DEPARTMENT OF THE INTERIOR
U.S. Geological Survey
Summary of Geotechnical and Hydrologic Data Collected Through April 30, 1990,
for the Alani-Paty Landslide, Manoa Valley, Honolulu, Hawaii
by
Rex L. Baum 1 , Steven R. Spengler2 , Jill D. Torikai2 , and Lori Ann S.M. Liu2
Prepared in Cooperation withthe City and County of Honolulu,
Department of Public Works
Open-File Report 90-531
This report is preliminary and has not been reviewed for conformity with U.S. Geological Survey editorial standards. Any use of trade names is for descriptive purposes only and does not imply endorsement by the U.S. Geological Survey.
Denver, CO 2Honolulu, HI
1990
INTRODUCTION
Following mapping of slow-moving landslides on the east side of Manoa Valley (Baum and others, 1989) we began a detailed investigation of the Alani- Paty landslide (fig. 1) in order to understand the physical processes active in it and similar landslides on Oahu. We have compiled observations and measurements collected during the first 8 months (from September 1989 through April 1990) of our investigation in order to make these basic data available to all parties that have interest in the landslide. The following brief summary highlights our preliminary observations of the depth, composition, and behavior of the Alani-Paty landslide, as well as the behavior of subsurface water. Five appendices containing logs of borings, laboratory test results, estimates of depth of the landslide, and graphs of subsurface water conditions, daily precipitation, and displacement follow the summary. Each appendix is preceded by a few paragraphs that describe the methods used to obtain the data.
SUMMARY OF MEASUREMENTS AND OBSERVATIONS
Subsurface exploration and laboratory testing The landslide material, as sampled by means of borings (fig. 2), consists of about 20 to 50 percent boulder-, cobble- and gravel-sized clasts of weathered basalt in a fine-grained matrix (Appendix A). The matrix is brown to gray, sandy to slightly sandy, highly plastic, clayey silt interlayered with dark brown to gray, highly plastic silty clay. At the time of drilling, most matrix material within the landslide was wetter than its plastic limit, while much of the material beneath the landslide (deeper than about 30 ft) was drier than its plastic limit.
Laboratory testing of several specimens (Appendix B) indicates that the matrix material has high plasticity and low residual shear strength. Plastic limits range from 29 to 54, and Liquid limits range from 59 to 137. The matrix contains roughly 50-75 percent clay, 10-30 percent silt, and 5-25 percent sand. Specimens that are rich in clay and have high liquid limits have residual strength parameters in the following ranges: friction angle from 6 to 11°, with cohesion intercepts from 0 to 217 Ibf/ft2 . One specimen having a relatively low clay content (48 percent) and low liquid limit (59) had a higher residual strength, characterized by a friction angle of 25° and cohesion intercept of 231 lbf/ft2 .
Most of the matrix material has no recognizable structure at the scale of the cores. However, some of the clay (called fissured clay in the logs, Appendix A) from depths greater than 20 ft crumbles into shiny flakes and blocks from 1/8 in. to 1/2 in. across. Slickensided shear surfaces were present in samples from several borings. The shear surfaces were from a variety of depths, and some of the shear surfaces were from different depths than the basal slip surface of the landslide.
Depth of the landslide The landslide is approximately 20 to 25 ft deep (Appendix C) in the vicinity of its head, at the hairpin-curve intersection of Alani Drive and Paty Drive and between the extension of Paty Drive and Kahaloa Place (fig. 2). Between Kahaloa Place and Lono Place, thickness of the landslide ranges from about 25 ft to perhaps 33 ft.
158° 00'
30'
Hulu-Woolsey landslide
Figure 1. Map showing location of landslides in the Woodlawn area, Manoa Valley, Honolulu, Hawaii.
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Instrumentation Instrumentation was installed at the surface of the landslide and in borings in order to measure rainfall, displacement, depth of the landslide, and ground-water levels. Surface instrumentation (fig. 2) consisted of rain gauges and an extensometer (for measuring displacement). Bore-hole instrumentation consisted of anchored cables for measuring displacement and open-tube piezometers for measuring water levels. Three borings each were cased for inclinometer and neutron-probe measurements. Rainfall observations are compiled in Appendix D and summarized below. Measurements of displacement are compiled in Appendix E. Difficulties resulting from materials at the site and from installation of the casing made the neutron probe ineffective for monitoring soil-moisture conditions. Displacement of the landslide since installation of the anchored cables has been insufficient (less than the diameter of a boring) to pull the cables down the hole a measurable amount. Consequently, no data from neutron-probe measurements or measurement of the cables are included in this report. The data collected from our piezometer and inclinometer measurements are compiled in Appendix C.
Rainfall and movement of the landslide Rainfall for the period from September 26, 1989, to April 24, 1990, totaled 44 in. at the head of the landslide. Most of this fell during October 1989 and January, February, and March 1990. Surface displacement (at the headscarp, fig. 2) from September through April totaled approximately 0.3 ft, and much of the displacement occurred during and after storms (Appendix E). Approximately 0.05 ft of movement occurred during and after a storm on October 3, 1989. Also, 0.1 ft of movement occurred from January 15 to 19, during and after a storm that lasted from January 14 to 18, 1990. An additional 0.1 ft of movement was recorded a few days later, from January 23 to 29, 1990. The nature of this additional movement is uncertain; our recorder appeared to have been disturbed during this time but tape and level surveys indicate that cumulative displacement at the extensometer site from September 13 to April 27 was slightly greater than that recorded by the extensometer (Appendix E). Creeping movements between storms account for the remaining displacement.
Crude measurements indicate that the head of the landslide moved approximately 1 ft between April 1989 and April 1990. Most of this movement must have occurred before our extensometer was put into operation.
Ground-water conditions Several trends are obvious in the ground- water observations. Water levels in several piezometers (in borings 1, 8, 9, 20 and 100) upslope from Kahaloa Place (fig. 2 and Appendix C) increased and then gradually returned to normal within a few days of the rainy period of January 14-18 as well as the rainy period of February 24 to March 1. Increases in water levels during January ranged from 1 to 10 ft. Water levels in most piezometers (except 16) downslope from Kahaloa Place changed insignificantly during and after storms. Water levels in piezometers at shallow and intermediate depths downslope from Kahaloa Place (borings 3, 4, 5, 13, 14, 16, 19, and 19x) have generally been steady since shortly after installation. Deep piezometers in borings 3 and 9 and the intermediate piezometer in boring 16 showed steadily declining or steadily increasing water levels, indicating that the water levels in these piezometers had not yet
reached equilibrium with their surroundings. Many of the deep (30-40 ft) piezometers are always dry (see table Cl in Appendix C).
;
Displacement in areas outside the mapped boundaries of the landslide -- Inclinometer measurements were made in two locations (borings 10 and 15, see fig. 2 and Appendix C) where incipient movement was suspected (Baum and others, 1989) and in one place (boring 6) that appears to be stable ground between the Hulu-Woolsey and Alani-Paty landslides. The inclinometer in Boring 15 indicates sliding occurred at a depth of 26 ft during January 1990. Thus far, borings 6 and 10 have shown only small random deflections but no unequivocal evidence of sliding.
ACKNOWLEDGEMENTS
We thank Sam Callejo and his staff of the Department of Public Works, City and County of Honolulu, for coordinating access to sites for drilling and instrumentation. We also thank residents and owners of property in the landslide area for their cooperation in providing access to sites for drilling and instrumentation of the landslide. George Erickson performed the laboratory tests reported in appendix B.
REFERENCES
Baum, R.L., Fleming, R.W., and Ellen, S.D., 1989, Maps showing landslidefeatures and related ground deformation in the Woodlawn area of the Manoa Valley, City and County of Honolulu, Hawaii: U.S. Geological Survey Open-File Report 89-290, 16 p. + 2 oversize plates.
APPENDIX A
Subsurface Exploration
This appendix contains logs of borings made in the study area and an explanation of symbols used in the logs (figs. Al, ..., A20). The logs describe the materials encountered in the borings, indicate where samples were taken, and show graphically the moisture content and penetration resistance of the materials. Boundaries between different materials indicated in the logs are located only approximately. Boring and sampling operations were performed by Geolabs-Hawaii, under contract with the City and County of Honolulu, Department of Public Works. We observed drilling, wrapped samples for storage, and recorded our observations. We kept records in the field of the progress of drilling, sample intervals, penetration resistance, materials encountered, locations of moisture samples, and so forth. Later, in the laboratory, we examined and described the samples in greater detail. The finished logs were constructed by combining information from our laboratory examinations with the data in our field logs.
Personnel from the City and County of Honolulu determined the surface elevations of most borings by leveling. USGS personnel extended the City/County surveys to most of the remaining borings. The surveyed elevations reported here have been rounded to the nearest 0.1 ft. We estimated elevations of the few borings that had not been surveyed using a topographic map made by R.M. Towill Corp. for STV/Lyon Associates.
All samples were collected either by driving a ring sampler or by coring with a diamond bit. The ring sampler was driven by the blows of a 140-lb hammer falling 30 in. Penetration resistance is reported as the number of blows required to drive the ring sampler through the last 12 in. of an 18-in. run. Where sample runs were shorter than 18 in., the penetration resistance is reported as the number of blows required to drive the sampler over the shorter interval. For example, 50:0.3' indicates that 50 blows were required to drive the sampler 0.3 ft.
Explanation of symbols used in logs of borings
I Ring sample, approximately 2-1/4 inches in diameter
I NX-size core
Clay or silty clay
Sandy clay or sandy silty clay
Clayey silt or mixture of clayey silt and silty clay
Sandy clayey silt or mixture of sandy clayey silt and sandy silty clay
Basalt (bedrock)
Gravel and cobble sized clasts of weathered basalt (boulders represented by larger ovals)
Figure Al
LOG OF BORING B(
+ Blows per foot Sample Moisture content
50 40 30 20 10 0
/64%J 10:0.0'
+ 50:0.7'
10:0.0'
50:0.3'
100:0.6'
j
+
16:0.5'
+
4
+
Corer
+
scovery 100%
69%
92%
76%
62%
)RING 1 Surface Elevation 288.6ft
- Depth (feet)
fUhobgfc symbol SQ|L DESCR|pT|ON usc
mm mm
H5 \J
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10
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35-
40
.
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Boulder
Brown, sandy, clayey silt and silty clay with gravel-, cobble-, and boulder-sized clasts ofweathered basalt; moist, stiff.
Boulder Brown sandy clay with gravel-, cobble-, and boulder-sized clasts of weathered basalt. Slickensides dipping 45° at 24.0 ft.
Gray to brown silty clay with gravel-, cobble-, and boulder-sized clasts of weathered basalt. Clay is fissured be tow 31 ft.
Boulder
* Boring terminated at 41.25 ft on 9/25/89
MH
MH
CH
CH
figure A2
LOG OF BORING BO+ Blows per foot Sample ~ Moisture content
50 40 30 20 10 0
67%
4
4
4
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Q recover 32%
43%
66%
30%
79%
100%
86%
y
RING 3 Surface Elevation 202.3 ft
Depth (feet)
[^'09teSymb01 SOIL DESCRIPTION
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Gray, slightly sandy, clayey silt and silty clay with gravel- and cobble-sized clasts of weathered basalt; moist, stiff.
Gray, slightly sandy, clayey silt and silty clay with gravel-, cobble-, and boulder-sized clasts of weathered basalt; moist, stiff.
Boulder
Boulder
Brown to gray, slightly sandy, silty clay with gravel-, cobble-, and boulder-sized clasts of weathered basalt. Well-developed slickensides, dipping from 0 to 15°, in zones from 26.5 to 27.5 ft and from 31 .5 to 32.5 ft.
Boulder
Brown to gray, fissured, clayey silt and sandy clayey silt with cobble- and boulder-sized clasts of weathered basalt.
Boulder
t- Boring terminated at 41.5 ft on 9/29/89
use
MH/ CH
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LOG OF BORING BO+ Blows per foot Sample - Moisture content
50 40 30 20 10 0
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43%
84%
94%
98%
100%
88%
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RING 4 Surface Elevation 230.8 ft
Depth (feet)
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Dark brown sandy clay with coral sand and gravel- and cobble-sized clasts of weathered basalt. Fill.
Gray and rust-brown slightly sandy clay with gravel-, cobble-, and boulder-sized clasts of weathered basalt; moist, stiff.
Dark-brown to gray-brown slightly sandy clay with gravel-, cobble-, and boulder-sized clasts of weathered basalt; stiff, moist.
Sandy below 21 ft.
Boulders
Gray to brown sandy, clayey silt and silty clay with gravel-, cobble-, and boulder-sized clasts of weathered basalt. Steeply dipping slickensided shear surface at 27.5 ft.
Boulder
Boulders
* Boring terminated at 41 .0 ft on 10/3/89
CH
CH
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MH/ CH
10 Figure A4
LOG OF BORING BC
+ Blows per foot Sample £ Moisture content
50 40 30 20 10 0
^0:0.5' :
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7%
58%
80%
64%
84%
82%
ry
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- Surface Elevation 231 .5 ft
Depth (feet)
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Brown clayey silt with gravel- and cobble-sized clasts of weathered basalt. Fill.
Brown clayey silt with gravel- and cobble-sized clasts of weathered basalt; stiff, moist, contains roots.
Water in fractures in cobble at 5.8 ft
Dark-brown clayey silt and silty clay with gravel-, cobble-, and boulder-sized clasts of weathered basalt; hard, moist.
Cobbles
Boulder
Gray-brown, fissured, clayey silt and silty clay with gravel-, cobble-, and boulder-sized clasts of weathered basalt. Well-developed slickensides in a layer having schistose structure between 26.5 and 28.5 ft.
Boulder
Cobbles
* Boring terminated at 41.5 ft on 10/6/89.
MH
MH
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MH/ CH
11Figure A5
LOG OF BORING (continued on next page) BC
+ Blows per foot Sample Moisture content
50 40 30 20 10 0
60%
64%^
^60
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Cor<3 recover
100%
20%
88%
52%
88%
52%
44%
/
)RING 6 Surface Elevation 223.9 ft
- Depth (feet)
[<***W«M so,,. DESCRIPTION USC
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Boulder
Gray and gray-brown sandy clay with gravel-, cobble-, and boulder-sized clasts of weathered basalt; stiff, moist.
Boulders
Fissured gray and gray-brown sandy clay with gravel-, cobble-, and boulder-sized clasts of weathered basalt.
Gray and gray-brown sandy (locally very sandy) clay and clayey silt with gravel-, cobble-, and boulder-sized clasts of weathered basalt.
Cobbles
CH
CH
CH
CH
CH/ MH
12Figure A6a
LOG OF BORING BORING 6 (continued)+ Blows per foot Sample Moisture content
50 40 30 20 10 0
Core recovery
80%
50
Depth (feet)
f****"*** SOIL DESCRIPTION USC
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^- Boring terminated at 50.0 ft on 10/1 1/89.
13 Figure A6b
LOG
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OF BORING BO
+ Blows per foot Sample ~ Moisture content
) 40 30 20 10 01~>
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Core recovery
91%
70%
86%
34%
26%
26%
92%
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RING 7 Surface Elevation 294.6 ft
Depth (feet)
l^ithologic symbol SOJLDESCR|pT|ON
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Asphalt concrete and base course.
Brown clayey silt with gravel- and cobble-sized clasts of basalt and fragments of brick. Fill.
Dark-brown sandy, clayey silt with gravel-, cobble-, and boulder-sized clasts of weathered basalt; hard. Basalt clasts less abundant below 21ft.
^^^9
^g Weathered gray basalt with thin seam of brown silt H at 40.0 ft.raBsi^a^^9^^^^8
RoSSSSSun^^^^^n^^^^^i
* Boring terminated at 41.0 ft on 10/17/89
use
MH
MH
14 Figure A7.
LOG OF BORING BO
+ Blows per foot Sample ~ Moisture content
50 40 30 20 10 0
30:0.5'
; .»
U:0.5'
4
Co
>
re recovc
44%
64%
28%
80%
84%
60%
try
RINC
m
5
:io
> o Surface Elevation 325.2 feet
Depth (feet)
rLith0l°9k:Symb01 SOIL DESCRIPTION USC
MM
15-
20
25
30
'
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35
40
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11 M I'MMI M
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Brown, sandy, clayey silt with gravel- and cobble-sized clasts of weathered basalt as well as fragments of brick and wood; stiff, moist. Fill.
Boulder
Brown, sandy, clayey silt and sitty clay with gravel-, cobble-, and boulder-sized fragments of weathered basalt; hard, moist.
Boulders
Boulders
Boulder
* Boring terminated at 41 .0 ft on 1 0/1 9/89
MH
MH/ CH
15 Figure A8.
LOG OF BORING BO+ Blows per foot Sample ~ Moisture content
50 40 30 20 10 0
61%
60%
^60
60%
*.
19:0.5'
+
++
Core
*
recovery
65%
22%
36%
60%
36%
76%
:
;
RING 9 Surface Elevation 324.0 ft
Depth (feet)
^ithologic symbol so|LDESCR(pT|ON ^
:5
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"10
15-
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20 .
25 i
30
35-
40
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Brown, sandy, clayey silt with gravel- and cobble-sized clasts of weathered basalt; stiff, moist. Fill.
Brown, sandy, clayey silt and silty clay with gravel-, cobble-, and boulder-sized clasts of weathered basalt; stiff, moist.
Boulder
Boulders
Boulders
L Boring terminated at 41 .0 ft on 10/23/89.
MH
MH/ CH
16 Figure A9.
LOG OF BORING (continued on next page) BO
+ Blows per foot Sample ~" Moisture content
50 ^0 30 20 10 0
«..
*
+
+
Core recover)
100%
20%
62%
44%
80%
88%
46%
67%
f
RING 10 Surface Elevation approx. 336 ft
Depth (feet)
[H-fth0l0giCSymb0l SO!L DESCRIPTION
\
- 5
10
15
20
25
30
35
.40
-mm
mmmc: ft::':::':!::: :?r
pll
'iVinVrui+Ti'n''>'r't>VK'r
Ona..;.:.;.:-:.:.:.: : >
SSHi
. 1 1 1 ! 1 1 1 1 1 .
^Oifi'rr:vrr:V:'i- nvirivi'ntpi
.l.'.l.l.'.l.'.l.i*!*
DOHi.'rrrrrrrrrifr^^f^pf^i'^t
Hi^X'X'X'J*'i i i i i i i 1 1 1 !*
iii>M hpjJM**
iii3fc£"SiliSJiS;
Id 1 1
IICL:
-o --1 1 o I
iQ::-CD-
Asphalt concrete and base course
Brown, clayey silt and sandy clayey silt with gravel- and cobble-sized clasts of weathered basalt as well as man-made materials; hard, moist. Fill.
Mottled gray to dark-brown sandy clay and clayey silt with gravel-, cobble-, and boulder-sized clasts of weathered basalt; stiff, moist.
Boulder
Boulders
Boulders
Fissured, brown, silty clay with gravel-, cobble-, and boulder-sized clasts of weathered basalt.
Cobbles
use
MH
CH/ MH
CH
17Figure AlOa
LOG OF BORING BOI+ Blows per foot Sample ~ Moisture content
50 40 30 20 10 0
Core recovery
0%
RINCa 10 continued
Depth (feet)
pLrthologic symbol so|LDESCR|pT|ON ^
50
lOr- 0?*
- -a - -
Cobbles
^ Boring terminiated at 48.5 ft on 1 0/27/89
18 Figure AlOb.
LOG OF BORING BO+ Blows per foot Sample ~ Moisture content
50 40 30 20 10 0i
30:0.5'
32:0.8'
4
' t
>
4
<
4
*Core
>
recovery
100%
26%
10%
58%
67%
f
]
]
RING 1 1 Surface Elevation 334.5 ft
Depth (feet)
r^ithologic symbol soiLDESCRlpT|ON ysc
]
M 5 ~""
JO
J5
20
25-
-30
35-
40
Sill?
§Q|zmii&
mi^-O^S*""
USI. . : : :-:-: : : : :?"
sS5-;-
1-511" p«t
O
i ii£:+Ko«ii ' & :*« : » i *i?:+h:Si 'Axiwii:^ji: |wi|:«w::;
£I:I:N* ?S-:?R-: r^. M^;.;^* . «
I* lW:W-4
i* «::*> 'H- H+X^.- ^
4> £*: &: <i4- H^Xtt:- 4
I«1M't W&
f. tff&ffi*.* W ::W:: \ * «": :::!««-: >
SjFSWi:':?
jrSspi'3 S5H5SJ7^ ?!^X«!*?:' '.
. ~:-':^:: . . uu:-:-^:-: .!* &+: _ :;M;:; « * ^::'i*ii':" H- i**:>O: i*i ;-ijji:::i*:: >iiii H^:-:iH>> « ^jfiij!**:: <M- '^w:-^*:' ^ir '**< * < i
i. -^r'::-^:: ,.- ii»:: iii.:- .
y^liS:^c *« :*« :»* .-t^^^M;:-1;
» :H<'':*«-: " ^'^ rw-: **::W:i-i;:
siiSl^
s:;ii.:;;S:i.
1PPIQM
Asphalt concrete and base course
Dark-brown clay and sandy day with gravel-sized clasts of weathered basalt; stiff, moist.
Gray to brown, slightly sandy, clayey silt and silty clay with gravel-sized clasts of weathered basalt; stiff, moist.
Boulders
Brown to gray, fissured, sandy to slightly sandy clay with gravel-, cobble-, and boulder-sized clasts of weathered basalt.
Steeply dipping slickensides in zone from 27 to 30 ft.
Dry, hard
Cobbles
L Boring terminated at 41.5 ft on 1 1/2/89.
CH
MH/ CH
CH/ MH
19Figure All
LOG OF BORING BORING 12 Surface Elevation 250.9 ft
50
Blows per foot Moisture content
40 30 20
Sample
10 0
Depth (feet)
DESCR|pT, ON use
19:0.5'
111
.98
,61
.27:0.3'
^40:0.5' 140
Brown, sandy, clayey silt with gravel- and cobble-sized clasts of weathered basalt, contains some roots and other organic matter. Fill.
5 ^1Gray sandy clay with rust-orange pockets of
i;:ii sand and gravel-, cobble-, and boulder-sized clasts of weathered basalt; stiff, moist.
10 "
Brown, sandy, clayey silt with gravel-, cobble- and boulder-sized clasts of weathered basalt; stiff, moist.
Boulder
Gray, slightly sandy clay with gravel- and cobble- sized clasts of weathered basalt; stiff, moist. Clay is brown below 21 ft.
Of
Brown, sandy, clayey silt with gravel, cobble-, and boulder-sized clasts of weathered basalt;
I ' m^Q^. hard, dry.
30 ___Numerous cobbles in interval from 30 to 40 ft.
Hi
tfJvPT 35 t
L20
Boring terminated at 40.5 ft on 11/6/89
Figure A12.
LOG OF BORING+ Blows per foot Moisture content
50 40 30 20
BORING 13 Surface Elevation 250.2 ft
Sample ]
10 0
Depth (feet)
ithologic symbolSOIL DESCRIPTION use
75%
21:0.0'
61:0.5' "
21
Brown, sandy, clayey silt with gravel- and MH boulder-sized clasts of weathered basalt. Fill.
Boulder
J_ 5 mm
I . |if||f| Brown, sandy, clayey silt and silty clay with MH/ gravel-, cobble-, and boulder-sized clasts of CH
iiiiStl weathered basalt; hard, moist. Abundant cobblesbelow 15 ft.
10
IpP^P Boulder 15
20
IQIH
ij-r30
I 35
Boulders and cobbles
40
-Boring terminated at 40.0 ft on 11/7/89
Figure A13.
LOG OF BORING BO+ Blows per foot Sample "" Moisture content
50 40 30 20 10 0
«?» '
.32:0.5'!
;
1
:
15:0.5'
< ^10:0.5'
RINC
5
_JO
T20
J_25-
30
35-
I
140
* .j 4 Surface Elevation 284.2 ft
Depth (feet)
rithologic symbol ncQrniPTinN MQP
M
mi^m
i
i
^
£*^
~ *" ^ "
Q~~ ^ -j .JQL_O
i:>ii::ii:::
1
IH?imiiS ii
1S-':?S':?? :"
5:ip^;:
*|:Wci-.|w
!fi::Sfi::v? ?'* ; ;*»< ; *'( : !
'&ij& ?^:/'ii:: '.fii, iftliii:;;* .*;W:|fi': ::"
I ?I !
o»:-:44<*:-w-:-p
i«iNN»>:<M< : **« '. ;
Loose gravel with clayey matrix. Fill.
Brown to gray, sandy to slightly sandy, organic clay with gravel-, cobble-, and boulder-sized clasts of weathered basalt; moist, stiff.
Gray-brown, fissured clay with gravel-, cobble-, and boulder-sized clasts of weathered basalt; moist, hard. Clay is locally sandy. Slickensides in intervals from 15 to 16 ft, 19.5 to 20 ft, and 29 to 30 ft. Slickensides in interval from 1 9.5 to 20.0 ft are well developed and dip from 0 to 15°.
Boulder
Brown sandy clay with gravel-, cobble-, and boulder-sized clasts of weathered basalt; dry hard.
^ Boring terminated at 40.5 ft on 1 1/22/89.
GP/ GC
OH
CH
CH
22 Figure A14,
LOG OF BORING (continued on next page) BORING 1 5 Surface Elevation 245'4 ft
4 Blows per foot Sample i Depth (feet) Moisture content
50 40 30 20 10 0 |^rth0l°9iC Symb°' SOIL DESCRIPTION USC
.68
^50:0.5'
.~0
63%
^2:0.5'
63%
^0:0.5'
38:0.5'
52:0.5'
^4:0.2'
<
:
4
4
*
4
5 ---
--10 -
_.
--I 16 ~
I :20
--
--25-
30
I
QC
I '
.
I '-"-40
i ;
±r:.-
*-
-o
OK-:«X « : -:?M|;:;-
l;ii;|i::-
i|$|:;;S|!
ijiiiiiiiiijiii.
i§&^:^;':iii»x«
iBji
111
i||III
fi
Pip»: : .-:«.- -Qk-;"---;.
T::^; : :''"'.: "
IlliISi^'i'vlv^lx^.
MMJMMiM
"vT?^^^
. :-!vi-:vl-lv!v
iii : i:;i :iaiiiiia
««W*«P*N«f4M
i i.i. .i.i.'.i.i.'ii'!**
T ' m .'.' V!*i>ll> l|il<l»
TTfT'TTT^
Brown clay and clayey slit with gravel- andcobble-sized clasts of weathered basalt; dry, hard.
Boulder
Gray to brown silty clay and sandy clayey silt withgravel-, cobble-, and boulder-sized clasts ofweathered basalt; stiff, moist. Clay locallyfissured between 1 8 and 32 ft. Well-developedslickensides dipping from 0 to 15° in intervalfrom 24.5 to 25.0 ft.
Ground water at approximately 13 ft
Boulder
Boulders
Gray to brown, sandy, clayey silt, fissured at bottom of interval, with gravel-, cobble-, andboulder-sized clasts of weathered basalt; hard,dry.
CH/MH
CH/MU Mn
MH
23 Figure A15a,
LOG OF BORING BORING 15 continued
+ Blows per foot Sample Depth (feet) Moisture content
50 40 30 20 ,10 0 [Lith0l09iCSymb°l SOIL DESCRIPTION USC
33:0.2' j50
8il
Boulders and cobbles
* Boring terminated at 50.8 ft on 1 1/27/90.
24 Figure A15b.
LOG OF BORING BO> Blows per foot Sample - Moisture content
50 ^0 30 20 10 0
89%
^47:0.5'
*
^2:0.6'
Refusal
.
:,
:
:^
1
] ]n
RING 1 6 Surface Elevation 247.5 ft
Depth (feet)
rUth0l°9iC» SOIL DESCRIPTION USC
[ ;5 -
i
"15
-20
25-
_ '
30-
-35-
140-
to>iip*X'**; v
-£ \fffffff .-f-: 't*y+^:. H.::^,::-ii:..W «i'-H""«
^:- M:: :W: < *«*;:»;*»:-M*i : **< fc^:':'-^c>^':'-i;->jji-'.-*^i;X^*:-:±*<^-<-~ :;:M»XMV«
11M-:::i^: ::^.::;.'^' ^' . -t-:-^.
?:':-^::S: ::r
ISJll
ii'-ilif &' :
SiffiiS' "
Mil-i:;i;:f^. .. : :« :' < i
qy CBiiiiii^ii 'i
lH:5 :??:: ? "
* -M* .:*» :4*)&* : *! S
111!Illlr-iiii* '
Hi^
OO:oii&iS*.
D . .-.~v>.-a-',-.-
1
Asphalt concrete and base course
Brown to gray, sandy, silty clay and clayey silt with gravel-, cobble-, and boulder-sized clasts of weathered basalt; stiff, moist.
Boulders
Boulders
Dark-gray to brown, sandy, clayey silt and silty clay with gravel-, cobble-, and boulder-sized clasts of weathered basalt; hard, moist.
Boulder
Boulders
L- Boring terminated at 40.5 ft on 1 1/28/90
CH/ MH
MH
25 Figure A16.
LOG OF BORING BORING 17 Surface Elevation aPProx- 321 ft
+ Blows per foot Sample i Depth (feet) Moisture content
r-Lithologic symbol _ _ ^ 50 <0 30 20 10 0 SOIL DESCRIPTION USC
*4:0.2'
'
i
. >
13:0.5'
11:0.5'
n
I 5
I :JoJ
-M5
20
25
30-
i 35 -
-*-40
^v***
HHI: :-: : : : : : : : : : :
-35320-
'tmO?want : :?:' ffl-i-fv
" Vl :^J»hp<
SOiiSi
Soi jiHliii3£i:>TflP^^
iioilipgg^U-!?!vf?1;-'^
Ii i i i'lVi in;
^ ^yi iVijVijVl)^
: !::Q:!:!;!:!;iv;
*iiQSi.
iSStt*
liiP: : : ; »: :-MV: : :; :-:
ISS!^??_^_
0r^pO1!-.-"ivMxXv:
::::^v:-::->:-'Y: :
HP
Sri^jgi?;
:>: »:¥:>¥:¥
^^^
lli;i-
11
1 Asphalt concrete and base course
Red-brown to brown sandy, clayey silt withabundant gravel-, cobble-, and boulder-sized clasts of weathered basalt; hard, moist.
Boulders
Gray to brown, fissured, slightly sandy clay with gravel- , cobble-, and boulder-sized clasts of weathered basalt. Slickenslides dipping approx . 45° at 39 ft.
^ Boring terminated at 42.0 ft on 1 1/30/89.
GC/ MH
CH
26 Figure A17
LOG OF BORING BORING 18 Surface Elevation 297- 5 ft
4 Bbws per foot Sample i Depth (feet) Moisture content
50 40 30 20 10 0 ^^ ^ SOIL DESCRIPTION USC
^0:0.2'
25:0.4'
42:0.5'+
.59
^0:0.5'
£4:0.8'
i
t
+
4
5 "~~"
I I<-i :
15
I ;
20 ~
i :X
25
IE
30
i35
I
40
T
*<>* >:-:-x-:-:-:-:-:-:-:
^.Q'Sivi^.
V»iV!'uet»M-
iVift>*M'K;*
i.'.'!!.''.''!"*'!'!'!"
IKlp*r
iO^iCT^**:*:::-
li§:l-o-;ii&
lHI
ssIS:-*!^
I'i^^"
H;|£|:!:!:"
|i^6-
^*i^«M-i4*:<7^i^)«
i i iiM^liii*
Wi
W S
^ii£ii
ill
"##:'.!.'>.!#!! !'!' !!! »> -
iS! ! ! .V>« J.U.
Oi^ rfL^rrr-i'i':'i'j':':':T:':':
^gjQfgir
lift
^ Concrete slab
Brown, sandy, clayey silt with gravel- and cobble-sized clasts of weathered basalt. Gravel abundant at base of interval. Fill.
Brown to gray slightly sandy clay with gravel-, cobble-, and boulder-sized clasts of weathered basalt; stiff to hard, moist.
Slickensides dipping from 1 0 to 15° at 22.5 ft.
Brown, sandy, clayey silt with gravel-, cobble- and boulder-sized clasts of weathered basalt; hard, moist.
Boulders
Brown-gray fissured sandy clay with gravel-sized clasts of weathered basalt; hard, moist.
Brown, sandy, clayey slit and organic silty clay with gravel-, cobble-, and boulder-sized clasts of weathered basalt; dry, hard.
r- Boring terminated at 44.3 ft on 12/1/89.
MH/ GC
CH/ OH
MH
CH
OH/ MH
27 Figure A18,
LOG OF BORING BORING 1 9 Surface Elevation 207- 8 ft
+ Blows per foot Sample Depth (feet) Moisture content
50 40 30 20 10 0 SOIL DESCRIPTION DSC
60%
.''
>
<10:0.5'
>
5 '
--10
15-
I :20-
25-
j30-
35
40
WxwxW:-
I: :-:->:-:-»xv:
" ' ' .-XvX'X.... - : : : : :-; :-
iBj
QHi
II
II16 -
- -o-
Brown, sandy, clayey silt with gravel- and cobble-sized clasts of weathered basalt. Layers of coral sand at 2.0 and 4.0 ft. Fill.
Boring encountered water between 1 .5 and 3.5 ft.
Boulder
Brown to gray, sandy to slightly sandy, silty clay and clayey silt with gravel-, cobble-, and boulder-sized clasts of weathered basalt; hard, moist.
Gray-brown fissured clay with gravel-, cobble-, and boulder-sized clasts of weathered basalt; stiff, moist. Slickensides dipping from 10 to 20° at 31.0ft.
^ Boring terminated at 35.3 ft on 12/4/89
MH
CH/ MH
CH
28 Figure A19.
LOG OF BORING (continued on next page) B(
+ Blows per foot Sample % Moisture content
50 40 30 20 10 0
^9:0.5'
^3:0.5'
17:0.5'*
<
<
4 '
.>
.+
%
Core
>
recovery
100%
100%
100%
DRING 20 Surface Elevation 313.0 ft
- Depth (feet)
[Lfth0l°9k:Symb01 SOIL DESCRIPTION USC
J- 5
V M
Z10
15
__20
M M
i :25
30
I
35-^
40 -1
1
SS^iH
miWm
m'&&!&£&*
vivijjij; iiii±
PlililtFlT*':^ »R-:: :
TSS?> %/» :+,.; ;.
"T-x* 1 ???: :*;£:££ |ii ;
M»>:W^^
*£S(+ :* :' £::'^i & :i-^ p:ii w ;
B!rr: ^r.;:^r ;?M. ^fcVil-. '.
HO::>: :;::::&: :
|Q1;r* *».¥** :
111^ * *: '+« i
M. ii: >* :i -i:^-
"' ^5i.'"' !
iOi^»4- 4^;-:-H4 iM. £££.
Sipiiiii:^. ^v#:
tt: +tKto:^r ^::;ii:'
|iSH* H'fX'M'X''
i*. **: :« .Ui: ^rxi*:
lil!|i|i|i;i
^^^^^^N
^ro^^m
flflflftjjfijdjflflflfijj
^^^^^^
Brown to gray, sandy, clayey silt and slity clay with gravel- and cobble-sized clasts of coral and weathered basalt; stiff, moist. Fill.
Brown, sandy organic clay with gravel-, cobble-, and boulder-sized clasts of weathered basalt, stiff, moist. Hard and dry below 23 ft.
Weathered, vesicular basalt.
MH
CH/ OH
29 Figure ,A20a,
LOG OF BORING BORING 20, continued
+ Blows per foot Sample ~ 41 Moisture content
50 40 30 20 10 0
Con3 recover
100%
f
50
«
i
^^ MMMM
MM
mmmm
M^
mmmm
^ M
mmm
1
Depth (feet)
HUhologic symbol so(LDEsCR|pT(ON usc
888^83^^
^^^
L Boring terminated at 50.0 ft on 12/6/89.
30 Figure A20b
APPENDIX B
Laboratory test results
This appendix contains a table (table Bl) of engineering properties determined for samples tested thus far in our laboratory, a soil plasticity chart (fig. Bl), and graphs (figs B2, ..., B7) showing results of direct-shear tests on the samples. Grain-size distributions were determined by standard methods of sieving and hydrometer analysis. Atterberg limits were determined by standard methods on materials that were air-dried prior to testing. Grain density was determined by means of a pycnometer using standard methods.
Residual strength tests were performed in a direct-shear device using remolded samples having pre-cut shear surfaces. Each sample was tested at normal loads of 720, 1440, and 3600 lbf/ft2 . Before testing, the samples were sieved to remove particles coarser than medium sand. Sufficient moisture was added to the material to bring it to the plastic limit, and it was compacted into a 2.5-in.-diameter frame. Each sample was consolidated at twice the normal load used to measure the shear strength. After consolidation was complete, the shear plane was cut with a wire while the sample was under the normal load. Each sample was sheared in forward and reverse cycles to a total displacement of 60 mm in order to develop the shear surface and reduce the strength to its residual value. Each sample was then sheared at a rate of 0.12 or 0.024 mm/min for a distance of 9 mm to determine the residual strength. The rate of shear was increased by a factor of three and then reduced by a factor of 10 to check for the development of pore pressures during the test.
Our laboratory uses SI (meter/kilogram/second) units. The following table of conversion factors can be used to convert the test results to engineering (foot/pound/second) units:
To convert from to multiply by
m ft 3.281m 2 ft 2 10.76mm in. 0.0394mm/min. in./min. 0.0394kN Ib 224.8kPa lb/ft 2 20.89
31
OJ ro
Tab
le B
l. So
il Sa
mpl
e T
est
Res
ults
Par
ticl
e Si
ze
Dis
trib
utio
n1
A.S
.T.M
. C
lass
ific
atio
n
Bo
rin
g
Sam
ple
Num
ber
N
um
ber
3 R
-25
3 T
T-3
44
394
41T
4 41
B5
R-5
75
TT
-61B
Hon
olul
u2
KA
13
Dep
thra
nge
(fee
t)
6.0-
7.5
36.5
-41.
57.
0-8.
510
.0-1
0.8
10.8
-11.
511
.5-1
3.0
26.5
-31.
5su
rfac
esu
rfac
e
Gra
vel
>4.7
6(m
m)
5 24 2 431
24 34 0 4
San
d<4
.76-
>0.0
75(m
m)
7 12 6 8 9 8 6 24 15
Sil
t<0
.075
->0
.005
(mm
)
15 14 13 9 16 17 15 28 23
Cla
y<0
.005
(mm
)
73 50 79 40 74 51 45 48 58
Att
erb
erg
Lim
its
1L
L
116 95 127
124
137
100
129 59 96
PL 48 44 48 44 46 44 54 29 48
PI 68 51 79 80 91 56 75 30 48
Gra
ind
ensi
ty(g
/cc)
2.72
.2.
80__
____
____
__2.
712.
74__
__2.
74
1 Per
cent
age
of
dry
sam
ple
wei
ght
2Cut
tings
le
ft
from
pr
ivat
e dr
illin
g op
erat
ion
behi
nd
hous
e at
30
22
Kah
aloa
Pl
ace.
^Fro
m
unde
r ho
use
at
3065
K
alaw
ao
Stre
et.
100
xo>
TJ
20
0 20 40 60 80 100 120 140
Liquid limit
Plasticity chart for soil samples from the Alani-Paty landslide
Figure Bl
33
DIRECT SHERR TEST RESULTS
Sample I.D.
HONOLULU
Submitter:
BflU
MD
ate
: 6/1
/89
OJ
2.8
8
1.6
8
1.6
8
~
1.4
8Z ~
1
.28
Q 0
1.8
8-J QC
. .6
8
CE U S *6
0A
n. *a
.28
8.8
8
- _
^.
.-
^. ' '
f^
\
-
i
-
--
,
+ M
i n
-
i
Pic
k
-» .
t Q
»
2
i-
1
488
~
328
id Q_ *
248
(A (A
Q) C W
16
8c id Q) -C en
88
- - _ ^ _ - - - ^J
*-^x^"
1 1
1
_^^
.s^
^s^
1 1
1
^-P
h"
-^ i i
i
^s^
^s*"^
*^
-25
.8*
i i
i
.s^
^^ i
i i
0123456789
10
°8
68
168
248
32
8
48
8
HO
RIZ
ON
TR
L
DIS
PLR
CE
ME
NT
(m
m)
No
rma
l S
tre
ss
(kP
a)
Plo
t F
ile
ID
Resid
ual
Str
ength
N
orm
al
load
Cohesi
on*
11.8
459
kPa
No.
__
__
__
__
_^N
)_ _____ _
^N
)_
__S
am
ple
a
rea
t .8
8316?
mete
rs
square
d
1 H
I .0
798
.10
92
2 H
21
.1467
.21
84
3 H
3 1
.29
00
.5
460
Fig
ure
B
2.
DIRECT SHERR TEST RESULTS
Sample I.D.
KR-1
Submitter:
FLEMING
Date:
7/10/89
OJ
Ui
Q o:
o
_j a a:
u
1.00 .90
.80
.70
.60
.50
.20
.10
0.0
0
- - - - 1 .....
I"i -
/ i
~ .I ii
- _
..
,
+ M
m
- __
_
.
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Date:
1/31/89
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DIRECT SHERR TEST RESULTS
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BRUM
Date:
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d
APPENDIX C ;
Subsurface Instrumentation
This appendix contains a table listing the instrumentation installed in the borings (table Cl), a table listing estimated thickness of the landslide (table C2), graphs of water levels in our piezometers (figs. Cl, .... Cll), and graphs of inclinometer measurements (figs. C12, ..., C17). A completion diagram for boring 4 shows schematically how the piezometers and anchored cables were installed (fig. CIS).
Each piezometer consists of l-in.-nominal diameter PVC pipe with a 6-in.- long porous tip. The tip is embedded in a column of coral sand 2 to 3 ft high and sealed above and below with columns of bentonite 2 to 3 ft high. Water levels were measured by means of a probe lowered from the surface down the PVC pipe. Measurements were made approximately weekly.
Anchored cables consist of a 5/16-in.-diameter wire rope connected to a short section of steel pipe that is capped at both ends and filled with shot. The pipe anchor was lowered to the bottom of the hole, presumed to be below the basal slip surface of the landslide. Back-fill materials placed in the boring hold the anchored end of the cable in place so that the cable is pulled down the hole as sliding occurs. A length of the cable was left protruding from the ground surface and movement is detected by repeatedly measuring the length of the protruding cable.
Depth of the failure surface was estimated from the locations of bends in many of the deep piezometer pipes. The bends were located by lowering sections of metal tubing (nominal l/2-in.-diameter galvanized electrical conduit), suspended from nylon fishing line, down the piezometers and measuring the depths where the sections stopped. We used sections of tubing 6, 12 and 18 in. long to locate the bends; the different lengths were used to estimate how sharp the bends were. The estimated depths reported in the appendix are accurate to about ±2 ft, or better. Our confidence in the measurements will increase if movement occurs in the coming year and sharpens the bends in the pipes.
Holes for inclinometer measurements were cased with ABS (acrylonitrile- -butadiene-styrene) tubing having special groves to align the inclinometer probe. The casing was secured in the holes by pouring grout down the annular space between the sides of the hole and outside of the casing. The cased holes are surveyed approximately monthly according to standard methods using an inclinometer probe. The algebraic signs of the deflections indicated in the graphs follow the convention that positive deflection on the A axis is upslope and negative is downslope; positive deflection on the B-axis is to the left of an observer looking downslope and negative is to the right.
40
Table Cl. Summary of depths of instruments in USGS boringsin the Alani-Paty landslide
Boring # Depth (feet)
Instrument Depth (feet)
Comments
41.3piezometer piezometer anchor
13.225.527.8
41.5piezometer piezometer anchor
5.030.036.3
41.0piezometer piezometer anchor
20.239.539.9
dry
41.5piezometer piezometer anchor
5.734.438.0
dry
50.0inclinometer 47.6(depth of lowest
measurement)
41.0piezometer piezometer
8.0 37.3
dry
41.0piezometer piezometer anchor
12.035.140.2
41.0piezometer piezometer anchor
8.625.141.0
10 48.5inclinometer 47.6
11
12
41.5
40.5
neutron probe 40.0
piezometer 18.0piezometer 35.8anchor 39.9
flooded flooded
41
Table Cl. (continued)
Boring # Depth Instrument Depth Comments (feet) (feet)
13 40.0piezometer 12.0piezometer 32.1 dryanchor 37.5
14 40.5piezometer 9.4 piezometer 21.9 piezometer 38.2 dry
15 50.8inclinometer 49.2
16 40.5piezometer 15.4 piezometer 20.7 piezometer 36.7 dry
17 42.0neutron probe 40.0
18 44.3neutron probe 40.0
19 35.3piezometer 14.4piezometer 31.8 dryanchor 35.3
19x 5.6piezometer 5.4
20 50.0piezometer 9.5piezometer 21.5piezometer 30.0 dryanchor 40.0
42
Table Cl. (continued)
INCLINED BORINGS
These borings were made by PR Drilling Co., Inc., for STV/Lyon Associates, to determine the distance to bedrock. STV/Lyon had no plans to instrument the holes, so we plugged the holes at shallow or intermediate depths and installed open-tube piezometers. Depths in the table below indicate slope distances down the borings, which slope 40° from the horizontal.
Boring # Depth Instrument Depth Comments (feet) (feet)
100 15.0piezometer 10.1
103 80.0piezometer 5.8 dry piezometer 56.0 dry
108 19.8piezometer 19.4 dry
43
Table C2. Approximate thickness of the Alani-Paty landslide
Boring # , Thickness Remarks(feet)
1 21
3 27
4 28
5 29
6 (inclinometer, see graph)
>24.5
10 (inclinometer, see graph) --
11
12
13
33(7)
27
Sliding not observed; in area between mapped boundaries of the Alani-Paty and Hulu- Woolsey landslides.
Outside mappedboundaries of landslide.
Outside mappedboundaries of landslide.
Sliding not observed; in area of suspected incipient movement.
Casing not sufficiently bent to determine depth of sliding.
Uncertain, presumed bend is near bottom of piezometer pipe.
14 20
15 (inclinometer, see graph) 26 In area of incipient movement outside mapped boundaries of landslide.
44
Table C2. (continued)
Boring # Depth of sliding Remarks(feet)
16 - - In area of incipientmovement outside mapped boundaries of landslide; pipe not sufficiently bent to determine depth of sliding.
17 -- outside mappedboundaries of landslide.
18 - - casing not sufficientlybent to determine depth of sliding.
19 13
20 23
45
Figure C1. Piezometers in boring 1
o
Q.0 Q
-2-
-4-
-6-
-8-
-10-
-12-
-14-
-16-
-18-
-20-
-22-
-24-
-26
Depth of piezometer tip
Q 13.2ft
25.5 ft
200 300 400 500
Time, in days; day 1 is January 1, 1989
Figure C2. Piezometers in boring 3
Q. 0 Q
0
-2-
-4-
-6-
-8-
-10-
-12-
-14-
-16-
-18-
-20-
-22-
-24-
-26
Depth of piezometer tip
5.0ft
30.0 ft
200 300 400 500
Time, in days; day 1 is January 1, 1989
46
Figure C3. Piezometers in borings 4 and 5
Q.0) Q
0
-2-
-4-
-6-
-8-
-10-
-12-
-14-
-16-
-18-
-20-
-22-
-24-
Depth of piezometer tip
Q #4, 20.2 ft
#5, 5.7 ft
200 300 400 500
Time, in days; day 1 is January 1, 1989
Figure C4. Piezometer in boring 7
Q.0) Q
" 1 *T
-16-
-18-
-20-
-22-
-24-B
-26-
-28-
-30-.
-32-"
-34-
-36-
-38-.
::
iiI|
j No data*I
1
i:i
i i i jJi|LA .^ft^^^^ft^ * i
^r^Wo<rf*rw' ~°"^i i
: i
i i !: ii i
<
«L
P^^kto
Pw
Depth of piezometer tip
o 37.3 ft
200 300 400 500
Time, in days; day 1 is January 1, 1989
47
Figure C5. Piezometers in boring 8
Q.0 Q
-10-
-20-
-30-
-40
200
Dry
Dry
300i
400
Depth of piezometer tip
0 12.0ft
35.1 ft
500
Time, in days; day 1 is January 1, 1989
Figure C6. Piezometers in boring 9
Q.<D Q
0-
-2-
-4-
-6-
-8-
-10-
-12-
-14-
-16-
-18-
-20-
-22-
-24-
-26
^S*i||>tt *» »^»Depth of piezometer tip
0 8.6 ft
25.1 ft
200 300 400 500
Time, in days; day 1 is January 1, 1989
48
Figure C7. Piezometers in borings 13 and 14
o
Q.0) Q
-2-
-4-
-6-
-8-
-10-
-12-
-14-
-16-
-18-
-20-
-22-
-24-
-26
Depth of piezometer tip
H #13, 12.0ft
#14, 21.9 ft
200 300 400 500
Time, in days; day 1 is January 1, 1989
Figure C8. Piezometers in boring 16
Q. 0) Q
-2-
-4-
-6-
-8-
-10-
-12-
-14-
-16-
-18-
-20-
-22-
-24-
-26
Depth of piezometer tip
H 15.4ft
20.7 ft
200 300 400 500
Time, in days; day 1 is January 1, 1989
49
Figure C9. Piezometers in borings 19 and 19x
0) 2.c
2
o~
Q. 0) Q
o5
C
O~
Q. 0) Q
u -
-2-
-4-
-6-
-8-
-10-
-12-
-14-
-16-
-18-
-20-
-22-
-24-
-26-
2C
/
tfw!** sfr~ r
I Depth of piezometer tip
Q #19, 14.8ft
tr 1 y*, iJ.'r 11
0 300 400 500
Time, in days; day 1 is January 1, 1989
0 -
-2-
-4-
-6-
-8-
-10-
-12-
-14-
-16-
-18-
-20-
-22-
-24-
-26-
2(
Figure C10. Piezometers in boring 20
Dry t Dry fa Dry
30 300 400 5(
Depth of piezometer tip
0 21.5ft
9.5 ft
)0
Time, in days; day 1 is January 1, 1989
50
Figure C11. Piezometer in inclined boring 100
o
Q. <D Q
-2-
-4-
-6-
-8-
-10-
-12-
-14-
-16-
-18-
-20-
-22-
-24-
-26
Note: Depth to water has NOT been corrected for inclination of the boring.
Depth of piezometer tip
D 10.1 ft
200 300 400 500
Time, in days; day 1 is January 1, 1989
r pavement
-piezometer tip-t4 -porous zone
-boring backfilled with bentonite
51
Ol
ft-f
tXIS
D
EF
LE
CT
ION
Dow
nslo
peU
p slo
pe
Z.S
IN
CH
ES
REF. DATE:
1ZQCT1S8S
. B9NQU1383
13DEC13S3
Q
Q7FEB13SQ
V
27FEB1330
Figure C12.
Inclinometer pr
ofil
e, Boring 6
Depth.
In feet
Ul
u>
Nort
hea
stB
-ftX
IS
DE
FL
EC
TIO
N2.5
IN
CH
ES
REF. DOTE*
12QCT13B3
, 03NQU13B3
-|-
13DEC13B3
&
Z6JON1330
Q
Q7FEB1330
27FEB1330
Figure C1
3.
Inclinometer Pr
ofil
e, Bo
ring
6
- 50
D«pth
In f««t
fi-ftXIS DEFLECTION
Dow
nslo
peU
psl
ope
Z.S
IN
CH
ES
Ln
REF. DftTEt
310CT1989
, Q9NOU1989
J_
13DEC1989
Figure C14.
Incl
inom
eter
pr
ofil
e, Bo
ring
10
- SB
Depth.
In feet
Nort
hea
stB
-ftX
IS
DE
FL
EC
TIO
NZ
.5
INC
HE
S
Ul
Ul
REF. DATE'
31OCT1989
» Q9NOU1989
J.
13DEC1989
Figu
re C1
5.
Inclinometer pr
ofil
e, Bo
ring
10
- sa
Depth,
in feet
ft-ftXIS DEFLECTION
Ul
ON
Dow
nslo
peU
psl
ope
2.5
IN
CH
ES
REF. DATE*
28NOU1989
13D
EC
1383
12O
PR
1390
Figure C16.
Incl
inom
eter
profile, Boring 15
- 50
Depth,
in feet
-2.s
N
ort
hea
st
Ul
REF . DATE :
28NOU1383
. 13DEC1383
4.
2SJAN133B
&
B7FEB133B
Q
27FEB133B
12APR133B
B-f
iXIS
D
EF
LE
CT
ION
South
wes
t2
.5
INC
HE
S
Figu
re C1
7.
Incl
inom
eter
profile, Bo
ring
15
De p
t h
. in
feet
10 -
Ground surface
Cement
Cuttings
Jentonite
a.OJQ
20
Sand
Open-tube piezometer at 20.2 ft
Bentonite
30 - Cuttings
5/16- in. steel cable, anchored at 39.9ft
'Bentonite
40 -i
Sand Open-tube piezometer at 39.5 ft
"Gravel
"Cave-in material
Figure C18. Sketch showing installation of instruments in boring 4
58
APPENDIX D
Measurement of Precipitation
This appendix contains graphs of daily rainfall at 3102 Alani Drive, in the head of the landslide (figs. Dl, ..., D8 and fig. 2). A tipping-bucket rain gauge at this site is monitored continuously by a datalogger that records 15-minute and daily increments of rainfall.
59
Figure Di. Daily rainfall during September 1989
5
c "va CC
<D
OC
"CS
CC
O-^T-r
No Data
i i i i i i i i i i i i i i i i i i i i i I T TCJCVJCVJCVJCVJCMCMCVJCVJCVJCO
Time, in days
Figure D2. Daily rainfall during October 1989
TTT
Time, in days
60
CMCVJCVJCVJCMCVJCMCVJCMCVJCOCO
Figure D3. Daily rainfall during November 1989
<D
U
.2c'(5
OC
^0 'iiiiTTTTTTllllTlllililllllilTi
Time, in days
Figure DA. Daily rainfall during December, 1989
0
o
"5 DC
0-Hrn- Pi iTJi i . iiTirF I I I I I To <«ttncor>-co
CVICMCMCVICVICVICMCMCVICVICOCO
Time, in days
61
Rai
nfal
l, in
in
ches
Rai
nfal
l, in
in
ches
roCO
en
n 00 c o ON D
*<"
Q. c (Q -n CD
cr CO
CO o
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CO
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H- OQ cOl
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JD Q.
C (Q C_
(1) ZJ c CO
CO o
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X)
o(D V)
0661- IMdv BuunpAIJBQ *sa
sXep uj 'eujj
p[I
33 (Uu"
oCD V)
0661-BuunpAJIBQ
APPENDIX E
Displacement of the landslide
This appendix contains a graph of cumulative displacement from September 1989 through April 1990, superimposed on a graph of cumulative rainfall (fig. El), a detailed graph of displacement and rainfall during January 1990 (fig. E2), and a map showing crude estimates of total displacement measured in April 1989 (Baum and others, 1989) and 1990 (fig. E3).
We monitored displacement at the head of the landslide (fig. 2) by means of a simple extensometer consisting of a digital recorder and a wire cable. The recorder was anchored to a wall upslope from the headscarp of the landslide, on non-moving ground. The wire cable was attached to the trunk of a large tree growing on the head of the landslide. The cable causes a wheel on the recorder to turn as the distance between the tree and the recorder changes. The recorder mechanism keeps track of position by counting the revolutions of the wheel from an arbitrary zero position. The mechanism records the current position of the wheel once every 15 minutes. Later, in the office, the recorded changes in the position of the wheel are converted back into displacements.
We used monthly surveys to check the displacement recorded by the extensometer. Using tape and level, we measured the distance from a point on the wall where the recorder was anchored to two points on the tree where the cable was attached. Our surveys indicate that cumulative displacement from September 13, 1989, to April 27, 1990, ranges from 0.35 to 0.41 ft. Displacement determined by the surveys is slightly greater than the displacement of 0.33 ft recorded by the extensometer for the period from September 25, 1989 to April 30, 1990. The surveys indicate displacement ranging from 0.12 to 0.22 ft between December 13, 1989, and February 7, 1990. The extensometer recorded 0.22 ft of displacement during the same period, which includes the questionable movement recorded from January 23 to January 29, 1990.
We made crude estimates of total displacement by measuring offsets of curbs and walls where they cross the lateral boundaries of the landslide. We measured the offsets by standing on one side of the boundary and sighting along a curb or wall on the opposite side. We then measured the perpendicular distance from the wall or curb on our side of the boundary to the projection of the wall or curb on the opposite side. Precision of the measurements varies from site to site, but averages about ± 0.5 ft.
64
Cumulative displacement, in feet
Q. (U
Q. (U
C. (U
C(1)
CD 00 CD
T] (Q'
C
CD
m
0) zj'
oT
ZJ Q.
Q. to'
oCD3CDZJ
CD
ZT CD
Q.
O-^»i * ZT CD
Cumulative rainfall, in inches
3D D
I f 5T ft)= 8
ZJ Q.en_ Q."
CD
Figure E2. Daily increments rainfall and cumulative displacement at the head of the Alani-Paty landslide during January 1990
EH-kB-Q-B-EH-H-T
t 1
Extensometer disturbed"""
during this period
khl
0.5
0.4<D*
C
0.3
0.2
0.1
0.0
CMCMCMCMCMCVJCMCMCMCMCOCO
c0)E o> o
JS a. w
T3a>
E 3 O
Rainfall
Displacement
Day
66
(8.4) ai«-
EXPLANATION (44) 52
( Lateral offset, in feet, April 1989
4.9 Lateral offset, in feet, April 1990
Scarp
Flank
Toe
(6.1) 8.0
(5.3) 7.9
Figure E3. Map showing lateral offsets of curbs and stone walls at boundariesof the Alani-Paty landslide. Base (map of landslide boundaries)
' from Baum and others (1989).
67