. 0.
*»PCSTABL5M
by
fc Purdue University
m
^ —Slope Stability Analysis-
Simplified Janbu, Simplified Bishop
p or Spencer's Method of Slices
m Run Date: 11-04-91
m Time of Run: 4:00 P.M
Run By: MIT
pi Input Data Filename: A:239.IN
|l Output Filename: A:239.OUT
Plotted Output Filename: A:239.PLT
PROBLEM DESCRIPTION HOME PLANT PUMP STATION CUT SLOPE WITH A
SSUMED WATER TABLE
BOUNDARY COORDINATES
5 Top Boundaries
7 Total Boundaries
Boundary X-Left Y-Left X-Right Y-Right Soil Type
No. (ft) (ft) (ft) (ft) Below End
1
2
3
4
5
6
7
25.00
30.00
44.00
55.00
59.50
55.00
44.00
30.00
30.00
44.00
55.00
59.50
55.00
44.00
30.00
44.00
55.00
59.50
150.00
150.00
150.00
30.00
44.00
55.00
59.50
59.50
55.00
44.00
1
1
2
3
3
2
1
pi
to
to ISOTROPIC SOIL PARAMETERS
p
m
k
pt
ta 3 Type(s) of Soil
^ Soil Total Saturated Cohesion Friction Pore Pressure Piez.
Type Unit Wt. Unit Wt. Intercept Angle Pressure Constant Surface
m No. (pcf) (pcf) (psf) (deg) Param. (psO No.
PI
p
11 1 PIEZOMETRIC SURFACE(S) HAVE BEEN SPECIFIED
Unit Weight of Water = 65.00
p
P
pi Piezometric Surface No. 1 Specified by 6 Coordinate Points
1
2
3
131.0
118.0
121.0
135.0
123.0
125.0
500.0
300.0
100.0
41.0
33.0
31.0
.00
.00
.00
.0
.0
.0
1
1
1
Point
No.
1
2
3
4
5
6
X-Water Y-Water
(ft) (ft)
25.00 30.00
30.00 30.00
35.00 35.00
39.00 39.00
59.00 39.00
150.00 39.00
A Critical Failure Surface Searching Method, Using A Random
Technique For Generating Circular Surfaces, Has Been Specified.
^ Janbus Empirical Coef. is being used for the case of c & phi both > 0
100 Trial Surfaces Have Been Generated.
PI
M 10 Surfaces Initiate From Each Of 10 Points Equally Spaced
p Along The Ground Surface Between X = 25.00 ft.
and X = 33.00 ft.
Each Surface Terminates Between X = 59.50 ft.
and X = 150.00 ft.
Unless Further Limitations Were Imposed, The Minimum Elevation
At Which A Surface Extends Is Y = 20.00 ft.
10.00 ft. Line Segments Define Each Trial Failure Surface.
Following Are Displayed The Ten Most Critical Of The Trial
Failure Surfaces Examined. They Are Ordered - Most Critical
First.
* * Safety Factors Are Calculated By The Modified Janbu Method *
Failure Surface Specified By 6 Coordinate Points
Point X-Surf Y-Surf
No. (ft) (ft)
1 33.00 33.00
2 42.60 35.81
3 51.13 41.02
4 58.02 48.27
5 62.79 57.06
6 63.37 59.50
*** ***2.007
PI Individual data on the 13 slices
H
Water Water Tie Tie Earthquake
Force Force Force Force Force Surcharge
Slice Width Weight Top Bot Norm Tan Hor Ver Load
No. Ft(m) Lbs(kg) Lbs(kg) Lbs(kg) Lbs(kg) Lbs(kg) Lbs(kg) Lbs(kg) Lbs(kg)
1
2
3
4
5
6
7
8
9
10
11
12
13
2.0 189.5 .0
4.0 1516.4 .0
3.6 2653.5 .0
1.4 1312.6 .0
3.8 3976.2 .0
3.3 3867.5 .0
2.8 3415.4 .0
1.0 1208.3 .0
3.0 3524.2 .0
1.5 1607.8 .0
2.2 1700.5 .0
1.1 468.4 .0
.6 86.1 .0
71.8
574.8
905.8
295.0
340.4
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0 .0
Failure Surface Specified By
Point X-Surf
No. (ft)
1 30.33
2 40.33
3 49.99
4 58.51
5 65.17
6 69.41
7 70.17
Y-Surf
(ft)
30.33
30.02
32.59
37.82
45.28
54.34
59.50
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
7 Coordinate Points
*»* o n<n »**2.060
Failure Surface Specified By 6 Coordinate Points
Point X-Surf Y-Surf
No. (ft) (ft)
1
2
3
4
5
6
33.00
41.90
50.34
58.27
65.61
68.94
33.00
37.57
42.93
49.02
55.81
59.50
*** o ion ***2.120
Failure Surface Specified By 7 Coordinate Points
Point X-Surf Y-Surf
No. (ft) (ft)
1
2
3
4
5
6
7
25.00
34.81
44.71
53.58
60.41
64.44
65.13
30.00
28.06
29.47
34.10
41.40
50.55
59.50
*** 0101; ***2.125
Failure Surface Specified By 8 Coordinate Points
Point X-Surf Y-Surf
No. (ft) (ft)
1
2
3
4
5
6
7
8
27.67
37.58
47.52
56.87
65.09
71.68
76.25
77.18
30.00
28.70
29.86
33.38
39.08
46.60
55.50
59.50
2.218 ***
p Failure Surface Specified By 7 Coordinate Points
ft.
IP
IM
Point X-Surf Y-Surf
No. (ft) (ft)
1
2
3
4
5
6
7
31.22
39.96
48.60
57.15
65.59
73.94
77.31
31.22
36.09
41.12
46.31
51.67
57.18
59.50
*** 9 o^n ***2.225
Failure Surface Specified By 6 Coordinate Points
Point X-Surf Y-Surf
No. (ft) (ft)
1
2
3
4
5
6
30.33
38.96
46.99
54.36
60.96
63.70
30.33
35.40
41.35
48.12
55.62
59.50
»** 0 OIV5 ***2.252
Failure Surface Specified By 8 Coordinate Points
Point X-Surf Y-Surf
No. (ft) (ft)
1
2
3
4
30.33
39.94
49.29
58.32
30.33
33.11
36.66
40.97
fef
5
6
7
8
66.96
75.18
82.89
84.39
45.99
51.69
58.05
59.50
*** ? 057 ***2.253
Failure Surface Specified By 8 Coordinate Points
Point X-Surf Y-Surf
No. (ft) (ft)
1
2
3
4
5
6
7
8
30.33
40.28
50.17
59.38
67.33
73.50
77.50
77.78
30.33
29.26
30.71
34.60
40.67
48.54
57.71
59.50
2.268 *»»
Failure Surface Specified By 7 Coordinate Points
Point X-Surf Y-Surf
No. (ft) (ft)
1
2
3
4
5
6
7
32.11
42.11
51.87
60.86
68.60
74.70
77.70
32.11
32.02
34.22
38.60
44.92
52.85
59.50
»*»2.293
Y AXIS FT
.00 18.75 37.50 56.25 75.00 93.75
18.75 +
»
5
*6
..4 1W
A 37.50 + ..5 7 W
..20863.
....4 1 *
5 7.
....92 813.
4 7
X 56.25 + 5 6. .*
92W4 1 *
1.1
5 284634
9.0 2 2
5
I 75.00 + 985
95
93.75 +
112.50 +
F 131.25 +
T 150.00 + W * * *
A Critical Failure Surface Searching Method, Using A Random
Technique For Generating Circular Surfaces, Has Been Specified.
Janbus Empirical Coef. is being used for the case of c & phi both > 0
70 Trial Surfaces Have Been Generated.
10 Surfaces Initiate From Each Of 7 Points Equally Spaced
Along The Ground Surface Between X = 42.00 ft.
and X = 54.00 ft.
Each Surface Terminates Between X = 59.50 ft.
and X = 150.00 ft.
Unless Further limitations Were Imposed, The Minimum Elevation
At Which A Surface Extends Is Y = 40.00 ft.
5.00 ft. Line Segments Define Each Trial Failure Surface.
p Following Are Displayed The Ten Most Critical Of The Trial
|l Failure Surfaces Examined. They Are Ordered - Most Critical
First.
* * Safety Factors Are Calculated By The Modified Janbu Method *
Failure Surface Specified By 8 Coordinate Points
Point X-Surf Y-Surf
No. (ft) (ft)
1
2
3
4
5
6
7
8
44.00
48.99
53.84
58.38
62.43
65.85
68.52
68.95
44.00
44.27
45.49
47.59
50.52
54.17
58.40
59.50
*** *> 14£ ***2.146
Individual data on the 10 slices
Water Water Tie Tie Earthquake
Force Force Force Force Force Surcharge
Slice Width Weight Top Bot Norm Tan Hor Ver Load
No. Ft(m) Lbs(kg) Lbs(kg) Lbs(kg) Lbs(kg) Lbs(kg) Lbs(kg) Lbs(kg) Lbs(kg)
In
1
2
3
4
5
6
7
8
9
10
5.0 1390.6 .0
4.9 3743.3 .0
1.2 1182.6 .0
3.4 3953.9 .0
1.1 1462.7 .0
2.9 3506.7 .0
3.4 2935.3 .0
.5 311.4 .0
2.1 727.5 .0
.4 28.8 .0
.0 .0
.0 .0
.0 .0
.0 .0
.0 .0
.0 .0
.0 .0
.0 .0
.0 .0
.0 .0
Failure Surface Specified By 7
Point X-Surf
No. (ft)
1 42.00
2 46.95
Y-Surf
(ft)
42.00
42.69
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
Coordinate
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
Points
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
3
4
5
6
7
51.61
55.70
59.01
61.34
62.34
44.52
47.39
51.14
55.56
59.50
2.224
Failure Surface Specified By 6 Coordinate Points
Point X-Surf Y-Surf
No. (ft) (ft)
1
2
3
4
5
6
46.00
50.56
54.86
58.82
62.39
64.29
46.00
48.04
50.61
53.66
57.15
59.50
*** O 1OR ***2.325
Failure Surface Specified By 6 Coordinate Points
Point X-Surf Y-Surf
No. (ft) (ft)
1
2
3
4
5
6
48.00
52.79
57.21
61.11
64.33
64.76
48.00
49.44
51.77
54.90
58.73
59.50
*** 2.352 ***
Failure Surface Specified By 9 Coordinate Points
Point X-Surf Y-Surf
No. (ft) (ft)
1
2
3
4
5
6
7
8
9
42.00
46.52
50.98
55.38
59.71
63.97
68.15
72.27
72.30
42.00
44.14
46.40
48.78
51.28
53.90
56.63
59.47
59.50
*** "5 1ft3 ***2.383
Failure Surface Specified By 8 Coordinate Points
Point X-Surf Y-Surf
No. (ft) (ft)
1
2
3
4
5
6
7
8
44.00
48.49
52.93
57.30
61.61
65.86
70.03
70.94
44.00
46.19
48.50
50.92
53.46
56.11
58.86
59.50
***2.396
Failure Surface Specified By 7 Coordinate Points
Point X-Surf Y-Surf
No. (ft) (ft)
1
2
3
4
5
6
7
44.00
48.32
52.49
56.52
60.38
64.07
64.76
44.00
46.52
49.27
52.24
55.42
58.79
59.50
***2.448
Failure Surface Specified By 7 Coordinate Points
Point X-Surf Y-Surf
No. (ft) (ft)
1
2
3
4
5
6
7
44.00
48.30
52.50
56.62
60.64
64.55
66.10
44.00
46.56
49.26
52.10
55.08
58.19
59.50
2.462
fc, Failure Surface Specified By 9 Coordinate Points
PI
ta Point X-Surf Y-Surf
No. (ft) (ft)
m
M 1 42.00 42.00
2 47.00 42.21
•» 3 51.91 43.12
m
m
4
5
6
7
8
9
56.65
61.12
65.24
68.91
72.07
73.55
44.71
46.95
49.79
53.18
57.05
59.50
2.510 ***
Failure Surface Specified By 8 Coordinate Points
Point X-Surf Y-Surf
No. (ft) (ft)
1
2
3
4
5
6
7
8
44.00
48.50
52.97
57.42
61.85
66.26
70.64
73.70
44.00
46.19
48.42
50.69
53.01
55.38
57.78
59.50
2.511 »»*
Y AXIS FT
.00 18.75 37.50 56.25 75.00 93.75
nO 4-,V/v_| -|-
m
18.75 +
m - W
A 37.50 + W
m . 2
m »
.2534
"• - ..153.
m - ..91.4...
X 56.25 + ...92534*
*" - W...1.2.37 *
m - ....9.1042.2
9 1643
"" - 9.511
M - 905
I 75.00 + 9
PI
S 93.75 +
112.50 +
F 131.25 +
T 150.00 + W * * *