Cyclic Triaxial Tests of the 

Bootlegger Cove Formation, 

Anchorage, Alaska 

U.S. GEOLOGICAL SURVEY BULLETIN 1825 

A cooperative research project between the 

U.S. Geological Survey and the 

State of Alaska Division of 

Geological and Geophysical Surveys 

Cyclic Triaxial Tests of the 

Bootlegger Cove Formation, 

Anchorage, Alaska 

By POUL V. LADE, RANDALL G. UPDIKE, 

and DAVID A. COLE 

A cooperative research project between the 

U.S. Geological Survey and the 

State of Alaska Division of Geological and Geophysical Surveys 

U.S. GEOLOGICAL SURVEY BULLETIN 1825 
DEPARTMENT OF THE INTERIOR 

DONALD PAUL HODEL, Secretary 

U. S. GEOLOGICAL SURVEY 

Dallas L. Peck, Director 

Any use of trade names is for descriptive purposes only and does not imply 

endorsement by the U.S. Geological Survey. 

UNITED STATES GOVERNMENT PRINTING OFFICE: 1988 

For sale by the 

Books and Open-File Reports Section 

U.S. Geological Survey 

Federal Center 

Box 25425 

Denver, CO 80225 

Library of Congress Cataloging-in-Publication Data 

Lade, P. 

Cyclic triaxial tests of the Bootlegger Cove Formation, Anchorage, Alaska. 

(U.S. Geological Survey bulletin; 1825) 

"A cooperative research project between the U.S. Geological Survey and the 

State of Alaska Division of Geological and Geophysical Surveys." 

Bibliography: p. 

Supt. of Docs. no.: I 19.3:1825 

1. Soils-Alaska-Anchorage Region-Testing. 2. Shear strength of soilsTesting. 3. Bootlegger Cove Formation (Alaska) I. Updike, Randall G. 

II. Cole, David A. Ill. Alaska. Division of Geological and Geophysical 

Surveys. IV. Title. V. Series. 

QE75.B9 no. 1825 557.3 s [624.1'762] 87-600446 

[TA710.3A4] 
CONTENTS 

Glossary of symbols used VI 

Abstract 1 

Introduction 1 

Scope 1 

Acknowledgments 2 

Regional geologic history 2 

Tectonic setting 2 

Quaternary history 3 

Engineering geologic facies of the Bootlegger Cove Formation 3 

Geologic history of the site 4 

Static engineering characterization of the site 7 

Field sampling and logging 7 

Dynamic laboratory testing program 7 

Unconsolidated-undrained tests 8 

Equipment 8 

Testing procedure 8 

Consolidated-undrained tests 9 

Equipment 9 

Testing procedure 9 

Cyclic loading tests 10 

Equipment 10 

Testing procedure 10 

Results of laboratory testing 11 

Soil index tests 11 

Static tests 11 

Cyclic loading tests 16 

Strength relations for intact specimens 16 

Discussion of cyclic stress ratio 18 

Strength relations for remolded specimens 18 

Comparison of strength relations for intact and remolded specimens 19 

Shear moduli 22 

Damping ratios 23 

Summary and conclusions from laboratory testing 24 

References cited 26 

FIGURES 

1. Photograph of the Turnagain Heights landslide 2 

2. Generalized map showing major faults in the vicinity of Anchorage 3 

3. Generalized map showing the location of the sample site 4 

4. Map showing the location of boreholes and cross-section lines 4 

5. Geologic cross section along line A-A 1 5 

6. Geologic cross section along line B-B I 6 

7. Photograph of triaxial testing equipment used for UU tests 8 

8. Photograph of triaxial testing equipment used for static ICU tests 9 

9. Photograph of cyclic triaxial testing equipment 10 

10. Plasticity chart for samples 11 

Contents Ill 
FIGURES 

11. Graph showing undrained shear strength versus water content derived 

from UU and ICU tests 14 

12. The p-q diagram showing effective normal stress versus maximum shearing stress determined by ICU tests 16 

13. Photograph of specimen CT-5 (F.IV) after consolidation and after 

failure by cyclic loading 17 

14. Photograph of specimen CT -3 (F .III) after consolidation and after 

failure by cyclic loading 18 

15. Photograph of specimen CT -4 (F.IV) after consolidation and after 

failure by cyclic loading 19 

16-47. Graphs showing: 

16. Peak-to-peak axial strain versus number of cycles for intact samples 

at Kc = 1.0 22 

17. Cyclic stress ratio from UU tests versus number of cycles for intact 

specimens at Kc = 1. 0 23 

18. Cyclic stress ratio from ICU tests versus number of cycles for intact 

specimns at Kc = 1.0 24 

19. Maximum axial strain versus number of cycles for intact specimens 

at Kc = 1.5 25 

20. Maximum axial strain versus number of cycles for intact specimens 

at Kc = 2.0 26 

21. Cyclic stress ratio from UU tests versus number of cycles for intact 

specimens at Kc = 1. 5 27 

22. Cyclic stress ratio from ICU tests versus number of cycles for intact 

specimens at Kc = 1.5 28 

23. Cyclic stress ratio from UU tests versus number of cycles for intact 

specimens at Kc = 2.0 29 

24. Cyclic stress ratio from ICU tests versus number of cycles for intact 

specimens at Kc = 2.0 30 

25. Cyclic stress ratio from UU tests versus number of cycles for intact 

specimens at Kc = 1.0, 1.5, and 2.0 31 

26. Peak-to-peak axial strain versus number of cycles for remolded 

specimens at Kc = 1.0 32 

27. Maximum axial strain versus number of cycles for remolded 

specimens at Kc = 1. 5 33 

28. Maximum axial strain versus number of cycles for remolded 

specimens at Kc = 2.0 34 

29. Cyclic stress ratio from UU tests versus number of cycles for 

remolded specimens at Kc = 1.0 35 

30. Cyclic stress ratio from UU tests versus number of cycles for 

remolded specimens at Kc = 1.5 36 

31. Cyclic stress ratio from UU tests versus number of cycles for 

remolded specimens at Kc = 2.0 37 

32. Cyclic stress ratio from ICU tests versus number of cycles for 

remolded specimens at Kc = 1.0 38 

33. Cyclic stress ratio from ICU tests versus number of cycles for 

remolded specimens at Kc = 1. 5 39 

34. Cyclic stress ratio from ICU tests versus number of cycles for 

remolded specimens at Kc = 2.0 40 

35. Cyclic stress ratio from UU tests versus number of cycles for 

remolded specimens at Kc = 1.0, 1.5, and 2.0 41 

36. Cyclic stress ratio from ICU tests versus number of cycles for 

remolded specimens at Kc = 1.0, 1.5, and 2.0 42 

IV Cyclic Triaxial Tests, Bootlegger Cove Formation, Anchorage, Alaska 
FIGURES 

37. 

38. 

39. 

40. 

41. 

42. 

43. 

44. 

45. 

46. 

47. 

TABLES 

A comparison of cyclic stress ratios for intact (UU tests) specimens 

and remolded (ICU tests) specimens 43 

A comparison of cyclic stress ratios for intact (estimated ICU tests) 

and remolded (measured ICU tests)specimens 44 

Normalized shear moduli for intact specimens using shear strengths 

from UU tests 45 

Normalized shear moduli for intact specimens using shear strengths 

from estimated I CU tests 45 

Normalized shear moduli for remolded specimens using shear 

strengths from UU tests 46 

Normalized shear moduli for remolded specimens using shear 

strengths from I CU tests 46 

A comparison of shear moduli versus number of cycles for intact 

and remolded specimens at Kc = 1.0 47 

A comparison of shear moduli versus number of cycles for intact 

and remolded specimens at Kc = 1.5 48 

A comparison of shear moduli versus number of cycles for intact 

and remolded specimens at Kc = 2.0 49 

Damping ratios versus percent strain for intact specimens 50 

Damping ratios versus percent strain for remolded specimens 51 

1. Summary of Atterberg limit and hydrometer tests 12 

2. Summary of torvane and UU triaxial tests 13 

3. Summary of ICU triaxial tests 15 

4. Summary of initial and stress conditions for cyclic tests on intact 

specimens 20 

5. Summary of initial and stress conditions for cyclic tests on remolded 

specimens 21 

CONVERSION FACTORS 

For readers who wish to convert measurements from the metric system of units to the inch-pound 

system of units, the conversion factors are listed below. 

Metric unit Multiply by To obtain inch-pound unit 

millimeter (mm) 0.03937 inch 

centimeter (em) 0.3937 inch 

meter (m) 3.281 foot (ft) 

centimeter2 ( cm2) 0.1550 inch2 

centimeter3 (cm3) 0.06102 inch3 

kilogram (kg) · 2.205 pound (lb) 

metric ton 1.102 ton, short (2000 lb) 

kilogram/ centimeter2 14.223 pound/inch2 (psi) 

(kg/cm2) 

gram/ centimeter3 62."43 pound/foot3 (lb/ft3) 

(g/cm3) 

Contents V 
GLOSSARY OF SYMBOLS USED 

B 

CL 

cu 

CUPI 

CUPR 

cv 

D 

Dso 

G 

Gs 

Ho 

He 

ICU 

Ke 

LL 

N 

N! 

Activity of clay; PI/percent clay 

Initial cross-sectional area of specimen 

Cross-sectional area of specimen after consolidation 

(Measured pore pressure increase)/(applied 

confining pressure increase) 

Unified Classification symbol for clay with 

low plasticity 

Consolidated-undrained (test) 

Consolidated-undrained cyclic (pulsating) test 

on intact specimen 

Consolidated-undrained cyclic (pulsating) test 

on remolded specimen 

Coefficient of consolidation 

Damping ratio 

Median particle diameter 

Shear modulus 

Specific gravity of soil particles 

Initial height of specimen 

Height of specimen after consolidation 

Isotropically consolidated-undrained (test) 

Consolidation stress ratio; a 1

/ a3

e 

Liquid limit 

Number of load cycles applied to specimen 

Number of load cycles to cause failure of 

specimen 

Maximum number of load cycles applied to 

specimen 

Cyclic (pulsating) deviator load 

Plasticity index; LL - PL 

Plastic limit 

Half of cyclic (pulsating) deviator stress; 

adp/2 

Sensitivity; Su(intact)/ SJremolded) 

'Ywet 

.6. veonsol 

.doeonsol 

€1consol 

€!max 

€veonsol 

Undrained shear strength 

Time to reach 50 percent consolidation 

Time to reach 100 percent consolidation 

Pore pressure 

Pore pressure at failure 

Maximum pore pressure 

Unconsolidated-undrained (test) 

Initial volume of specimen 

Water content 

Single-amplitude shear strain 

Wet density 

Volume change of specimen due to consolidation 

Vertical deformation of specimen due to consolidation 

Vertical strain of specimen due to consolidation 

Vertical strain at failure 

Maximum vertical strain 

Volumetric strain of specimen due to consolidation 

a1 Principal applied stress in trixial cell 

ale Principal applied stress during consolidation 

a3 Confining pressure in triaxial cell 

a3e Confining pressure during consolidation 

a 31 Effective confining pressure at failure 

(a1-a3)max Deviator stress 

(a'/ a' 3)max Effective stress ratio 

a de Deviator stress during consolidation 

a dmax Maximum deviator stress applied to specimen; 

ade + adp 

a dp Cyclic (pulsating) deviator stress 

cJ> Friction angle 

cJ>' Effective friction angle 

VI Cyclic Triaxial Tests, Bootlegger Cove Formation, Anchorage, Alaska 
Cyclic Triaxial Tests of the 

Bootlegger Cove Formation, 

Anchorage, Alaska 

By Poul V. Lade1, Randall G. Updike, and David A. Cole2 

Abstract 

Earthquake-induced landslides in the Anchorage area 

have resulted primarily from cohesive soil failures within the 

Bootlegger Cove Formation. A suite of ten undisturbed samples 

from various formational facies were tested in an investigation 

of representative stress-strain and strength properties under 

static and cyclic loading conditions. A sequence of soil index 

property tests was followed by unconsolidated-undrained static 

triaxial tests on intact and remolded specimens, isotropically 

consolidated-undrained static triaxial tests on remolded specimens, and cyclic triaxial tests on intact and remolded specimens at various consolidation ratios. The intent of this testing 

program was to "calibrate" the static and dynamic behavior 

of the cohesive fac ies of the formation in the previously determined zone of failure. The results indicate that, at higher consol idation stress ratios, higher cyclic stress ratios are required 

to cause a given amount of strain for a finite number of cycles. 

Though the evidence is not conclusive, there is an indication 

that soils remolded in landslide areas have strengths equal to 

those of soils in areas that have not failed. Sensitivity values 

determined on these samples are substantially lower than those 

reported in the literature, which suggests that criteria other than 

sensitivity must be considered in evaluating the stability of the 

Bootlegger Cove Formation during earthquakes. 

INTRODUCTION 

The City of Anchorage lies within one of the most 

active tectonic regions of the world and is therefore subjected to frequent seismic events which have magnitudes 

as great as that of the catastrophic Prince William Sound 

earthquake of March 27, 1964. Moderate- to largemagnitude earthquakes can be expected to occur in the 

region within the design life of most major buildings now 

existing or planned for construction in the city. During 

1

School of Engineering and Applied Science, University of 

California, Los Angeles, California. 2DOWL Engineers, Inc., Anchorage, Alaska. 

the 1964 earthquake the primary cause of property 

damage and loss of life in Anchorage was related to 

ground failure (landslides) that resulted from the intense 

shaking (fig. 1). These landslides have been attributed to 

three failure mechanisms: (1) gravity fall along unstable 

slopes, (2) liquefaction of silts and sands, and (3) collapse 

of sensitive silts and clays. The second and third types 

are primarily limited to the Bootlegger Cove Formation, 

which underlies much of Anchorage. Technical studies 

in the years immediately following the 1964 earthquake 

gave support to both of these mechanisms (for example, 

Shannon and Wilson, Inc., 1964; Kerr and Drew, 1965; 

Hansen, 1965; Seed and Wilson, 1967). However, recent 

research has firmly demonstrated that liquefaction of 

sands within the formation was not the primary cause of 

ground failure (Idriss and Moriwaki, 1982; Updike, 1983, 

1984). Thus, interest has recently begun to focus on the 

cyclic stress-strain behavior of the cohesive soils of the 

formation although actual test data for these soils have 

been limited. A study of the cyclic strengths of the clay 

and silt was performed by Seed and Chan (1964) for the 

postearthquake investigations that were conducted by 

Shannon and Wilson, Inc., for the U.S. Army Corps of 

Engineers. This study utilized the then-emerging technology of cyclic testing of soils. In order to better assess the 

potential for further landslides during future earthquakes, 

it is necessary to more fully understand the cyclic stress 

behavior in the light of current perceptions of the 

formation. 

Scope 

The objective of this study was to establish with 

greater confidence the static and dynamic characteristics 

of the Bootlegger Cove Formation and, if possible, to 

relate these characteristics to basic soil index values. To 

achieve this objective, a comprehensive testing program 

was conducted to gain knowledge on formational dynamic behavior characteristics which could be applied to 

Introduction 
Figure 1. The Turnagain Heights landslide was one of several 

Anchorage landslides resultant from failure of the Bootlegger 

Cove Formation during the 1964 Prince William Sound earthquake (Photo from NOAA/EDS files, No. 140-2). 

the formation on a regional scale. During the geotechnical 

foundation studies for a high-rise building in downtown 

Anchorage, high-quality, undisturbed, thin-walled 

Shelby-tube samples were acquired and were provided to 

the authors by the building owners, with the agreement 

that site location would remain confidential. The testing 

of those samples is the focus of this report, with primary 

emphasis on soils typical of the Bootlegger Cove Formation in downtown Anchorage. Samples that were found 

to be metastable and that, in some cases, began to deform 

immediately after extrusion from samplers were not included in this study because of the potential problems of 

disturbance during transportation, extrusion, and laboratory preparation. The intent of this study is to establish 

a benchmark of cyclic test data on "typical" cohesive soil 

samples of the Bootlegger Cove Formation, from which 

point future studies can focus on the metastable soil 

horizons that are critical to future seismic stability 

evaluations. 

Acknowledgments 

This project was supported by a grant from the 

Federal Emergency Management Agency (FEMA) to the 

Alaska Division of Emergency Services (ADES), which 

contracted the authors to conduct the research. The project was further supported by a cooperative agreement 

between the U.S. Geological Survey (USGS) and the 

Alaska Division of Geological and Geophysical Surveys 

(ADGGS) under the Earthquake Hazards Reduction 

Program. The testing was conducted at the geotechnical 

laboratories of DOWL Engineers, Anchorage; University 

of California-Los Angeles Civil Engineering Department; 

and ADGGS Engineering Geology Section. Catherine 

Ulery, Peter Glaesman, and Michael Pritchard (ADGGS) 

assisted with the cartography. Rodney Combellick 

(ADGGS), Harold Olsen (USGS), Henry Schmoll 

(USGS), and Hans Pulpan (University of AlaskaFairbanks Geophysical Institute) provided technical 

reviews of the manuscript. The owner and developer of 

the site where the samples were obtained has reserved the 

right to remain unnamed, but the drilling and field 

logistics support provided by that party made the project possible within the budget provided by FEMA-ADES 

and by USGS-ADGGS. The authors particularly wish to 

thank Alvaro Espinosa, (USGS, Golden, Colo.) who, 

through his USGS-funded Anchorage Earthquake 

Hazards Project, provided both the encouragement and 

organizational support necessary for the publication of 

this report. 

REGIONAL GEOLOGIC HISTORY 

The Anchorage area is located in the upper Cook 

Inlet region of south-central Alaska. This inlet has had 

a varied history during Quaternary time in response to 

fluctuations in sea level, advance and retreat of adjacent 

mountain glaciers, and tectonic uplift and subsidence. 

The geologic record produced by the interplay of these 

systems is indeed complex and not well understood; however, some generalizations can be made. 

Tectonic Setting 

Cook Inlet is situated in a tectonic forearc basin 

that is bounded to the west by the Bruin Bay-Castle 

Mountain fault system and to the east by the Border 

Ranges fault system (which includes the Knik fault along 

the west front of the Chugach Mountains) (fig. 2). Most 

of the regional seismicity can be attributed to underthrusting along the Benioff Zone of the plate boundary 

megathrust which extends beneath the inlet (Fogelman 

and others, 1978). There is, however, some evidence suggesting that both the Castle Mountain (Bruhn, 1979; Lahr 

and others, 1986) and Border Ranges fault systems 

(Updike and Ulery, 1983) may be active and capable of 

propagating moderate earthquakes. Each year earthquakes with magnitudes above 4.5 are felt in Anchorage 

as a result of this seismic setting. 

The tectonic basin is bounded to the east in the 

Chugach Mountains by Mesozoic metamorphic rocks 

(graywackes, phyllites, metavolcanics, and argillites of 

the Valdez and McHugh Groups). To the west, the basin 

is confined by the igneous and metasedimentary rocks 

of the Alaska Range. Within the basin, and lying a few 

2 Cyclic Triaxial Tests, Bootlegger Cove Formation, Anchorage, Alaska 
1540 

0 50 MILES 

l1 11 1

1 I 1

1 1

1 1 1

1 

0 80 KILOMETERS 

1500 

Figure 2. Generalized map showing major faults in the vicinity 

of Anchorage. 

hundred meters below Anchorage, are Tertiary clastic 

sedimentary rocks that have been deposited in the structural depression; these sedimentary rocks wedge out 

against the older rocks along the basin boundaries. 

Quaternary History 

The Quaternary history of upper Cook Inlet has 

been discussed in considerable detail by Miller and 

Dobrovolny (1959), Karlstom (1964), Schmoll and 

Dobrovolny (1972), and Reger and Updike (1983). 

Karlstrom proposed that at least five major glaciations 

occurred in upper Cook Inlet which were, from oldest 

to youngest, Mount Susitna, Caribou Hills, Eklutna, 

Knik, and Naptowne glaciations. The three earlier glaciations (Mount Susitna, Caribou Hills, and Eklutna) were 

presumably far more extensive than the later ones (Knik 

and Naptowne), and ice of these earlier glaciations 

coalesced to fill the Cook Inlet trough. The later glaciations, though not as extensive, were capable of significantly restricting the movement of fresh and marine 

waters in the inlet. It is quite probable that glacially 

dammed lakes were produced during the late Pleistocene 

so that glaciofluvial, deltaic, lacustrine, and marine 

sedimentation were juxtaposed with ice-contact deposits. 

The Bootlegger Cove Formation3 was a product of this 

type of glaciomarine/ glaciolacustrine environment. 

Although the following discussion relates to this stratigraphic unit as exposed in the Anchorage area, the depositional environment was undoubtedly duplicated elsewhere 

in Cook Inlet at various times during the Quaternary, 

which resulted in several other Bootlegger Cove-type 

deposits. 

The Bootlegger Cove Formation is a stratified sequence of clastic sediments that range from clay to 

boulders which, on the basis of paleontologic evidence 

(Schmidt, 1963), were deposited in brackish or marine 

waters. The formation is known to occur at shallow 

depths beneath most of the western half of metropolitan 

Anchorage, as well as northward in the Knik Arm area 

and westward to the Susitna River. Several radiometric 

dates have consistently yielded a late Wisconsin age 

(about 14,000 years B.P .) for a horizon in the upper part 

of the formation (Schmoll and others, 1972). Generally, 

the formation is underlain by glaciofluvial sands and 

gravel or by glacial till. Dependant upon the location, the 

formation may be overlain by till (for example, the 

Elmendorf Moraine), glaciofluvial sediments, or eolian 

silts and peat. 

Engineering Geologic Facies of the Bootlegger 

Cove Formation 

Seven sedimentary facies of the Bootlegger Cove 

Formation have been identified by Updike and Carpenter 

(1986) in order to better characterize intraformational 

variations of composition and geotechnical characteristics. Each facies is distinguishable as a function of subtle 

differences in depositional environment (for example, turbidity, energy regime) and postdepositional modifications 

(for example, overburden pressures, ground-water 

leaching). The defined facies are intricately intercalated 

so that the scale of units portrayed can vary depending 

on the objective of the study. For mapping purposes, 

units less than 1 m in thickness must be considered as 

lenses or layers within a larger facies unit (Updike, 1986; 

Updike and Carpenter, 1986). By contrast, a laboratory 

geotechnical study of the facies, such as the present 

report, must isolate a finite suite of undisturbed samples 

representative of those defined facies. The facies which 

have been differentiated as distinct units at both scales 

are: 

3This stratigraphic unit was originally named the Bootlegger 

Cove Clay by Miller and Dobrovolny (1959) for typical sections exposed 

at Bootlegger Cove in Anchorage. Because the unit varies greatly in 

composition and because clay is commonly a secondary constituent, 

Updike and others (1982) have renamed the unit the Bootlegger Cove 

Formation. 

Regional Geologic History 3 
Facies F .I Clay with very minor amounts of silt. 

Facies F .II Silty clay and (or) clayey silt. 

Facies F.III Silty clay and (or) clayey silt, sensitive. 

Facies F .IV Silty clay and clayey silt, with silt and 

fine sand lenses. 

Facies F.V Silty clay and (or) clayey silt, with random stones. 

Facies F. VI Dense silty fine sand, with silt and clay 

layers. 

Facies F. VII Fine to medium sand, with traces of 

silt and gravel. 

In addition to the geologic distinction of the facies 

based on sedimentologic criteria, each facies may be further defined by statistical analyses of geotechnical 

characteristics, including natural moisture content, Atterberg limits, plasticity index, liquidity index, standard 

penetration test, undrained shear strength, unconfined 

compressive strength, and sensitivity ratio. The composite 

of the geologic and geotechnical criteria defines each of 

the seven engineering geologic facies, as discussed in detail 

by Updike (1986). 

GEOLOGIC HISTORY OF THE SITE 

The site at which the undisturbed samples of the 

Bootlegger Cove Formation were collected was found to 

be geologically typical of the 60 city blocks that form the 

metropolitan "core area" of Anchorage (fig. 3). The formation here is overlain by 8-13 m of gravelly sand and 

sandy gravel which were deposited over the superface of 

the Bootlegger Cove Formation as a glacial outwash plain 

that extended southwest from the Eagle River area. These 

stratified glaciofluvial sediments predominantly consist 

of medium to coarse sands in the lower half of the unit 

and grade upward to coarser sandy gravels with interbeds 

of sand and silt. 

The distribution of boreholes at the site is shown 

in figure 4. The stratigraphic logs from these holes have 

been assessed on the basis of the engineering geologic 

facies criteria, and geologic cross sections of the site have 

been constructed (figs. 5, 6). 

Of the several boreholes drilled at the site, only hole 

6, which reached a depth of 65 m, penetrated the base 

of the formation. This hole and sites previously drilled 

nearby indicate that the total thickness of the formation 

generally exceeds 40 m. This thickness approaches the 

maximum formational thicknesses recorded elsewhere in 

the city, which suggests that the site is situated toward 

the center of the primary Bootlegger Cove Formation 

depositional basin. The logs of the deep boreholes indicate that stratified sandy gravel and silty gravelly sand 

of good aquifer quality were encountered below the base 

of the formation. Such deposits are typical of highenergy, glaciofluvial sedimentation. Other deep boreholes 

Figure 3. Generalized map showing the location of the sample site in Anchorage. The site is not more specifically located 

to maintain confidentiality of the land owner. 

e Borehole 

t-------1 Cross section 

1 2 8 

• 

---- Contour - Top of the Bootlegger Cove Formation 

Contour Interval 5 Feet 

N 

i------_:_1 0'--0----rS 0 _ __,2 0 0 ~~ ~ TE R S 

1 

• 

Figure 4. Map showing the location of boreholes and crosssection lines at the investigation site. Contours show elevations 

of the top of the Bootlegger Cove Formation in feet above mean 

sea level. The borehole data has been projected to the section 

line. 

4 Cyclic Triaxial Tests, Bootlegger Cove Formation, Anchorage, Alaska 
Depth 

ft 9 5 6 2 3 Elevation 

m ft m 

A I I I I 0 100 A' 30 

1 0 90 

2 0 80 

3 0 •.•. 0 . . 70 

10 20 

4 0 . . . rJ ·(·. · : ' 60 

50 50 

6 0 40 

20 10 

7 0 30 

8 0 20 

9 0 10 

1 0 0 30 0 0 

1 1 0 -10 

1 2 0 -2 0 

% ¢ 

1 56+47.5 -56+-17 

# ~ 198_.1_60 -98 _L -30 

Figure 5. Geologic cross section along line A-A'; location shown on figure 4. Symbols: GP = sandy gravel; ML = 

inorganic silt and very fine sand; SM = silty sand; SP = gravelly sand; Roman numerals are facies of the Bootlegger 

Cove Formation. The borehole data have been projected to the section line. 

in the downtown area indicate that the sand and gravel 

are underlain by a compact stony silt (diamicton) which 

is believed to be a glacial till. 

Based upon stratigraphic correlations, we have interpreted the following history for the site: 

(1) During late Knik or early Naptowne time 

(20,000 years B.P .), a glacier advanced across 

what is now downtown Anchorage and 

deposited till and glaciofluvial sediments over 

a preexisting glacial topography of Knik age. 

At present, these glacial sediments are at depths 

greater than about 60 m at the site and include 

the overconsolidated bouldery silts and confined aquifers (sandy gravels) that are commonly encountered in deep boreholes. 

(2) Subsequently, ice retreated entirely out of the 

area and a period of weathering and erosion 

ensued until about 18,000 years B.P. when ice 

readvanced into the region. However, in contrast to the previous glaciation, during this 

episode ice did not enter the present-day downtown area but instead bordered the area to the 

west and north. These late Naptowne glaciers 

fronted in a marine or brackish-water basin 

bounded by the ice and the Chugach Mountains. Glaciodeltaic fans that extended away 

from these glaciers and into the basin deposited 

coarse gravels that grade basinward to dominantly sands and silts. Within the deep, quiet 

part of the basin, silts and clays accumulated 

with discontinuous sand lenses. These glaciodeltaic fan deposits, which prograde to glaciolacustrine silts and clays (as occur at the study 

site), are of late Naptowne age and compose the 

Bootlegger Cove Formation. The clayey silts 

with random stones (Facies F. V) that were 

encountered in the lower parts of the site boreholes represent the early sedimentation of this 

period, with ice-rafted dropstones being accumulated in a dominantly suspended load 

Geologic History of the Site 5 
Depth 

ft m 1 1 7 6 2 Elevation 

ft m 

B 0 100 30 B' 

1 0 90 

2 0 80 

3 0 70 

1 0 20 

4 0 60 

50 50 

60 40 

20 10 

7 0 30 

80 20 

9 0 10 

30 1 0 0 0 0 

1 1 0 -10 

1 2 0 -2 0 

!l ~ 156+47.5 

1 

198.1_60 

-56+ -17 

~ -981-30 

Figure 6. Geologic cross section along line B-B'; location shown on figure 4. Symbols: GP = sandy gravel; SM = 

silty sand; SP = gravelly sand; Roman numerals are facies of the Bootlegger Cove Formation. The borehole data have 

been projected to the section line. 

deposition. The fluctuations indicated by 

sedimentation of the Facies F.I to F.IV above 

Facies F. V record a stabilization and stagnation of the nearby ice front that resulted in 

quiet-water silt and clay accumulation with occasional influxes of sand (F. VI and F. VII). 

These subtle variations in bedding texture and 

structure were a response to the relative position and continuity of ice margins and marine 

waters and to the resultant changes in sediment 

transport energy. There was a general trend 

toward shallower water environments, occasionally even subaerial, in the later stages of 

Bootlegger Cove Formation deposition, as indicated by increasing presence of F. VI and 

F.VII. The final phase of deposition is marked 

by total dominance of fine to medium wellsorted sands (F. VII) which probably signifies 

the draining of the basin and tidal flat sedimentation. 

6 Cyclic Triaxial Tests, Bootlegger Cove Formation, Anchorage, Alaska 

(3) Either as a stillstand in the retreat of the glaciers 

described above or as a subsequent readvance, 

during latest Naptowne time a glacier from the 

north reached the present area of Elmendorf 

Air Force Base, and glaciofluvial sediments 

were deposited southward across the Bootlegger Cove Formation. This occurred at 10,000-

12,000 years B.P. and resulted in the brown 

sandy gravels that were recorded in the upper 

8-13 m of the boreholes at the site. 

(4) During the Holocene (last 10,000 years) the 

region has been subjected to vertical elevation 

adjustments in response to isostatic rebound 

and tectonics, juxtaposed against fluctuations 

in sea level. This has resulted in the development of erosional bluffs along Cook Inlet and 

along streams (for example, Ship Creek) that 

drain into the inlet. Scarp retreat due to mass 

movement along these bluffs has been ongoing 

for several hundred years and is gradually 
progressing toward the project site. Consolidation and salt leaching within the stratigraphic 

column has been enhanced by the gradual uplift 

of the soils with respect to sea level. There is 

no geologic evidence to suggest that the Bootlegger Cove Formation has been overridden by 

ice since it was deposited, nor that during the 

Holocene it was previously buried under a 

significantly thicker sediment cover than at present. Further, there is no evidence to imply that 

the soil sequence below the uppermost 15 m has 

ever been other than saturated and nonfrozen. 

STATIC ENGINEERING 

CHARACTERIZATION OF THE SITE 

Field Sampling and Logging 

At each borehole location (fig. 4) standard splitspoon samples were collected by Cole at 5-ft intervals to 

characterize the soils being penetrated by the hollow stem 

auger; characteristics such as texture, relative density, and 

relative moisture content were described. Standard penetration testing (SPT), in accordance with ASTM standard 

procedure D1586-67, was performed at each sample 

depth. Where test samples were desired,thin-walled, 3-inch 

(7.6 em) diameter Shelby tube samplers of 2.5- and 5.0-ft 

(0.75 and 1.50 m) lengths were slowly pushed into the undisturbed soil below the hollow stem auger casing. These 

Shelby tubes were transported directly from the drill site 

to the DOWL geotechnical lab where extraction of the 

samples proceeded within 48 hours of arrival. Each extracted sample was sketched, visually described, and characterized by penetrometer tests, torvane, natural moisture 

content, and Atterberg limits. During this phase, samples 

were classified, separated, and sealed for advanced static 

and dynamic testing. 

Four phases of advanced laboratory testing followed 

the indices characterization of the borehole samples. 

These tests, and the facilities where they were performed, 

are: static triaxial compression (DOWL and UCLA), consolidation (DOWL), resonant column (Harding and Lawson Engineers, Inc., Novato, Calif.), and cyclic triaxial 

compression (UCLA). The results of the resonant column 

testing have been reported elsewhere (Updike and others, 

1982). The results of the static as well as the dynamic 

testing programs are presented in this report. 

DYNAMIC LABORATORY 

TESTING PROGRAM 

Ten undisturbed samples (each approximately 8 inch 

[20 em] in length) of the Bootlegger Cove Formation were 

selected from the cores extracted from thin-wall Shelby 

tube samplers. The samples consisted of: 

CT-1 Facies F.IV. Clayey silt, with some fine silty 

sand layers; depth 84ft (25.6 m), test hole 3. 

CT-2 Facies F.II. Silty clay, uniform texture, 

moderately firm; depth 91 ft (27 .8 m), test 

hole 3. 

CT-3 Facies F.III. Silty clay, sensitive, uniform texture, layered; depth 96.5 ft (29.4 m), test hole 

9. 

CT-4 Facies ·F.IV. Clayey silt, with some fine silty 

sand layers; depth 80 ft (24.4 m), test hole 6. 

CT-5 Facies F.IV. Clayey silt, with some fine silty 

sand layers; depth 81 ft (24. 7 m), test hole 7. 

CT-6 Facies F.IV. Clayey silt, with fine sand seams; 

depth 83.5 ft (25.5 m), test hole 6. 

CT-7 Facies F.IV. Clayey silt, with fine sand seams; 

depth 84.5 ft (25.8 m), test hole 6. 

CT-8 Facies F.II. Silty clay, uniform texture, 

bedded, medium soft; depth 87 ft (26.5 m), 

test hole 6. 

CT-9 Facies F.II. Silty clay, uniform texture, 

bedded, medium soft; depth 87 ft (26.5 m), 

test hole 6. 

RC-6 Facies F.II. Clayey silt, uniform texture, 

massive; depth 81 ft (24.7 m), test hole 9. 

After the samples had been selected and catalogued 

they were sealed and hand-carried by Updike to the University of California-Los Angeles Soils Mechanics Laboratory for testing. The testing program was supervised by 

Lade. Standard soil indices tests (torvane, grain-size distribution, moisture content, density, and Atterberg limits) 

were performed on each sample in order to relate the dynamic properties of the facies obtained through advanced 

tests with the routinely obtained standard soil indices. 

Each sample was cut into halves; one half was used for 

static strength tests and the other half was used for cyclic 

loading tests. The testing program and the objectives for 

each series of tests for the ten samples are given below: 

(1) A series of ten static triaxial compression tests 

were performed on intact specimens to establish 

the unconsolidated-undrained (UU) stress-strain 

behavior and shear strength of the soil. The 

specimens were then remolded and another 

series of static triaxial tests were executed to 

define the remolded UU shear strength and 

estimate the sensitivity of the soils. 

(2) A series of ten triaxial compression tests with 

pore pressure measurements were performed on 

the remolded specimens to defin~ the remolded 

isotropically consolidated-undrained (ICU) 

stress-strain behavior and shear strength of the 

soil in order to assess the postfailure consolidation of zones within the deposit which may have 

failed during previous earthquakes. 

Dynamic Laboratory Testing Program 7 
(3) A series of ten stress-controlled cyclic triaxial 

tests were conducted on intact specimens, which 

were initially consolidated at overconsolidation 

stress ratios of 1.0, 1.5, and 2.0 and tested at 

the appropriate cyclic stress ratios, to establish 

the dynamic shear moduli, damping ratios, and 

number of cycles to cause various amounts of 

strain. 

(4) A series of ten stress-controlled cyclic triaxial 

tests on remolded specimens of item 3, which 

were initially consolidated at overconsolidation 

stress ratios of 1.0, 1.5, and 2.0, were conducted at appropriate cyclic stress ratios to 

establish the dynamic shear moduli, damping 

ratios, and number of cycles to cause various 

amounts of strain. 

Unconsolidated-Undrained Tests 

Equipment 

The testing equipment used for the UU tests is 

shown in figure 7. It consists of a triaxial cell placed in 

a 5-ton Wykeham Farrance4 loading machine. A confining pressure is applied in the triaxial cell by air pressure, 

which is regulated and measured as shown on the left side 

of figure 7. A load cell, mounted below the cross bar on 

the loading machine, is used to measure the vertical 

deviator load that is applied to the triaxial specimen. The 

electrical signal from the load cell is measured by the BLH 

Strain Indicator shown on the right side of figure 7. A 

dial gauge is employed to measure the vertical deformation of the specimen. 

Testing Procedure 

The intact soil was trimmed to produce a final cylindrical specimen with a diameter of 1.40 inches (3.57 em) 

and a height of 3.00-3.50 inches (7 .62-8.89 em) for UU 

testing. The specimen was inspected, and a sketch with 

location and geometry of sedimentary laminae was 

drawn. The specimen was measured and weighed for 

determination of wet density. The specimen was then 

placed between a lucite cap and base, and two rubber 

membranes, each 0.002 inches (0.005 em) thick, were 

rolled up around it. A layer of high-vacuum silicone 

grease was smeared on the inner membrane before the 

outer membrane was rolled up. Two 0-rings were used 

4Any use of trade names in this report is for descriptive purposes 

only and does not imply endorsement by the U.S. Geological Survey. 

Figure 7. Triaxial testing equipment used for the 

unconsolidated-undrained static tests. 

on each end to seal the membranes to the cap and base. 

The specimen was then placed in the triaxial cell, and a 

confining pressure of 50 psi (3.52 kg/cm2

) was applied 

by compressed air. The specimen was sheared at a constant rate of deformation of 0.020 inches/minute 

(0.050 em/minute), which corresponds to a strain rate of 

0.57 percent/minute for a 3.50-inch (8.89 em) specimen 

and 0.67 percent/minute for a 3.00-inch (7 .62 em) specimen. Measurements of load and deformation were taken 

at appropriate intervals throughout the test. At the end 

of each test, the triaxial cell was disassembled and the 

membranes were carefully removed to inspect the final 

shape of the specimen, to locate shear planes (recorded 

on a sketch), and to take a photograph of the failed 

specimen. 

To perform a UU test on remolded soil, the previously intact specimen was mixed with part of the rough 

trimmings and thoroughly remolded. A cylindrical 

specimen was trimmed from the remolded soil, measured 

and weighed, and placed between the cap and base. The 

remolded specimen was tested under UU conditions 

without membranes and without confining pressure. The 

testing procedure for the remolded specimen was otherwise similar to that described above for the intact 

specimen. 

8 Cyclic Triaxial Tests, Bootlegger Cove Formation, Anchorage, Alaska 
In addition to the ten UU tests on remolded soil 

performed without confining pressure, for comparative 

purposes, one UU test on remolded soil was performed 

on sample CT -8 (F.II) with a confining pressure of 50 

psi (3.52 kg/cm2}. For this specimen the membranes 

were mounted around the soft remolded specimen using 

a vacuum jacket. 

Consolidated-Undrained Tests 

Equipment 

The testing equipment used for consolidatedundrained (CU) tests is shown in figure 8. It consists of 

a triaxial cell placed in a 5-ton Wykeham Farrance 

loading machine. The cell water is pressurized by 

regulated air pressure in a separate lucite cylinder connected with the cell. This arrangement is used to avoid 

air penetration through the specimen membranes, thereby 

maintaining a high degree of saturation of the specimen. 

The drainage line from the triaxial specimen is connected 

to a volume change and pore pressure measuring device 

shown at the right in figure 8. A back pressure can be 

applied in the specimen through this device. A load cell, 

mounted below the cross bar on the loading machine, is 

used to measure the vertical deviator load applied to the 

specimen. An L VDT (linear variable displacement 

transducer) is employed to measure the vertical deformation of the specimen. The electrical signals from the load 

cell, the pore pressure transducer, and the L VDT were 

measured and recorded by the Digitec 1000 datalogger 

shown at the left in figure 8. 

Testing Procedure 

The CU tests were performed only on remolded 

specimens because the limited intact sample material that 

was available needed to be conserved for the dynamic 

tests. The remolded specimen previously tested under UU 

conditions was again mixed with part of the rough trimmings and thoroughly remolded. A cylindrical specimen 

with a diameter of 1.40 inches (3.57 em) and a height of 

3.00-3.50 inches (7.62-8.89 em) was trimmed from the 

remolded soil, measured, and weighed. A water-saturated 

carborundum filter stone was fitted on the stainless steel 

base to provide drainage for the CU specimen, which was 

placed on the filter stone. A lucite cap was placed directly on top of the specimen. Vertically slotted filter paper 

was wrapped around the specimen to provide radial drainage. The filter paper was then wetted to make it cling to 

the specimen. The 0-ring at the end of the inner rubber 

Figure 8. Triaxial testing equipment used for the isotropically consolidated-undrained static tests. 

membrane was cut off to avoid penetration into the soft 

remolded soil. Without this 0-ring and with the additional strength provided by the filter paper drains, it was 

possible to roll the inner membrane up around the 

specimen, while avoiding severe indentation in the specimen. A thin layer of high-vacuum silicone grease was 

smeared on the inner membrane before the outer membrane was rolled up. Two 0-rings were used on each end 

to seal the membranes to the cap and base. After having 

assembled the specimen on the bottom plate of the triaxial cell, the cell wall and the top plate were installed, the 

cell was filled with de-aired water, and a confining 

pressure was applied. 

With the drainage line connected to the volume 

change and pore pressure measuring device and with the 

drainage valve closed, the desired cell pressure of 80 psi 

(5.63 kg/cm2) and back pressure of 30 psi (2.11 kg/cm2

) 

were applied. An effective isotropic confining pressure (cell 

pressure minus back pressure) of 50 psi (3.52 kg/cm2

) 

was employed in all tests. By opening the drainage valve, 

the specimen was allowed to consolidate isotropically; in 

other words, it was an isotropically consolidated-undrained 

(ICU) test. Measurements of volume change, vertical deformation, and time were taken to produce a consolidationtime curve. The information from this curve was used to 

calculate an allowable vertical strain rate for the undrained 

shearing of the specimen. Because a datalogger was employed for the shearing phase of the test, it was possible 

to further reduce the vertical strain rate, thus insuring a 

high degree of pore water pressure equalization inside the 

specimen. A deformation rate of 0.00024 inches/minute 

(0.0006 em/minute) was 'used in all tests except those on 

samples CT-1 (0.00016 inches/minute; 0.0004 em/minute) 

and CT-6 (0.00048 inches/minute; 0.0012 em/minute). 

Dynamic Laboratory Testing Program 9 
With maximum vertical strains between 22 percent and 

36 percent, each test lasted from 1.5 to 3 days. 

The value of pore pressure parameter B (measured 

pore pressure increase/applied confining pressure increase) was measured immediately before shearing to 

obtain an indication of the degree of saturation of the 

specimen. During shearing, the.;vertical load, vertical 

deformation, and pore water pressure were measured at 

appropriate time intervals and recorde9 by the datalogger. At the end of each test the triaxial cell was disassembled and the failed specimen was photographed. 

The specimen was then quartered by vertical cuts, and 

one quarter was used for water content determination. 

The remaining parts were stored with the trimmings for 

determination of liquid and plastic limits. 

Cyclic Loading Tests 

Equipment 

The testing equipment used for cyclic loading tests 

is shown in figure 9. It consists of a triaxial cell placed 

in a cyclic loading machine. The cell water was pressurized 

by regulated air pressure in a separate lucite cylinder connected with the cell through a Y4-inch nylon tube. This 

arrangement was similar to that used for the ICU tests. 

The drainage line from the triaxial specimen was connected to a volume change and pore pressure measuring 

device (figure 9). A back pressure can be applied in the 

specimen through this device. A load cell, mounted below 

the double-acting piston on the cross bar of the cyclic 

loading frame, was used to measure the vertical cyclic 

load applied to the triaxial specimen. Static and cyclic 

air pressure was applied in the double-acting piston from 

the Pneumatic Sinusoidal Loader. An L VDT was employed to measure the vertical deformation of the specimen. The electrical signals from the load cell, the pore 

pressure transducer, and the L VDT were measured and 

recorded versus time on a 4-channel Sanborn strip-chart 

recorder. A Houston 2000 X-Y recorder was used for 

recording cyclic deviator stress versus vertical strain. 

Testing Procedure 

Cyclic loading tests were performed on intact and 

remolded specimens. The cylindrical specimen with a 

diameter of 1.40 inches (3.57 em) and a height of 

3.00-3.50 inches (7.62-8.89 em) was measured and 

weighed. A water-saturated carborundum filter stone was 

placed on the stainless steel base to provide drainage for 

the specimen during the initial consolidation. The specimen was placed between the filter stone and a lucite cap. 

Figure 9. Cyclic triaxial testing equipment used for the cyclic 

loading tests. 

Filter paper slotted at 45 X was wrapped around the cyclic 

loading specimen to provide radial drainage. The filter 

paper was then wetted to make it cling to the specimen. 

Two thin rubber membranes were rolled up around the 

cylindrical specimen. A layer of high-vacuum silicone 

grease was smeared on the inner membrane before the 

outer membrane was rolled up. Two 0-rings were used 

on each end to seal the membranes to the cap and base. 

After having assembled the specimen on the bottom plate of the triaxial cell, the cell wall and the top plate 

were installed. De-aired water was introduced to fill the 

cell completely, and the cell water was pressurized. After 

consolidation and immediately before the cyclic loading, 

the water level in the triaxial cell was reduced to about 

one inch above the cap of the specimen, thus allowing 

vertical cyclic loading of the specimen without inducing 

cyclic cell pressures. The triaxial cell with the specimen 

was then mounted in the cyclic loading frame with the 

bottom plate rigidly attached to the table top, and the 

loading rod was attached to the load cell fixed to the end 

of the double-acting piston. With the drainage line connected to the volume change and pore pressure measuring 

device, the desired cell pressure of 80 psi (5.63 kg/cm2) 

and back pressure of 30 psi (2.11 kg/cm2) were applied. 

The uplift pressure on the rod was counterbalanced by 

an adjustment of the pressure on one side of the doubleacting piston, thus insuring isotropic consolidation pressures on the specimen. An effective isotropic confining 

pressure (cell pressure minus back pressure) of 50 psi 

(3 .52 kg/cm2

) was employed for the initial consolidation 

stage, for all cyclic loading tests. 

10 Cyclic Triaxial Tests, Bootlegger Cove Formation, Anchorage, Alaska 
By opening the drainage valve, the specimen was 

allowed to consolidate. Measurement of volume change, 

vertical deformation, and time were taken to produce a 

consolidation-time curve. This curve was plotted and 

traced to insure that full primary consolidation had taken 

place before cyclic loading of the specimen was initiated. 

For specimens with final consolidation stress ratios 

of Kc = 1.5 and 2.0, the initial consolidation (Kc = 1.0) 

was first achieved to let the specimen gain some strength 

before the deviatoric consolidation stress was applied. 

This was done to avoid static failure due to pore pressure 

increase of the specimens upon application of the deviatoric consolidation stress. This stress was applied in one 

step to obtain a consolidation stress ratio of Kc = 1.5 

and in two steps to obtain Kc = 2.0. Full consolidation 

was achieved for each step before the next step was 

applied. 

Before the triaxial cell with the specimen was 

mounted in the cyclic loading frame, the sinusoidal cyclic 

load to be applied to the specimen was determined relative to the previously determined static undrained shear 

strength. The equipment was adjusted to provide that 

calculated cyclic load. The cyclic load was also recorded 

on the strip chart by the Sanborn Recorder before the 

actual test was performed, thus providing a calibration 

for possible further changes in cyclic load after installing the specimen in the cyclic loading frame. The 

actual cyclic deviator stress applied to the specimen 

after consolidation was calculated after the test was 

completed. 

The deformation of the specimen during cyclic 

loading was measured with an L VDT, which was individually calibrated for each test (due to different specimen 

heights) to produce direct measurements of strain on the 

Sanborn Recorder and on the X-Y Recorder. Pore 

pressures were also calibrated and recorded on the strip 

chart by the Sanborn Recorder. The X-Y Recorder was 

used to obtain stress-strain relationships throughout or 

at a selected number of applied load cycles for determination of shear moduli and damping ratios. At the end of 

each test, the triaxial cell was disassembled and the failed 

specimen was photographed. 

To perform a cyclic loading test on remolded soil, 

the previously intact specimen was thoroughly remolded 

and prepared in the same manner as the remolded UU 

specimens. The testing procedure for the remolded specimens was also similar to that used for the intact 

specimens. 

In an attempt to get a direct comparison between 

properties of the intact specimens and those of the 

remolded specimens, the same cyclic deviator load was 

applied in both cases. However, because the intact specimens consolidated less than the remolded specimens, the 

cyclic deviator stress applied to the former was slightly 

lower than that applied to the latter. 

40 ~------------------------------------~ 

CH 

30 

20 

1 0 

0 L-----~----~----~----~~----~----~ 

0 10 20 30 40 50 60 

LIQUID LIMIT 

Figure 10. Plasticity chart for samples of the Bootlegger Cove 

Formation tested in this study. 

Following the cyclic test on the remolded specimen, 

the triaxial cell was disassembled, the failed specimen was 

photographed, and water content was determined. 

RESULTS OF LABORATORY TESTING 

Soil Index Tests 

The results of the Atterberg limit and hydrometer 

tests are summarized in table 1. The Atterberg limit tests 

were performed on soil from the static section of the 

samples. The results of these tests are plotted on the 

plasticity chart (fig. 10). All samples have low plasticity 

and are inorganic (above the A-line); thus they correspond 

to a unified classification of CL. 

The grain-size distributions were determined by 

hydrometer tests on soil from the cyclic section of the 

samples. A standard value of the specific gravity of 

Gs = 2.782 was used for all calculations related to these 

tests. The median grain diameter (D50) and the percentage of clay, silt, and sand are given in table 1. Only 

one sample (CT -2) contained a measurable amount 

of sand (about 22 percent). The static section of sample 

CT -4 contained one pebble-sized grain. Activities 

for all samples, also listed in table 1, were between 0.18 

and 0.42. 

Static Tests 

The results of the torvane tests and the UU tests 

on intact and remolded specimens are summarized in 

table 2. Also summarized in this table are the water contents, specimen geometries, wet densities, and calculated 

sensitivities. Detailed test results, including sketches of 

Results of Laboratory Testing 11 
.... 

1-.) 

r'l 

Q. 

;::;· 

:;4 

;· 

>li 

ei 

.... 

~ 

? 

= 0 

~ Table 1. Summary of Atterberg limit and hydrometer tests on the Bootlegger Cove Formation 

gg [Particle size boundaries are: sand/silt = 0.075 mm; silt/clay = 0.002 mm. See "GLOSSARY OF SYMBOLS USED" for definitions of symbols] ~ 

r'l 

0 

~ ., 

0 

3 

a 

o· 

? 

~ 

:I 

l"'l 

:::r 

0 

~ 

~ 

~ 

c:i" 

Cll 

Ill':'" 

llol 

Sample CT-1 CT-2 CT-3 CT-4 

--

Liquid limit1 ....... 3 5. 1 31.2 31.3 35.7 

Plastic limit1 ...... 22.5 21.5 2 0. 1 23.2 

Plasticity index (PI) 1 2. 6 9.7 11.2 12.5 

D5o ( mm)2 ........... 0.0033 0.0027 0.0012 0.0024 

Percent clay 2 ....... 38.0 42.0 62.0 45.0 

Percent silt2 ....... 62.0 36.0 38.0 55.0 

Percent sand2 ....... 0 2 2. 0 0 0 

Activity = PI ... 0.33 0.23 0. 18 0.28 

% clay 

1 values determined from static sections of samples. 

2values determined from cyclic sections of samples. 

CT-5 CT-6 CT-7 CT-8 

41.8 39.9 32.5 4 2. 3 

23.8 20.8 19. 6 24.6 

18.0 1 9. 1 1 2. 9 1 7. 7 

0.0023 0.0026 0.0058 0.0017 

46.0 45.0 3 2. 0 53.0 

54.0 55.0 68.0 47.0 

0 0 0 0 

0.39 0.42 0.40 0.33 

CT-9 RC-6 

4 0. 9 40.4 

24.9 22.7 

16.0 17.7 

0.0015 0.0022 

55.0 47.0 

45.0 53.0 

0 0 

0.29 0.38 
Table 2. Summary of torvane and UU triaxial tests on intact and remolded specimens of the Bootlegger Cove Formation 

[nd, not determined. See "GLOSSARY OF SYMBOLS USED" for definitions of symbols] 

Sample CT-1 

Kc = o-1 clo-3 c before cyclic • • 1. 0 

loading. 

Initial length of sample (em) 21.5 

Torvane tests, static section! 

Su (intact)(kg/cm2 ) nd 

Su (remolded)(kg/cm2 ) ••••• nd 

S t • • • • • • • • • • • • • • • • • • • • • • • • nd 

Torvane tests, cyclic section! 

Su (intact)(kg/cm2 ) ••••••• 0.44 

Su (remolded)(kg/cm2) ••••• 0.07 

st • • • • • • • • • • • • • • • • • • • • • • • • 6. 3 

00 triaxial tests, intact2 

w/c (outer 0.5 em of ••••••• 28.08 

sample) (%). 

w/c (trimmings)(%) ••••••••• 30.14 

A0 (cm2 ) ••••• ••••••••••••• 9.931 

H0 (em) ••• ••••••••••• ••••• 8.87 

V0 (cm3 ) • • • • • • • • • • • • • • • • • • 88.04 

Ywet (g/cm3 ) •••••••••••••• 1.958 

Su (kg/cm2 ) ••••••••••••••• 0.507 

00 triaxial tests, remolded3 

CT-2 

1. 5 

23.0 

0.52 

0.07 

7.4 

0.48 

0.07 

6.8 

26.04 

27.86 

9.931 

8.99 

89.30 

2.010 

0.624 

CT-3 

1. 5 

18.0 

0.64 

0.12 

5.3 

o. 61 

0.08 

7.6 

25.54 

26.80 

9.931 

7.75 

7 6. 94 

2.032 

0.672 

CT-4 

2.0 

21.5 

o. 51 

0.08 

6.4 

0.49 

0.07 

7.0 

30.02 

32.55 

9.931 

8.84 

8 7. 7 8 

1. 9 31 

0.531 

CT-5 

1. 0 

23.0 

nd 

nd 

nd 

0.56 

0.08 

7.0 

30.28 

32.54 

9.931 

8.87 

88.04 

1.948 

0.603 

CT-7 

1. 0 2.0 

19.0 19.5 

0.86, 0.69 

1.80 

0.18, 0.13 

0.30 

4. 8' 5. 3 

6.0 

0.91 0.82 

0.19 0.07 

4.7 11.7 

24.79 23.95 

24.72 26.26 

9.931 9.931 

8.48 8.84 

84.25 87.78 

2.044 2.041 

1.189, 0.798 

1. 1 2 6 

1.5 

19.0 

0.59 

0.08 

7.4 

0.56 

0.08 

7.0 

33.77 

36.62 

9.931 

8. 31 

8 2. 48 

1. 8 98 

0.620 

CT-9 

2.0 

15.0 

0.68 

0.10 

6.8 

0.83 

0.08 

10.4 

32.09 

34.31 

9.931 

7. 4 2 

7 3. 66 

1.923 

0.829 

RC-6 

1. 0 

21.0 

0.53 

0.07 

7.6 

0.60 

0.09 

6.7 

30.22 

32.35 

9.931 

8.84 

8 7. 7 8 

1.947 

0.560 

w/c (trimmings)(%) •••••••• 28.95 27.19 26.61 32.31 32.37 23.72 25.39 31.69, 33.74 nd 

31.36 

A0 (cm2 ) •••••••••••••••••• 9.931 9.931 9.931 9.931 9.931 9.931 9.931 9.931, 9.931 9.931 

9.931 

H0 (em) ••••••••••••••••••• 8.05 8.31 7.75 8.76 8.48 7.16 8.59 7.11, 7.82 8.81 

8. 4 8 

V0 (cm3 ) •••••••••••••••••• 79.97 82.48 76.94 87.03 84.26 71.13 85.26 70.63, 77.69 87.53 

84.25 

~et (g/cm3 ) •••••••••••••• 1.960 2.012 2.036 1.958 1.915 2.050 2.048 1.894, 1.914 1.955 

1.966 

Su (kg/cm2 ) ••••••••••••••• 0.126 0.171 0.156 0.115 0.155 0.428 0.175 0.128, 0.130 0.139 

0.224 

St (UU Tests) ••••••••••••••• 4.0 3.7 4.3 4.6 3.9 2.8 4.6 4.8, 6.4 4.0 

2.6 2.8 

1Average values are given for each of static and cyclic sections. 

2 confining pressure 

3confining pressure 

3.52 kg/cm2 (SO psi). 

o. 

4 sample CT-6 had a stiff layer over about half of the static section. Therefore, interpretation is in 

terms of two different heights. 

5Remolded specimens tested with o-3 0 and o-3 

specimens before and after failure, photographs of failed 

specimens, and stress-strain curves were recorded for later 

inspection and possible correlation studies. 

The UU tests on intact specimens were performed 

with confining pressures of 50 psi (3.52 kg/cm2) to 

3.52 kg/cm2 , respectively. 

simulate effective overburden pressure, whereas the tests 

on remolded specimens were performed as unconfined 

tests. One test on remolded soil (from sample CT -8) 

was performed with a confining pressure of 50 psi 

(3.52 kg/cm2). The undrained shear strength from this 

Results of Laboratory Testing 13 
test was substantially higher than that from the 

corresponding unconfined test which results in a correspondingly lower sensitivity number. Thus, the true sensitivities of tested samples may be somewhat lower than 

those listed in table 2 because the in-situ remolded soil 

is under a confining pressure. 

The undrained shear strengths from the torvane 

tests on intact samples are comparable to those obtained 

from the UU tests on intact specimens. However, the 

remolded shear strengths from the torvane tests are 

lower than those obtained from the corresponding UU 

tests. 

The undrained shear strengths from the UU tests 

are plotted versus water content and are compared with 

results of other tests in figure 11. Although a considerable 

amount of scatter appears to be present, the test results 

were actually clustered in groups consistent with the type 

of test (UU or ICU) and the condition of the soil (intact 

or remolded). The strength values from the UU tests on 

intact specimens are lower than those from the ICU tests 

on intact and remolded specimens. This is reasonable, 

because the effective consolidation pressure in the ICU 

tests is 50 psi (3.52 kg/cm2

) or higher. The effective confining pressures in the UU -tests are unknown but are 

smaller than 50 psi, which is the approximate effective 

overburden pressure in-situ. 

The results of the ICU tests on remolded specimens 

are summarized in table 3. Summarized in this table are 

the water contents, specimen geometries, initial wet densities, vertical and volumetric strains due to consolidation, consolidation times, coefficients of consolidation, 

and all information related to failure at maximum effective stress ratio (u' / u' 3)max and at maximum deviator 

stress (u1

-u3)max· Detailed test results, including consolidation curves, stress-strain and pore pressure curves, 

effective stress-paths, and photographs of failed specimens, are available from the authors. 

Figure 12 shows a plot of the results of triaxial ICU 

tests on remolded samples, on a p-q diagram. The data 

points give the values of effective normal stress, p, and 

10~------._--~--~~~~_.~~------~--~--~~~~~~~------._~_._.~~~~_.~ 

0. 1 1. 0 1 0 

UNDRAINED SHEAR STRENGTH, IN KG/CM2 

Figure 11. Undrained shear strength versus water content as derived from unconsolidated-undrained (UU) tests and isotropically 

consolidated-undrained (ICU) tests. Solid line indicates relationship for ICU tests, determined during resonant column testing 

program (see Updike and others, 1982). 

14 Cyclic Triaxial Tests, Bootlegger Cove Formation, Anchorage, Alaska 
Table 3. Summary of ICU triaxial compression tests on remolded Bootlegger Cove Formation specimens 

[See "GLOSSARY OF SYMBOLS USED" for definitions of symbols] 

Sample 

Before consolidation 

w/c (trimmings)(%) 

A0 ( cm2 ) 1 ••••••••••••••• 

H0 (em) 1 •••••••••• , ••••• 

V0 (cm3 ) •••••••••••••••• 

Ywet (g/cm3) •••••••••••• 

After consolidation 

6Vconsol (cm3 ) •••••••••• 

6 8consol (em) ••••• , ••••• 

€vconsol (%)/ ••••••••••• 

€1consol (%). 

Ac ( cm2 ) 1 ••••••••••••••• 

He (em) 1 •••••••••••••••• 

t 50 (min) ••••••••••••••• 

t 10 o (min) •••••• , , , , • , , , 

CT3c (kg/cm2 ) •••••••••••• 

w/c (after test)(%) ••••• 

B-value2 , ••••••••••••••• 

cv•I0 5 (cm2 /sec) •••••••• 

Shearing 

Deformation rate (em/min) 

umax /a-3 c 3 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 

( CT'1/o-'3)max 3 '•••••••••• 

CT'3f (kg/cm2)3 ......... . 

uf (kg/cm2 ) 3 0 0. 0 0 0. 0 0 0 0 0 

€lf (%) 3 0 0 0 0 0 0 0. 0 0 0 0 0 0 0 0 

¢' (degree)3 •••••••••••• 

(CT1-CT3)max (kg/cm2)4 •••• 

CT'3f (kg/cm2)4 .......... 

Uf (kg/cm2)4 •••••••••••• 

Elf (%) 4 •,, •,,,,,,.,,,,, 

cp (degree) 4 •••••• , •••• , , 

€1max (%) ••••••• , ••• , , , • 

CT-1 

27.61 

9.931 

7.823 

77 0 69 

1. 9 8 6 

7.990 

0.150 

10.28/ 

1. 6 5 

9.084 

7.67 

180 

980 

3.488 

21.24 

1.42 

1.051 

CT-2 CT-3 

26.34 25.79 

9.931 9.931 

8.179 8.814 

81.22 87.53 

2.062 2.072 

7 0 148 

0.138 

·8.80/ 

1.70 

8.985 

8.24 

350 

1800 

3.436 

20.08 

nd 

0.540 

9.494 

0.154 

10.85/ 

2.39 

8.80 

8.87 

230 

1000 

3.421 

19 0 21 

1. 3 3 

0.822 

CT-4 

31. 18 

9.931 

8.763 

87.03 

1. 9 51 

11.647 

0.219 

13.38/ 

3.04 

8.45 

8.90 

170 

850 

3.439 

22.81 

1. 3 7 

1.113 

CT-5 

30. 18 

9.931 

8.255 

81.9 8 

1. 976 

10.433 

0.251 

12.73/ 

2.09 

8.939 

8.01 

150 

690 

3.449 

22.76 

1. 58 

1. 2 61 

CT-6 CT-7 

23.78 25.17 

9.931 9.931 

6.858 8.484 

68.11 84.25 

2.056 2.092 

5.506 

0.143 

8.08/ 

1. 24 

9.323 

6.72 

85 

400 

3.446 

21.04 

1. 10 

2.225 

9.356 

0.110 

11. 11/ 

2.70 

8.53 

8.78 

105 

470 

3.455 

19.20 

1. 18 

1.802 

0.0004 0.0006 0.0006 0.0006 0.0006 0.0006 0.0006 

0.578 0.609 0.514 0.590 0.559 0.583 0.563 

2.867 2.778 3.088 2.971 2.585 2.853 3.306 

1.938 2.269 1.746 1.558 1.829 2.078 1.872 

1.551 1.167 1.675 1.880 1.621 1.368 1.583 

12.344 13.804 9.510 11.039 17.066 9.024 9.974 

28.9 28.1 30.7 29.8 26.2 28.7 32.4 

4.296 5.295 4.777 3.805 3.361 5.198 5.457 

2.478 3.248 2.523 2.086 2.248 3.327 2.570 

1.010 0.188 0.898 1.352 1.202 0.119 0.886 

22.567 32.529 26.345 24.932 26.698 27.401 24.128 

27.7 26.7 29.1 28.5 25.3 26.0 31.0 

22.567 32.529 28.789 30.502 26.698 35.951 24.128 

CT-8 CT-9 RC-6 

33.49 31.60 30.79 

9.931 9.931 9.931 

8.788 8.788 8.204 

87.28 87.28 81.48 

1.936 1.974 1.976 

llo 6 33 

0.244 

13.33/ 

2.03 

8.60 

8.80 

220 

1000 

3.451 

24.80 

lo 11 

0.860 

10.612 

0.184 

12 0 16/ 

1. 2 4 

8.65 

8.86 

220 

1020 

3.420 

2 3. 83 

1. 2 6 

0.860 

10.405 

0.172 

12.77/ 

2.03 

8.56 

8.31 

96 

440 

3.433 

22.58 

1. 15 

1. 970 

0.0006 0.0006 0.0006 

0.632 0.577 0.521 

2.537 2.790 2.670 

1.993 1.814 2.423 

1.458 1.606 1.011 

15.730 11.885 15.896 

25.8 28.2 27.1 

3.639 4.066 4.455 

2.557 2.701 2.779 

0.893 0.719 0.654 

29.741 33.133 24.827 

24.6 25.4 26.4 

29.741 34.579 33.176 

1 some of the soft, remolded specimens elongated slightly upon placement of the membranes, This is 

considered in calculation of Ac and He (V 0 = constant), 

2B-values are determined after 5 minutes or, in a few cases, after 10 minutes. 

3At (CT'1/CT'3)max' 

4At (CT1-CT3)max' 

maximum shearing stress, q, that correspond to the peak 

points of the stress-strain curves for each test. The line 

drawn through these points, commonly termed the K1 

line, has a slope angle, a, of 25.54 °. The effective friction angle c/>' is related to a (Lambe and Whitman, 

1979) by 

sin cJ>' = tan a. 

From figure 12, a = 25.540; therefore, the mean effective 

friction angle for the Bootlegger Cove Formation samples 

tested is approximately 28.5 °. 

The undrained shear strengths from the ICU tests 

are also shown on figure 11. Partly due to the substantial volumetric compression of the remolded specimens 

during the consolidation phase, their undrained shear 

strengths are much higher than those obtained from the 

ICU tests that were performed on the intact specimens 

during the resonant column testing program (see Updike 

and others, 1982). 

Results of Laboratory Testing 15 
~ u 

........ 4 

(!) 

~ 

z 

t5' +N 

b 3 

CJ) 

(/) 

w 

a: 

1-

(/) 

(!) 

z 2 

a: 

<! 

w 

I 

(/) 

~ 

:::> 

~ 

x 

<! 

~ 

2 3 4 5 6 7 

EFFECTIVE NORMAL STRESS, u,, +u31 , IN KG/CM2 

2 

Figure 12. The p-q diagram of effective normal stress versus maximum shearing stress as determined by ten iostropically 

consolidated-undrained tests on the Bootlegger Cove Formation. The angle of inclination, a, of the "best-fit line", Kf' through 

the points is 25.54°. 

Cyclic Loading Tests 

The initial conditions and the stress conditions for 

the cyclic loading tests on intact specimens are summarized in table 4, and those for the cyclic loading tests on 

remolded specimens are summarized in table 5. These 

tables contain the water contents, specimen geometries, 

initial wet densities, vertical and volumetric strains due 

to consolidation, consolidation times, coefficients of consolidation, actual Kc -values, and stresses applied during 

static and cyclic phases of the tests. These tables also show 

that the B-values for the triaxial specimens decrease with 

increasing consolidation stress ratios. This behavior does 

correspond to fully saturated specimens as discussed in 

detail by Lade and Kirkgard (1984). Detailed test results 

including sketches of intact specimens, consolidation 

curves, and X-Y recordings of cyclic stress-strain relationships were also recorded. Figures 13-15 show 

representative deformed shapes of three samples, under 

both intact and remolded initial conditions. 

Strength Relations for Intact Specimens 

In order to interpret the strength results of the 

cyclic loading tests that were performed on specimens 

with consolidation ratios of Kc = 1.0, the axial peak-topeak strains are plotted versus number of cycles on a 

semilog diagram for different cyclic stress ratios (fig. 16). 

The cyclic stress ratio is defined as u dma/2Su, in which 

Su is the static undrained strength and admax = <Tdc + <Tdp' 

in which a de is the stress difference during consolidation and a dp is the cyclic (pulsating) stress difference. 

Based on the diagram in figure 16, another diagram 

is constructed in which the cyclic stress ratio is plotted 

versus the number of cycles that are required to 

cause various amounts of axial peak-to-peak strains 

(figs. 17, 18). 

The values of undrained shear strength, Su, that 

were determined from the UU tests on intact specimens 

were used for calculation of the cyclic stress ratio shown 

in figure 17. ICU tests on intact specimens were not performed. However, based on the shear strength diagram 

in figure 11, approximate values of Su from tests on intact specimens were estimated and used for the cyclic 

stress ratios employed in figure 18. Diagrams of this type 

are plotted for all cyclic tests on intact specimens. These 

diagrams are produced to make a direct comparison of 

results from cyclic loading tests on intact and remolded 

16 Cyclic Triaxial Tests, Bootlegger Cove Formation, Anchorage, Alaska 
Figure 13. Specimen CT -5 (facies F.IV of the Bootlegger Cove Formation) after consolidation at stress ratio, Kc = 1.0, and after failure by cyclic loading. Note the sample failed in 

extension. A, Intact specimen; 8, Remolded specimen. Specimen about 15 em long. 

specimens. For this comparison a common basis, such 

as results of ICU tests, is required. 

There are, however, several reasons why the 

estimated values of undrained shear strength from ICU 

tests on intact specimens may be incorrect. The estimated 

strengths are based on results from tests on remolded 

specimens or from tests on intact specimens which were 

first exposed to resonant column testing (see fig. 11). 

Because remolded or disturbed specimens may behave differently from intact specimens of sensitive soils, it is 

preferable to employ truly intact specimens for determination of undrained shear strengths. Therefore, to provide 

a common basis for comparisons of the type described 

above, ICU tests on intact specimens should be performed 

in connection with future studies of the cyclic behavior 

of the Bootlegger Cove Formation. Unfortunately, this 

work was beyond the scope of funding and sample 

availability in the present study. 

For the cyclic loading tests with initial consolidation stress ratios of Kc = 1.5 and 2.0, the maximum 

axial strains are plotted versus number of cycles on 

semilog diagrams for different cyclic stress ratios for intact specimens (figs. 19, 20). Based on these diagrams, 

other diagrams are constructed on which the cyclic stress 

ratio is plotted versus the number of cycles that are required to cause various amounts of maximum axial 

strains (figs. 21-24). 

The permanent axial strains observed in the cyclic 

loading tests on specimens with Kc = 1.0 are negative 

and relatively small, and this corresponds to failure in 

extension as observed in these tests (see fig. 13). The permanent axial strains obtained in tests with Kc = 1.5 and 

2.0 are positive and increase to large values, and failure 

in these tests occurs in compression (figs. 14, 15). The 

axial peak-to-peak strains in these tests are comparatively small (€max = 3 percent for Kc = 1.5, and €max = 0.4 

percent for Kc = 2.0). Thus, a common basis for a 

direct comparison between tests with Kc = 1.0 and tests 

with Kc = 1.5 and 2.0 is absent. Nevertheless, to get 

an idea of the relative strengths obtained from the tests 

with different Kc-values, cyclic stress ratios are plotted 

versus number of cycles on a semilog diagram for axial 

Results of Laboratory Testing 17 
Figure 14. Specimen CT -3 (facies F. Ill of the Bootlegger Cove Formation) after consolidation at stress ratio, Kc = 1.5, and after failure by cyclic loading. Note the sample failed in 

compression. A, Intact specimen; 8, Remolded specimen. Specimen about 15 em long. 

peak-to-peak strains of 5.0 for Kc = 1.0 and for maximum axial strains of 10 percent for Kc = 1.5 and 2.0 

(fig. 25). This figure indicates that the cyclic stress ratio 

to cause 10 percent axial strain (peak-to-peak or maximum) increases with increasing consolidation stress ratio 

for a given number of cycles. 

Discussion of Cyclic Stress Ratio 

The cyclic stress ratios discussed above involve the 

undrained shear strengths that were determined from the 

UU tests on intact specimens. In an attempt to obtain 

a direct comparison between tests on intact soil and tests 

on remolded soil, the cyclic load applied in the tests on 

intact specimens was also used for the remolded specimens. Thus, it was not necessary to rely on a static undrained shear strength for the remolded soil to estimate 

the cyclic stress from a cyclic stress ratio. However, due 

to the larger amounts of volume change for the remolded 

specimens, the cross-sectional areas of these specimens 

were smaller and the cyclic . stress therefore was higher 

for the remolded specimens than for the intact specimens. 

Depending upon the objective, it is possible to use 

two different static, undrained shear strengths for calculation of the cyclic stress ratio for remolded soil: (1) that 

obtained from UU tests, and (2) that obtained from ICU 

tests. The first value is very easy to obtain, but it is a small 

number with substantial scatter, which results in high 

cyclic load ratios with significant scatter. Furthermore, 

this value does not reflect the consolidation that follows 

disturbance due to an earthquake. To obtain the second 

value requires relatively advanced equipment and a considerable amount of time. However, the second value is 

much higher and should be more consistent than the first 

value. Its use will result in lower cyclic stress ratios, 

with less scatter. Both values have been employed in 

separate evaluations of the cyclic loading tests on remolded soil. 

Strength Relations for Remolded Specimens 

The procedure for evaluation of the cyclic loading 

tests on remolded specimens is similar to that described 

above for the intact specimens. Figures 26-28 show the 

18 Cyclic Triaxial Tests, Bootlegger Cove Formation, Anchorage, Alaska 
Figure 15. Specimen CT -4 (facies F.IV of the Bootlegger Cove Formation) after consolidation at stress ratio, Kc = 2.0, and after failure by cyclic loading. Note the sample failed by 

compression. A, Intact specimen; 8, Remolded specimen. Specimen about 15 em long. 

axial strains (peak-to-peak for Kc = 1.0 and maximum 

for Kc = 1.5 and 2.0) plotted versus number of cycles 

for tests with various cyclic stress ratios. Corresponding 

to the two different types of undrained shear strengths, 

two values of cyclic stress ratios are indicated on these 

figures. Figures 29-31 show the cyclic stress ratios in 

terms of the undrained shear strength from the UU tests 

plotted versus the number of cycles that are required to 

cause various amounts of axial strain. In figures 32-34, 

the cyclic stress ratios in terms of the undrained shear 

strength from the ICU tests are plotted versus the number 

of cycles that are required to cause various amounts of 

axial strain. The application of the strengths from the UU 

tests results in much higher stress ratios than those obtained using the strengths from the ICU tests. 

Comparison of Strength Relations for 

Intact and Remolded Specimens 

Using the undrained shear steength from the UU 

tests, a comparison of all tests on remolded soils is shown 

in figure 35. Despite the problems with such a comparison, it can be seen that the cyclic stress ratio that is 

required to cause 10 percent axial strains (peak-to-peak 

or maximum) increases with increasing consolidation 

stress ratio for a given number of cycles. The test results 

for the intact specimens are also shown on figure 35, and 

the cyclic stress ratios that are required to cause 10 percent axial strain in these specimens are much smaller than 

those required for the remolded specimens. It should be 

recalled, however, that the unconfined shear strength used 

for the remolded soil does not reflect the effect of consolidation after remolding. These strengths are relatively 

small and result in high cyclic stress ratios for the remolded specimens. 

Using the undrained shear strength from the I CU 

tests, a comparison of all tests on remolded soil is shown 

in figure 36. The cyclic stress ratios are substantially lower 

than those shown in figure 35, but the conclusions regarding the cyclic strength are similar to those presented 

above. In comparing the cyclic stress ratios for the · 

remolded specimens with those for intact specimens (fig. 

37), it appears that the intact specimens are stronger than 

the remolded specimens. However, thi~ is misleading. The 

undrained shear strengths used in the cyclic stress ratios 

are not directly comparable because the intact specimens 

are exposed to lower effective confining pressures in the 

Results of Laboratory Testing 19 
~ 

0 

n 

-< Q. 

i=i' 

~ 

c:i' 

>< 

~ 

-l 

~ 

;: 

t= 

0 

a 

gf 

~ 

n 

0 

< 

~ 

0 "'" 

3 

2::. 

s· 

? 

> ::I 

l"l 

:: 

0 

~ 

~ 

> ;-

<ll 

~ 

AI 

Table 4. Summary of initial and stress conditions for cyclic loading tests on Bootlegger Cove Formation intact specimens 

[See "GLOSSARY OF SYMBOLS USED" for definitions of symbols] 

Sample CT-1 

Before consolidation 

wlc (trimmings)(%) • 28.06 

A0 (cm2 ) ••••••••••• 9.931 

H0 (em) •••••••••••• 7.518 

V0 (cm3 ) • • • • • • • • • • • 74.67 

Ywet (glcm3) •.••••• 1.981 

After consolidation 

6Vconsol (cm3 ) ••••• 

6Sconsol (em) • • • • • • 

Evconsol (%)1 •••••• 

Elconsol (%). 

Ac (cm2 ) ••••••••••• 

He (em) ••••••.••.•• 

t 50 (min) ••••.••••• 

t 100 (min) ••••••••• 

cr3 c (kg I cm2 ) ••••••• 

CTdc (kglcm2)1 •••••• 

Kc = CT1 ciCT3 c • • • • • • • 

cv•10 5 (cm2 1sec) ••• 

B-value 2 •••••••••.• 

KciDelay (min) ••••• 

Cyclic Loading 

Frequency (Hz) 

5.587 

0.219 

7.481 

2.91 

9. 4 64 

7.30 

14 

94 

3.515 

o.o 

1. 0 

11.82 3 

1. 012 

1.0110 

*Pdv (kg) •••••••••• ±14.9 

±CTdp = ±PdpiAc ••••• 

(kglcm2 ). 

CTdmax = CTdc + CTdp • • 

(kglcm2 ). 

±1. 58 

1. 58 

Su (static)(kglcm2) 0.507 

s P 1 s u < s P = 112 cr d P) • 1 • s 6 

Nmax [=Nf] ••••••••• [=75] 

CTdmax1 2Su • • • • • • • • • • 1. 56 

CT-2 

30.08 

9.931 

8.839 

87.78 

1.983 

6.315 

0. 401 

7. 1 9 I 

4.54 

9.66 

8.39 

150 130 

760 700 

3.515 

1. 80 7 

1. 514 

l. 2 61 

0.9381 

1. 012 

1.515, 

1.5110 

±20.8 

±2. 15 

3. 9 6 

CT-3 

38.47 

9.931 

8.433 

83.75 

1. 865 

5.686 

0.562 

6. 7 91 

6.67 

9.92 

7. 8 7 

56 

270 

3. 515 

1. 7 59 

1. so 1 

1. 4 55 

0.890 

1. sIs 

±16.0 

± 1. 61 

3.37 

CT-4 

3 2. 6 8 

9. 931 

8.585 

85.26 

1. 944 

7. 6 91 

1. 18 9 

9.021 

13.84 

10.49 

7.40 

70 

440 

3. 5 15 

3.328 

1. 9 4 7 

3.378 

0.878 

2. o Is 

±2 0. 7 

±1. 97 

5.30 

CT- 5 

30 . 66 

9. 9 31 

8.484 

84.25 

1. 9 57 

4.599 

0.249 

5.461 

2.94 

9.67 

8.23 

86 

420 

3. 5 15 

o.o 

1.0 

2.702 

1. 0281 

1. o Is 

±19.6 

±2.03 

2.03 

CT-6 

28.65 

9. 9 31 

8.407 

8 3. 4 9 

2.000 

4.230 

0.264 

5.071 

3. 14 

9.73 

8. 15 

32 

150 

3. 5 15 

o.o 

1. 0 

2.200 

0.967 

1. o Is 

±3 5. 9 

±3.69 

3.69 

CT-7 

2 3. 1 3 

9. 9 31 

8.814 

87.53 

2.079 

2.674 

0.280 

3.051 

3. 18 

9.94 

8.53 

100 

740 

3. 515 

3.512 

1. 9 9 9 

5. 9 11 

0.769 

2.015 

±2 2. 7 

±2.28 

s. 79 

CT-8 

34.40 

9. 9 31 

8.814 

8 7. 53 

1. 9 3 5 

5. 188 

0.353 

5.931 

4.01 

9. 7 3 

8.46 

70 

500 

3. 5 15 

1. 7 94 

1. 510 

1. 8 9 2 

0.9831 

0.8941 

0.882 

1.015, 

1.515, 

2.015 

±17.2 

±L 77 

3.56 

CT-9 

31. 6 9 

9. 9 31 

7.087 

70.38 

1. 9 57 

4. 100 

0.456 

s. 83 I 

6.43 

10.00 

6.63 

92 

430 

3. 5 15 

3. 4 91 

1. 9 93 

0.370 

0.9351 

0.8841 

LOIS, 

I. SIS, 

±16.5 

± 1. 65 

5. 14 

RC-6 

29.76 

9. 9 31 

8.839 

8 7. 7 8 

1. 980 

5.467 

0.221 

6.231 

2.50 

9.55 

8.62 

3. 515 

o.o 

1.0 

2. OS 6 

0.9291 

1. 000 

LOIS, 

1.0110 

±17.3 

± 1. 81 

1. 81 

0.624 0.672 0.531 0.603 1.126 0.798 0.620 0.829 0.560 

1.72 1.20 1.86 1.68 1.164 1.43 1.43 1.00 1.62 

[=14] [=26] [=47] [ = 15] [=2] [=96] [=31] [=75] [=32] 

3.17 2. 51 4.99 1.68 1. 64 3.63 2.87 3. 10 1. 6 2 

1B-values are determined after 5 minutes or, in a few cases, after 10 minutes. 
, 

~ 

Ill 

s. 

Ill 

Q 

·-,.... 

Dol 

cr 

Q 

~ ~ 

...... 

'~ 

~ 

:r 

CJQ 

!::: 

Table 5. Summary of initial and stress conditions for cyclic loading tests on Bootlegger Cove Formation remolded specimens 

[nd, not determined. See "GLOSSARY OF SYMBOLS USED" for definitions of symbols] 

Sample 

Before consolidation 

w/c (trimmings)(%) • 

Ao (cm2) 1 • • • ••••••• 

H0 (cm) 1 ••••••••••• 

V0 (cm3 ) ••••••••••• 

Ywet (g/cm3) ••••••• 

After consolidation 

6vconsol (cm3 ) ••••• 

68consol (em) • • • • • • 

Evconsol (%)/ •••••• 

€lconsol (%). 

Ac (cm2 ) ••••••••••• 

He (em) •••••••••••• 

t 50 (min) •••••••••• 

t 100 (min) ••••••••• 

cr-3c (kg/cm2) 

crdc (kg/cm2) ••••••• 

Kc = cr-1c/cr3c • •••••• 

w/c (after test)(%) 

B-value •••••••••••• 

Kc/Oelay (min) 

Cyclic Loading 

Frequency (Hz) 

CT-1 

27.54 

9.931 

7.569 

75.17 

2.030 

7.871 

0.030 

10.47/ 

0.40 

8.93 

7.54 

70 

330 

3.515 

o.o 

1. 0 

20.25 

0.867 

1.0/5 

=Pdp (kg) •••••••••• =14.4 

=cr-dp = =Pdp/Ac ••••• ±1.61 

(kg/cm2). 

(Tdmax = crdc + crdp •• 

(kg/cm2 ). 

1. 6 1 

s~ (static)(kg/cm2 ) 0.126 

$plsu (SP = 1/2cr-dp) • 6.39 

Nmax [=Nf] ••••••••• [=60] 

cr-dmaxl 25 u • • • • • • • • • • 

cv•I0 5 (cm2 /sec) ••• 

6. 3 9 

2.365 

CT-2 

27.56 

9.931 

8.814 

8 7. 53 

2.034 

9. 617 

0.226 

10.99/ 

2.57 

9.07 

8.55 

580 

3200 

3. 515 

1.924 

1. 54 7 

19.25 

1. 0 7 9 

1. 0/5 

±2 1. 3 

±2.35 

4.27 

0. 1 7 1 

6.87 

[=133] 

1 2. 4 9 

0.326 

CT-3 

36.22 

9.931 

8.814 

8 7. 53 

1. 940 

11.911 

0.460 

13.61/ 

5.22 

9.05 

8.35 

560 

3200 

3. 515 

3.929 

1. 54 9 

25.36 

0.944/ 

0.930 

1. o I 5, 

1. 5/5 

±16.0 

±1. 77 

3.70 

o. 156 

5.67 

1500 

11.8 6 

0.338 

CT-4 

lst run 2d run 

30.82 

9.931 

8. 712 

86.52 

2.012 

10.744 

0.522 

12.42/ 

5.99 

8.42 

8.19 

230 

1100 

3.515 

4. 14 6 

2. 179 

nd 

0.904 

2.0/5 

nd 

nd 

nd 

nd 

nd 

11. 133 

nd 

nd 

1 0. 11 

7.46 

nd 

nd 

3. 515 

3.543 

1.982 

20.63 

nd 

nd 

CT-5 

29.46 

9.79 

8.738 

85.51 

1. 9 96 

8.739 

0.151 

10.22/ 

1. 7 3 

8.94 

8.59 

180 

900 

3.515 

o.o 

1. 0 

21.93 

1. 2 81 

1.0/5 

::1::20.7 ::1::29.9 =19.9 

±2.46 ±2.96 ::1::2.23 

6.61 6.41 2.23 

0.115 0.115 0.155 

10.70 12.87 14.39 

1504 1506 [=201 

28.74 27.87 14.39 

0.822 nd 1.051 

CT-6 

27.30 

9.781 

8.832 

81.98 

2.025 

7. 7 21 

0.093 

9.42/ 

1. 11 

8.96 

8.29 

180 

940 

3. 515 

o.o 

1.0 

20.99 

1. 077 

1.0/5 

=3 5. 2 

±3.93 

CT-7 

1st run 2d run 

22.65 

9.931 

8.712 

87.52 

2. 178 

8.430 

0.316 

9.74/ 

3.63 

9.30 

8.39 

100 

500 

3.515 

3.753 

2.068 

nd 

0.930 

2.0/5 

nd 

nd 

nd 

nd 

nd 

8.809 

nd 

nd 

10.49 

7. 41 

nd 

nd 

3. 5 15 

3.328 

1.947 

15.98 

nd 

nd 

::1::23.1 ::1::38.3 

±2.48 ±3.65 

CT-8 

31.99 

9.931 

8.814 

87.53 

1.958 

11.542 

1. 43 9 

13.17/ 

4.98 

9.07 

8.37 

400 

1700 

3.515 

1. 924 

1. 54 7 

2 2. 3 4 

0.925 

1. 5/5 

::1::17.2 

±1.90 

CT-9 

30.40 

9.931 

8.788 

87.28 

2.030 

10.495 

0.691 

12.02/ 

7.86 

9. 48 

8.10 

450 

2300 

3.515 

3.682 

2.048 

2 1. 81 

0.863 

2.0/5 

RC-6 

28.80 

9.82 

8.941 

87.78 

2.019 

8.500 

0.160 

9.68/ 

.79 

9.03 

8.78 

170 

870 

3.515 

o.o 

1.0 

20.50 

1. 022 

'd. 0/5 

1 .. 

=16.7 ::1::17.9 

::1::1.76 ::1::1.98 

3.93 6.23 6.98 3.45 5.44 1.98 

0.428 0.175 0.175 0.128 0.130 0 •. 139' 

9.18 7.09 10.43 7.42 6.77 7.12 

[ = 4 1 1 5o 8 ·s o.o 1 5 1 o 1 5o 8 r = 4 o 1 

9.18 17.80 19.94 13.48 20.92 7.12 

1.051 1.892 nd 0.473 0.420 1.1·13 

1 some remolded specimens elongated slightly upon placement of the membranes. This was considered in calculat~on of Ac and He• 
)!~ I "'-!.. \ I I I ~~ - ~ P-~ I 

0 

1--

z 

w 

u 

5 

ffi 1 0 0.. 

z 

Ill 

<l 

z 15 

~ 

~ ...J 

~ 20 X 

<{ 

::w::: 

<{ 

w 

0.. 

6 25 I-

~ <{ 

w 

0.. 

30 

35 

Lr' 

---~ ~ ""'~: 

(~ 

\ 

\ i 

(~ I 

\ 

1 .• 4/1.(J 5 

(CT-8) 

1 

..... 

t~.l :--.~ 

~ 

1" ! ~ \, \ \. 

l~ 

: \ \ ~ \ ' ~ \ , t ~ I 

II ~ 

I 

~.88/1.08 ' 

(CT-5) 1.8~ 

(RC 

10 

~ 1.b 

I 

Intact sp tel ~e s c= 

' I i 

! : 

( ) 

() l 

! 

Su det arm in d i fl om 

~ UU tests IC u .. : •• 

"" 

( 88 tl"'•,rd~ 

\ 1\.. 

f\ " II 

I 

I 

If dmax/2X Su ' .E r· 8 

CPT 1, 

I ~0.9~ 

I -8) 

100 1000 

NUMBER OF CYCLES, N 

Figure 16. Peak-to-peak axial strain versus number of cycles for intact samples CT -1, CT -5, CT -6, and RC-6, all at initial consolidation ratios of 1.0. 

UU tests, which results in lower shear strengths, than 

those employed in the ICU tests on remolded specimens. 

A comparison of cyclic strengths of intact and 

remolded specimens on a more equitable basis is shown 

in figure 38. Values of undrained shear strength from ICU 

tests are used for both intact (estimated values) and 

remolded (measured values) specimens. Although the 

estimated values for intact specimens may be questionable 

in many respects, figure 38 indicates that the cyclic stress 

ratios for intact and remolded specimens are comparable 

in magnitude. However, a final evaluation and conclusion must be postponed until actual ICU tests on intact 

specimens have been performed in future testing 

programs. 

Shear Moduli 

Comparisons of shear moduli obtained from cyclic 

loading tests and resonant column tests are shown on 

figures 39-42. The shear moduli are normalized on the 

basis of undrained shear strengths as determined in UU 

tests and ICU tests. The average relationship between normalized shear moduli and single-amplitude shear strain 

that previously was suggested by Seed and Idriss (1970) 

for clay soils is shown in these figures for comparison. 

This relationship is only valid for specimens with initial 

isotropic consolidation and symmetric cyclic loading. 

Thus, comparison with the present results should only 

be made for tests with Kc = 1.0. However, results from 

tests with Kc = 1.5 and 2.0 are also shown on the 

diagrams. 

Figures 39 and 40 show the results for intact soil. 

The shear moduli from the cyclic loading tests are normalized on the basis of the undrained shear strengths 

from UU tests in figure 39, whereas the estimated values 

from ICU tests are used in figure 40. Because only ICU 

values are available for the specimens used for resonant 

column tests, the best comparison is that shown in figure 40. The results from the cyclic loading tests with 

22 Cyclic Triaxial Tests, Bootlegger Cove Formation, Anchorage, Alaska 
I l l ! I I II 1 

! 

I l 

I I 

±11.0 .. I I I I : I : I 

6£= 12.$-.. 1 I 5!%) ±1 0% t(20% 'Pea k t p Fe k~ l l 

(~I t~l \' ' 

! ll I 

, I 

L~\ I J I J I~ I I I 

1. 7 0 

I~ Ill .~NT l 

I ' ~4-l ~~It 0 

·~+RC I ! 

I I ; I 

6 

I '"""' A I 

j I i i 

u) 

N 

~ 

e 

~ 

d 1.60 

! 

! I 

~~ ~ I : ! I ! 

I I I ! ' . ' I I I l 

I ~ II I I I ~~illl:cT-1 I . 

i= 

<( 

a: 

CJ) 

CJ) 

w i 

a: 

i I 

I 

I 

l 

I I 

I ' ol I Intact S p c im an s · Kc ~ 1 I 

! 

i 

I ' Su det rm n ed f 0 uu t s 

i I ! j i I I I 

~ 

CJ) 

u 

::::i 

~ u 1.5 0 

I I jl l I 

1.4 0 l I I I 

10 100 1000 

NUMBER OF CYCLES. N 

Figure 17. Cyclic stress ratio versus number of cycles for three intact specimens at initial consolidation ratio of 1.0. Cyclic stress 

ratios determined from unconsolidated-undrained testing. 

Kc = 1.0 compare well with the Seed-Idriss relationship, 

whereas lower values of shear moduli are obtained from 

the resonant column tests (Updike and others, 1982) than 

those indicated by the Seed-Idriss relationship. 

Figures 41 and 42 show similar results for remolded 

specimens. Very high values of normalized shear moduli 

are obtained when the remolded shear strengths from UU 

tests are used (fig. 41), whereas values comparable to the 

Seed-Idriss relationship are obtained on the basis of undrained shear strengths from ICU tests (fig. 42). 

Direct comparison of shear moduli (not normalized) versus number of cycles for the intact and remolded 

specimens are shown on figures 43-45. Note that only 

results from the same sample may be directly compared 

in these figures. For a given low number of cycles, the 

shear modulus from the intact specimen is higher than 

that from the remolded specimen for conditions with 

Kc = 1.0. At higher numbers of cycles the curves on 

figure 43 cross over each other, and the reverse relationship is obtained. Figures 44 and 45 show that the shear 

moduli are generally higher for remolded soil than for 

intact soil. 

Damping Ratios 

Damping ratios determined from the X-Y recordings are given on figures 46 and 47 for intact and remolded specimens, respectively. The relationship 

proposed by Seed and Idriss (1970) is shown for comparison. The results of the resonant column tests form 

consistent relationships which are comparable to and 

within the range obtained by Seed and Idriss. The results from the cyclic loading tests show substantially 

more scatter. The majority of data points for Kc = 1.5 

and 2.0 indicate higher damping ratios than those obtained for Kc = 1.0. The values obtained for Kc = 1.0 

scatter across the range suggested by Seed and Idriss 

with a considerable number of data points outside this 

range. 

Results of Laboratory Testing 23 
l I ! I ! 

' .1(, 

I j \ ·"" v t I 

1\ I i I 

CD 0' ; $\j [!]- CT~5 ! ! •1 t ~ . t S p e c i m e n • Kc 1i . c i ! l 

l I ':1\ ! 

I 

I s~ i•rtlmated tu •H• ''" I i I I 

l I jtb~ intact s, ec m, nt ~ l 

i i . ! 

0\~ ! l I (~ EJ-r- R C -6 

1.2 

1.1 

1.0 

u) 

N 

':: 

E 

j I \ I I g 

a 0.9 

! \ I 

i i i i I I I 

! i I ; I 1\: I l J : i l 

! I'< II : I 

I I I ! i I ' 

i I ' 

i I I I ' 

I 

i I I ! : c:~ R 1- ·H; 1 I J I I i 

! i i ! I i\ 

I . I \ i I 

I I I : 

i I ! !' I 

i= 

<t: 

a: 

en 

en 

w 

a: 0.8 

t; 

u 

:J 

~ u 0.7 

0.6 

IP n lc o I' r :eJ !a'~ i I ! 0.5 

10 100 1000 

NUMBER OF CYCLES, N 

Figure 18. Cyclic stress ratio versus number of cycles for three intact specimens at initial consolidation ratio of 1.0 and using 

strength values estimated from isotropically undrained testing. 

SUMMARY AND CONCLUSIONS FROM 

LABORATORY TESTING 

Ten undisturbed samples of the Bootlegger Cove 

Formation (mainly facies II and IV) have been tested in 

an investigation of representative formational stress-strain 

and strength properties under static and cyclic loading 

conditions. Soil index tests were performed in this investigation to determine liquid and plastic limits, grain-size 

distributions, water contents, and densities. Static undrained strength tests such as torvane and unconsolidatedundrained triaxial compression tests were performed on 

intact and remolded specimens, whereas isotropically 

consolidated-undrained tests were performed on remolded specimens. Cyclic triaxial loading tests were performed on intact and remolded specimens with initial 

consolidation stress ratios of 1.0, 1.5, and 2.0. The static 

tests were performed to serve as background and basis 

for evaluation of the cyclic loading tests. The latter tests 

were performed to establish the number of cycles and 

cyclic stress ratios that are required to cause various 

amounts of strain, and to determine the magnitude and 

variation of the shear moduli and the damping ratios with 

single-amplitude shear strain. 

The results of the cyclic loading tests indicate that 

higher cyclic stress ratios are required at higher consolidation stress ratios to cause a given amount of strain in a 

given number of cycles. Although the basis for comparison between results from intact and remolded specimens 

is questionable, it appears that they may have equivalent 

strengths. Although the data base is insufficient to provide completely conclusive statements to this effect, there 

is an indication that soils remolded in landslide areas have 

strengths equal to that of soils in areas that have not 

failed. This conclusion would significantly modify current 

concern in Anchorage for construction on old landslides. 

The relationship between shear moduli and singleamplitude shear strain obtained from cyclic loading and 

resonant column tests shows a pattern similar to that suggested by Seed and Idriss (1970). The magnitudes of normalized shear moduli compare best with the Seed-Idriss 

24 Cyclic Triaxial Tests, Bootlegger Cove Formation, Anchorage, Alaska 
1-

z 

w 

u 

a: 

w 

a.. 

z 

I 

10 

II 

100 1000 

NUMBER OF CYCLES, N 

Figure 19. Maximum axial strain versus number of cycles for three intact specimens at initial consolidation stress ratios of 1.5. 

values when the experimental data are normalized on the 

basis of shear strengths obtained from isotropically 

consolidated-undrained shear tests (figs. 40, 42). The 

damping ratios from these tests show considerable scatter but generally follow the relationship proposed by Seed 

and Idriss (1970). 

All the samples were collected from depths between 

81 and 97ft. The sediments in this interval were deposited 

during the quiet-water glaciolacustrine episode of accumulation of clay and silt. It is within this stratigraphic 

interval that the soil failures associated with the 1964 

Prince William Sound earthquake are believed to have 

occurred (Shannon and Wilson, Inc., 1964; Updike, 

1986). It should be noted that none of the samples tested 

yielded sensitivity values above 12. As previously noted, 

concerns for sample disturbance effects manifest in the 

more unstable samples combined with the intent to characterize the "typical" cohesive facies of the formation 

dictated the range of sample types tested. Nevertheless, 

the sensitivity values, which are generally below 10, pose 

the question as to whether the Bootlegger Cove Formation can be characterized as having soil horizons of extremely high sensitivity that would fail under seismic 

loading. It may be shown by future testing that failurezone soils are collapsing or liquefying under a mechanism 

that is as yet poorly understood. If this is the case, then 

the traditional approach of assessing ground failure 

potential of the cohesive facies of the formation based 

strictly on sensitivity ratios is erroneous. In light of the 

fact that soils within the tested interval did fail in 1964, 

the test data reported here must be taken as a baseline 

for future assessment of ground failure potential in 

downtown Anchorage. Strength data determined from 

future testing that are significantly divergent from our 

data may identify the soils responsible for failure. 

The foregoing presentation of data and intepretation is intended to "calibrate" the static and dynamic 

behavior of the cohesive facies of the Bootlegger Cove 

Formation. In order to further enhance this insight, a 

companion study should conduct static ICU tests on both 

intact and remolded soil in order to provide a common 

and consistent basis for comparison of results obtained 

from the cyclic loading tests. The emphasis of the study 

reported here was to conduct a carefully monitored 

Summary and Conclusions from Laboratory Testing 25 
~ 

I- 5 

- ~ ........ :J ~I I I I 

I 1 

...... 

~~ l 

"!: 

I I In c Spe cirr len is, Kr =2 0 

0 

z 

w 

u 

a: 

w 

a.. 

z 

1 0 

! ,3 6 3 

·)·~\tN ! 

I ,c TlI , i . Su dete mi 1e 1 ir o m: I 1 ' I I ! 

~~N 

+ 

E 

~ IU 1 5 

II 

E 

1111 

z 

:;;: 

a: 20 

I-

(/) 

....J 

! 

,~1· ! 

u :u t 

! 

sts estr 

~ .......... \ 

I 

1--- ~!'- -6 /2 X 'L 1j0 3 .t I I I ! 

I~ :' ..,, I 

I I~ l I ! j j I I I i i I i I 2. 

. Lo. 

! I 4. I 

< x i m d I ) ~ 

< i ,4 25 ' ! (CT-i4)---- I i I I 

~ 

::::> 

~ 

x 

< 

~ 30 

I 

I ! 

I I I I ! 

I ~ I 

i 

! I ! 

I I 

I I 

I I I 

i i I I l I l 

35 i i I I 

10 100 1000 

NUMBER OF CYCLES, N 

Figure 20. Maximum axial strain versus number of cycles for three intact specimens at initial consolidation stress ratios of 2.0. 

sequence of static and dynamic triaxial tests on typical 

specimens of the Bootlegger Cove Formation. Highly sensitive specimens of facies F .III were intentionally avoided 

because the anticipated response of this facies would not 

benefit the objective of the study, which was to establish 

behavior norms for the predominant facies. The authors 

recommend that future investigations explore the comparative cyclic properties of each cohesive facies of the 

formation. 

REFERENCES CITED 

Bruhn, R.L., 1979, Holocene displacements measured by trenching the Castle Mountain Fault near Houston, Alaska: 

Alaska Division of Geological and Geophysical Surveys 

Geologic Report 61, p. 1-4. 

Fogelman, K., Stephens, C., Lahr, J.C., Helton, S., and Allen, 

M., 1978, Catalog of earthquakes in southern Alaska, 

October-December, 1977: U.S. Geological Survey Open-File 

Report 78-1097, 28 p. 

Hansen, W.R., 1965, Effects of the earthquake of March 27, 

1964, at Anchorage, Alaska: U.S. Geological Survey Professional Paper 542-A, p. A1-A68. 

Idriss, I.M., and Moriwaki, Yoshihaiu, 1982, Anchorage Office 

Complex geotechnical investigation, Anchorage, Alaska, v. 

1, Seismic hazards evaluation: San Francisco, WoodwardClyde Consultants, p. 6-1 to 6-3. 

Karlstrom, T.N:V., 1964, Quaternary geology of the Kenai 

Lowland and glacial history of the Cook Inlet Region, Alaska: U.S. Geological Survey Professional Paper 443, 69 p. 

Kerr, P.F., and Drew, I.M., 1965, Quick clay movements, Anchorage, Alaska: Springfield, Va., National Technical 

Information Service, Document AD630-11, 133 p. 

Lade, P.V., and Kirkgard, M.M., 1984, B-value tests for soil 

specimens with anisotropic stress states: American Society of Civil Engineers, 5th Engineering Mechanics Division 

Specialty Conference, Laramie, Wyoming, Proceedings, 

p. 1304-1307. 

Lahr, J.C., Page, R.A., Stephens, C.D., and Fogleman, K.A., 

1986, Sutton, Alaska, earthquake of 1984-evidence for 

activity on the Talkeetna segment of the Castle Mountain 

fault system: Seismological Society of America Bulletin, 

v. 76, p. 967-983. 

26 Cyclic Triaxial Tests, Bootlegger Cove Formation, Anchorage, Alaska 
I - ~ I I . " 1~" 201r. fmax- 2 

\ I \ I\ \ In 84 t Sp •clmena, ~('= .6 

(~ I 

~ D 

~\ CT-2 

d et [e . n lned fron u ~ t •• t I 

~ Su 

~I \ 

~ \\01 IGtC -~ I 

Jl 

CD & 

~ I l j 

\ I\\\ I . I 

~ I : 

\ I 

~R ~ \~ ~- I I 

I 

CT~3 I . 

3.4 

3.2 

en 3.0 

N 

' i 

~ 

0 2.8 ~ 

~ 

Ul 

Ul 

w 

a: 2.6 t;; 

u 

:::i 

~ 2.4 

\ \ I\ ' 

2.2 

2.0 

1 10 100 1000 

NUMBER OF CYCLES, N 

Figure 21. Cyclic stress ratio (determined from unconsolidated-undrained tests) versus number of cycles, for three intact specimens 

under initial consolidation ratio of 1.5. 

Lambe, T.W., and Whitman, R.V., 1979, Soil mechanics, SI 

version: New York, John Wiley, 553 p. 

Miller, R.D., and Dobrovolny, E., 1959, Surficial geology of 

Anchorage and vicinity, Alaska: U.S. Geological Survey 

Bulletin 1093, 128 p. 

Reger, R.D., and Updike, R.G., 1983, Upper Cook Inlet region 

and the Matanuska Valley, in Pewe, T.L., and Reger, R.D., 

Richardson and Glenn Highways-Guidebook to permafrost and Quaternary geology: Alaska Division of Geological and Geophysical Surveys Guidebook 1, p. 185-263. 

Schmidt, R.A.M., 1963, Pleistocene marine microfauna in the 

Bootlegger Cove Clay, Anchorage Area, Alaska: Science, 

v. 141, p. 350-351. 

Schmoll, H.R., and Dobrovolny, E., 1972, Generalized geologic 

map of Anchorage and vicinity, Alaska: U.S. Geological 

Survey Map I-787-A, scale 1:24,000, 1 sheet. 

Schmoll, H.R., Szabo, B.J., Rubin, M., and Dobrovolny, E., 

1972, Radiometric dating of marine shells from the 

Bootlegger Cove Clay, Anchorage area, Alaska: Geological 

Society of America Bulletin, v. 83, p. 1107-1114. 

Seed, H.B., and Chan, C., 1964, Pulsating load tests on samples 

of clay and silt from Anchorage, Alaska, in Report on Anchorage area soil studies, to the U.S. Army Engineer 

District, Anchorage, Alaska: Seattle, Wash., 109 p. 

Seed, H.B., and Idriss, I.M., 1970, Soil moduli and damping 

factors for dynamic response and analyses: University of 

California, Berkeley, Earthquake Engineering Research Institute Report No. 70-10, 34 p. 

Seed, H.B., and Wilson, S.D., 1967, The Turnagain Heights 

landslide, Anchorage, Alaska: Journal of the Soil 

Mechanics and Foundation Division, American Society of 

Civil Engineers, v. 93, p. 325-353. 

Shannon and Wilson, Inc., 1964, Report on Anchorage area 

soil studies, Alaska: Seattle, Wash., Shannon and Wilson, 

Inc., 109 p. 

Updike, R.G., 1983, Seismic liquefaction potential in the Anchorage area, south-central Alaska: Geological Society of 

America Abstracts with Programs, v. 15, no. 5, p. 374. 

___ 1984, The Turnagain Heights landslide-an assessment 

using the electric cone penetration test: Alaska Division of 

Geological and Geophysical Surveys Report of Investigations 84-13, 48 p. 

___ 1986, Engineering geologic maps, Government Hill area, 

Anchorage, Alaska: U.S. Geological Survey Map I-1610, 

scale 1 :4800, 1 sheet. 

Updike, R.G., and Carpenter, B.A., 1986, Engineering geology 

of the Government Hill area, Anchorage, Alaska: U.S. 

Geological Survey Bulletin 1588, 32 p. 

References Cited 27 
to flr-21 11'111 j I ~~~ 1. ~~· ~~I I l . I i II I . II I I l I 

I I 

I 

! I . I I I i 

(;") {.) A 

' 

I 

! 

I i I I I I I I , I i 

I 

jl 

I I ! 

i 

I I I 

l 

I I . I 

~I , I : l 

I I 

I II tl 1.0 ~----~----~~--~~~~~------~--~~--~~~~~------~~~~~~~~~ 

0 L+-~·-f II I I l I I I 

1 10 100 1000 

NUMBER OF CYCLES, N 

Figure 22. Cyclic stress ratio (estimated from isotropically consolidated-undrained tests) versus number of cycles, for three intact specimens under initial consolidation ratio of 1.5. , 

Updike, R.G., Cole, D.A., and Ulery, C.A., 1982, Shear moduli 

and damping ratios for the Bootlegger Cove Formation as 

determined by resonant-column testing: Alaska Division 

of Geological and Geophysical Surveys Geologic Report 

73, p. 7-12. 

Updike, R.G., and Ulery, C.A., 1983, Preliminary geologic 

map of Anchorage B-6 NW (Eklutna Lake) Quadrangle: 

Alaska Division of Geological and Geophysical Surveys 

Geologic Report of Investigations 83-8, scale 1:10,000, 2 

sheets. 

28 Cyclic Tria~ial Jests, Bootlegger Cove Formation, Anchorage, Alaska 
l 

I 

i 

! ! 

I 

I i : J i 

NUMBER OF CYCLES, N 

Figure 23. Cyclic stress ratio (determined from unconsolidated-undrained tests) versus number of cycles, for three intact specimens 

under initial consolidation ratio of 2.0. 

References Cited 29 
u) 

N 

~ 

E 

g 

0 

~ a: 

(/) 

(/) 

w 

a: 

ti 

u 

::J 2.0 

~ 

; 0 8GJ- CiTr9 

_L-----+-·--1--i _ _:__ L-L _______ -----+ .. -~... -+·---+-+-~-"---t--+·-+--<---~ I 

& ~--)c~- l 

i j 

I 

1.0 ~----~----~~--L--~LJ~~-------~--.~~--~-L-~~L--------~~~~~~~~~ 

1 10 100 1000 

NUMBER OF CYCLES, N 

Figure 24. Cyclic stress ratio (estimated from isotropically consolidated-undrained tests) versus number of cycles, 

for three intact specimens, all at initial consolidation ratios of 2.0. 

30 Cyclic Triaxial Tests, Bootlegger Cove Formation, Anchorage, Alaska 
u) 5 

C\1 

~ 

E 

~ 

0 4 

;::: 

< a: 

CJ) 

CJ) 

w 

a: 3 

1-

CJ) 

u 

::J 

~ 2 

1 0 100 1000 

NUMBER OF CYCLES, N 

Figure 25. Cyclic stress ratio versus number of cycles for seven intact specimens at consolidation ratios of 1.0, 1.5, and 2.0. 

Maximum strains of 5 percent (for K = 1.0) and 10 percent (for K = 1.5 and 2.0) were taken from figures 17, 21, and 23, 

which were based on unconsolidated-undrained tests. c 

References Cited 31 
5 

tI I I 

z I w 

u 

a: 

w 10 a.. 

z 

oi 

<:1 

z 1 5 

I i f Is, deter,ln .• rqmJ <{ 

a: I ' I ' I 

t- • ; I ~ U tea~ ~ C 1'1• Ia fJ) 

...J 

<( 20 I I i I - ' I ~! x 

<( ftfax/2xSu r· 9/ ·~ 5 ~ 

<( . • (CT,1) w I a.. 

6 25 . ' 

t-

~ 

I 

<( 

I 

w 

a.. 

35 L-----~--~~-L~~~-L~-------L--~--~-L-L~~~------~~~~~~~~~ 

1 10 100 1000 

NUMBER OF CYCLES, N 

Figure 26. Peak-to-peak axial strain versus number of cycles for four remolded specimens, all at initial consolidation ratios of 1.0. 

32 Cyclic Triaxial Tests, Bootlegger Cove Formation, Anchorage, Alaska 
Figure 27. Maximum axial strain versus number of cycles for three remolded specimens, all at initial consolidation ratios of 1.5. 

References Cited 33 
1-

z 

w 

u 

a: 

w 

a.. 

z 

~~N 

+ 

E 

~ 1&1 

II 

~ 1&1 

0 ~ 

p 

I 

l 

5 

Figure 28. Maximum axial strain versus number of cycles for five remolded specimens, all at initial consolidation ratios of 2.0. 

34 Cyclic Triaxial Tests, Bootlegger Cove Formation, Anchorage, Alaska 
NUMBER OF CYCLES, N 

Figure 29. Cyclic stress ratio (determined using unconsolidated-undrained tests) versus number of cycles, for three remolded 

specimens, under initial consolidation ratios of 1.0. 

References Cited 35 
1 1 '---------1--....._____._--'--J.--1.......1-~--l...--->--...J...-...J.-......L-....L.-J....J...J....------1--...I..-..I-""--'-...1..-...1-...J......J.....I. 

1 10 100 1000 

NUMBER OF CYCLES, N 

Figure 30. Cyclic stress ratio (determined using unconsolidated-undrained tests) versus number of cycles, for three remolded 

specimens, under initial consolidation ratios of 1.5. 

36 Cyclic Triaxial Tests, Bootlegger Cove Formation, Anchorage, Alaska 
u) 10 6 

N 

.......... 

~ 

~ 

0 1.5 

i= 

< a: 

CJ) 

CJ) 

w 

a: 1 0 4 

I I I I 

1

1 ill I jill 1\1 I II! Ill I I 

I I I IJi; ilil I ~ I 11

1

11 I I ~ 

CJ) 

u 

::::i 

~ u 1 0 3 

Figure 31. Cyclic stress ratio (determined using unconsolidated-undrained tests) versus number of cycles, for four remolded 

specimens, under initial consolidation ratios of 2o0o 

References Cited 37 
1.5 

1. 3 

u) 

N 

';: 

E 

~ 

d 1 . 1 

i= 

<{ 

a: 

CJ) 

CJ) 

UJ 

a: 0.9 

1-

CJ) 

u 

::::i 

~ u 0.7 

0.5 

0.3 

1 10 100 1000 

NUMBER OF CYCLES, N 

Figure 32. Cyclic stress ratio (determined using isotropically consolidated-undrained tests) versus number of cycles, for three 

remolded specimens, under initial consolidation ratios of 1.0. 

38 Cyclic Triaxial Tests, Bootlegger Cove Formation, Anchorage, Alaska 
0.6~----+~---+--~~~~~-+------~---~!--+1-+~~~~~----+-+-~4~-~4-~~ I 1 t 

I 

I i I I I I ! i i I 0.5 ~----~--~--~~~~~-------L--~--~~~~~------~~~~~~~~~ 

1 10 100 1000 

NUMBER OF CYCLES, N 

Figure 33. Cyclic stress ratio (determined using isotropically consolidated-undrained tests) versus number of cycles for three 

remolded specimens, under initial consolidation ratios of 1.5. 

References Cited 39 
30 I ! I l 1 

I I Jl I I I ! i l I I l I' I' 

I RJmolld !d 

I I . I I CTI- i I ~~IE ( I ~~ I f mex =1< I t ) L~ 

: i : ' . :\rl I I I 

I K~=2.j0 I ! ~ ..... ; I I 

I 

( ~ ld In 

l s~ : E I r r ~ill 14 f IR U ~ t 

I : : 

28 

u) 26 

N 

';: 

E 

~ 

d 24 ~ <( 

cc 

en 

en 

w 

cc 22 ~ 

en 

u 

:::J 

~ u 20 

I 

I 

I 

I 

I 

1 I l I 

I I I ' ~ 

I I I I ~· I i I I 

I 

I 

I 

· II I 

I 

1 IW 

. I ! I 

i i l I I i I N 

j 

lcr-t 

! 

I 

l I I I , I l I I \ ! 

I I I II I l i ! c~:jj I I I , I I I 

I I A ! > i l ' i l -~ll, l I I I I 11 I < ~ ,rt1)1 ~ i'\ I l1 l I I . ll 

I 

n I I 

I 

! 

I 

1\i II I l l i l I l I I I 

! I i I j I ! II !~ !I I' I I l 

I 

I I ! II II ! 

I I ! Ill I I l ·. I< 11 ~ : -, l n) 

I I l ' 

I I 1 

i i I 

! II ! 

I I ! I 

I I 1 ·I I i l I . l 

I il i II l I Ill II I I I l I 

18 

16 

1 10 100 1000 10,000 

NUMBER OF CYCLES, N 

Figure 34. Cyclic stress ratio ~determined using isotropically consolidated-undrained tests) versus number of cycles for four 

remolded specimens, under initial consolidation ratios of 2.0. 

40 Cyclic Triaxial Tests, Bootlegger Cove Formation, Anchorage, Alaska 
25 

u) 

N 

~ 

E 

g 

c5 20 

~ <{ 

0:: 

(/) 

(/) i I w 

0:: 1 5 

1-

(/) ! I 

u 

::::i 

~ u 10 

Figure 35. Cyclic stress ratio versus number of cycles for six remolded specimens at consolidation ratios of 1.0, 1.5, and 2.0. 

Axial strains of 5 percent (for Kc = 1.0) and 10 percent (for Kc = 1.5 and 2.0) were taken from figures 29, 30, and 31 (UU tests). 

Curves for intact specimens, as shown in figure 25, are given for comparison. 

References Cited 41 
2.0 

u) 

N 

~ 

e 

b' 

d 1.6 

i= 

<( 

a: 

CJ) 

CJ) 

w 

a: 1. 2 

1-

CJ) 

u 

::J 

~ 0.8 

10 100 1000 

NUMBER OF CYCLES, N 

Figure 36. Cyclic stress ratio versus number of cycles for remolded specimens at Kc = 1.0, 1.5, and 2.0, based upon shear 

strengths determined by isotropically consolidated-undrained conditions. 

42 Cyclic Triaxial Tests, Bootlegger Cove Formation, Anchorage, Alaska 
0 L-~~~~-L~~~~-L--L-~-L~U-~~--~~~~~--~~~~~~~ 

1 10 100 1000 10,000 

NUMBER OF CYCLES, N 

Figure 37. A comparison of cyclic stress ratios for intact specimens (determined from unconsolidated-undrained tests) with 

ratios of remolded specimens (determined from isotropically consolidated-undrained tests). Note apparent lower strength of remolded specimens at all consolidation ratios. 

References Cited 43 
oL--L-L--L-l-~~~--L-~-L~-L~~~~~--J-~~~~--~~----~~~~ 

1 10 100 1000 

NUMBER OF CYCLES, N 

Figure 38. A comparison of cyclic stress ratios for intact specimens (estimated from isotropically consolidated-undrained (ICU) 

tests) with ratios for remolded specimens (measured from ICU tests). In contrast to figure 37, a much closer agreement in strength 

between intact and remolded specimens is shown in this graph. 

44 Cyclic Triaxial Tests, Bootlegger Cove Formation, Anchorage, Alaska 
0.01 0.1 1.0 10 100 

SINGLE AMPLITUDE SHEAR STRAIN,"/, IN PERCENT 

Figure 39. Normalized shear moduli for intact specimens using shear strengths determined by unconsolidated-undrained tests. 

Also shown are moduli results from resonant column tests (see Updike and others, 1982) and normalized curves from Seed 

and ldriss (1970). 

:::::i 

::::> 

Cl 

0 

~ 

a: 

<( 

w 

I 

(/) 

Cl 

w 

~ ...J 

<( 

~ 

a: 

0 

z 

~--~~--+-~~~~+----~~--~,_~++-t+l 'I' I I 

-+--+---+ !--+~t-+-l-+----+-t--t--+-+-!-H+---+! -t--+-t-tI lntact ~pee im ~n 

t---+j-+--t-1. +i-t-t1__._1+-'- I. --+-1 ...... '---+--+--J-HI ++---+--+--+-+-+--;-+-f:'++-__,Kc"-= 1 · o ... _ , ,. 

- ~ l I , 1 • I I I I I Kc ~:·!~ or i~hlc'tlapecir ens 

- -. 

I 

I 

I I 

I ; L 

! j I 

! 

I 

II I i I 

I I I 

I 

I 

I I ~~~ 1 :I i 

I I , j I l . I II 

0.01 0.1 1.0 10 

SINGLE AMPLITUDE SHEAR STRAIN, Y. IN PERCENT 

I 

I 

I 

i 

i l 

I 

j' 

! 

J I! i I I I 

! ill 

i. i; 

• ! , I. 

I 

i ll 

! : l 

100 

Figure 40. Normalized shear moduli for intact specimens using shear strengths determined by estimates of isotropically 

consolidated-undrained shear tests. Also shown are moduli results from resonant column tests (see Updike and others, 1982) 

and normalized curves from Seed and ldriss (1970). 

References Cited 45 
- •< 

I L 

I l I I 

! I 

I i 

I I :I 

I II -- ..... I "' I '"' .+ -+- "- '- ........ " - 1'1 I 

I- I ~ I ......... I' I I I ' I'T I I I 

I I I i • ---- ---:--- l 

-- I N.J "-..] 1'... I I ' J:i. I I I 

l ! ! l I I 'j.. ~ ~ I . I i '-";,=).,J I I i - : I ! I J I I 1 \"- I l'J l I , I ~~~ I . I 

I I l I 

,I', I 

I 

, ! 'I 

~' )'hLI iiI (!) ! \.:1 I I I' I I I ' i : iII I I,.,. . , I i 

! 

! 

! ! I I ~ II 

I I I J)l 

I N l1ntl :\.:/~~ I ; I : 

l I I 

, I 

! 

j 1:11 I I I: I 10 I Iii I I i I 

0.001 0.01 0.1 1.0 10 100 

SINGLE AMPLITUDE SHEAR STRAIN. 'Y. IN PERCENT 

Figure 41. Normalized shear moduli for remolded specimens using shear strengths determined from unconsolidated-undrained 

tests. Note the two different confining pressures, u3

, for a consolidation ratio of 1.5. Data points suggest higher strength than 

the Seed and ldriss (1970) normalized moduli curves would suggest. 

::::; 

~ 

0 

0 

~ 

a: 

<{ 

w 

::L 

(/) 

Cl 

w 

N 

::::; 

<{ 

~ 

a: 

0 

z 

1 

o o o ES~E=E:, ....... =ti_ 3:

1

3:. It :s:: __ ......... =_ =r .......... ~-s!"'o!.~E;_;I,+-~=fli+-1 __ iE-;...... __ =-_=-_~--I~--_ ~--=--t-+E ___ Er __ !=,_--tTI 1-_l __ r---_E_ --~+]+-_:=_-=-=--====---~-.==:EJS:=_;=i=r-~-'-+--t:._==_ .-:-.. :-!· -===----,2:.--Ls~~--~=:==l 

: I "'-L ' i _ ---L ~ 'N ~--- ~~ --r:::l i . • ~-~ ----------.-~~-~---t-----·•-----------·---

~. I :w I __ "' ~ I r.i7 ~ -;. -~+--r~-+-L--+-------<-i--r-~-~--i--,~------t-

!-----r.-J--l..-~.:;--+-, t__ ~._I· Y. I 41. ~L1_+ ·_ -~-- +---~----:-L:--

1 ! : ~r::! \7 I w Pff~-~~~~ ~~~ ~ . ~~, .. ;, 

I : \II . I I I '.1':--~~~{ N-! ~ l I ! : I . ~_:___:__--==~~--:-::=t=~ ~ ~ ~ X ---'k----+----t--+---~---+---+-->--t 

t---+--+---+-+-+-+++1---1--+---+--+--+-+-++++-----+----L l!!li~l Ylr-1.--....... L ""J I I i ! • ! I I i I I I .,.... I~ " r.... ll 

0.01 0.1 1.0 10 100 

SINGLE AMPLITUDE SHEAR STRAIN_ y, IN PERCENT 

Figure 42. Normalized shear moduli for remolded specimens using shear strengths determined from isotropically consolidatedundrained (ICU) tests. The Seed and ldriss (1970) moduli curves from figure 41 are in much closer agreement with data points 

based upon ICU tests. The low-strain resonant column data points (from Updike and others, 1982) show reasonable continuity 

with the cyclic triaxial test data. 

46 Cyclic Triaxial Tests, Bootlegger Cove Formation, Anchorage, Alaska 
100 N 

~ 

u 

" (.!) 

~ 

z 

d 

....J 

::> 

Q 

0 

~ 

a: 

<( 

w 

I 

(/) 

1 0 100 1000 

NUMBER OF CYCLES, N 

Figure 43. A comparison of shear moduli with respect to number of cycles for the intact and remolded states of three specimens, 

all at a consolidation ratio of 1.0. Specimens CT -1 and CT -5 represent facies F.IV of the Bootlegger Cove Formation; specimen 

RC-6 is from facies F.ll of the Bootlegger Cove Formation. 

References Cited 47 
1000 

N 100 

~ 

u 

" <.9 

:::£ 

z 

ci 

.....J 

::::> 

0 

0 

~ 

a: 

<! 

w 

:::c 

(f) 1 0 

10 100 1000 

NUMBER OF CYCLES, N 

Figure 44. A comparison of shear moduli with respect to number of cycles for the intact and remolded states of three specimens, 

all at a consolidation ratio of 1.5. Specimens CT -2 and CT -8 represent facies F.ll of the Bootlegger Cove Formation; specimen 

CT -3 is from facies F. Ill of the Bootlegger Cove Formation. 

48 Cyclic Triaxial Tests, Bootlegger Cove Formation, Anchorage, Alaska 
.....J 

::> 

0 

0 

~ 

a: 

<( 

w 

::r: 

(/) 

1 0 100 1000 

NUMBER OF CYCLES, N 

Figure 45. A comparison of shear moduli with respect to number of cycles for the intact and remolded states of three specimens, 

all at a consolidation ratio of 2.0. Specimens CT -4 and CT -7 represent facies F.IV of the Bootlegger Cove Formation; specimen 

CT -9 is from facies F.ll of the Bootlegger Cove Formation. 

References Cited 49 
1- 25 

z 

w 

u 

0:: 

w 

ll.. 

z 20 

ci 

cj 

i= 

~ 

0:: 1 5 

(.9 

z 

a: 

~ 

~ 

0 1 0 

0 L--L-L~L-~-LLLU-~~--~~~~~--~~~~-L~~~~~--~~~~~ 

0.001 0.01 0.1 1.0 10 

SINGLE AMPLITUDE SHEAR STRAIN, 7, IN PERCENT 

Figure 46. Damping ratios versus percent strain for intact specimens tested at various consolidation ratios. Damping ratio curves 

from Seed and ldriss (1970) and data points from resonant column tests (Updike and others, 1982) are also shown. 

50 Cyclic Triaxial Tests, Bootlegger Cove Formation, Anchorage, Alaska 
5 >--t ~:::::: ._r+-~............. I. !w ~~ ~e-H I~ v I. ~ S;e 11' <l, r r ~ I d i 8 ( 1 7 ( ) 

~~~ -~ t~ r-~i'~~-~ --~~ lj i I ·l; , !1.1 I 

l 

: i 

oL--L-L--L-LJ-LLLU-~~--~~~~~--~~~~~~~~~~--~~~~~10 l l I : i l 1 

0.001 0.01 0.1 1.0 

SINGLE AMPLITUDE SHEAR STRAIN,.,, IN PERCENT 

Figure 47. Damping ratios versus percent strain for remolded specimens tested at various consolidation ratios. Damping ratio 

curves from Seed and ldriss (1970) and data points from resonant column tests (Updike and others, 1982) are also shown. 

References Cited 51 

* U.S. GPO: 1988 573~7/fffSl.