ENGINEERING PROPERTIES OF THE ORINOCO CLAY

ENGINEERING PROPERTIES OF THE

ORINOCO CLAY

by

Robert William Day

B.S.E., Villanova University (1976)M.C.E., Villanova University (1978)

SUBMITTED IN PARTIAL FULFILLMENTOF THE REQUIREMENTS FOR THE

DEGREES OF

MASTER OF SCIENCE INCIVIL ENGINEERING

and

CIVIL ENGINEER

at the

MASSACHUSETTS INSTITUTE OF TECHNOLOGY

December 1980

Robert William Day 1980

The author hereby grants to M.I.T. permission to reproduce andto distribute copies of this t-esis document in whole or in part.

Signature of Author

/ Department of ivil Engineering' ecember 15, 1980

Certified by

I CZ'les 9'%ddThps Su9 sor

Accepted by

//'KC. Allin CornellCha rman, Department Committee

ARCHIVESMASSACHUSETTS INSTITUTEOF TECHNOLOGY

APR 1 1981

LIBRARIES

2

ENGINEERING PROPERTIES OF THE

ORINOCO CLAY

by

Robert William Day

Submitted to the Department of Civil Engineering on December15, 1980 in partial fulfillment of the requirements for theDegrees of Master of Science in Civil Engineering and CivilEngineer.

ABSTRACT

Sediments from the Orinoco River have formed a thick(30-40 m) deposit of soft, highly plastic clay along vastareas of offshore Eastern Venezuela. Whereas conventionalpractice for the design of oil platforms relies on empiricaluse of results from simple strength index testing, thisthesis utilized the SHANSEP method to develop a more reliableestimation of the in situ undrained shear strength (s )anddeformation characteristics of the Orinoco Clay deposit.Radiography of sampling tubes containing Orinoco Clay detectedthe presence of gas pockets, cracks, and zones of disturbedclay and also served to identify the best quality specimensfor sophisticated laboratory tests such as oedometer and K0Consolidated-Undrained Direct Simple Shear (CK0UDSS) tests.

Results of oedometer tests run on undisturbed tubesamples from two borings separated by 125 km indicate thatthe Orinoco Clay deposit at both borings has essentially thesame maximum past pressure and is either normally consolidatedor slightly overconsolidated. The oedometer and CK0UDSS testdata reveal that the Orinoco Clay exhibits normalized behavior,but with two strata having significantly different engineeringproperties. The lower stratum is more compressible with anormalized undrained shear strength less then the upper stratum.This distinct difference in engineering properties is probablycaused by a considerable increase in the content of swellingminerals in the lower stratum.

The SHANSEP undrained shear strength profiles at the twowidely separated borings were almost identical, whereas s ufrom the strength index tests (e.g. UU Triaxial, Lab Vane, etc.)yielded wide scatter due to sample disturbance, strain ratedifferences, and anisotropy effects. Because of the verysimilar engineering properties and SHANSEP s profiles, andcorroborated by geophysical data, it is concluded that the

3

Orinoco Clay exists as basically the same deposit aroundand between the two borings.

Thesis Supervisor:

Title

Charles C. Ladd

Professor of Civil Engineering

4

ACKNOWLEDGMENTS

I am indebted to my parents for their encouragement

in completing this thesis.

I would like to especially thank Professor Charles C.

Ladd, my thesis supervisor, for his constructive criticism

and Instituto Tecnologico Venezolano del Petroleo (INTEVEP)

for their financial aid.

My thanks also to Enrique Urdaneta Lafee and Aziz M.

Malek for their friendship and assistance in the laboratory.

5

TABLE OF CONTENTS

PAGE NO.

TITLE PAGE 1

ABSTRACT 2

ACKNOWLEDGMENTS 4

TABLE OF CONTENTS 5

LIST OF TABLES 7

LIST OF FIGURES 8

LIST OF SYMBOLS 10

CHAPTER 1. INTRODUCTION 13

1-1 ORINOCO CLAY 13

1-2 BORINGS El AND Fl 14

1-3 ORGANIZATION OF THESIS 17

CHAPTER 2. SHANSEP METHOD 22

2-1 TV, LV, AND UUC TESTS 22

2-2 SHANSEP METHOD 24

2-3 SUMMARY 27

CHAPTER 3. INDEX PROPERTIES AND COMPOSITION OF 30ORINOCO CLAY

3-1 UNDRAINED SHEAR STRENGTH FROM STRENGTH INDEXTESTS: TV, LV, AND UUC

3-2 INDEX PROPERTIES: NATURAL WATER CONTENT 32

3-3 INDEX PROPERTIES: ATTERBERG LIMITS 32

3-4 IN SITU VERTICAL EFFECTIVE STRESS 33

3-5 COMPOSITION ANALYSES: MINERALOGY 34

3-6 SALT CONCENTRATION AND ORGANIC MATTER 35

3-7 SUMMARY 36

6

PAGE NO.

CHAPTER 4. RADIOGRAPHY

4-1 INTRODUCTION: X-RAYS

4-2 DESCRIPTION OF M.I.T.'s RADIOGRAPH FACILITY

4-3 RADIOGRAPHY OF SAMPLING TUBES CONTAININGORINOCO CLAY

4-4 SUMMARY

CHAPTER 5. STRESS HISTORY AND CONSOLIDATION PROPERTIES

5-1 INTRODUCTION: TEST PROCEDURES FOR OEDOMETERTESTS

5-2 EFFECTS OF SAMPLE DISTURBANCE

5-3 STRESS HISTORY

5-4 COMPRESSIBILITY AND COEFFICIENT OFCONSOLIDATION

5-5 EMPIRICAL CORRELATIONS

5-6 SUMMARY

45

45

46

48

52

60

60

62

65

66

68

68

CHAPTER 6. NORMALIZED SOIL PROPERTIES AND SHANSEPSTRENGTH PROFILES

6-1 NSP FROM NORMALLY CONSOLIDATED CK UDSSTESTS

6-2 OVERCONSOLIDATED CK0UDSS TEST DATA

6-3 ANISOTROPY

6-4 SHANSEP STRENGTH PROFILES

CHAPTER 7. SUMMARY AND CONCLUSIONS

REFERENCES

APPENDIX A. CONSOLIDATION TESTS

APPENDIX B. CK0UDSS TESTS

APPENDIX C. CK UC AND CK UE TESTS

77

77

82

83

85

101

107

109

122

138

7

LIST OF TABLES

TABLE

1-1

1-2

2-1

3-1.

3-2

3-3

5-1

5-2

6-1

6-2

6-3

TITLE

SAMPLE LOCATION, TYPE AND PRINCIPAL TESTS:BORING El

SAMPLE LOCATION, TYPE AND PRINCIPAL TESTS:BORING Fl

SHANSEP APPROACH

UNIT WEIGHTS AND EFFECTIVE STRESS

CLAY MINERALOGY SUMMARY FOR BORING Fl

CLAY MINERALOGY SUMMARY FOR BORING El

SUMMARY OF OEDOMETER TEST DATA: BORING El

SUMMARY OF OEDOMETER TEST DATA: BORING Fl

SUMMARY OF CK UDSS TEST DATA: N.C. ORINOCOCLAY

SUMMARY OF CK UDSS TEST DATA: O.C. ORINOCOCLAY

SUMMARY OF CK U TRIAXIAL TESTS: N.C. ORINOCOCLAY

ENGINEERING PROPERTIES OF THE ORINOCO CLAY

PAGE NO.

19

20

28

37

38

39

69

70

90

91

92

7-1 106

8

LIST OF FIGURES

FIGURE .TIE PAGE NO.

1-1 BORING LOCATIONS 21

2-1 APPLICATION OF SHANSEP TO UNDRAINED STABILITY 29ANALYSIS USING CK U DIRECT SIMPLE SHEAR TESTS

3-1 NATURAL WATER CONTENT AND STRENGTH INDEX 40TESTS: BORING El

3-2 NATURAL WATER CONTENT AND STRENGTH INDEX 41TESTS: BORING Fl

3-3 EFFECTS OF DISTURBANCE AND STRAIN RATE ON 42TORVANE DATA: SAMPLE F1557 4

3-4 PLASTICITY CHART: ORINOCO CLAY 43

3-5 SALT CONCENTRATION AND ORGANIC MATTER: 44ORINOCO CLAY

4-1 RADIOGRAPHY OF A SAMPLING TUBE CONTAINING 54ORINOCO CLAY

4-2 OEDOMETER AND STRENGTH DATA ON SAMPLE 55FlS57 FOR COMPARISON WITH RADIOGRAPH

4-3 SAMPLE F1557: RADIOGRAPH PRINT SHOWING 56SAMPLE DISTURBANCE

4-4 SAMPLE E1512: RADIOGRAPH PRINT SHOWING 57GAS POCKETS

4-5 SAMPLE ElS21: RADIOGRAPH PRINT SHOWING 58HORIZONTAL CRACKS

5-1 EFFECTS OF DISTURBANCE ON OEDOMETER TEST 71DATA: SAMPLE F1557

5-2 OEDOMETER TEST DISTURBANCE INDICES: 72ORINOCO CLAY

5-3 STRESS HISTORY: ORINOCO CLAY 73

5-4 COMPRESSIBILITY AND COEFFICIENT OF 74CONSOLIDATION: ORINOCO CLAY

9

FIGURE -TIE PAGE NO.

5-5 EMPIRICAL CORRELATIONS WITH NATURAL WATER 75CONTENT: ORINOCO CLAY

5-6 EMPIRICAL CORRELATIONS WITH LIQUID LIMIT: 76ORINOCO CLAY

6-1 CK UDSS TEST DISTURBANCE INDICES: ORINOCOCIAY 93

6-2 NORMALIZED STRESS PATHS FROM CK 0UDSS TESTS:N.C. ORINOCO CLAY

6-3 NORMALIZED STRESS VERSUS STRAIN FROM CK0UDSS 95TESTS: N.C. ORINOCO CLAY

6-4 NORMALIZED UNDRAINEDCMODULUS FOR CK 0UDSS 96TESTS: N.C. ORINOCO CLAY0

6-5 s lavc VERSUS PI FOR NORMALLY CONSOLIDATED 97CL AND CH CLAYS

6-6 EFFECT OF OCR ON s /avc 98

6-7 COMPARISON OF UNDRAINED STRENGTH DATA: 99BORING El

6-8 COMPARISON OF UNDRAINED STRENGTH DATA: 100BORING Fl

10

LIST OF SYMBOLS

Prefix A indicates a change

A bar over a property indicates value in terms of effectivestress

GENERAL

BBC Boston Blue Clay

EABPL East Atchafalaya Basin Protection Levee

z Depth below mudline

INDEX PROPERTIES

e Void ratio

e Initial void ratio

G s Specific gravity of solids

LI Liquidity index

P.I. Plasticity index which equals w1 - w

S Degree of saturation

w Liquid limit

w Natural water contentn

w Plastic limitp

Yb Buoyant unit weight

Ysw Unit weight of salt water

Yt Total unit weight

Yw Unit weight of water

CONSOLIDATION PARAMETERS

cv Coefficient of consolidation for vertical flow

11

C Virgin compression index = -Ae/Aloga

Cs Swelling index

Ca Rate of secondary compression = Ae /Alog t

CR Virgin compression ratio = Av /Aloga

K 0ho vo, the in situ lateral stress ratio forone-dimensional vertical strainduring deposition

OCR Overconsolidation ratio = a or a /lvc

RR Recompression Ratio

SR Swelling ratio

t Time

t Consolidation time for preshear a vc

E: Vertical strain

avc Vertical consolidation stress

av In situ vertical effective stress

av Maximum past pressure

STRENGTH AND DEFORMATION PARAMETERS

E Young's modulus

E Undrained secant Eu

E5 0 Eu half way to failure

s uUndrained shear strength

s /W Normalized undrained shear strength where a isSvc the consolidation vertical effective stress priorto undrained shearing (applicable for CKQU strengthtests)

Angle of rotation of the principal stress duringshearing for a CK0U strength test

Shear strain

12

y Shear strain needed to reach s

Vertical effective stress during shearing(Direct Simple Shear test)

T h Shear stress on horizontal plane during shearing(Direct Simple Shear test)

Slope of Mohr-Coulomb failure envelope

CONSOLIDATION AND STRENGTH TESTS

CK0 U K0 Consolidated Undrained shear test

CK UC CK U Triaxial Compression test

CK0 UDSS CK U Direct Simple Shear test

CK UE CK U Triaxial Extension test

LV Lab Vane

Oed Oedometer test

TV Torvane test

UUC Unconsolidated Undrained Triaxial Compressiontest

13

1. INTRODUCTION

Laboratory soil tests were performed to determine

the engineering properties of the offshore Orinoco Clay

deposit and the objective of this thesis is to present the

results of those tests. The SHANSEP method is utilized to

obtain normalized soil properties and the undrained shear

strength profiles at two widely separated borings off the

coast of Eastern Venezuela. The-engineering properties

of the Orinoco Clay are needed for the design of oil plat-

forms.

1-1 ORINOCO CLAY

Transgression is defined as a rise in sea level rela-

tive to the land which causes areas to be submerged and

new deposition to begin in that region. In the past

fifteen thousand years, sea level has risen about 100

meters caused by the termination of an ice age and melting

of glaciers. In Venezuela, transgression produced a wider

continental shelf upon which the Orinoco Clay has been

deposited.

The Orinoco River (see Fig. 1-1) has a length of 2500

kilometers and transports an estimated sediment load of

108 tons/year (Butenko and Hedberg, 1980). The river

deposits most of it's granular soil inland, while the

suspended clay particles are carried into the Atlantic

14

Ocean. Salt water causes these particles to flocculate

and then the flocs settle to the sea floor. For the past

fifteen thousand years, clay deposition has produced a

vast and thick "mud wedge", extending up to 60 to 100

kilometers from the shoreline for a distance of about 450

kilometers along the continental shelf, with a maximum

thickness of 50 to 70 meters. The swift longshore Guyana

Current also transports some of the suspended flocs towards

the West where deposition occurs in the placid waters of

the semienclosed Gulf of Paria (Fig. 1-1). This offshore

clay deposit composed of sediments derived from the Orinoco

River has been termed the Orinoco Clay

1-2 BORINGS El AND Fl

Jackup exploration and oil production platforms will

be constructed in the Atlantic Ocean within the Orinoco

River delta and in the Gulf of Paria. The Orinoco Clay

deposit will totally support the jackup platforms and to

determine their stability to ocean waves, winds, and plat-

form dead and live loads, the undrained stress-strain-

strength and consolidation properties of the deposit must

be determined. For the oil production platforms, tubular

steel piles will be driven through the Orinoco Clay deposit

and into the stronger underlying dense sand and stiff clay

strata. The oil production platforms will not rely upon

15

the Orinoco Clay to support axial loads, but the clay

deposit must resist lateral pile deformations due to

horizontal loads from wind and waves acting upon the oil

platforms. In order to determine the resistance of the

Orinoco Clay to lateral pile deformations, the undrained

shear strength (su) and the stress-strain characteristics

(e.g. Young's moduli, E ) of the clay deposit must beu

ascertained. Borings El and Fl (Fig. 1-1) were drilled to

obtain Orinoco Clay for laboratory soil tests. The water

depth and thickness of the Orinoco Clay deposit at each

boring are presented below:

-Boring Water Depth (f t) Deposit Thickness (f t)

El 86 149

Fl 78 134

Orinoco Clay was sampled using cylindrical thin-

walled stainless steel tubes. The sampling tubes were

two to three feet long and 0.1 inch thick with an outside

diameter of 3 inches. Two processes were utilized to

penetrate the sampling tubes into the clay. At the top

40 to 60 feet of the deposit, the tubes were hammered into

the soil. At greater depths, Orinoco Clay was obtained

by using Fugro's "WIP" sampling equipment which consists

of pushing the sampling tube into the soil at a constant

velocity of about 0.8 inch per second (Fugro, 1979).

After the tube samples were hoisted onboard the Fugro

16

drilling ship, some of the clay was used to classify the

soil and to estimate the undrained shear strength by*

performing Lab Vane (LV), Torvane (TV), and Unconsolidated

Undrained Triaxial Compression (UUC) tests. The remaining

Orinoco Clay was sealed by pouring molten wax into both

ends of the sampling tube. M.I.T. received 17 tubes

containing Orinoco Clay for laboratory soil tests: 6 tubes

from boring El and 11 from boring Fl. Tables 1-1 and 1-2

present the sampling tube location and type of laboratory

tests performed on Orinoco Clay specimens for borings El

and Fl respectively. Each table presents the following

data:

(Column 1) Depth below the mudline of the tube sample.

(Column 2) Sampling tube number; for example, E1512

means sampling tube number 12 from boring El.

(Column 3) Type of sampler used; either "WIP" or

hammered sampler where N is the number of blows (from a

198 pound hammer falling five feet) required to drive

the sampling tube one foot.

(Column 4) The in situ vertical effective stress at

the depth of the sampling tube.

(Column 5) The condition of the Orinoco Clay observed

* Shannon and Wilson, Inc. Seattle, Washington, manufacturethe Torvane device, a hand operated torsional vane sheardevice.

17

upon extrusion from it's sampling tube. For example,

the Orinoco Clay from tube ElSl2 was highly disturbed

and neither composition nor engineering tests were perforned.

(Columns 6, 7, and 8) Composition results. "Salt"

means that the salt concentration of the pore fluid was

determined, "Org" refers to an estimation of the organic

content of the soil, and "Mineral" pertains to X-ray

diffraction analyses to determine the type of minerals

present.

(Columns 9, 10, and 11) Engineering tests. Mostly

oedometer (Oed) and Direct Simple Shear (CK UDSS) tests

were performed upon Orinoco Clay specimens.

Of the 17 tubes containing Orinoco Clay received by

M.I.T., four of the tubes had soil suffering from excessive

sample disturbance causing the clay to be too soft to trim

for engineering tests.

1-3 ORGANIZATION OF THESIS

Chapter 1 has introduced the Orinoco Clay and borings

El and Fl.

Chapter 2 discusses Lab Vane, Torvane, and UUC tests

which generally give unreliable values of the undrained

shear strength with large scatter because of sample

disturbance, strain rate effects, and anisotropy. The

SHANSEP method is presented, which is generally a more

reliable method to determine a s profile.

18

Chapter 3 presents index properties and composition

analyses of the Orinoco Clay.

Chapter 4 discusses radiography, an invaluable tool

used to detect those portions of Orinoco Clay within the

sampling tubes least likely to be disturbed and hence most

suitable for sophisticated laboratory tests such as

oedometer and Direct Simple Shear tests.

Chapter 5 presents the stress history and consolidation

properties obtained from oedometer tests.

Chapter 6 presents the normalized soil properties

obtained from Direct Simple Shear (CK0UDSS), K Consolidated

Undrained Triaxial Compression (CK UC) and Extension (CK UE)

tests and the SHANSEP undrained shear strength profiles at

borings El and Fl.

Chapter 7 is the thesis conclusion.

SAMPLE LOCATION, TYPE AND PRINCIPAL TESTS: BORING El

Depth No. Type (1)emarks Composition Engineering(2)

(ft) (kg/cm ) Salt Org. Mineral. Oed. CKoU Other

37-40 12 N-3 0.77 Highly disturbed - - - - - -

55-57 15 N-10 1.13 Uniform clay with yes yes yes Oed-l DSS-2 Effect ofgas pockets DSS-3 salt on wL

83-84 18 WIP 1.74 form clay with yes yes yes Oed-2 - -

DSS-498-100 21 WIP 2.08 horiontal crac yes yes yes Oed-3 DSS- -

TC-3

113-116 24 WIP 2.41 Disturbed yes yes - - - -

Oed-13133-136 27 WIP 2.84 Uniform clay yes yes yes Oed-14 DSS-13-

(1) Computed for Ga - 2.72 and S - 100% (see Table 3-1)

(2) Test No: DSS - Direct Simple Shear; TC - Triaxial Compression; TE - Triaxial Extension

Hk0

TABLE 1 -1

TABLE 1-2 SAMPLE LOCATION, TYPE AND PRINCIPAL TESTS: BORING F1

- (1) Composition (Engineering)(2)Depth no. Type. ov Remarks(ft) (kgycm2) Salt Org. Mineral. Oed. CK U Other

25-27 54 WIP 0.44 Disturbed yes yes - - -

27-29 9 N=4 0.48 horizont a i few yes yes yes Oed-5 DSS-12 -

36-38 12 N-8 0.64 Uniform clay yes yes - Oed-9 DSS-6

51-52.5 15 WIP 0.93 Slightly disturbed with yes yes yes Oed-11few horizontal cracks

65-67 55 WIP 1.20 Disturbed yes yes yes - -

66-68 18 WIP 1.22 Uniform clay yes yes yes Oed-4 DSS-l1 -

81-83 21 WIP 1.51 Platy Structure yes yes - Oed-8 DSS-10 -

96-98 24 WIP 1.80 Platy Structure,Disturbed yes yes yes Oed-6 DSS--

111-113 27 WIP 2.09 Uniform clay yes yes yes Oed-1-

126-128 30 WIP 2.38 Uniform clay with Oed-7. shell fragments Oed-16

Oed-12 -127-130 57 WIP 2.41 Very uniform clay yes yes yes Oed-18 S_- . - II E-i

(1) Computed for Ga = 2.72 and S = 100% (see Table 3-1)

(2) Test No; DSS = Direct Simple Shear; TC = Triaxial -Compression; TE - Triaxial Extension

t~J0

SCALE I a 2,000,000

TRINIDAD

GULF OF PARIA

-. BORING El ..

: . .. BORING Fl

VENEZUELA -- '1

RINOCO RIVER.- .....

FIGURE 1-1 BORING LOCATIONS

NI

H

22

2. SHANSEP METHOD

2-1 TV, LV, AND UUC TESTS

Several types of engineering tests can be used to deter-

mine the undrained shear strength (su) of a clay specimen.

Some examples are Torvane (TV), Lab Vane (LV), and Uncon-

solidated Undrained Triaxial Compression (UUC) tests. But

TV, LV, and UUC test suffer inaccuracies because of such

factors as:

(1) Sample disturbance: the more disturbed the soil

structure, the lower the value of the undrained shear strength.

Sample disturbance can be caused by stress relief when making

a borehole, by hammering or pushing the sampling tube into

the clay stratum, expansion of gas during retrieval of the

sampling tube, jarring or banging the sampling tube during

transportation to the laboratory, roughly removing the clay

from the sampling tube, and crudely cutting the clay specimen

to a specific size for a laboratory test. These actions

cause a decrease in the effective stress, a reduction in

the interparticle bonds, and a rearrangement of the soil

particles. An "undisturbed" soil specimen will have little

rearrangement of the soil particles and perhaps no distur-

bance except that caused by stress relief where there is a

change from a in situ K condition to a isotropic "perfect

sample" stress condition. (Ladd and Lambe, 1963). A disturbed

soil specimen will have a disrupted soil structure with

23

perhaps a total rearrangement of soil particles. The results

of laboratory tests run on undisturbed specimens obviously

better represent in situ properties than laboratory tests

run on disturbed specimens.

(2) Strain rate: the faster a soil specimen is sheared,

i.e. a fast strain rate, the higher the value of su . For

Torvane, Lab Vane, and UUC tests, the strain rate is very

fast with failure occuring in only a few minutes or less.

(3) Anisotropy: clay has a natural strength variation

where su depends on the orientation of the failure plane,

thus su along a horizontal failure plane will not equal s

along a vertical failure plane. Lab Vane and Torvane tests

have simultaneous horizontal plus vertical failure planes

with an undrained shear strength that rarely equals s u

from a UUC test which has an oblique failure plane.

Because of sample disturbance, strain rate effects, and

anisotropy, considerable scatter in TV, LV, and UUC results

usually occurs (for example, see Fig. 3-1). Neglecting

anisotropic effects, an average line drawn through the s

data points in Figure 3-1 will not equal the in situ undrained

shear strength unless there is a fortuitous cancellation of

factors: i.e. the increased su due to a high strain rate is

compensated by an equal reduction in su due to sample

disturbance. In addition, stress-strain curves can not be

obtained from TV and LV tests, and moduli from UUC tests

are typically much too low.

24

2-2 SHANSEP METHOD

Several important symbols and there representative

definitions are presented below:

avo - in situ vertical effective stress, which equals (forsubmerged soil) the buoyant unit weight (Y timesthe depth below the mudline (z) .

a - maximum past pressure, obtained from the compressioncurve of an oedometer test by using Casagrande'smethod (see page 297 of Lambe and Whitman, 1969)..

OCR - overconsolidation ratio, which equals /Clay that is at equilibrium under the mafimmon verticaleffective stress it has ever experienced is normallyconsolidated (OCR = 1.0), whereas clay that is atequilibrium under a vertical effective stress lessthan that to which it once had is overconsolidated(OCR > 1.0).

a vertical consolidation stress, for laboratory testsvc such as oedometer and CK 0UDSS tests.

s - undrained shear strength, from strength tests such asTV, LV, UUC, and CK 0 UDSS tests.

s / - normalized undrained shear strength, where avc isu vcthe vertical consolidation stress prior to shearing.

s /a is only applicable for strength tests wheretie Ygil specimen is first consolidated to a , thensheared (e.g. CK 0 UDSS, Triaxial tests). vc

The SHANSEP method (Ladd and Foott, 1974) was developed

to obtain the stress-strain and strength properties of soft

clay deposits. This method is based upon experience which

indicates that the in situ stress-strain and strength prop-

erties of many clay deposits are controlled by the stress

history of the deposit; for 'example, the undrained shear

strength is proportional to the overconsolidation ratio.

* An acronym for Stress History And Normalized SoilEngineering Properties.

25

A clay deposit must exhibit "normalized behavior" for

SHANSEP to give reliable values of su. Normalized behavior

means that laboratory strength tests on clay specimens

having the same overconsolidation ratio will have similar

normalized stress-strain curves and identical values of

su vc. But naturally cemented clays and "quick clays"

have their interparticle bonds broken during the consolidation

portion of the SHANSEP laboratory strength testing technique

and thus su by SHANSEP does not represent in situ strength.

Table 2-1 presents the basic components of the SHANSEP

method. Figure 2-1 illustrates the SHANSEP procedure to

determine the undrained shear strength profile for a uniform

clay deposit subjected to a bearing capacity failure. The

SHANSEP method has -two distinct parts: stress history and

normalized soil properties.

Stress History

The first step in SHANSEP is to establish the stress

history of the clay deposit. This means that both Q and

a versus depth must be ascertained (Fig. 2-la). The in

situ vertical effective stress versus depth can be computed

from the index properties (wn, S, Gs). The maximum past

pressure data points in Figure 2-la were obtained from

oedometer tests. Knowing the -vo profile and estimating

the j profile from oedometer tests, the overconsolidation

ratio (OCR = /7vo) can then be calculated (Fig. 2-lc).

26

A reasonably well defined stress history is essential for

reliable s values from SHANSEP.u

Normalized Soil Properties

The second step in SHANSEP is to obtain the normalized

undrained shear strength (sU vc ) versus OCR relationship

(Fig. 2-lb). This consists of one-dimensionally (K0 ) consol-

idating a clay specimen in a Direct Simple Shear apparatus

beyond the in situ maximum past pressure and into the normally

consolidated region to a preshear vertical consolidation

stress (avc ) and then shearing the specimen to obtain s /Gvc

for OCR = 1.0. Additional CK 0 UDSS specimens are consolidated

into the normally consolidated region, but then unloaded,

allowed to swell, and then sheared to obtain the normalized

undrained shear strength at varying overconsolidation ratios,

such as OCR = 2, 4, and 8. This laboratory testing program

establishes the s /a versus OCR relationship plotted inu vc

Figure 2-lb.

Example of Obtaining s by SHANSEP Method

At El. 85, the stress history results in Figure 2-la

indicate that a = 1.8 and a = 7.2, an-overconsolidatedvo vm

clay with OCR = 4.0- Laboratory CK UDSS test data plotted

in Figure 2-lb indicate that if a clay specimen has an

overconsolidation ratio of 4.0, then s /avc = 0.60. As

27

shown in Figure 2-ic, multiplying 0.6 times a gives anvo.

su = 1.08, which is plotted in Figure 2-id.

2-3 SUMMARY

The SHANSEP method will be used to determine the

undrained shear strength profiles for the Orinoco Clay at

borings El and Fl. Knowing the index properties (wn',

G s), the in situ vertical effective stress ( vo) versus

depth can be computed (Chapter 3). The stress history of

the Orinoco Clay deposit is obtained by performing oedometer

tests where the maximum past pressure (F v) can be deduced

by Casagrande's method and the overconsolidation ratio can

then be calculated (Chapter 5). From Direct Simple Shear

tests run on Orinoco Clay specimens, a plot similar to

Figure 2-lb of the normalized undrained shear strength

(s /3vc) versus overconsolidation ratio (OCR) is presented

(Chapter 6). Then by performing the computations illustrated

in Figure 2-ic, the undrained shear strength profiles can

be drawn for the Orinoco Clay at borings El and Fl.

28

Table 2-1

SHANSEP Approach

After Ladd (1971)

Stress History And Normalized Soil Engineering

Properties Method of Estimating

Stress-Strain-Strength Properties of Clay

Generation of Data

1. Consolidate samples to appropriate conditions

a) If N.C. clay, use avc = 1.5 - 4 x avo

If O.C. clay, use a > in situ aVc vm

b) Use K = in situ K, such as K

c) Allow secondary compression to simulate

"aging".

2. Shear samples under appropriate conditions

a) Same stress system (Mode of failure)

(Proper a2 and rotation of principal planes)

b) Proper strain rate

Presentation of Data

1. Use "normalized" parameters such as su vc

and E/3vc; plot vs. OCR = a lavc

Utilization of Data

1. Determine in situ OCR and stress system

2. Select normalized parameter

3. Multiply parameter by in situ avo

z0I.-

wj

EFFECTIVE STRESSO 2 4 6 8 10

100------ -SAND

90 -

80 /

UNIFORM70 CLAY 0

DEPOSIT -- e60-

50 .1t _

ou

ANDsu

v0 o

(a) IN SITU SOIL PROFILE AND STRESS HISTORY

EL. Tvo rvm OCR su

85 1.8 7.2 4.00 0.60 1.08

75 2.8 5.3 1.90 0.34 0.95

65 3.8 5.8 1.50 0.28 1.06

55 4.8 6.5 1.35 0.25 1.20

(c) COMPUTATION OF SHANSEP su VALUES

1.0

0.8

0.6

0'

CKJJDSS TEST DATA

- ou /(vc Vs.

4-

FIELD APPLICATION

[su /&,o vs. IN SITU lvm /dvo]

I , (LOG SCALE)-

OCR 0 vm (vc AND OVm '0o(b) NORMALIZED UNDRAINED STRENGTH vs. OCR

z0I-

w

UNDRAINED STRENGTH,

to-(

60 -I%

su1.4

(d) SHANSEP su PROFILE FOR ANALYSES

0.8 1.0 1.2

FIGURE 2 -1 APPLICATION OF SIANSEP TO UNDRAINED STABILITY ANALYSIS USING CK U DIRECT SIMPLESHEAR TESTS

0.4

0.2

.

30

3. INDEX PROPERTIES AND COMPOSITION OF ORINOCO CLAY

Chapter 3 begins the presentation of results from

laboratory tests upon Orinoco Clay. Many of the laboratory

tests presented within this chapter were performed upon

clay specimens of unknown quality. For specific gravity

tests, Atterberg Limits, X-ray diffraction tests, and

organi6 matter determinations, an initially disturbed

clay specimen should not effect the results. However,

natural water contents and TV, LV, and UUC strength tests

can be significantly altered by sample disturbance.

3-1 UNDRAINED SHEAR STRENGTH FROM STRENGTH INDEX TESTS:TV, LV, AND UUC

Figures 3-1 and 3-2 present undrained shear strength

(s ) values obtained by Torvane, Lab Vane, and UUC tests.

After retrieval of a sampling tube containing Orinoco

Clay, some of the soil was used onboard the Fugro ship

to perform these strength tests. Notice the wide scatter

in results; for example, in Figure 3-1 at z = 130 feet,

2s varies between 0.35 to 0.75 kg/cm . This scatter is

caused by sample disturbance, strain rate effects, and

clay anisotropy (Chapter 2).

Figure 3-3 illustrates how the strain rate and sample

disturbance influence Torvane undrained shear strengths.

The Torvane tests on "undisturbed" F1S57 clay specimens

31

(open symbol,A) indicate that the faster the soil specimen

is sheared (i.e. a fast strain rate), the higher the value

of s . Standard Torvane tests usually have failure in

less than 10 seconds, and the very fast strain rate causes

about a 20% increase in s for F1S57 clay specimens. Torvane

tests on deliberately disturbed (remolded) clay specimens

(closed symbol,A) have much lower su values, the reductionu2

in the undrained shear strength is from 0.5 to 0.1 kg/cm2

Figure 3-3 clearly shows that su can be reduced much more

by sample disturbance than by differences in strain rate.

Figures 3-1 and 3-2 also illustrate the effects of

different sampling techniques. It has been stated (Wilun

et al, 1972) that "the method of forcing the sampler into

the ground has a considerable effect on the sample disturb-

ance; samplers pushed into the soil at a fast uniform rate

produce little disturbance whereas samplers driven into

the soil with individual blows induce considerable disturb-

ance".* At z = 60 feet in Figure 3-1 and at z = 40 feet in

Figure 3-2 there is a distinct discontinuity in the undrained

shear strength. Above these depths, sampling tubes were

hammered causing sample disturbance with low values of su

Below these depths, sampling tubes were pushed into the

soil strata at a fast uniform rate by using Fugro's "WIP"

sampling equipment causing less sample disturbance and

values of su more representative of the in situ undrained

shear strength.

32

3-2 INDEX PROPERTIES: NATURAL WATER CONTENT

Figures 3-1 and 3-2 also present the natural water

content (wn) for Orinoco Clay recorded onboard the Fugro

ship, at M.I.T., and at Catholic University (C.U.) in

Venezuela for borings El and Fl respectively. For boring

El (Fig. 3-1), the natural water content decreases from

7S% at the mudline to 45% at a depth of 55 feet. Below

55 feet, the natural water content increases and is constant

with depth at 53 & 2%. Except for results from sampling

tubes ES1l2 and E1S24, good agreement exists between the

water contents determined by Fugro, C.U., and M.I.T.

Sampling tubes ElS12 and ElS24 contained highly disturbed

clay with very high natural water contents that probably

do not correspond to the wn of the in situ clay.

For boring Fl (Fig. 3-2), the natural water content

decreases from 90% at the mudline to 63% at a depth of

30 feet. Below 30 feet, the water content is essentially

constant at 65 . 5%. Once again, good agreement exists

between M.I.T. and Fugro data except for tubes F1S54 and

F1S55 which contained highly disturbed clay.

3-3 INDEX PROPERTIES: ATTERBERG LIMITS

The results of Atterberg Limits performed by M.I.T.

and C.U. are plotted on Casagrande's Plasticity Chart,

Figure 3-4. For boring El, the plasticity index (P.I.)

33

ranges from 25 to 45%, classified as a CH clay. At boring

Fl, the plasticity index above z = 70 feet is generally

40 to 50%, while below z = 70 feet, the P.I. is 50 to 65%.

The Orinoco Clay at boring Fl is classified as a CH to CH-

OH clay and is more plastic then at boring El.

3-4 IN SITU VERTICAL EFFECTIVE STRESS

Six specific gravity tests were performed at M.I.T.

with an average of the specific gravity of solids (G s

equal to 2.72 and values ranging from 2.69 to 2.74.

Table 3-1 presents data for computing the in situ

vertical effective stress at borings El and Fl. Each

boring was divided into layers where the change in natural

water content was approximately constant; then using wnl

with Gs = 2.72, a unit weight of salt water (y ) equal,

to 64 pounds per cubic foot, and assuming 100% saturation,

both yb and y were calculated using the equations presented

in Table 3-1. The in situ vertical effective stress. was

obtained by assuming hydrostatic in situ pore water pressures:

therefore avo equals depth below mudline times buoyant unit

weight (yb)'

For comparison, Table 3-1 also presents the yt values

obtained by Fugro: they weighed a sampling tube containing

Orinoco Clay, subtracted the weight of the steel liner and

then divided this value by the volume of the sampling tube.

Most values computed by Fugro are close to the M.I.T. yt

34

calculations.

3-5 COMPOSITION ANALYSES: MINERALOGY

In mineralogy, X-ray diffraction is the process of

identifying mineral structures by exposing crystals to

X-rays and studying the resulting diffraction peaks. X-ray

diffraction (XRD) tests on Orinoco Clay specimens reveal

the same basic types of minerals at both borings El and

Fl. One-third to one-half of the soil consists of clay

minerals. The clay minerals are kaolinite, illite, and

swelling minerals (smectite). The rest of the soil contains

quartz, mica, and very weathered feldspar grains withsmall

amounts of diatom fragments, sponge spicules, and organic

matter.

Table 3-2 presents the XRD peaks for the clay minerals

from Orinoco Clay specimens from boring Fl. S9, 515, S55,

etc. at the top of Table 3-2 refer to the sampling tubes

from which the test specimens were extracted. The XRD peaks

for kaolin are between 40 to 50 for all specimens which

indicates that there is about the same amount of kaolinite

in all specimens tested. For illite, the XRD peaks vary

from 100 to 250. "Total Swelling" refers to the XRD peaks

for swelling minerals (smectite). Except for S18, the

XRD peaks range from 100 to 225 for samples above z = 70

feet and for samples below z = 70 feet, the XRD peaks are

about double with values from 300 to 400. A doubling of

35

the XRD peak does not necessarily imply a doubling in the

amount of swelling minerals, but it can be stated that below

z = 70 feet the clay contains considerably more swelling

minerals. This discovery is very important because swelling

minerals have profound effects upon engineering properties.

Unfortunately, only four mineralogy tests were performed on

boring El specimens and, as shown -if Table 3-3, an increase

in swelling minerals below z = 70 feet is not indicated by

the scant data.

3-6 SALT CONCENTRATION AND ORGANIC MATTER

As shown in Figure 3-5, the salt concentration of the

pore fluid for both borings El and Fl decreases with depth

from 35 grams/liter at the mudline to 25 + 5 grams/liter

at z = 130 feet. The salt concentration woild -be expected

to be 35 grams/liter for the entire deposit since the

Orinoco Clay has been deposited in salt water. Perhaps

the reduction in salt concentration with increasing depth

is caused by chemical diagenesis. The pore fluid, incompatible

and/or unstable minerals (feldspar grains), organic matter,

and carbonates interact with each other to bring the soil

into equilibrium, perhaps causing the salt concentration to

decrease with time.

Figure 3-5 also presents the percentage of the soil

mass that is organic matter. The organic matter content

is very small, 2 + 0.5%, but it does decrease slightly

36

at depths greater than 100 feet.

3-7 SUMMARY

In Figures 3-1 and 3-2 there is considerable scatter

in the undrained shear strength from TV, LV, and UUC tests.

A distinct discontinuity exists in the undrained shear

strength data at z = 60 feet in Figure 3-1-and at z 40

feet in Figure 3-2 caused by different sampling techniques

where hammering a sampling tube causes more sample disturb-

ance than Fugro's "WIP" sampling procedure.

The Orinoco Clay at boring El is classified as a CH

clay and has a P.I. between 25 to 45%. The Orinoco Clay

at boring Fl'is classified as a CH to CH-OH clay with a P.I.

between 40 to 50% above z = 70 feet, while below z = 70

feet, the P.I. is 50 to 65%.

Mineralogy results indicate that the Orinoco Clay at

both borings El and Fl contains the same basic minerals;

one-third to one-half of the soil being clay minerals such

as kaolinite, illite, and swelling minerals (smectite).

The rest of the soil consists mostly of quartz, mica, .and

weathered feldspar grains. For boring Fl, there is consid-

erably more swelling minerals below than above z = 70 feet.

TABLE 3-1 UNIT WEIGHTS AND EFFECTIVE STRESS

Yt= GsYw (1 + wn)/(I + wnGsywysw) Assuming 100% saturation

Yb t sw

avo b(z) Assuming hydrostatic in situ pore water pressures

Using the above yt equation, with Gs = 2.72, y w = 62.4 pcf, and y = 64 pcf

Svo(kg/cm2) = a0 + a1Z(ft)

Assumed FUGRO Parameters -

Boring Depth Y (tube)

(ft) VN (t pcf a0 ai(M) (pcf) Ave. i SD

0-55 59 105.2 101.6 ± 8.2 0 0.0201

El 55-75 49 110.0 105.0 t 1.4 -0.129 0.0225

75-140 52 108.4 107.1 ± 5.8 -0.0703 0.0217

0-30 77 98.8 94.2 ± 4.0 0 0.0170

Fl30-140 63 103.6 104.4 ± 9.4 -0.0703 0.0193

(1)

(2)

TABLE 3-2 CLAY MINERALOGY SUMMARY FOR BORING Fl

Absolute Peak Amplitude

S9 S15 S55 S18 S24 S27 S57Phase (27') (51') (66') (66') (96') (111') (127')

Kaolin 45 45 40 40 40 50 45

Illite 200 120 100 200 250 200 220

Total Swelling 225 200 100 400 400 300 400

W~h

co

TABLE 3-3 CLAY MINERALOGY SUMMARY FOR BORING El

Absolute Peak Amplitude

PhseS15 S18 S21 S27Phase (55') (83') (99') (134')

Kaolin 50 40 50 40

Illite 150 120 250 120

Total Swelling 270 190 250 210

WN (%)50 60 70 Rfl 0

0

20

104

TWIP

su (TSF, kg /cma)0.2 0.4 0.6 0.8 l.0

NATURAL WATER CONTENT AND STRENGTH INDEX TESTS: BORING El

MITSAMPLES

40

cD

00

0

some0

00

000 000am a

00

0

0 1o O FUORO

C * MIT

- -1 -0 C.u.

40[ 512

S 5-

4..

Id0

80

100

120

S18

-S21

S24

S27140L

e x FUGRO

t x TORVANE

20 - 0 LAB VANE

XV* 0 uucxe C

40 --

x e>

x 6

0 0x ()p80 -o i3K 0

x 00

1000 0

K 60

120K 00

x 6 0S 00

401-

FIGURE 3-1

LES WN N50 60 T 80 90 100 0

0

20

TWIP

20

40

00

0

(WIP) 0 o

0 00a_ ___

00 0

000

40

0

000

00

00

00 0 FUGRO

0 MIT

0.2su (TSF, kg/cma)

0.4 0.6 0.1

C FUGRO

X TORVANE

C LAB VANE

APXx ,0 uuc

e 0

o e

_ _ _ O _ _ _ _

x

X00

0

X C0x

C

>OC

00x ex' C

A A 1

NATURAL WATER CONTENT AND STRENGTH INDEX TESTS; BORING Fl

MilSAMP

60

80

100

120

140

401

S54

S12

S15

S55SIB

604-

I--

80 -21

1 V243001-

S27

H 1

12011530[S57

140L

.

0

FIGURE 3-2

- - IA

A

A

A Sample F1S57 z = 129 ft

A - "UNDISTURBED" CLAY

A - REMOLDED CLAY

ONBOARD TV = 0.48 kg/cm 2

20 40 60 80 100

TIME TO FAILURE (SECONDS)

FIGURE 3-3 EFFECTS OF DISTURBANCE AND STRAIN RATE ON TORVANE DATA: SAMPLE F1S57

0.50

0.40

ra)

0.30

0.20

0.10

00

N)J

70 - OIN -ET -f -0

0

600

O>NG DT

00 50I 0__ 00. (i.__ __ __

o20

() By C.U.-40 ALL OTHER DATA BY MIT

200

20

10 20 30 40 50 60 70 s0

LIQUID LIMIT, wL ()

PLASTICITY CHART: ORINOCO CLAY

III

U)

FIGURE 3-4

so IOU ilu0

SALT CONCENTRATION (g/l) ORGANIC MATTER (%)IC

o

20

40

60

15 20- I

El 0FI O

25 30 35 0

00

I _ I__ -1_0_

80

100

(20 0120

00

0

I 2 3

00

0

0

l 0

0 M

'9

SALT CONCENTRATION AND ORGANIC MATTER: ORINOCO CLAY

wa

I

FIGURE 3- 5

45

4. RADIOGRAPHY

4-1 INTRODUCTION: X-RAYS

In 1895, Wilhelm Konrad Roentgen discovered X-rays,

which are one form of electromagnetic radiation. Other

examples of electromagnetic radiation are radio waves and

visible light where a distinguishing characteristic is .the

wave length; defined as the distance, measured in the direc-

tion of propagation of the wave, between two successive

peaks. The approximate wave lengths for X-rays and visible

light are 100 millionths and 20 thousandths of a centimeter

respectively, while radio waves have wave lengths that vary

between a meter to several kilometers in length. The fact

that X-rays have wave lengths that are 5,000 times smaller

than those of visible light accounts for the penetration

through metals by X-rays compared to the reflection or

absorption of light waves.

X-rays are produced when electrons traveling at high

speeds collide with matter. The kinetic energy of a high

speed electron is transferred into heat and X-ray photons

as it strikes the nucleus of a stationary atom. One

mechanism that produces X-ray photons is the cathode ray

tube.

Photography using X-rays is called radiography. A

radiograph is the photographic record produced by the

passage of X-rays through an object and onto a white photo-

46

graphic film. If silver halide crystals are placed upon

a white photographic film and then bombarded with X-rays,

the chemicals will react with X-ray photons causing the

photographic film to darken. As X-ray photons travel

through a solid medium, some photons will be absorbed and

the denser a material the more photons absorbed. For

example, a radiograph produced after positioning a man's

chest between an X-ray source and a photographic film will

distinctly reveal the bones of the chest cavity which are

much denser than the surrounding flesh, tissue, and organs.

4-2 DESCRIPTION OF M.I.T.'s RADIOGRAPH FACILITY

M.I.T. received radiograph facilities for use in

geotechnical engineering research by a N.S.F. equipment

grant (number ENG78-10435). The facilities include:

(1) a X-ray source generator containing a double

beryllium window,

(2) a constructed enclosure 12 feet by 8 feet by 7

feet containing lead shielding on all walls, and

(3) a dark room to develop the radiographs.

The major advantage of radiography is that a photo-

graph of the soil can be obtained before the soil is

extruded from it's sampling tube. Worm holes, coral

fragments, cracks and gravel inclusions can easily be

identified by -using radiography (e.g. Allen et al., 1978).

Photons contain energy with zero mass and thus X-rays

47

can not displace or disturb soil particles. X-rays can

kill organisms, for example bacteria, fungi, etc. living

within the soil mass, but the lethal dose for such organ-

isms is several orders of magnitude greater than that

induced during radiography.

A sampling procedure using thin-walled cylindrical

sampling tubes was utilized to obtain Orinoco Clay. The

sampling tubes are stainless steel having a thickness of

0.1 inch with an outside diameter of 3 inches. Tubes

were two to three feet long with both ends sealed with

approximately two inches of wax. Hitherto, the only means

of examining the clay was to extrude it from the tube.

Because the sampling tubes are cylindrical, X-rays

that strike at the center of the tube (point A, Fig. 4-la)

must travel through 0.2 inches of stainless steel and 2.8

inches of soil, while those X-rays that strike at point B

(Fig. 4-la) travel through much less soil. The density

at point A is much greater than the density at point B and

aluminum plates of varying thickness are arranged so that

the density across the tube is approximately uniform. The

vertical lines in the radiograph prints (for example, see

Fig. 4-3) are caused by the varying thickness of the

aluminum plates.

Some X-ray photons are reflected off the walls and

these photons could strike the photographic film from behind.

To eliminate this scatter radiation, lead shielding is

48

positioned behind and around the photographic film (Fig.

4-1).

The variables for the radiography of sampling tubes

are the input voltage and current to the X-ray source, the

duration of X-ray bombardment of the photographic film,

the distance from the X-ray source to the photographic

film, and the developing time of the photographic film.

After numerous trials, the following values produced the

best radiographs for 3 inch diameter sampling tubes:

Input Voltage: 160 kilovolts

Input Current: 3.9 milliamperes

Exposure Time: 5 minutes

Distance From X-ray Source: 6 feet

Developing Time: 15 minutes

4-3 RADIOGRAPHY OF SAMPLING TUBES CONTAINING ORINOCO CLAY

This'section will present radiograph prints, that have

been reproduced as positives using the radiograph as.a

negative, of Orinoco Clay within sampling tubes. Light

areas represent zones of low soil density and dark areas

represent zones of high soil density. The radiograph

prints are close to true scale.

Sampling Tube F1S57, Sample Disturbance

Figure 4-3 is a radiograph print of the top 10 inches

of sampling tube F1S57 (depth = 127 to 130 feet). Lead

49

numbers (0 through 9) and letters (A, B, C, etc.) were usually

attached at one inch nominal distances along each tube and

radiographs taken at 10 inch intervals, which is the size of

the photographic film.

The top of Figure 4-3 at letter E is the top wax seal,

which has a very low density. As the Orinoco Clay was

extruded from sampling tube F1S57, Torvane and engineering

tests were performed and the results are presented in Figure

4-2. Several important conclusions can be obtained by

comparing Figure 4-2 with Figure 4-3.

(1) Figure 4-3 illustrates a swirling mass of clay

containing large voids. The clay between letters Z to U is

highly disturbed with Torvane undrained shear strengths

less than 0.1 kg/cm2 . Possibly this highly disturbed clay

is cuttings inadvertently left at the bottom of the bore-

hole. Some of the disturbance could also be caused by

tube friction during sampling as the clay near the tube

wall may become remolded as it travels up the tube.

(2) In Figure 4-3, the Orinoco Clay below letter U

is uniform in appearance and does- not contain voids.

Figure 4-2 indicates that between letters U to S the

Torvane undrained shear strength increases from 0.1 to

20.5 kg/cm2. Below letter S, the Torvane undrained shear

strength is constant at 0.5 kg/cm2 and this value is very

close to the Torvane strength obtained onboard the Fugro

ship.

50

(3) The Orinoco Clay between letters T-S appeared to

be of excellent quality when viewing Figure 4-3 and was

used for oedometer test No. 12 (oed-12). The oedometer

results indicated that the Orinoco Clay at this depth of

127.7 feet was underconsolidated (OCR = 0.56). The Torvane

undrained shear strengths obtained directly above the

oedometer specimen were considerably less than the Torvane

s value obtained onboard the Fugro ship (0.3 versus 0.48

kg/cm2). The lower Torvane su value of 0.3 kg/cm2 was

caused by sample disturbance and the clay specimen for the

oedometer test No. 12 was also disturbed resulting in a low

maximum past pressure and subsequent low OCR. A new

oedometer test was performed on a better quality specimen

(Oed-18, see Fig 4-2) and the results indicated a slightly

overconsolidated deposit (OCR = 1.15). In this instance,

only the radiograph was used to select oedometer test No.

12 specimen, yeti comparing the Torvane undrained shear

strength obtained above the oedometer specimen (TVoed)

to the Torvane strength obtained onboard the Fugro drilling

ship (TVboat would have provided an additional assurance

of a good quality specimen.

Sampling Tube ElS12, Gas Pockets

Figure 4-4 is a radiograph print of a 10 inch portion

of tube ElSl2 (depth = 37 to 40 feet). The white specks

dispersed throughout the print represent voids. The voids

51

probably. occurred- when air and -hyarogen sulfide gas (H2S)

came out of solution as the in situ confining pressure was

reduced to zero during retrieval of a sampling tube. As

the dark gray Orinoco Clay was extruded from tube ElSl2,

a pungent odor of rotten eggs assailed one's senses. The

clay was exceedingly soft, it was closer to a viscous liquid

than a solid, and it possessed negligible shear strength

(Torvane readings were zero).

Tubes ElS24 (depth = 113 to 116 feet), F1S54 (depth =

25 to 27 feet), and F1S55 (depth = 65 to 67 feet) had

similar looking radiographs that contained white specks

(voids). Upon extrusion from the sampling tubes, the

Orinoco Clay was highly disturbed with low Torvane strengths

and high natural water contents.

Sampling Tube ElS21, Horizontal Cracks

Figures 4-5a and 4-5b are radiograph prints of tube

ElS21 (depth = 98 to 100 feet). The Orinoco Clay at the

top of Figure 4-5a was disturbed with very low Torvane

undrained shear strengths. The bottom of Figure 4-5a

shows numerous horizontal cracks, probably the result of

gas coming out of solution. At the top of Figure 4-5b,

the horizontal cracks diminish in number with excellent

quality soil between letters E through I. Radiograph

prints can also reveal the type of soil structure, e.g.

in Figure 4-5b the clay has a slightly layered appearance.

52

Figures 4-5a and 4-5b clearly demonstrate the value

of using radiography to select zones of good quality soil

for laboratory tests. Only a small portion of the Orinoco

Clay within sampling tube ElS21 was suitable for the

sophisticated engineering tests. All the Orinoco Clay

above letter E was extruded and used for index tests, then

the good quality clay between letters E through I was

extruded and used for oedometer, triaxial, and CK0 UDSS

tests.

4-4 SUMMARY

Radiography is an invaluable tool that can be used to

detect those portions of soil within the sampling tubes

least likely to be disturbed and hence most suitable for

sophisticated laboratory tests such as oedometer and Direct

Simple Shear tests. The radiograph prints presented

within this chapter clearly show several important features:

(1) Zones of disturbed Orinoco Clay due to:

(a) possible cuttings inadvertently left at the bottom

of the borehole and/or highly remolded soil (Fig. 4-3),

and

(b) expansion of gas pockets as the gas comes out of

solution upon release of in situ confining pressures (Fig.

4-4).

(2) Zones containing horizontal cracks, presumably

caused by expanding gas (Fig. 4-5)

53

(3) Different soil structure; for example, very

uniform (bottom of Fig. 4-3) or slightly layered (middle

of Fig. 4-5b).

The radiograph prints clearly indicated the proportion

of "good-excellent" quality clay to that of disturbed soil.

Thus radiography enables the geotechnical engineer to locate

the best quality clay before extruding the soil from the

sampling tube. This aids in planning a soil testing program

and reduces the likelihood of performing meaningless labora-

tory tests on severely disturbed soil.

54

ALUMINUM RADIOGRAPH FILM

PLATES B

TUBE SAMPLE

X-RAYS

X-RAY HEAD

NOTE: TARGET AREASURROUNDED BY

LEAD SHIELDING

(a) ELEVATION VIEW

6 F

10 IN. RADIOGRAPH FILM

TUBESAMPLE

ALUMINUMPLATES

X-RAYS

EJ X-RAY HEAD

(b) PLAN VIEW NOT TO SCALE

FIGURE 4-1 RADIOGRAPHY OF A SAMPLING TUBE CONTAINIUG ORINOCOCLAY

.

MARKINGS

I TUBEw WAX

VOID

N

0 0

(I)

ENGINEERINGTESTS

NOTE:

(1) STRESSES IN kg/cm2

(2) EST. TVO= 2.40

(3) ONBOARD TV=0.48

UUc No. 4

su =0.14

WN=72.2 %

OED No. 12, wN= 6 4 .8 %

vm =1.35, CR=0.25

OED No. 18, WN= 6 6 .5 %

Ivm=2.75, CR=0.36

0su (kg/cm2)

0.1 0.2 0.3 0.4 0.5

z

FIGURE 4-2 OEDOMETER AND STRENGTH DATA ON SAMPLE FlS57 FOR COMPARISON WITH RADIOGRAPH-

127.01-

01-

wa

127.51-

128.0O

0 TORVANE

0 uuc

444

>00z

L,u,

FIGURE 4-3 SAMPLE F1S57: RADIOGRAPH PRINT SHOWING SAMPLE DISTURBANCE

(from Ladd, et al. 1980)

EU51M~

FIGURE 4-4 SAMPLE ElS12: RADIOGRAPH PRINT SHOWING GAS POCKETS


uL

FIGURE 4-5a SAMPLE ElS21: RADIOGRAPH PRINT SHOWING HORIZONTAL CRACKS


FIGURE 4-5b SAMPLE ElS21: RADIOGRAPH PRINT SHOWING HORIZONTAL CRACKS


60

5. STRESS HISTORY AND CONSOLIDATION PROPERTIES

5-1 INTRODUCTION: TEST PROCEDURES FOR OEDOMETER TESTS

Seventeen oedometer tests were performed on Orinoco

Clay specimens in the M.I.T. geotechnical laboratory,

five from boring El and twelve from boring Fl. The

procedures used for all oedometer tests are the same

as those described in Lambe (1951), except as noted

below:

(1) The oedometer tests were performed with a load

increment ratio equal to 1.0, except near the presumed

maximum past pressure where it was reduced to approximately

0.5 in order to better define the maximum curvature-of the

compression curve.

(2) The maximum past pressure was obtained by using*

Casagrande's method (Casagrande, 1936) for compression

curves based on vertical strain (Ev) versus vertical consol-

idation stress (7vc), where the vertical strains are those

corresponding to the end of primary consolidation (Ladd

1973). The load increments were applied for a time interval

of sufficient duration to enable the determination of the

end of primary consolidation.

Oedometer Orinoco Clay specimens were cylindrical,

2.5 inches in diameter and approximately 1.0 inch in height.

During testing, the clay specimens were continuously

surrounded by distilled water in the oedometer apparatus.

61

Some of the dissolved salt in the pore fluid of the clay

specimen will diffuse into this distilled water. To

investigate whether or not a change in the pore fluid

salt concentration will effect engineering properties,

two Atterberg Limits were performed on ElS15 clay specimens

where the liquid limit was 63% for an original specimen

having a pore fluid salt concentration of 29 grams/liter

and when the pore fluid salt concentration was diluted to

1 gram/liter, the liquid limit was essentially unaltered

(64%). Since a significant reduction in the pore fluid

salt concentration does not alter liquid limits, then the

small change in pore fluid salt concentration during an

oedometer test should not effect the result's.

Table 5-1 summarizes all oedometer results for boring

El and Table 5-2 for boring Fl. Both tables present the

following data:

(Column 1) Depth of oedometer specimen and sample

tube number.

(Column 2) Oedometer test number.

(Column 3) The natural water content and the Atterberg

Limits for each oedometer test as measured from test

specimen trimmings.

(Column 4) Two sample disturbance indices; TV(oed/boat)

is the ratio of Torvane undrained shear strength obtained

directly above the oedometer specimen to that recorded

onboard the Fugro ship during sampling operations, and also

62

the vertical strain (e ) during recompression to '

(Column 5) The in situ vertical effective stress ( vo)

using the equations presented in Table 3-1.

(Column 6) Best estimate (along with a range) of the

maximum past pressure determined by the Casagrande method.

(Column 7) Virgin compression ratio (CR), defined as

the slope of the vertical strain versus log consolidation

stress in the normally consolidated region. Swelling ratio

(SR), defined as the average slope, over one log cycle, of

the rebound curve starting from the maximum consolidation

stress.

(Column 8) Average coefficients of consolidation (c

determined from the dial reading versus log time and square

root time curves, in the normally consolidated region.

(Column 9) The rate of secondary compression (Ca

defined as the slope of the secondary compression line

from a log time curve, in the normally consolidated region.

(Column 10) An assessment of the quality of each

oedometer specimen (excellent, good, fair, or poor) based

on it's disturbance indices, TV(oed/boat) and Ev at avo'

and the general appearance of the compression curve (e.g.

sharp break at a , etc.).

5-2 EFFECTS OF SAMPLE DISTURBANCE

This section will discuss how sample disturbance

effects oedometer results by comparing Oed No. 12 and

63

Oed No. 18 (specimens from sampling tube F1S57). As

discussed in Chapter 4, Oed No. 12 was disturbed and had

significantly different engineering properties than Oed

No. 18, yet the clay specimens were within two inches of

each other (see Fig. 4-2). From Table 5-2, the ratio

TV(oed/boat) for Oed No. 12 is 0.63, while for Oed No. 18

the value is 1.06.

Figure 5-1 presents the compression curves and values

of the coefficient of consolidation for Oed No. 12 and

Oed No. 18. By comparing these two oedometer tests, we

can observe the effects of sample disturbance:

(1) An increase in the measured vertical strain for

disturbed specimens. The vertical strain during recom-

pression to -vo is 11.3% for Oed No. 12, but only 5.5%

for Oed No. 18.

(2) A reduction in the maximum past pressure for

. 1 - 2disturbed specimens. Oed No. 12 has a = 1.35 kg/cm2

2.while for Oed No. 18, F = 2.75 kg/cm2. Because a =

2.4 kg/cm2, the results of Oed No. 12 indicate an under-

consolidated clay deposit (OCR = 0.56) but the results

for Oed No. 18 indicate a slightly overconsolidated deposit

(OCR = 1.15).

(3) Sample disturbance caused a reduction in the

virgin compression ratio (CR). The value for CR is 0.245

for Oed No. 12 and 0.355 for Oed No. 18. Sample distur-

bance has caused a 30% reduction in the virgin compression

64

ratio.

(4) During recompression to %vo' the coefficient of

consolidation (c ) is less for disturbed specimens. At

2 -4 2avc = 0.75 kg/cm2, Oed No. 12 has a c = 3 x 10 cm2/sec,

-4 2but Oed No. 18 has a cv = 11.5 x 10 cm /sec. Sample

disturbance does not effect c. in the normally consolidated

region where both Oed Nos. 12 and 18 have cv = 2 x 104 cm2 /sec.

(5) Oed Nos. 12 and 18 have rebound curves that are

almost parallel. The swelling ratio (SR) was not altered

by sample disturbance.

It must be reemphasized that Oed No. 12 was disturbed

and this caused the significant difference in engineering

properties between Oed No. 12 and Oed No. 18. An excellent

quality specimen was used for Oed No. 18, and the results

of this test better represent the in situ soil properties

(e.g. - , CR, etc.).

Figure 5-2'presents the oedometer disturbance indices

TV(oed/boat) and ev at 'vo for all oedometer tests .performed

at M.I.T. As previously discussed, disturbed specimens

will have a TV(oed/boat) ratio less than 1.0, a high value

of ev at avo, and a low value of av with a subsequent low

OCR. In Figure 5-2, the undisturbed or slightly disturbed

specimens are open symbols (e.g. [, 0) and the disturbed

specimens are closed symbols (e.g.E,@0). The radiographs

enabled what appeared to be good quality specimens to be

chosen for oedometer tests, yet the disturbance indices

65

presented in Figure 5-2 indicate that 5 out of the 17

oedometer tests were performed on disturbed specimens.

5-3 STRESS HISTORY

Figure 5-3 (similar to Fig. 2-la) presents a plot of

in situ vertical effective stress (Fvo) versus depth for

borings El and Fl using the equations presented in Table

3-1. A specific gravity of 2.72, a degree of saturation

of 100%, and hydrostatic pore water pressures were used

to compute jvo at both borings El and Fl. The difference

between the two Ivo profiles is caused by the different

natural water contents at each site, e.g. at z = 40 feet,

wn = 54% at boring El and wn = 60% at boring Fl.

Maximum past pressure data from Tables 5-1 and 5-2

are also plotted in Figure 5-3. The open symbols for

borings El and Fl suggest that these deposits both have

the same maximum past pressure profile and the dashed

straight line is a reasonable linear fit through the data

points. Considering only the oedometer tests upon

excellent-good quality specimens, the overconsolidation

ratio is approximately 1.0 for boring El and 1.15 for

boring Fl. A normally consolidated deposit (OCR = 1.0)

is what would be expected for the offshore Orinoco Clay

since the mudline has always been below sea level and

the deposit has a recent depositional history. An

overconsolidation ratio of 1.15 at boring Fl is difficult

66

to explain since essentially the same geologic conditions

are believed to exist at both borings El and Fl. Since

boring Fl is exposed to larger ocean waves than boring

El (see Fig. 1-1), the very small amount of overconsolidation

could be caused by wave induced cyclic shear stresses

(Madsen, 1978). However, the author doubts that these

shear stresses could create a uniform OCR of 1.15. The

author has no rational explanation for the slightly over-

consolidated clay at boring Fl.

5-4 COMPRESSIBILITY AND COEFFICIENT OF CONSOLIDATION

Figure 5-4 presents the virgin compression ratio (CR),

swelling ratio (SR), and normally consolidated coefficient

of consolidation (c v) versus depth for borings El and Fl.

Considering only the excellent-good oedometer data, the

virgin compression ratio, swelling ratio, and coefficient

of consolidation have significantly different values above

than below z = 70 feet. Suggesting a distinct boundary

at z = 70 feet is only for convenience, since a transition

zone of engineering properties probably exists between

z = 60 to 80 feet.

Appendix A contains the laboratory data from consol-

idation tests and a summary of oedometer results is

presented in the following table:

67

STRESS HISTORY AND CONSOLIDATION PROPERTIES

Boring El Boring Fl

z<70 ft t z>70 ft z<70 ft I z>70 ft

Overconsolidation Normally Slightly

Ratio (OCR) Consolidated Overconsolidated

Virgin CompressioniriCor0.19 0.30 0.22 0.33

Ratio (CR)

SwellingRatin(R)0.03 0.05 0.04 0.08Ratio (SR)

N.C. Coefficient of

Consolidation 7x10 2x10 4 5x10 2x102

(c ) in cm /sec

As shown in the preceding table, the values of CR,

SR, and c v are almost identical at both borings El and

Fl but different above and below z = 70 feet. In Table

3-2, mineralogy data for boring Fl indicate considerably

more swelling minerals below z = 70 feet. The doubling

of the swelling ratio (SR = 0.04 versus 0.08) below

z = 70 feet is caused by the increase in swelling minerals.

Also, the author believes that the higher compressibility

(CR = 0.22 versus 0.33) and lower normally consolidated

coefficient of consolidation (cv = 5 x 10-4 versus 2 x 10-4

cm 2/sec) is caused by the increase in swelling minerals

below z = 70 feet.

-1

68

5-5 EMPIRICAL CORRELATIONS

Figures 5-5 and 5-6 compare data obtained from the

oedometer tests versus some empirical correlations published

in the literature: Nishida (1956), DM-7 (1971), and Terzaghi

and Peck (1967). There is considerable scatter in both

figures, but the data are distributed symmetrically above

and below the empirical correlations. Thus, the empirical

correlations derived for the most part from land based clays

are also applicable for the offshore Orinoco Clay.

5-5 SUMMARY

As shown in Figure 5-3, the Orinoco Clay at boring

El is normally consolidated (OCR = 1.0) and at boring

Fl it is slightly overconsolidated (OCR = 1.15). Similar

geologic conditions exist at both borings El and Fl which

suggests that both deposits should be normally consolidated.

The author has no rational explanation for the slightly

overconsolidated clay (OCR = 1.15) at boring Fl.

At both borings El and Fl, two distinct zones of

Orinoco Clay exist, one above and the other below z = 70

feet. The virgin compression ratio for the Orinoco Clay

above z = 70 feet is 0.19 at boring El and 0.22 at boring

Fl, while below z = 70 feet the Orinoco Clay is much more

compressible, CR equals 0.30 at boring El and 0.33 at

boring Fl. A considerable increase in the swelling

minerals is probably the cause of the different consol-

idation properties below z = 70 feet.

TABLE 5-1 SUMMARY OF OEDOMEIER TEST DATA: BORING El

All stresses in kg/cm2 (A) TESTS PERFORMED AT MIT

z(ft) Oed. WN WL TV(Wd/Boat) Est. 'Uvo Est. Uvm CR Normal Consolidated Remarks(Sample) Test No. PI LI (ev at 5 ) (Range) (SR) 6 (10~ cm /sec) Ca(Z)

55.7 1 48.1 58.0 1.75, 1.12 1.3 0.190 7.1510.15 0.55 Good(S15) 32.5 69.5 (6.50) (1.1-1.5) (RR-0.031)

83.3 2 63.1 74.0 0.94 1.74 1.6 0.260 3.0010.30 0.83 Poor(S18) 42.7 74 (10.50) (1.5-1.7) (RR-0.060)

99.3 3 52.7 64.8 1.14 2.08 2.2 0.300 2.95±0.05 0.94 Good(S21) 31.5 62 (6.50) (2.1-2.3) (RR=0.056 )

133.8 13 54.6 76.5 1.04 2.83 2.9 0.300 1.9010.40 1.04±0.35 Good(S27) 39.4 44 (6.40) (2.8-3.0) (0.053)

133.9 14 53.5 76.5 1.04 2.84 2.8 0.300 2.80±0.50 0.6010.07 Good(S27) 39.4 42 (6.40) (2.7-2.9) (0.051)

(B) TESTS PERFORMED AT CATHOLIC UNIVERSITY, CARACAS

75 56 70 1.56 1.35 0.32 0.60t0.20 - Fair(S16B) 41 66 (1.3-1.4) (0.038)

125.5 52 65 1.8 0.25 3.00±2.00. - Poor(S25C) 38 66 2.65 (1.7-1.9) (0.077)

145.5 55 73 3.11 3.0 0.30 5.001.00 - Fair(S29D) 40 55 (2.7-3.3) (0.046)

TABLE 5-2 SUMMARY OF OEDOMETER TEST DATA: BORING Fl

All stresses inrkg/cm 2

Normally Consolidatedz(ft) Oed. WN UL TV(Oed/Boat) Est. 4v Est.UVM CR Remarks

(Sample) Test No. PI LI (ev at -a.) (Range) (SR) Cv(10:4cm2/s1ec) Ca(Z)

27.2 5 63.5 81.8 1.27 0.46 0.55 0.205 4.7310.95 0.55±0.10 Good(S9) 46.6 61 (4.2) (0.45-0.65) (0.035)

36.6 9 63.3 80.0 1.43 0.64 0.75 0.230 5.43±1.09 0.67±0.03 Excellent(S12) 43.7 62 (4.8) (0.70-0.80) (0.045)

51.6 11 66.2 96.5 0.75 0.93 1.00 0.245 5.18±1.36 0.53±0.11 Fair(S15) 57.5 47 (5.3) (0.90-1.10) (0.055)

66.7 4 64.1 80.7 1.09 1.22 1.50 0.305 4.73±0.96 0.54±0.08 Excellent(s18) 47.9 65 (6.4) (1.40-1.60) (0.060)

81.5 8 67.0 104 1.07 1.50 1.85 0.315 4.00±0.55 0.89±0.08 Good,"Platy"(S21) 64.9 43 (8.0) (1.70-2.00) (0.075) Structure

96.3 6 62.5 87.5 1.06 1.79 2.40 0.255 7.10±2.22 0.5310.13 Excellent(S24) 51.2 51 (5.1) (2.30-2.50) (0.060) 'Platy"Struc.

111.4 10 66.5 90 0.82 2.08 2.00 0.310 3.10±0.75 0.75±0.05 Poor(S27) 48.3 51 (6.3) (1.90-2.10) (0.070)

111.8 17 68.3 93.0 1.22 2.09 2.20 0.325 3.50±0.45 1.0010.24 Good(S27) 56.4 56 (5.2) (2.10-2.30) (0.080)

126.2 7 59.8 101.8 0.68 2.37 1.60 0.260 2.33±0.51 0.75±0.11 Poor(S30) 67.8 38 (11.3) (1.50-1.70) (0.090)

126.5 16 65.0 96.0 0.97 2.37 2.80 0.330 2.55±0.35 0.820.03 Excell.-good(S30) 55.4 44 (4.9) (2.70-2.90) (RR=0.075)

127.8 12 64.8 99.0 0.63 2.40 1.35 0.245 2.15±0.13 0.84±0.15 Poor(S57) 57.1 40 (11.3) (1.25-1.45) (0.085)

128.0 18 66.5 99.0 1.06 2.40.- 2.75 0.355 2.08±0.48 1.0510.18 Excell.-good(S57) 57.1 43 (5.5) (2.65-2.85) (0.0900)

.40

71

5 __ _vm m2.75

10

15

20

SYM. TEST wN TVNo. (%) (TSF)

0 is 66.5 0.51

0 12 64.8 0.30

0.1 0.2 0.2 5 10

12 1~- bi1

18 -8

0.5 1 2 5 100.1 0.2

CONSOLIDATION STRESS, Tc (kg/cm2 )

EFFECTS OF DISTURBANCE ON OEDOMETER TESTSAMPLE F1 S57

.

U,

20

c-

0C(nz0u

0

z

w0uL

E

00)c*E

FIGURE 5-1 DATA:

TV (OED)/(BOAT) E6 (%) AT Mo OCR a (m 1T.o0.4 0.6 0.8

01 1 11.0 1.2 1.4 1.6

cu

0

400

60 -

0

0-

0100 - -- --- --

* 0

120 -

0(2 TESTS)

1.75

0 2 4 6 8 10 1214 .4 0.6 0.8 1.0 1.2I I I

1.4 1.6

FIGURE 5-2 OEDOMETER TEST DISTURBANCE INDICES: ORINOCO CLAY

(-

BORING EXCELLr FAIR-GOOD POOR

El 0 UFl 0 __

0

0

0

0

- ----- -

00

o T0(2 TESTS)

I I I I

- -- -~ -0

0

0

00

@0

- -

-4Is.)

0.5 1.0(r.0 AND Tvm (kg /cm?)

1.5 2.0 2.5 3.0 3.5 4.0

BORING TEST EXCELL- FAIR-BY GOOD POORcu _ _

20 MIT 0 U

4 0F l M IT 0 _ _ _

40

60

_ _O(FI)

100

120

140

o (E1)

I I

STRESS HISTORY: ORINOCO CLAY

0

3-

a.0

FIGURE 5-3

020CR= Cc/(1+e)

025 0.30 0.35 0.40 4

BORING EXCELL7 FAIR-GOOD POOR

El 0 U20 -- ----- -

Ft 0 .

40 - - - -

VF60

80 --

N%

0--+

- 0 0._00 __

120 __1 t -- 'I___0 0

~JJ0

a4 1~ - II

nSRa C /(I+e)

005C, (10

4 cm/sec)0.J0 0 5 10

NOTE: AVE. FROM -AND LOG t METHODS

- IN N.C. RANGE

0

0

0

0

00---

- 0 .

04

COMPRESSIBILITY AND COEFFICIENT OF CONSOLIDATION: ORINOCO CLAY

C

-.1

-0----1

FIGURE 5-4

75

0.6

0.5

O3 0.4

z 0.30*vi

w

0

20.2

0

FIGURE 5-5 EMPIRICAL CORRELATIONS WITH NATURAL WATER CONTENT:ORINOCO CLAY

BORING EXCELL.- FAIR-GOOD POOR

El 0 a

- Ft 0

0

NISHIDA (1956)

uw

0

20 40 60 80 100 120 140 160

NATURAL WATER CONTENT, wN (%)

76

0

E

U:

'O

0

-J0

z

0

wc-

a.

0

0

FIGURE 5-6

LIQUID LIMIT, WL ()

EMPIRICAL CORRELATIONS WITH LIQUID LIMIT:ORINOCO CLAY

DM-7 (1971)

80

0 0

00

2 0uDO

50 60 70 80 90 100 110 120

BORING EXCELL.- FAIR -

GOOD POOR

El 0 a TERZAGHI AND PECK (1967)

F 0 0

0.8

0.6

D.450 60 70 80 90 too I10 120

77

6. NORMALIZED SOIL PROPERTIES AND SHANSEP STRENGTH PROFILES

Stress history results showed that both borings El and

F1 have an identical and well defined maximum past pressure

profile (Fig. 5-3). Because the Orinoco Clay is normally

consolidated at boring El (OCR = 1.0) and only very slightly

overconsolidated at boring Fl (OCR = 1.15),.the CK0 U Direct

Simple Shear testing program first concentrated on obtaining

the normalized soil properties (NSP) for normally consolidated

Orinoco Clay. Overconsolidated CK0U Direct Simple Shear

results will be presented next, followed by a brief discussion

of how anisotropy effects undrained strength, and then this

chapter will be concluded by comparing the SHANSEP su profile

and TV, LV, and UUC data.

6-1 NSP FROM NORMALLY CONSOLIDATED CKIUDSS TESTS0

The Direct Simple Shear apparatus was built by Geonor

and a description of the device was published by Bjerrum

and Landva (1966). The test procedures used for all CKIUDSS

tests are the same as those presented in Appendix B of Ladd

and Edgers (1972), but using cylindrical Orinoco Clay

specimens having an area of 35 cm2 and a height of about

2.5 centimeters.

A CK0 UDSS test has two parts: consolidation and shearing.

(1) In the consolidation portion, the clay specimens

were one-dimensionally (K0) consolidated beyond the in situ

78

maximum past pressure and into the normally consolidated

region in accordance with the SHANSEP technique. To assess

the quality of a clay specimen, a compression curve can be

drawn to determine the vertical strain (e ) during recom-

pression to -a and the maximum past pressure by Casagrande'svo

method. These "disturbance indices" (Fig. 6-1) will be

compared with oedometer disturbance indices (Fig. 5-2).

(2) The shearing portion consists of shearing the clay

specimen along a horizontal plane at a strain rate of about

4% of the specimen height per hour while varying the effective

stress (a ) to maintain a constant height and hence constantv

volume. The failure plane is assumed to be horizontal and

the maximum value of the applied horizontal shear stress

(Thmax) is equal to the undrained shear strength.

Nine normally consolidated CK UDSS tests were performed,

three upon boring El specimens and six from boring Fl. By

using the radiographs, the very best quality Orinoco Clay

specimens were selected for these CKQUDSS strength tests

and all TV(DSS/boat) ratios are equal to or greater than

1.0 (Fig. 6-1). For some CK UDSS tests, a was only

slightly greater than the in situ FvM, which made it

difficult to determine the virgin compression curve and

hence am by Casagrande's method.

Figures 6-2, 6-3, and 6-4 present data from the

shearing portion of the normally consolidated CKQUDSS

strength tests, which are discussed in the following

79

subsections.

a) Normalized Stress Paths

The stress paths in Figure. 6-2 are plots of the stresses

(Thand v) on the horizontal plane normalized by dividing

them by the preshear a. At the start of shearing, a

equals vc and Th equals zero and thus all normalized stress

paths start at Ev vc = 1.0 and Th Vc = 0.0. As the hori-

zontal shearing force is applied to the clay specimen,

deformation occurs, av decreases until Thmax is reached,

and then both Th and Ev decrease due to strain softening.

The normalized stress paths fall into two groups,

those for clay specimens above (open symbols: &,0, etc.)

and below z = 70 ft (closed symbols: A,E , etc.). Notice

that for specimens below z = 70 ft, there is a lower

normalized undrained shear strength (s /1 = 0.20) and

a lower friction angle at maximum obliquity (T = 200).

b) Normalized Stress-strain Curves

As illustrated in Figure 6-3, the normalized stress-

strain curves fall into two groups, above and below z =

70 ft. As stated in Chapter 2, normalized behavior means

that laboratory strength tests on clay specimens having

the same overconsolidation ratio will have similar norm-

alized stress-strain curves and identical values of s /avc

independent of the magnitude of E and vm. CK UDSSvc v

80

Test Nos. 2 and 3 from boring El at z = 56 ft have the

same in situ maximum past pressure but Test No. 2 has a

preshear i = 2.26 kg/cm2 while Test No. 3 has a preshearvC2

avc = 4.57 kg/cm , yet these tests have identical normalized

stress-strain curves. Similarly, CK 0 UDSS Test Nos. 10, 8,

and 9 were performed on clay specimens below z = 70 ft at

boring F1 having different in situ maximum past pressure

and preshear - values but identical normalized stress-vc

strain curves. Although there is some scatter (e.g.

compare Test Nos. 12 and 6), generally at both borings

above and below z = 70 ft there are unique normally con-

solidated normalized stress-strain curves irrespective

of the in situ maximum past pressure and Evc and therefore

the Orinoco Clay exhibits normalized behavior.

The normalized stress-strain curves indicate that all

CK0 UDSS tests have a large strain (yf = 11 + 4%) before

reaching the undrained shear strength. Beyond Thmax,

most stress-strain curves remain relatively horizontal up

to about 18% strain.

c) Secant Moduli Data

Figure 6-4 presents a plot of secant values of E /su u

versus the applied shear stress level Th/s u The normal-

ized moduli are slightly higher for those DSS tests run

on specimens above z = 70 ft. The Orinoco Clay (P.I. =

35 to 55%) moduli data plot between Boston Blue Clay and

81

EABPL clay results.

The data presented in Figures 6-2, 6-3, and 6-4 are

summarized in Table 6-1 and in the table below:

Normalized Soil Properties From CK UDSS Tests on N.C.Orinoco Clay 0

Boring El Boring Fl

z<70 ft z>70 ft z<70 ft z>70 ft

su a 0.23 0.19 0.24 0.20

260 200 260 200rn.o.

E /S 340 215 290 + 20 270 + 40so u - -

As discussed in Chapter 5, the compressibility and

swelling ratio increase below z = 70 ft. The reason for

the difference in consolidation properties is an increase

in the amount of swelling minerals below z = 70 ft, which

is probably also the reason for the reduction in both i

at maximum obliquity and su vc

Figure 6-5 presents a comparison of su /vc from CK0 UDSS

tests upon normally consolidated Orinoco Clay and other CL

and CH clays [Ladd and Edgers (1972) and Ladd et al., (1977)].

The Orinoco Clay data above z = 70 ft fit in well with

published test results but the data below z = 70 ft are

lower than other CH clays. As mentioned, the considerable

increase in swelling minerals below z = 70 ft is probably

part of the reason for this unusual behavior.

82

6-2 OVERCONSOLIDATED CK 0UDSS TEST DATA

To obtain overconsolidated CK UDSS strength data,0

Orinoco Clay specimens were K consolidated in a Direct

Simple Shear apparatus into the normally consolidated

region, then unloaded (allowed to swell) and then sheared

to obtain the normalized undrained shear strength at varying

overconsolidation ratios such as OCR = 2, 4, and 8. Six

CK 0 UDSS tests were performed on Orinoco Clay specimens, all

at depths greater than z = 70 ft. The results are summarized

in Table 6-2.

Normalized undrained shear strength (s / vc) versus

overconsolidation ratio (OCR) data from the six CK0UDSS

tests are presented in Figure 6-6. Several important

conclusions are evident from this figure:

(1) For the Orinoco Clay below z = 70 ft, the s /au vc

versus OCR relationship plots very close to that of Boston

Blue Clay.

(2) CK 0 UDSS Test No. 5 was performed upon a very

disturbed Orinoco Clay specimen resulting in a high value

of s /7vc (0.383). Therefore, consolidating highly disturbed

Orinoco Clay specimens well into the normally consolidated

region does not necessarily restore the in situ soil

structure.

(3) CK0 UDSS Test No. 7 was consolidated to Evo rather

than using the SEANSEP consolidation technique. The higher

s /c value (0.276) was probably caused by the decrease inu vc

83

water content during recompression to avo'

The Orinoco Clay s versus OCR relationship plottedU VC

in Figure 6-6 can be expressed mathematically as:

su vc = (0.20) (OCR) 0.72 (Orinoco Clay, z>70 ft) .... 1

No overconsolidated CK0 UDSS test were performed upon

specimens above z = 70 ft, but it has been stated (Atkinson

and Bransby, 1978) that equation 1 can be approximated

without performing overconsolidated tests. Knowing s_______U/ vc

for normally consolidated clay and the consolidation

parameters CR and SR, then:

s / = (su 1/a for N.C. clay) (OCR) (1 - SR/CR)u vc vc *..2

Above z = 70 ft at boring Fl, s /Uv = 0.24 foru c

normally consolidated clay, SR = 0.04, and CR = 0.22.

Substituting these values into equation 2, the relationship

is:

su/ivc = (0.24) (OCR) 0.82 (for Orinoco Clay at boring 3Fl, z<70 ft) 3

Normally consolidated and overconsolidated CK0UDSS

laboratory data are presented in Appendix B.

6-3 ANISOTROPY

This section is presented to illustrate the effects

of anisotropy upon F1S57 clay specimens. Table 6-3

84

summarizes the results of one CK 0 UE and three CK0 UC tests.

The stress paths, stress strain curves and other laboratory

data are presented in Appendix C.

Test Nos. TEl, TC4, and CK UDSS No. 9 were all performed0

upon excellent quality normally consolidated F1S57 clay

specimens and sheared at about the same strain rate. Since

these tests do not suffer from sample disturbance nor strain

rate differences, we can observe the effects of anisotropy

by comparing these three tests.

Anisotropy Effects* **

Test Test No. s/U CY f E5 0/s U M.O.

CK0 UC TC4 00 0.23 3.4 390 270

CK UDSS No. 9 30-600 0.20 12.5 225 200

CKOUE TEl 9o0 0.16 9+ 130 270?

As shown by the above table, the Orinoco Clay exhibits

a stress-strain-strength behavior that depends on the

applied stress system and the rotation of principal stresses.

The strength from the CKQUC test is an upper bound strength

* 6= angle between the major principal stress directionat failure and the vertical direction.

su= 0.05(at-t-a3)Cs for triaxial tests and s = Thmaxfor DSS :te-zts.

85

due to the vertical loading with no rotation of principal

stresses. The strength from the CK0 UE test is- a iowor bound

strength due to anisotropy and increased pore pressures

caused by a 90 degree rotation of principal stresses with

a2 = a3 at the start of shearing and a1 a2 at the end

of shearing. The CK0 UDSS test has an s u/E1,c value that is

the average of the CKIUC and CK UE results and this "average"

strength is deemed most appropiate for bearing capacity and

stability analyses. --

6-4 SHANSEP STRENGTH PROFILES

a) Boring El

Fugro TV, LV, and UUC strength data (from Fig. 3-1);

TV data recorded in the M.I.T. geotechnical laboratory;

and the SHANSEP undrained shear strength profile are

presented in Figure 6-7. The SHANSEP s profile was

obtained from the following data:

(1) Stress History:

As shown in Figure 5-3, the in situ vertical effective

stress is about equal to the maximum past pressure deter-

mined from oedometer tests. The Orinoco Clay at boring El

is normally consolidated (OCR = 1.0).

(2) Normalized Undrained Shear Strength:

From laboratory CK0 UDSS strength tests upon normally

consolidated specimens:

86

From 0 to 60 feet, s / = 0.23

From 80 to 140 feet, s 0/vc = 0.19

As previously discussed, the engineering properties

do not have an abrupt change at z = 70 ft and a transition

zone in engineering properties probably exists between

z = 60 to 80 ft. A linear transition in the SHANSEP

strength profile was used between z = 60 to 80 ft. The

table below (similar to Fig. 2-1c) presents some repres-

2entative calculations (stresses in kg/cm ):

SHANSEP DSS Strength Profile (Boring El)

Depth (ft) o OCR su savo ujv UFvc u

20 0.40 0.40 1.0 0.23 0.09

60 1.22 1.25 1.0 0.23 0.28

80 1.67 1.69 1.0 0.19 0.32

140 2.97 3.02 1.0 0.19 0.56

In Figure 6-7 above z = 60 ft, most undrained shear

strength data from TV, LV, and UUC tests are less than

the SHANSEP strength profile because the sampling tubes

were hammered, resulting in increased sample disturbance

and lower values of su. Below z = 60 ft, almost all the

LV and UUC data are greater than the SHANSEP strength

profile. This is because the sampling tubes were pushed

into the soil strata using Fugro's "WIP" sampling

87

equipment resulting in much less sample disturbance with

higher LV and UUC data due to strain rate effects and

anisotropy.

b) Boring Fl

In Figure 6-8, two SHANSEP undrained shear strength

profiles are presented. The lower SHANSEP profile was

obtained from the following data:

(1) Stress History:

The Orinoco Clay at boring Fl was assumed to be

normally consolidated (OCR = 1.0).

(2) Normalized Undrained Shear Strength:

From laboratory CK UDSS strength tests upon normally

consolidated specimens:

From 0 to 60 feet, s /_c= 0.24t~vc

From 80 to 140 feet, s / c = 0.20

with a linear transition between z = 60 to 80 feet. The

table below presents some representative calculations

(stresses in kg/cm 2

Lower Bound SHANSEP Strength Profile (Boring Fl)

Depth (ft) avo OCR su vc su

20 0.34 1.0 0.24 0.08

60 1.09 1.0 0.24 0.26

80 1.47 1.0 0.20 0.29

140 2.63 1.0 0.20 0.53

88

The upper SHANSEP strength profile (Fig. 6-8) corres-

ponds to an OCR = 1.15. This su profile was computed by

substituting OCR = 1.15 into equations 1 and 3 to obtain

s /3 = 0.27 for Orinoco Clay above z = 60 ft and su /vc

0.22 for Orinoco Clay below z = 80 ft. However, since the

reason for the slight overconsolidation (OCR = 1.15) at

boring Fl is unknown, the author recommends using the

lower SHANSEP strength profile for stability and bearing

capacity analyses.

From z = 20 to 40 ft (hammered samplers), most TV, LV,

and UUC data are below the SHANSEP strength profiles. Even

though below z = 40 ft better quality specimens were obtained

because of pushed samplers, about half of the LV and UUC

results plot below the SHANSEP strength profiles, probably

because these tests were performed on more disturbed

specimens resulting in lower su values.

c) Comparision Between SHANSEP Strength Profiles at BoringsEl and Fl

Comparing the SHANSEP profiles at borings El and Fl,

the SHANSEP profile in Figure 6-7 plots midway between the

two SHANSEP profiles in Figure 6-8. Hence, borings El and

Fl have very similar undrained shear strength profiles.

But by comparing only TV, LV, and UUC data (e.g. compare

Fig. 3-1 and 3-2) this important conclusion is not so evident

due to the very large scatter in the results of these

89

conventional strength tests. Thus, because the SHANSEP

method has considered the effects due to sample disturbance,

strain rate differences and anisotropy, more reliable su

profiles were obtained by this procedure, which also

indicated that both borings El and Fl have an almost

identical undrained shear strength versus depth.

TABLE 6-1 SUMMARY OF CK UDSS TEST DATA: N.C. ORINOCO CLAY

All stresses in kg/cm2

- - At Maximum Th At Maximum ObliquityZf Test UP Eat. c at0 0 T a 17Tz(ft) WN(%) vo vo vc h v o E50 h 00 Remarks

No. _(1) Y _1 Y(Boring) oample) PI(Z) Est. U £ at v te(day) ) aa a U M

(L (9) 46.6 0.4 13.2 0.99 10.9 0.238 0.576 22.5 275 27 0.170 27.7 I FAI )

36.8 6 61.0 0.64 3.1 2.02 EXCELLENT(Fl) (S12) 43.7 0.74 15.2 0.91 15.2 0.243 0.599 22.1 270 27.5 0.193 25.0 . ( E Z. 0.82) (2 )

55.8 2 45.0 1.13 11.6 0.226 0.576 21.4 340 30 0.173 26.9 D )

(E) (sS5) 33 0 1.16 1.7 1.7 11.6 0.229 0.593 21.1 340 32 0.165 26.2 GD 3)(2)(El) 0S15) 33.0 1.16 21.2 0.98 142 029059 11 30 32 0152.

67.6 18) 45.9 1.2 9.3 .86 7.3 0.240 0.635 20.7 310 23 0.114 24.7 FAIR

(F) (s1) 9 1.74 125.0 2.86 10.7 0.204 0.603 18.7 260 25.7 0.110 21.3 VEY 1GO.5 (2)

96.5 8 61.0 1.79 6.0 4.98 2nd shear(Fl) (S24) 48.9 2.06 15.7 1.66 8.1 0.200 0.666 16.7 310 22 0.145 19.3 of No. 7

128.1 9 65.6 2.40 5.2 2.86 12.5 0.204 0.607 18.6 225 27 0.098 20.1 EXCELLENT(Fl) (S57) 57.1 2.78 8.2 1.07

14 .13 51.8 2.84 8.0 13 0.193 0.605 17.7 215 25 0.098 18.7 GOOD(El) (S27) 39.4 2.90 14.7 0.99

(1) from dashed line in Fig. 5-3

(2) estimated from CK UDSS test

0

SUMMARY OF CK UDSS TEST DATA; 0,C. ORTNOCO CLAY

All stresses In kg/cm 2

At Maximum h At Maximum ObliquityTest wN(%) Est. £vo y at vo -y Th E50 l h h

z(ft) No. vm oo_5(Boring) (Sample) PI(%) Est. c £ at 5 (OCR) (%) a s (%) a Remarks

vm v vc vc vc u VC v

96.5 7 61.0 1.79 6.0 1.72 Recompression

(1) 2.40 (Est) 5.3 0.276 0.709 470 Not Reached to aIO(F) (S24) 48.9 2.40 6.0 (1.4 Est) t C 0.84 days

98.8 5 60.2 2.07 16.3 2.02 Poor sample

2)12.0 0.383 1.018 280 28 0.23 0.42 (a .)3(El) (S21) 42.8 2.11(2) 21.4 4.00 1 = 2.dy

._(1.98) __c = 2.1 days

99.8 4 57.0 2.10 8.5 2.50 Fair sample

14.6 0.337 0.986 180 21 0.32 0.36 (5 z 2.0)(3)

(El) (S21) 32.0 2.13(2) 19.1 5.00t - 0.31 days______(2.00) 0.1dy

128.3 16 62.9 2.41 9.3 2.29 Fair sample(3 )

(2) 11.0 0.328 1.073 190 19 0.31 0.32 (a ::: 1.7)(Fl) (557) 63.4 2.77(2 16.4 4.55 t = 3.0 days

(1.99) t_=.da

128.9 17 64.2 2.42 8.5 1.16 Fair sample

(Fl) (S57) 61.0 2.78(2) 13.5 16.3 0.545 1.348 125 18 0.54 0.41 (a vM 1.9/3)F7 . 23 4.9'1)t - 1.0 days

(3.91) c

129.1 18 62.9 2.42 6.7 0.59 Excellent saple

(Fl (57) 545 278(2) 9. .3 15.2 0.875 1.829 80 17 0.86 0,49 (a-vM -: 2.5)(3)

(Fl) (S57) 54.5 2.78 9.4 4.53 t = 1.0 days(7.70) t _ = 1.0 c

(1) Based on test No. Oed-6(2) From dashed line in Fig. 5-3(3) Estimated from CK UDSS test

H

TABLE 6r-2

TABLE 6-3 SUIVARY OF CK U TRIAXIAL TEST DATA: N.C. ORINOCO CLAY

All stresses in kg/an2

At Maximum q At maximum Obliquity

z (ft) Test w,(%) Est. Gvo E at a0vo vc q Eso q Remarks

(Boring) (Sample) PI(%) Est. ; (1 E at 5 K ( ) 0 5 (%) ainn vc vc C vC vc U VC

99.1 TC3 57.4 2.08 7.0 3.52 Good SampleLarge Au at

4.8 0.269 0.621 25.7 410 13 0.257 27.1 start of shec

tc - 2.8 days(El) (S21) 39.0 2.11 14.6 0.625

99.5 TC2 51.5 2.09 6.0 3.48Good Sample

6.2 0.277 0.617 26.7 300 NOT REACHED tc - 2.7 days

(El) (S21) 31.5 2.13 12.7 0.61

128.7 TEl 60.1 2.41 2.5 3.01

(2)6.2 0.175 0.510 20.1 130 NOT REACHED t = 2.2 days

C

(Fl) (S57) 57.1 2.77 4.1 0.60

129.3 TC4 61.8 2.43 3.7 2.90 NOT ACCURATE. Excellent sample

2.6 0.260 0.715 21.3 390 FAILURE PLANE t - 1.7 daysDEVELOPED AT

(Fl) (s57) 51.9 2.79 5.7 0.60 c - 2 to 3%

'.0I,.j

(1) From dashed line in Fig. 5-3 (2) Extent of reliable data

TV (DSS)/(BOAT)0.4 0.6 0.8 1.0 1.2 1.4 1.6

20

0

40

0

80- 0

100300 -- - - - - - - --

120

140 --

ev (%) AT Mvo OCR a im /do0 2 4 6 8 10 1214 0.4 0.6 0.8 1.0 1.2 1.4 1.6

2,5

CK UDSS TEST DISTURBANCE INDICESs ORINOCO CLAY

3-

La-w.

BORING EXCELL.- FAIR-GOOD POOR

El 0 U

00

03

0

0

0

- - - - - -- - - -- -

FIGURE 6- I1

- ~1~~ ~ -

0

0

0

-U- -

'.0U)

1(t) TEST SYM. BORING ww Pi

No. (%) (%)

27.5 12 a Fl 62.5 46.6

36.8 6 0 Fl 61.0 43.755.8 2 0 El 45.0 33.056.0 3 0 El 47.0 33.067.6' I v F1 59.4 47.982.0 10 A Fl 59.2 43.996.5 8 a FI 61.0 48.9128.0 9 * FI 65.6 57.1134.0 13 0 El_ 51.8 39.4

n 4 1

0.1 0.2 0.3 0.4 0.5

rv / fvc

0.6 0.7 0.8 0.9 1.0

FIGURE 6- 2 NORMALIZED STRESS PATHS FROM CK UDSS TESTS: h.C. ORINOCO CLAY

0.3

Th

oVcO.2

0.1

0

26'

ENVELOPES AT MAXIMUM OBLIQUITY

I I

0.30 -rn - u -V r mm, injinp w

5 i t k I-- I 1

0a-~o--

ZIrZIIF~~Iz (ft) TEST SYM. BORING WN P1

No. 4%) 4%)

27.5 12 A Fl 62.5 46.6

0 - 36.8 6 0 Fl 61.0 43.7 -

55.8 2 0 El 45.0 330

560 3 0 El 470 33.0676 I V I Fl 594 47.9

5 820 10 A Fl 59.2 439- 6. 8 Fl 6[0 48.9

128.0 9 0 Fl 65.6 57.1

134.0 13 1E 5.8 39.4-

a 4 6

-a--

8 10 12 14 16 Is 20

SHEAR STRAIN, y (%)

FIGURE 6-3 NORMALIZED STRESS VERSUS STRAIN FROft CK UDSS TESTS: N.C. ORINOCO CLAY

0.

00.2Th

ov c0.

0.1

0.0

ti'.0

0

0.3C

.0--

R5 -Jjpv-

96

134.0 13 El 51.8 39.4

N

_________ 4 t

(PI=21 %)7

200

100

IF____SP ____ ____ 10.2 0.4 0.6 0.8

0 BC

Lo

Th/su

FIGURE 6- 4 NORMALIZED UNDRAINED MODULUS FOR CKUDSS TESTS:.N.C. ORINOCO CLAY *

z (ft) TEST SYM. BORING w " P,No. (%) (%)

27.5 12 a F1 62.5 46.636.8 6 3 Fl 61.0 43.7

55.8 2 o El 45.0 33.056.0 3 0 El 47.0 33.0

67.6 11 7 Fl 59.4 47.9

82.0 10 A Fl 59.2 43.9

96.5 8 I F1 61.0 48.9128.0 9 Fl 65.6 57.1

1000

800

400

0

so0

afnL- I I

I I

17

0.35 1

0.30 w

0

0.250

000

0.20 - - _-

0.15 -0 FROM LADD 8 EDGERS (1972)AND LADD ET AL. (1977)

i < 7d ORINOCOx z>70 J CLAY

0.101 1_ _ .. 1__._.0 20 40 1 60 80 100

PLASTICITY INDEX, PI (%)

Fu /v- VERSUS PI FOR NORMALLY CONSOLIDATED CL AND CH CLAYS

C)

lbN1I.

I

FIGURE 6-5.

98

ORINOCO CLAY

DEPTH N.C. O.C.

z<70' -

z >70'

,1

/I,

/'I,

(0.200) (OCR) 0 .7 2

(2 TESTS)

RECOMPRESSION TO y

I-

2

OCR a rm/rc

4

Me. ORGANIC(P1=34%)

EABPL(P1=75 %10)

BBC(PIZ21 %)ORINOCO

CLAY

6 8

FQURE 6-6 EFFECT OF OCR ON Su /vc

1.61

1.4

12

o -0

W.

0.'

0

W.

I

0UNDRAINED SHEAR STRENGTH, su (TSF, kg/cmt)

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.6 0.9 1.0

X LEGEND

FUGRO: LAB VANE *20 ------ - - -_ -- TORVANE X

SUUc 0

0 MIT: TORVANE +40 -- - -_-- - - - - - - -_-- -_ - -

4 x SHANSEP DSS

a FROM tvm PROFILE (OCRaI.0)X 0 ++

60 - -- -- - - --- ----

WIP X) 00SAMPLES

80+ ++ + 6

x D0100 -- -

x 0+ x x 0

120 -

+ x 0141

COMPARISON OF UNDRAINED STRENGTH DATA: BORING El

IIIIin

FIGURE 6 - 7

UNDRAINED SHEAR STRENGTH, Su (TSF, kg/cma)0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

- -

LEGEND

FUGRO: LAB VANE 020 - TORVANE X

Xix + UuC 0

40 meA_ + MIT: TORVANE +T p SHANSEP DSSSAMPLES

+ + +60 c0\

4f1+ X + (0: +X C0 FROM im PROFILE (OCR 1. 15)

so

MINIMUM FOR N.C. CLAY (OCRaI)X

100 -- -

04 - x+ +

X0

+. + + X 0

140L-

FIGURE 6-8 COMPARISON OF UNDRAINED STRENGTH DATA: BORING Fl

0

X-

1-

H0303

09 1

101

7. SUMMARY AND CONCLUSIONS

The Orinoco Clay is a thick deposit (30-40m) of soft,

highly plastic CH-OH soil encountered throughout vast areas

of the Gulf of Paria and the Orinoco Delta. Undisturbed

tube samples of Orinoco Clay obtained from borings El (Gulf of

Paria) and Fl (Orinoco Delta) were utilized for laboratory

soil tests in order to determine their engineering properties,

and a major objective of this thesis has been to present

the results of those tests. The engineering properties of

the Orinoco Clay are needed for the design of oil platforms

to be built in offshore Venezuela.

(a) Results of Classification Tests and Composition

Analyses

The Orinoco Clay at boring El is classified as

a CH Clay and has a P.I. between 25 to 45%, whereas the clay

at boring Fl is classified as a CH to CH-OH clay with a P.I.

between 40 to 65%. Table 7-1 summarizes the plasticity

index and natural water content data.

Mineralogy results indicate that the Orinoco Clay at

borings El and Fl has the same basic composition, the prin-

cipal clay minerals being kaolinite, illite, and swelling

minerals (smectite). The rest of the soil consists of

quartz, mica, and weathered feldspar grains with small

amounts of carbonates and organic matter (about 2%).

102

b) Radiography

Sampling tubes containing Orinoco Clay were

radiographed and the radiograph prints detected the pres-

ence of gas pockets, cracks, zones of disturbed soil, and

different soil structures. The radiograph prints clearly

indicated the proportion of "good-excellent" quality clay

to that of disturbed soil. Thus radiography was an

invaluable tool used to locate the best quality Orinoco

Clay specimens before extruding the soil for sophisticated

laboratory tests such as oedometer and CK UDSS tests.

c) Stress History and Consolidation Properties

The results of seventeen oedometer tests showed

that borings El and Fl both had an identical and well

defined maximum past pressure. But due to different natural

water contents, the computed in situ vertical effective

stress assuming hydrostatic pore pressures and 100% saturation

is less at boring Fl. At boring El, the in situ vertical

effective stress is about equal to the maximum past pressure

and thus the Orinoco Clay at this location is normally

consolidated (OCR = 1.0). At boring Fl, the deposit is

slightly overconsolidated, OCR = 1.15 (see Fig. 5-3),

perhaps caused by wave action,

The consolidation properties (i.e. CR, SR, c ) are

very similar at both borings, but with different values

above and below z = 70 ft. Below z = 70 ft, the Orinoco

Clay is more compressible, probably caused by a significant

103

increase in content of swelling minerals.

d) SHANSEP Stress-Strain-Strength Parameters

The SHANSEP strength testing program concentrated

on obtaining normalized stress-strain-strength properties

from CK UDSS tests because this type of test yields an

"average" strength (due to anisotropy) which is deemed

most appropriate for stability and bearing capacity analyses.

At both borings El and Fl, the DSS tests yielded similar

normalized soil properties (see Table 7-1) but once again

with different values above and below z = 70 ft. This

different behavior is probably also caused by the increase

in content of swelling minerals below z = 70 ft.

e) Comparision of "Conventional" and SHANSEP

Undrained Strength Profiles

Figures 6-7 and 6-8 compare su data at borings El

and Fl obtained by "conventional" practice and the SHANSEP

method. The former includes results from Lab Vane, Torvane,

and UUC tests, and these tests yielded wide scatter due to

sample disturbance, strain rate differences, and anisotropy

effects.

Above z = 60 feet at boring El, the sampling tubes

were hammered, causing increased sample disturbance and

hence a majority of the TV, LV, and UUC strengths were

less than the SHANSEP strength profile (Fig. 6-7). Below

z = 60 ft in Fig. 6-7, almost all of the LV and UUC data

show higher su values. These higher strengths from "pushed"

104

samples probably result from a combination of: better

sample quality; the fast strain rate; and consideration of

anisotropy (pecular mode of failure in LV tests and vertical

loading with no rotation of principal stresses in UUC tests).

From z = 20 to 40 ft (hammered samples) at boring

Fl, most TV, LV, and UUC data are below the SHANSEP strength

profiles (Fig. 6-8). At depths greater than z = 40 ft,

about half of the LV and UUC data plot below the SHANSEP

strength profiles, probably because these tests were performed

on more disturbed specimens resulting in lower s values

even though better quality specimens were obtained because

of pushed samplers.

Comparing the SHANSEP strengths at borings El and Fl,

the s profile in Fig. 6-7 plots midway between the two

SHANSEP lines in Fig, 6-8. This is because of the identical

maximum past pressure at both borings and similar normalized

undrained shear strengths from strength tests. But, comparing

only "conventional" TV, LV, and UUC data (e.g. compare Figs.

3-1 and 3-2) this important conclusion is not so evident

due to the very large scatter in the results.

Because of the similar SHANSEP strength profiles at

both borings El and Fl, they could be used at other sites.

Suppose a decision is made to construct an oil platform

between borings El and Fl. Geophysical survey data reveal

that the Orinoco Clay is continuous between borings El and

Fl and if an in situ test, e.g. a piezometer probe, gives

105

approximately the same results at borings El, F; and

new site, then the SHANSEP strength profile in Fig. 6-7

(which is the average of the two profiles in Fig. 6-8) can

be used at the new site for preliminary oil platform designs.

106

TABLE 7-1 ENGINEERING PROPERTIES OF THE ORINOCOCLAY

Boring El Boring Fl

z < 70 ft i z > 70 ft z < 70 ft z > 70 ft

INDEX PROPERTIES

Natural

water 75-45% 53% 90-63% 1 65%

content

Plasticity 30-38% 38-45% 40-50% 50-65%IndexI

STRESS HISTORY AND CONSOLIDATION PROPERTIES

OCR Normally Consolidated Slightly Overconsolidated

OCR = 1.0 OCR = 1.15

CR 0.19 0.30 0.22 0.33 ± 0.01

SR 0.03 0.05 0.04 0.08

N.C. c -4 - 4 -4 -4C.v 7 x 10~ 2 x 10~ 5 x 10 2 x 10

cm2/sec

NORMALIZED SOIL PROPERTIES (N.C. CK 0UDSS TESTS)

s /9 0.23 0.19 0.24 0.20u vc

~ at M.O. 260 200 260 200

E /s 340 215 290 ± 20 1270 ± 40

SHANSEP STRENGTH PROFILES (FIGS. 6-7, 6-8)

z < 60 ft z > 80 ft z < 60 i z > 80 ft

-s** **s /a 0.23 I0.19 0.27 0.22

U vc

* Linear transition for strength profiles between z = 60 to 80 ft.

** Upper bound strength profile in Figure 6- 8 for OCR = 1.15.

107

REFERENCES

Note: ASCE = American Society of Civil EngineersASTM = American Society for Testing and MaterialsJGED = Journal of Geotechnical Engineering

DivisionJSMFD = Journal of Soil Mechanics and Foundation

DivisionICSMFE = International Conference on Soil Mechanics

and Foundation Engineering

Allen, L.R.; Yen, B.C.; and McNeill, R.L. (1978), "Stereo-scopic X-Ray Assessment of Offshore Soil Samples",Offshore Technology Conference, Vol. 3, pp. 1391-1399.

Atkinson, J.H. and Bransby, P.L., The Mechanics of Soils,McGraw-Hill, London, 1978, pp. 329-336.

Bjerrum, L. and Landva, A. (1966), "Direct Simple ShearTests on Norwegian Quick Clay", Geotechnique, Vol. 16,No. 1, pp. 1-20.

Butenko, J. and Hedberg, J, (1980), "The Distribution ofthe Orinoco Soft Clay", Report by INTEVEP in Venezuela,July, 161 p.

Casagrande, A. (1936), "The Determination of the Precon-solidation Load and Its Practical Significance", Proc.lst Int. Conf. Soil Mech. and Found. Eng., Cambridge,Mass., p. 60-64.

DM-7 (1971), Design Manual - Soil Mechanics, Foundations, andEarth Structures, U.S. Naval Facilities EngineeringCommand Publication, Washington, D.C.

Fugro Gulf, Inc. (1979) "Geotechnical Investigation GolfoDe Paria, Offshore Venezuela", Report to INTEVEP inVenezuela, Report No. 79-005-5, December, 82 p.

Ladd, C.C. (1971), "Strength Parameters and Stress-StrainBehavior of Saturated Clays", M.I.T. Research ReportR71-23.

108

Ladd, C.C. (1973), "Settlement Analysis for Cohesive Soils",M.I.T. Research Report R71-2, No. 272, 115 p. (revised1973).

Ladd, C.C.; Azzouz, A.S.; Martin, R.T.; Day, R.W.; andMalek, A.M. (1980), "Evaluation of Compositional andEngineering Properties of Offshore Venezuelan Soils,Vol. 1", M.I.T. Research Report R80-14, No. 665, 286 p.

Ladd, C.C. and Edgers, L. (1972), "Consolidated-UndrainedDirect-Simple Shear Tests on Saturated Clays", M.I.T.Research Report R72-82, No. 284, 354 p.

Ladd, C.C. and Foott, R. (1974), "New Design Procedure forStability of Soft Clays", JGED, ASCE, Vol. 100, No.GT7, pp. 763-786.

Ladd, C.C.; Foott, R.; Ishihara, K.; Schlosser, F.; andPoulos, H.G. (1977), "Stress-Deformation and StrengthCharacteristics", Proc. 9th ICSMFE, Tokyo, Vol. 2,pp. 421-494.

Ladd, C.C. and Lambe, T.W. (1963), "The Strength of 'Undis-turbed'Clay Determined from Undrained Tests", ASTM,STP 361, pp. 342-371.

Lambe, T.W. (1951), Soil Testing for Engineers, John Wileyand Sons, New York.

Lambe, T.W. and Whitman, R.V. (1969), Soil Mechanics, JohnWiley and Sons, New York.

Madsen, O.S. (1978), "Wave-Induced Pore Pressures and Effec-tive Stresses in a Porous Bed", Geotechnique, Vol. 28,No. 4, pp. 377-393,

Nishida, Y. (1956), "A Brief Note on Compression Index ofSoil", JSMFD, ASCE, Vol. 82, No. SM3, pp. 1207-1 -1207-14.

Terzaghi, K. and Peck, R.B. (1967), Soil Mechanics inEngineering Practice, John Wiley and Sons, 2nd ed.,New York, 729 p.

Wilun, Z.and Starzewski, K. (1972), Soil Mechanics inFoundation Engineering, Vol. 1, John Wiley and Sons,New York, pp. 187-190.

109

APPENDIX A

CONSOLIDATION TESTS

This appendix presents typical laboratory data from

oedometer tests performed on Orinoco'Clay specimens. Six

representative consolidation test data and compression

curves (Figs. A-i to A-6) were chosen to further

illustrate the effects of sample disturbance.

TEST NO.

16

7

18

12

14

2

COMPRESSION CURVE

Fig. A-i

Fig. A-2

Fig. A-3

Fig. A-4

Fig. A-5

Fig. A-6

QUALITY

Excellent

Poor

Excellent

Poor

Good

Poor

Additional laboratory data from oedometer tests is

presented in Appendix B of Ladd et al. (1980).

SAMPLE

FlS30

FlS30

F1S57

FlS57

ElS27

ElS18

CONSOLIDATION TEST

Project /rATvCEF Type of Test srAA4b4i

Soil Type ORI__oCO

C.L.AV

Location

Initial w(%) 65--o Gs 2.72.

Void Ratio e /,7 S/6(%) /o/ /

Fl S*s

WN(%)-.o WL(%

WP(%)YO. .P. 1.(%

No.oe&-/k Tested by x.ib. Date Z A3j. I/,o

Sample Height /.'tp a

Sample Diameter 6..3,) 9,o Corrections APPA19ATv! e_"om6 -ss ,Lpry)5 5-j/ Units: &vC 7/c c Cr L 5ecJv

C>

GEOTECHNICAL LABORATORYDEPT. OF CIVIL ENGR.

M. I. T.

Remarks E. v SASEb Co too L6M to. -/lmc- cux0vf

Primary Total Coef.of Consol. Remarks_vc _t( h r Ev(%) e t(hr) Ev(%) e C (%) frogkt0,/0 .co.9 /.7,v7 - ec /. ?/? - I _

1.00 O.4/ 2. /.9ZZ~ /.'/'4 /2,.3 2.37 /.4 ______ .8_~Z,5 o.-o o 2.oo 1'3 . ?q7 q.1 0. 000 /.7/7- oz.o -3o /LL3L /.-1/ 0LL... L/-./2. /. 72q

1.33 zo.k913 1,1741 21.r-C /(. O7 97-~SL

.15,0 2.0 /3.3 0 8 /' zq.o /z.9zs /-312 - _

2.00 0-7 /6.7 7 /.3/5~ / /5.7? /,3/3 -- %_1?_. O.53 22.KI /.1 1/ 23.o z .SiZ.. .0/ _

2.00 O.47 20./0 /-/9L/ V1.7 /9. S;77 2.20c F---Si40.5~0 2.5"0 15-. C;- 1.317 ./ 15.4 0 /- o_,? WkrER

a.5' '.2 3oAl -.( 9 33 q,.'lo0 /. 41s.

CONSOLIDATION TEST

Project AITE VE P Type of Test srAb, 'A No. oel>- 7 Tested by A, w. 1. Date An r/977Location Fps o S

S

Initial w/(%) 5-1.' Gs 2'72 WN(%) -5. P WL(%) /0/. Correc

Void Ratio e /.C95 S(%)9-5. wp(%)7V'/o RI.(%)LL.g Units:

imple Height Z.35 e-#..

3mple Diameter - - s-,

t ions A rf/T ATu-s COe/O/Z /,(ry

SVc Ih/ cv <-22 s 4 .e

HHH


M. I. T.

Remarks E 3A6 oAj d

Cu ' .

Soil Type -- / ,Ao 0

CLA Y

Primary Total _cc((%) Coef. of Consol.VC t(hr) Ev(%) e t (hr) Ev(%) e C ) ogt Remarks

0.10 ,0 /.0 o0o00o /9, 5 0 (1950.2 O) Z 01370 6/.45, /4c o.'/z? L.~' S? _____

0./ .52. 2.t/T J. / . 2.2S /.1.3. 1._ _5

/10/ 0.99 /-5.6' 0 /q . 5.117 /.65_/.7s 2.00 f.. C/: /. 6,07- 84.i/ /./?7 / 4___7

2.So 2, 5 /1.8 7 /.395 /1./0 2.4/a7 ._34.o Z 313,5T0 2.b /5.20i /.29 5z.q2. /4.-09 2.z. O.7 / /.

/_._00 2.S 2129 1.1/24 Z/e9L 22-/62 /-0'? 0.352- --7 - y/2.00 22.S 29.406 0.397 I?.iz. 30.2V/ 6.9 o.7 z.I 10

3.00 2.06' 2.1q59 q o.8z 2,,az. 26.3i( 0.9_ __

-5.6o 6 - /9.?Y?. /./f3 70.q7 /9/o1 /. / ? F0./0 2.4 I.fJ! ."23 2 q-07,27o 35 ____

FoPA Lo6- T/ME

CONSOLIDATION TEST

Project /TrC vcp Type of Test :rAtbqb No. o0b- lo Tested by 8. LO.b. DateSoil Type opwog o

Ca-Al

Location

Initial w(%) (o- Gs z.7z

Vold Ratio e /-71 S(%) /00(.

F1 55-7

WN(%)6..bWL(%) 99.o Cor

w p(0/%/-? P.RI.(%) 5-- Un i

Sample Height 1.1_s __ e

Sample Diameter /- 4- e

rections AeeAtA-rus CorE'cW55d,3

ts:.Ty

ovc kJ/ Cv cA/s.-c

Hu


M.I.T.

Remarks Ev 645Eb ON FoM -o- -T/MA

(1 TU OF-b-Q2

Primary Total Coef. of Consol.____c t ( hr) E(%) e t ( hr) ev(/) e C.(%) V ogt Remarks

._ O2__ _0.0 Q 00 f-J /.7'1/ o_ oo /-'/5? ______

0.0 2L O.g /o300 /.7 /.3f /.799 --

00 0.23 7.27 . 13.07 2..z 7 /.7Zg -- _2-_x

Ic_0:.9__ _ c; 7 _ /.6S5 I. '1 _ _.. 0 0__|_. iKI3,21' /./2 .7/3 /1,1*5 ~ 6.2.5 1-.,3 zt /4,5~.39

6.'G1. C 0 1. /2- I 10 1 /-29?. 1 .2-01) ) 7e. ZG . - /2 5 1 W/ -q x xtIZ.00 0.80 2 . 8 e/.oT .7-12 ol.4 .02.q /.235-3.oo .57 2/.272 /.//1 /2.3q 23.7S /./3-

o.50 2. , /7./31 /317 ''.33 /f-. 5-0Z /-337_ 0_to '.S . ,9$ /.9' 2?.Oo /o..1 /1 b

CONSOLIDATION TEST

Project /'U TE vr P Type of Test sfAAIUWf

Soil Type 9 /A/oc.o

C tA

Location

No. ocb-r.. Tested by R. w.b. Date 1r 7

Sample Height

Sc

Initial w(%) 6Y.8, Gs 2.,?z wN(%)4/..d. wL(%) 11.o Correc

Void Ratio e /.767 S(%) 9?7- wp(%).Y/.l PI.(%) 5-7. Units:

Primar Total Coef. of Consol. RfvC t(hr) Ev(%/) e t(hr) Ev(%) e cc/) yr logt

0,0 / ----_ 0.co0 /.7?1 0 3.0X2 /.?49 _ _ _

0,10 0.19 /.?4. 6.Zo O./i9 /. __

0, 2-g 5 0? .91 {.796 /0,- 1y I?

0. 5 /.17 2.1/ 1o 2.33 Z..Ie0 /-7o9 -

/.0 /.33 ./7 /.5 2.6 9 g 1.6!- 7_ qq- 2 -

/.?.-.-- . x /0

.2. g7-4. 6P /I.q6 l ,1/7 z /2.7Y7 /.0 -_6x

?__56 2. 93 ,q(s7 /3 1q 2q.67 /6.02< 42-25 6.73q V41, qs. 20.g2-, /19L 21.-2 2 1 /./q3 0.987 2

/2.~~~~2 2., /q 3, 0g, x.9 //0-1102~O-5 06

R_ 6. F3 Z 3 . /9 6( Z.Z el 21 /o?/0.5 15._ --.-3 /.- -o 1 | . ' l3 5

.1 3 _.? / 3,oV"7 /.Yo( 21.00 /2.i7g /32. _


M. I. T.

Remark s E v B ASE b ON 16C () kVrI S

mple Diameter . ci--'

tions A gWArOs (OAR55/C.1rY

Cvc .-

r

Fgbeim Lo&- riE

Z.o 00 e

CONSOLIDATION

Project / tF7vcP

Soil Type Ogimo-oType of Test srAlTbA#>Location Et. s 2.7-

No. oEt- Tested by R- W. b DateSample Height 2.09 C'".

Initial w(%) . Z.72. WN(%) 53 WL(%) 7.-

Sample Diameter 4 - .

Corrections APPARATUS MPCSs B/Ty

Void Ratio e /-7? S(%) 72.3 wp(%)3.L./ PI.(%) 3T-/ Units: &vc kP / cA C rSIA

____ Primar y_ Total ______ Coef. of Consol.dVC t(hr) E(%) e t (hr) e(%) e C (%) Vr logt Remarks

0./o - 0.000 /.~S77 ---- .oOO /.5776.1s~ 0.03 6. 3 /.57(. 17.0 0.0 /.5

o.6z. . / 9 . 0.764 /-5S71.00 o 2.P97 /.S2/ 1. z.. /.025/. /I IS/?

/.?S jf 3-3 /.'z? 1J i 9.,( -39 -1

3.50 . ' .7C. /-.35/, 20.1 9.5j /.331 -

C.oO 2-33 /5 .7 1473 /'/.5 /6.637 ./s' *J 0,6 3./ / -I .- x/0

/2.00 / .61 .3.07 0.95'2. 75.3 2q.03 .95- 0. :'3 S- 3.3 X /O 2.3-x10

3.oo /.oo 7-.0s /-0,3 '/8,7 zo. /.O-/o0.! o 4.7-o 1,.6 7 /.18 239.o y. 5b'e /.Zo3 _

0.10- I 9-54'S 1,33) 27. F 2./o1 J1IL. __


M.I. T.

Remarks E V A oM J100

e..oK vES.

FRoM LoG' TIAi

TEST

HHa~.

CONSOLIDATION TEST

Project 1"TE 'F P

Soil Type 0 -4#Noco

initial w (%) is.i Gs 2.?2.

Void Ratio e S(%)

Type of Test 6r-ANbArb

Location E I. I

WN(%) L l WL(%

w p(%/) P. , P.l.(

No. oED- 2 Tested by R.w.b. Date .Tuy, 117?

Sample Height /,143

Sample Diameter 6.3Y/2. cn

,) 7.o Corrections 4PPAgArOS COMP,?-e5,8,6/ry

,) 7 Units: Svc C/c - C j%

ul


M. I. T.

Remarks g 13AS66 i J Fv ,, -R

Primor Total _ Ca(%) Coef. of Consol.OVC t(hr) E v(%) e t (hr) E(%) e C %) It Remarks

b,00 -- __-- o.oco -_000__

0.2 d. . 2.3 - .C

0, So 6. 5'/ 3,52. o.82- 3?-,L2. -

1.00 Q.j 4.2. 0.Z 6.-H2. __-/

2.00 0.9i /0.1s 1 -75 to. 99(. --

.00 _ .3: .?:r._ . / . '/ 30.2 1/5 //. -. 2.'. 2. //. -. - )( 10-4

l 0.oO o.7 < /3.T3 0 . 1 . / 3 15 1 ? ) 5 --2.,00 01,/1 /i .- 1 0 ?2. /4.029 x

_ ._. __ 0.(2. q.q 0.42. /9.(0 7 -

9,00 6./ 25.3 21,93 .3- 3_0

/,oo b.6/ 22.9 o.S2 22.52.-

41 .G /8./0 XI.T3 17.

116

0.2 0.5CONSOLIDATION

1 2STRESS &vC

Sample No.=FIS30Depth = 126.5 ftSoil Type=

Orinoco Clay

o At t ore At ( ) hr

hr

WN(%) = 65.0

W L(%) = 96.0wp(%) = 40.6

P..(%) = 55.4

Remarks ev(%)corrected for

Estimated

vo= 2.37 &m =280±0.10CR=O.330 RR=O.075

Gs=2.72 e =l.75 S(%)=101.1based on dIoo from log time-apparatus compressibility


M.I.T.

COMPRESSION CURVE

TEST NO. Oed-16

FIGURE A-1

0

5

10

15

20

.0-

z

I-

25

5(kg/cm 2 )

10

(24.0)

(2 5.7-

(2 3.0)-

0.13

117

5

10

15

>0

a5 ' '' ' ' '

0.1 0.2 0.5CONSOLIDATION

Sample No.= FIS30

Depth = 126.2 ftSoil Type=

Orinoco Clay

o At tp or

eAt (19.1) hrhr

GEOTECHNICAL LABORATDEPT. OF CIVIL ENG

M. I. T.

1 2STRESS &vC

5(kg/cm 2 )

10

wN(%) =59.8 Estimated

wL(%) 101.8 0: =2.37 &vm=1.6±0.1wp(%) =34.0 CR=0.260 SR=0.090

P. I.(%) =67.8 Gs=2.72 eo=1.695 S(%)=95.7

RemarksEv(%) based on dio0 from log timescorrected for apparatus compressibility

ORY COMPRESSION CURVE.

TEST No. Oed-7

FIGURE A-2

z

w'

3

118

25

3010.1

I I I I I I

0.2 0.5CONSOLIDATION

Sample No.=FIS57

Depth = 128.0 ftSoil Type=

Orinoco Clay

o At tp ore At (7.4) hr

hr


M.I.T.

1 2STRESS &vC

L I I -

5(kg/cm2 )

10

w N (%) = 66.5 Estimated

w L(%) = 99.0 :o= 2.40 &vm= 2.75±0.10w p(%) = 41.9 CR=0.355 SR=0.090

P.1.(%) = 57.1 Gs=2.72 eozI.8OS(%)=100.6Remarks=ev (%) based on d1oo from log time

corrected for apparatus compressibility

COMPRESSION CURVE

TEST NO. Oed-18

FIGURE A-3

0

5

10

15

20

z

I-

I I

119

5

I I

.1I I I

0.2 0.5 1 2CONSOLIDATION STRESS ov

5(kg/cm 2 )

10

Sample No. = FIS57Depth = 127.8 ft

Soil Type=Orinoco Cloy

o At tp or* At (18.2) hr

hr


M.I.T.

WN(%) 64.8 Estimated

w L(%) 990 &VO= 2 .4 0 &vm=I.35±0.10w (%) 41.9 CR=0.245 RR=0.085

P.l.(%) 57.1 Gs=2.72 e =i.769S(%)=99.7Remarks= based on d, 00 from log time-corrected for apporotus compressibility

COMPRESSION CURVE

TEST NO. Oed-12

FIGURE A-4

-ir FmTT -

______ ____I________ ___________ _________ _________ 2

______ __I____ ____ I________ j

0

z

w.

10

15

20

25

3010.

120

25

30'0 .1 0.2 0.5

CONSOLIDATION

Sample No.= EIS27Depth = 133.9 ft

Soil Type=Orinoco Clay

o At tp or. At (75.3) hr

hr


M.I.T.

1 2STRESS -vC

5( kg/cm 2)

10

W N (%)= 53.5 Estimated

w L(%) 76.5 &v.=2.84 avm=2 .80±0.10wp(%)=37.I CR=0.30 SR=O.051

P..(%)= 39.4 Gs=2.72 e =l.58 S(%)=92.3Remarks = based on d, 00 from log timecorrected for apparatus compressibility

COMPRESSION CURVE

TEST NO. Oed-14

FIGURE A-5

0

5

S

10

15

20

z

w

.L.LL I I

F--

I -I I I i i 1 1 1 1

121

r(2 2.)

(21.8)~

Si I I I I -I I I I i I

0.1 0.2 0.5 1 2 5 10CONSOLIDATION STRESS &vc (kg/cm 2 )

Sample No.= EISI w N (%) 6 3 .1 EstimatedDepth = 83.3 ft wL(%) =74.0 &o=1. 7 4 &vm=1.60±0.1Soil Type= wp(%) 31.3 CR =0.26 RR =0.06

Orinoco Clay P. .(%) =42.7 Gs =2.72 eo- S(%)-At tp or hr Remarks = based on dI 0 0 from /t curves

At ( ) hr corrected for apparatus compressibility

GEOTECHNICAL LABORATORY COMPRESSION CURVEDEPT. OF CIVIL ENGR.

M.I.T. TEST NO. Oed-2

FIGURE A-6

0

5

10

15

20

6-2

z

w.

25

3

0

0

In

122

APPENDIX B

CKQUDSS TESTS

Appendix B presents representative laboratory data

from four CK0UDSS strength tests. One normally consolidated

CK0UDSS test (No. 9) and three overconsolidated CKQ0UDSS

tests (Nos. 16, 17, and 18) are presented in tables and

figures as follows:

(1) Tabulated laboratory data.

(2) Normalized stress paths for all overconsolidated

CK0UDSS tests (Fig. B-1) and the stress path for Test

No. 9 (Fig. B-2).

(3) Normalized stress-strain and pore pressure curves

(Figs. B-3 to B-6).

(4) Normalized undrained modulus (Figs. B-7 to B-10).

Additional laboratory data from CK0UDSS tests is

presented in Appendix C of Ladd et al. (1980).

123

Sheet I of 2

DIRECT - SIMPLE SHEAR TEST

PROJECT HN7rvEP TYPE OF TEST IK-v7U55 NO. 2-OCR 1.

SOIL TYPE OR/NOnco

LOCATION Fl s"7'

TESTED BY R-14-6 DEVICE (EOA4O DATE e4,u r- 80

CONSOLIQATION (Stressos in ktc/)

fvc 7 hc _vm _22:

tc(Day) 1-07 ff/.) ?fal/%.CL0 t,(Day) -,-

w H/. e S,/ ( )

Ini ial 95-. J 2.. 0 7 oPresheor - I 6 1. / I

IFinal 1 -7 ? /12 ?.3 1

DURING SHEARControlled Strain Stress

11.399 Rate (%/ Hr.) A-1

SOIL MECHANICS LABORATORYDEPT. OF CIVIL ENGINEERINGMASSACHUSETTS INSTITUTE OF TECHNOLOGY

TIME STRAIN Th A" . 7. .J-L. .. !(Hr.) (/0) F o drOc 5. m vm5

/;30 e. 000 4. o 0,00- I.coc 0.000 0.002. /.cc, -

0.0001 0002-.. /.coo 0C000 0-.oc /._000

0. 005 6.005 CQ 0c 4.000 0.02. 0.O0c /- O c c

___ 0.023 -0- /o 0.000 /.000 0.049 .OCl /-.000 9

0.12.. c. 1.000 6.0 .3 0.o /. __0 _ _&

0.05's~ 0.2 -. coo /,000 n.2.e.2 -%O. /IW_ ._ 0r3 o. . / L 1000 .Cc a SYYI

Q.17.9 0.0 0.00- C c?. o. ZI/ o.o 4 9 Q.1 5002.1l:Th 0./5 is ~f o.g o.v/5" C.c5s c.9tC I G

2. ' a.C58 c .o* .l |.1 _.2___ c.ot n.1 ____

____ .?z. 0.7o ouZ. a-.7? 0.?3 o-G p.9li __~___

___ .9oZ. 0.0 0.'/ .9 .97? &-.11 0.os'1 c.1

/2-'0'7 o.s5-of. 0.0 5-0O. f 0. c10.<,/ 0.095 o.35" j2j___ .G92 0./01-- 0 -9q5 o.5-00 cX/'2. ni'? 217

___ .gs'q c.I!'z 0.c0S' c.9? 2.j1j c.n1. c.9?f (9______ .z 2.... 0."9i( O. ~ O-./2./ 0.9/4, /2./

____ 7L41. a./?Q &,C92 o.97 0..C3 o.12o 1.90g' Is-P'2.'1 p.4/1/ o.;35 0.??2. 6-.2 C~t 0.02.. /39

;I./S . o e,/2.(. ./.J/? 0.0. C-77d /'______

____2...O30 0./5-4 9g jlf O. Q.s? 4 / o.gt;, o0.-1 o./C3 .07-- 2 . 0.c .2 n . .. I__-8 0. < 0 3 L;"-

7- :0( 0.5-21. 015 05Jbc 0. __ ro 0 .,(,0

REMARKS:

124

4

SOIL MECHANICS LABORATORYDEPT. OF CIVIL ENGINEERING

REMARKS.

MASSACHUSETTS INSTITUTE OF TECHNOLOGY

Sheet 2 of 2

DIRECT - SIMPLE SHEAR (continued)

PROJECT /WrveP SOIL OR '^10CO <-A"TYPE OF TEST LNO.

TIME STRAIN Au 3. lh i. __L(Hr.) (%) C =vc avc U vm vm _

3.'9 C.l'1 0.2-4 0.820 . 0. o2.0.S,'? 1 Q a 1 0,700 _.__ _. _ _ _

?.l13 o.Zf'- 0.7 90"/ l _ o.09 - ____._ _ 0_90z.4 7 '7 2. o.0 0.70 S. 0.0 /_?7L/1

r'.3I 0.1j- -4 0-1 6._;57 _.-8. 1 , 1 9 6. x 4 . / .,4

S .5'2 c.lt __.__. O.? .- 0 _ _0

_____ ./34 0. 1' 70 . .. -j3 0.44?/.Zo 0.7(.3 _____

/O.2A 0 0.2j 0 0 .. 0.2o 0.4/ _r._C

C.3/1 6. -zoo 0.3'2.. 0o otO z.ooL 0. 2?0

1,-7 - 6 .2; 7 0.f,/aZ3 - .0. (,( 3

z.T,3R 0. z. q 0.: 9 t.a,, C;.0 c1r,/ 1:o / .'2? Oo., 3 0 - 31 0G29 O-2 0.02.5 20q S

/IT: 0 3 .l _ 0. ? (_ 0, q _ 0_2..4/ 0.___ _ _ /..32 c.2.eV C-.93 0.o7 __.___ .- ,o? _ _ _ _ _

_ 3.(. .2.0.0 40n'z . _____ . C.-4 0.1____54/5:5o I9.or., 0.. __ __ .__ _ ____ ,_ 4 a __ __ _

f2 .94 O.2.a2. 0-4'? o.5-; _. , 0.507

2_ _ .0 3.f CA7 0*5 33 ___ _ o-4'3 _ _ __

_ _ o7.7 4 0.15q _0.0 0 0.- C _ _

/ . 12. n. 197 0. -fg 0.q12 0. a5/9 0___ __ 2.?'/C o,1 /eL o. (2 /9 ____ _ _.__ __

___.' ;.o'9 0., . . o.(oc o o.104 o -I$0 1 __ __d

___.? 2.i7 o.'3! Oo Z c.C o.3' ____ c? 2 0.34'2 .'70 o./3. 0 ./,6 0.-370C.G o.

2.7.073 0./34 _.4__ _- I2 .4/ . . 0.490 ?-W20 o./ o

143-970 Z0./3q7 0-72-0 0 -'Z70 0./ 1 .370.Zg.2.1 o.,i' o.4.o c.?zo _._ 0-3Z.0

iV.2.5 2.*3 0.IQ02 0.Z2. .217 ____ 0.02 . 2-'0 __

2..2' Q.C9T 0 . 2.G ____ . cW o.z __.:__

125

Sheet I of I.DIRECT - SIMPLE SHEAR TEST

PROJECT ILTIE/P TYPE OF TEST C NO. OCR

SOIL TYPE9L . ".o TESTED BY 2- DEVICEGE COR DAT E

LOCATION 7 CONSOLIDATION (Stresses in )

vc Thc _

fc(Day) erf.) /X:. C(%).- (Day) -3,w */ Ie S,%/o H ( ,m)

P sin i hi a r -0,9 '/-7 3 .1(0 2 -pPreshear /4 71, 1 - 1 -.. /

DURING SHEARControlled Strain '--'' Stress

SOIL MECHANICSDEPT. OF CIVILMASSACHUSETTS

LABORATORYENGINEERINGINSTITUTE OF TECHNOLOGY

Final V.D / . 6 1 Rate 0/%/ Hr.) S. b

TIME STRAIN Th A&L 7 .rh.. .. j jF

Hr.) (1/0) 'Fe -1v c r m O m

,/'Ls O.oo0 CO(Oo o~c /. -- 000Oi'n,025, 6.nzo 0o~c /.ooo - 0-010 0So,4

o-OSS 0.6 0 no ccou /.ooo 0-o .c .C015' __-j.T 4 Y ,

in o - 0 - .00G. /.- ao 4 l ,/77 I0-o29 o.sCo7 3n, 24 .i3( - / -. Q..' t Q0A 2 ? I --. 04t 2.0. , i .0 - ./57 0. -3( -0.o1 /,109 O._ 1-cq _s__ __6;

0,7;i 0.-17Z- .- -V Z. _.5. n.067 IO I?1 / 1221 0.207 -m -,7 /.0 -67 /.4 . 10.t4 _7 / _7

2.ol.74 0.27 ,. . / 7 / o. a /t-_It_ '_ _ %'11 O.32.( -. 1., /.//g' O.92o q ./3 3 0- S . _ _

././ -0.215 C - 7 7 ? .0- e7 111 ^_Z-*, //3i a.29? -ej . . /, // o I.' r, c> -5c 2-

Z. /O 0.313 2 ./7 /4 0? 7 j. 0 -2 5.7 214r 0.?z.o-17 oS97 no 07 n 4'_.7-11.1y' o."3.- -0.072 A,072 0./6' 6-5 4//. 023 S .10 .? ...n-.07n I 0. y 7.45 0.,7-1

H. 31? 0.32.-7 - at /,/ -- 2 ")/34 1.3-5/2

/ 272 0.',116 0.0( O-- .. 3o 1'^./60 n - IqO

7q,3. / 0. 7so 10.n q.C .2 .5 .

24. /0Z- -77 ^O, 2 0-72 151o e4/9 7 ,

.24 .. reI 0.2zTZ 0. t7l o.3Zj 0,jo5 -,./27 c).4 1717'./T 127,407 /0. 20C T .-85 0.905'C -30q 0, /Z. 3 10- cof

REMARKS:

126

Sheef I of IDIRECT - SIMPLE SHEAR TEST

PROJECT INE\E/? TYPE OF TEST C utD- NO. '7 OCR 3.1

SOIL TYPE C4 TESTED BY A a DEVICE - DATE _o

LOCATION 7 CONSOLIDATION (Stresses in

Tvc _hC_ _

fc(Day) - Ep/.) 4-:.. fc(%/)- tc(Day) /A 0'

W,% 6 H (C.)

Initial (i. 2 /- I% I~I7I. u.I4 cPreshear -- / -171Final 27, I .

DURING SHEARControlled Strain Stress

Rate (% / Hr.) 3-

SOIL MECHANICS LABORATORYDEPT. OF CIVIL ENGINEERING

INSTITUTE OF TECHNOLOGY

TIME STR AIN Th A_ F _ h _(Hr.) (%) Fc avc vc Vm "V I

-oo ~ o-coco /ceo ___ 0C-coo C~r.. -

o.olg O.0 O.. /,ooo --- ,. c.-0.0 ?( o~n c-0*6 /- o4 0-14 . -/?V

0.3:';4 -o-i;, /C3 .I 1.02L !.40 ___ ___

4 ._ / / I 0 7-3 -. V 7o i-C. 14 0.i 'j f.,9? 2 D

/ n 6.2(5 -216 /./4/ .4 .y. . 1 /3/

_76 o.2 - .3q0 __ _ _

72. 7 . .. -- y o /,9 0-40r 0.09) 1 n03/ -. 9 -, / >.(,/95- 0OP7 2.3 9 _ .

3.77K& 0. 40-4 -o. . /.Q .. 7 Sit o.//c3 .3 Z o. 777 i -z / - ?i Afl? 1 0 229 .3)31 C

6 . /4'2- 6 .4'-, f- 0. . .1 40.\I c. 97, D3 I 79 - 0-d-i/. CO ioo n.IK 0.1

/C,,, 350 - . /, %41?/3 c iM

1* /il IT 1 . 3 - 1,j 3V4f 0 9 1. /2? a. 3/_&, , .43 -c M / f (,0 Ir" 0/1 0 .3,

173 : 05 7 , 13% 0.0 ,D 34;2 Pg

/cM .4 3 -1~ - j 6, 0.4O 0,/3? .392 . 21 0.09-2Z j. 0 -11 0f 0~ -, /2/ 3/ q

17'.lo~~~~~~~~~ .0Ms ~/ .s //N 2 9o/(. o i

REMARKS:

MASSACHUSETTS

127

Sheet I ofDIRECT - SIMPLE SHEAR TEST

PROJECT lMT)JE TYPE OF TEST NO. 1 OCR 7-~70

SOIL TYPE c A TESTED BY DEVICE GEO102C. DATE Igo

LOCATION 7 CONSOLIDATION (Stresses in )4vc rhc - - vm

c(Day) OZ.)tDING (DARy)

w % e S,% H ) ^

Initial -M/7% S6 . D. 4,Presheoar 70o ----- 2.0 iFina l.

DURING SHJEARControlled Strain- Stress

Rate V%/ Hr.) 3.?

TIME STRAIN T1 . A M T Tt h 0 ( Hr.) (s%) Fvc O7 vm IF m ovm

/L:. 0'e, il 0.0339 n. n - c., _

0.06a O.C94 c z '. .9 jal 1 _ _ _

0.1 a lo jq 0.N -o.u /,4q Oqo n. /42 o oll o/3. 2 7

(:4r o. 4 . -0.-S . - . a. . _____ /720. 7Z2 0. "1 - 0.194 /. - .331 In g 32 0./q= /Ii/n

S/./5/ 0-3S4 - -1./ .4c,5 LnA 4 6 ./6'/ /0 S _

___/, ~o5 o.37 o / L oL~ .i. .. pOJ/g 7.2. 6't g.47c - .3012 ./. 2 o ; 0.537 6- jl6 . ./ 7" c 19

36 3. Y o.5' -o.330 /,332 t -/. ? b.- 0. /7 3

r.,13 3 0.54/ -6, /MS $ 57 .1, a,6 012 r -0 1IW_3_ 0./ # 47 /. e 0O RS ( ./I L____ 'o O.?? - - N / -su oo o,~, ___ __

7./7/ 6. 7' . -t-3 3 . 2/0

/3: 3 , r o. 772 & L,41I2. 41 01 .03 0. 3 _

/,___o- 31 -. 5 j/,7~ 7't II (N ,7 .23

4_ 7 -7 1 - 0 -4 1 1 - o .Q 2L / . 2 64. -i23i1

_ _ _ _ /? 7 - a .. - / 1 9 0 .. / 5 1 /0 1__._1

7 .5- 1 5.7Y- -e-6, / 2 Yi Z O.o'f 0.,217 . 7 /6, 196 -O.'Y 11 () . 4 0.010 0; 1154).?/ / 6. 5 7 -6.9 { ' 1 0-41 c o .0 5 _a 2ol

22.3, 0 - T'f-D - 0,q / I /','7 o40f 1,0 t I~o Z'3., Y.2 r>.71 11. '171Q 385 _ 0at TYo, I.191

SOIL MECHANICS LABORATORYDEPT. OF CIVIL ENGINEERINGMASSACHUSETTS INSTITUTE OF TECHNOLOGY

REMARKS:

Test Sample No. Depth wN &Vc 6vm OCR SymbolNo. (f t) (%) (kg/cm 2) (kg/cm2

7 FIS24 96.5 61.0 1.72 2.40 1.40 0

5 EIS21 98.8 60.2 2.02 4.00 1.98 0

4 EIS21 99.8 57.0 2.50 5.00 2.00 A

_ ____ F S'1 I11(.1 4. .E 1..1 l.f 0

I9 FIS _________ 6a. 1. 0-;, o '1 115 7. 1o v

GEOTECHNICAL LABORATORYDEPT. OF CIVIL ENGR., M. 1.T.

0.4

0.3

0.2

0.1

0 0.1 0.2 0.3 0.4 0.5

v vm

NORMALIZED STRESS PATHS FROM

0.6 0.7 0.8 0.9

BORING - SOIL TYPE ORINOCO CLAY

0rh

0'1

:0mn

to.

Ht'J

1.0

CKOUDSS TESTS.

liii'

I~1j ii

th~L

i-fIf'

ii'fiT

"ii,

li-n

44;

II~iIi'

Fi~

I

Ii

I.Ii

'if:1

~i1Jilt

iiJ~iii:14

iiiII

ill',III

lIDii"

I'!"I

IDI'Ini-LiIi,

'11

Ii ll

iD-f~'IfI

Fl,

14~

1~ili-ti

tEL.

0 0.1 0.2 0.3

NORMALIZED

it oi'Li4ij{

ii

44

hi

$itill

i~If"444

4:4

iii0.4

In,

'Ja

144

i

If',

ifl~t1

14t

fin

,11L 1

'i-f,~tii

1I

ii

it,-''

'if

0.5

av / vm

if

ILI-

0.6

ff1'Hi

liii

ii-:it"

-liltIi Iii~

IiIiIf"iL

0.7


M.I.T.

"''Il

4,-iy~

I';

ill'ftDIi'

III'~IIn,

II

'Utff1-ItittLI

ih~ I

in

'flu

I,,

K

I'llliii

Im1

.1liiiii'ii

IJiFiii~

I 44

till

0.8 0.9 1.0

STRESS PATHS FROM CKOUDSS TESTS

Boring Soil Type C O^-w( (A

Test Depth wN &vc Ovm OCR SymbolNo. Sample No. D%) ( .

S Fic,97 //. d(,OE470 -o-

0.4

0.3

0.2

Th

6vmn

to

0.1

-Ti

GCP1

0

i;;,144441 4

------

Illllllllilllllilllllllllll I Illll lilllllllllIlllli

130

*........................----

~~ 4:

-- --- - - - - - - - -

itsr ----- -------

77~ -7-

t:

.0

.2 ... .. .. .

... .....-.-

.. .. . .. ... .

-- -- -- --

.. ... . .. -- ------.. .... .. .. . . . .. .. .

..:. .. ...:7 - 7

n . .. ...... .... ....5~. ..-..2..4

5 10 15SHEAR STRAIN X'

20 40

(%)

Sample No. w N &vcN(%) ('z' A 12 t c(Days) -L>

Depth(.) /2.L wL(%) & Svm(4/ ) OCR /o

Soil Type C 0 0 c wp(%) I Estimated &*o(A // ) -.

GEOTECHNICAL LABORATORY NORMALIZED STRESS VS STRAINDEPT. OF CIVIL ENGR.

M. I. T. CK.UUDSS TEST NO. 7

FIGURE B-3

0

vh

cVC ,

1.

C

Aurc.

0

0

.. 7~~_ __ _ :71 ::: 77: ... .

20

SHEAR STRAIN Y (%)

Sample No. FWs7 WN(%)i 0.cI avc( /,-z )2210 tc(Days) C-9

r+)t /zF w L(% 10' a vm(/ )M OCR /?PC

Soil Type C O--o w p(%) A Estimated aGo/ / ) 2/C U


M.I.T. CKoUDSS TEST NO. ___

FIGURE B-4

131

I

4jK.p -..

7L ---t- ii7:T h

I',

--- - ---- ----

t

H:p

... - . - -- -

.....-.. ... ... ......... 4

7-p ... -..-.

b.777t:-- ... ... -... . . .... .. ... .. ... . ... .. ... ......... ..........

-.7 i 'A

A

VC

0

0 5 10 15

0.&1

T-T -T Ti y T F E T

132

0 5 10 15 20 3w 40SHEAR STRAIN 2r (%)

Sample No. 'S 7 wN(%) k' ( d - ) tc(Days) i

Depth(#) /4 - wL(%) o&vm(6 /~2 R 7/

Soil Type - w p/(%) _ Estimated avo(k ) 2lC-Q


M.I.T CK.UDSS TEST NO. /7

FIGURE B-5

- - ------ --

T , -- - - --- +--

K - H H

77-- 7 p *

:=. :4 - - rz:*

Th C

5~vc

0

uo-.v c

F F t-.... -.. - -.... -7

7 . ... .. . ... ....

.. . .. . .

... . .. .. . ... .

-.. .. ....

0 5 10 15 20 _A_

O.z

.) .4

......... . ..... . 1::. :j 7 7":

tr 7-. ....I ....

t

...............

.... ...... .. .... I--.- ........... ..... .. t77:::777- .... .....

I ---- ------ .... .... .... ....

.... . .. .... I... --------- . .. ....:

-:1:7

7:-_: 7

----- --------- "-t-=7.' =7

Z-47--- J:7- :r7=

at

-- -------- ------------------- ---- ------ -............... ----- --

.7+

:7.:

HH..=

tt,

0 5 10 15 20 -30 4C...... .........--------- -........ .......... .... .... ................ ......... . ...... ............ . -------.... ......... .. ............. ... ...... ...... 1' -11'........ . ...... ......... ......... ......... ........ '-7 7: t:

:% _"1::: . ......... ... .... I .... .I .... ........... ........ 1 1. --:........ . ..... .. .... ....... -..... :.. . - -- j .. ..... - ---------

. ......... ......... - -,::::: --.. .: -: .... .......... ............ ..... .. ......... I --------

.......... . ......... .

..... ......... ---- ------------- : ..... .... ........ .... ...... .........

.. .... ...... -7 ....... . .......... .........

z.:: ..... ... 7-7........ ....:-:1 7= ......

--------- ----..... .........

.. . ... ....

7 .. ........ ---------- .. ... ........ ......... ... ......... .... ..

.... ......... --------

Sample No. W N evc(/z4 tc(Days)Depth (;4 0 C R -7. 7 0

wL(%) a:vm(

Soil Type c14 (0,4-4f- wp(%) Estimated &vo(/C

GEOTECHNICAL LABORATORY NORMALIZED STRESS VS STRAINDEPT. OF CIVIL ENGR. CKOUDSS TEST NO.M. 1. T.

FIGURE B-6

133

Th

O'vc 0.4

0.2.

0

0.0

0 5 10 15 20 -W7a

4er2-T

Au -0-,j

c'vc

SHEAR STRAIN a' (%)

134

2000

i fiI iI I

1000

Soo

600

400

100

80

60

40L0

I (IN

+11 II I

0.2 0.4 0.6 0.8 1.0rh /Su~

Test wN vNo. Sample No. Depth WN V6 OCR Symbol

___ /-_ _S-7 /.)'G5~ . o - 0-

NORMALIZED MODULUS FROM CK.UDSS TESTS

BORING zl SOIL TYPE c < C-Q

FIGURE B-7

Eu

su

200

z

0

1-;w

0

Ix

0

0z(D

411 i i i i H I, + i i

! 1 1 it 1 1 ! 1 j 1 ,

135

I L i I I! ! ;I I I I I

2000

1000

800

600

400

I MIII i

0.2

I I

0.4 0.6 0.8 1.0T'h /Su

Test wN vNo. Sample No. Depth WN VC OCR Symbol

/S 5' i7 /2 .3 (o). 2-;J,0 6 -Q

NORMALIZED MODULUS FROM CKoUDSS TESTS

BORING f. SOIL TYPE O ke- e

FIGURE B-8

ii Ij ~*jiIII II

I IIII

'I

EuSu

200

100

80

60

40 L0

z

-

0

CL0

0

w

0

0

1111fi-1-11

I I I I I I I I I I I 1 1.

11

136

2000

1000

800

600

400

I I I I

Eusu

200

100

80-

60

40 -

0

I I ) I I i 1i i iI iI I +i1.11 I i IL

11 1

0.2 0.4 0.6 0.8

7tI

I I I i

1.0Th/Su

Test W NNo. Sample No. Depth g VC OCR Symbol

17 F-/__D-~7 _/2. V.2 /'/ / SAI ---

NORMALIZED MODULUS FROM CK.UDSS TESTS

BORING LL SOIL TYPEC4 O - C-

FIGURE B-9

0zw

-

.-0

Fa.

0

ca

.a0co

w4

0.

-

I I I I

~I I I

137

~I[F

I II I I I II!iiliii IF i~ j

1 1 1 1 1 1 1 M 1 1 1 1 !-q 1 1 I M I l ! ; i i ! ! 1 1 7

0.8

! I ltII ! ; L i II ,

II I I I I ',Ii I I I I I I -

N I i

0.2 0.4 0.6

'I .'

I I i

i I I

1.0

Th /su

rest wN vNo. Sample No. Depth WN YC OCR Symbol

/___ __/____ /2./t. ( . o.si 770 0

NORMALIZED MODULUS FROM

BORING F1 SOIL TYPE

CKoUDSS TESTS

C'a cL 4Cla~

FIGURE B-10

2000

1000

800

600

400

Eusu

200

100

80

60

40

C9z

U-0

0

uJ

0

I.-0a:0

0

4+4I i I I

I I L!17 -1,

tt+-t

I I ..; I

; i i

I ! I i I I i i

I j ! I i i , ! i I : ;

138

APPENDIX C

CK UC AND CK UE TESTS0 0

Appendix C presents laboratory data from CK UE and

CK UC tests. The following data is summarized in this

appendix:

(1) Figure C-1 presents the stress paths for all

triaxial tests.

(2) Figure C-2 presents the stress-strain curves for

all triaxial tests.

(3) Laboratory data from CK0UC Test No. TC4 is

presented in the next two tables.

Additional information concerning pertinent test

procedures can be obtained from Appendix D of Ladd et

al. (1980).

z (ft) TEST SYM. BORING WN Pi I24.5 , 27.0.3 No. (%) (%) -

99.1 TC3 0 El 57.4 39.099.5 TC2 A El 51.5 31.5

0.2 128.7 TEl O Fl 60.1 57.1

I'l.3 TV 9 Fli 61.8 519

0.Iq

crvc

0.00.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

-0.1 OF

q= 0.5 ((V - Oj) .

-0.2 p=0.5(&,+-

FIGURE C-i STRESS PATHS FOR CK UC AND CK0 UE TESTS: N.C. ORINOCO CLAY

t.0

140

3 4

AXIAL STRAIN , e0 (%)

FIGURE C-2 STRESS VERSUS STRAIN FOR CK UC AND CK UE TESTS:N.C. ORINOCO CLAY

z (ft) TEST SYM. BORING wN pf

No. (%) (/)

99.1 TC3 0 El 57.4 39.099.5 TC2 a El 51.5 31.5

128.7 TEl 0 Fl 60.1 57.11 .3 Tc V F1 GIA. g.9

4

6

-0.

-0.0 2 5 6 7

0.

0.

. v c7 iO

I

141

Sheet I of 2

CONSOLIDATED - UNDRAINED TRIAXIAL TEST

Project /AWfF E? Type of Test C .O- No. TC'L OCR /LQSoil Type C & , Location FISS7 Tested by A w.

Date .A/LfStresses in ,i / UB 26. B (%)B M Strain Rate (%/ hr) /

w (%) e L(cm) A(cm2 ) V (cc)

Initial 61- 16 4 7 77 '??37 1.1Preshear T./9 7 71/ 1 . 23 .9

Remarks TV O.4r 4/- ( -

WL(%M V. wp M 3 7.4. PI.(%M2.,1L

CONSOLIDATION DATAStep 2 3 4 5 6 7 8 9 10

avc 0.80.1% /.q V_ / . /J?&hc o,4 0.74 A .*S / .4 /.7.

tc (Day) 0. . o 7 .O /.71 1 --

S(%) 0.0q .7 /S-g 2.-1.C Vol M% ~ y ./4g

- 114 11


M. I.T.ILA"

e-4 e.o ta-

Time C0 (0 v- 0 h) u-a O. A q Eu(h) % vc &vc &h A &v- q f

7 23 NcJ O 2 , g /,477 O.2 .' c .770oa Qo .qi 0-ooi /-7// n. 6,1 0-20? 0,7'17 /7f 5q~s .44G.- 1) -0-3 /. G2 .s40 0 -o 0 ' o.794 5,32

g.82 0.472 0.00 1 1.29 Z.&91 29 77 -) 7 C, jL .j'.j o. /0 / - 4 .2q76 o ? /-37

4 . I o- 5o psa(I . 27; . 3 0 .o 7 4 ..)7 ____ _____4z 0 9 n. "1 . 77 Iq 2' 0,(711.3E w:7 -D .2 y

1? . rTl 0-l 10 & S .9j o. 0. : '.?9 4,9 0 -~ Q .( 2-0t , ). 74 n -25 n7 .7

Q 7 --5 -,13\ 2,11 1 0,Z6 ..72.TC 7 .2-,9 .1149 1,t '7 :A; C " /

32 0 5 0 -. 1 I ,5177 7~' n. -% !s .70-2

.'-oo 14. 7 9 5 -T1 76" 2. 1 t 1 m.7 0.4774,3, q-io o 177 g. z-.o T.3 7 02- ,7C, 5 c~o .5 0 , 24 -41,4 1.L.Sl >-2 L- 6 S( . 0 2 6S C q -,197 1.7-.A34 0517 121:1-4 OC41

Lk~s

.7&/ .;"/ 11 1 11 11/c 7

142

Sheet 2 of 2

CONSOLIDATED -'UNDRAINED TRIAXIAL TEST (continued)

Project Aj!VP Soil ( ~ Type of Test CA- uc. No. 7C4

Time ea (Ov'-G6h) (Au-A A -(hr) . (%) &vc a6vc- &h A _c _f

C. 373 2.rco Ojfj .3' / 0,S v 5.(%4:__ I..'7 o.'o A-2o ' 3% /.?60 (. .;a 4 .7 _ _,_

To 4 0.u ZE ,M /. . / 92 & -15-.(

9 793t W, q n 2. 6.01 e's /7 a- n, 0.

7,. f n. -;- I o. 179/ O


M.I.T.

SLLDA~A-(-

A

-2-1

ENGINEERING PROPERTIES OF THE ORINOCO CLAY

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