Closure of "Effect of Sampling Disturbance on Properties of Singapore Clay"

This paper examines results from triaxial unconfined compression tests and undrained compression tests on reconsolidated samples of a Singapore marine clay retrieved using two sampling methods that offer differing quality of samples. Both local internal strain measurements using a Hall-effect transducer and external strain measurements using LVDTs were employed in the triaxial tests. Bender elements were embedded in some of the samples to establish the maximum shear modulus. If the samples are not reconsolidated, the shear strength and stiffness determined from triaxial tests are found to be sensitive to the quality of the samples, and generally lower than that determined by in situ tests. However, if the samples are subjected to isotropic or \iK\d0 consolidation to the estimated in situ condition, there is little difference between the shear strengths of samples retrieved using different samplers, and also consistent with results from vane shear tests. However, for the maximum shear modulus, even with reconsolidation, there is still a 10% difference between the results from samples retrieved using different samplers. Further, the laboratory determined maximum shear moduli are about 10% lower than the value determined in an in situ seismic cone test.

[1]  C.R.I. Clayton,et al.  The use of hall effect semiconductors in geotechnical instrumentation , 1989 .

[2]  Pankaj Sharma,et al.  COMPARATIVE STUDY ON SAMPLE QUALITY USING SEVERAL TYPES OF SAMPLERS , 1996 .

[3]  Dm Milovic.  Effect of Sampling on Some Soil Characteristics , 1971 .

[4]  R. Jardine,et al.  Evaluation of Geotechnical Parameters from Triaxial Tests on Offshore Clay , 1985 .

[5]  B. Hardin,et al.  VIBRATION MODULUS OF NORMALLY CONSOLIDATED CLAY , 1968 .

[6]  K. H. Head,et al.  Manual of soil laboratory testing , 1980 .

[7]  Fumio Tatsuoka,et al.  Measurements of elastic properties of geomaterials in laboratory compression tests , 1994 .

[8]  J. Graham,et al.  Stress release, undrained storage, and reconsolidation in simulated underwater clay , 1987 .

[9]  C.R.I. Clayton,et al.  Effects of sampler design on tube sampling disturbance—numerical and analytical investigations , 1998 .

[10]  J. H. Atkinson,et al.  Interpretation of bender element tests , 1995 .

[11]  R. Jardine.  Some Observations on the Kinematic Nature of Soil Stiffness , 1992 .

[12]  Chung-Tien Chin,et al.  Disturbances Due to “Ideal” Tube Sampling , 1987 .

[13]  C.R.I. Clayton,et al.  Progressive destructuring of Bothkennar clay. implications for sampling and reconsolidation procedures , 1992 .

[14]  Richard J. Jardine,et al.  The measurement of soil stiffness in the triaxial apparatus , 1984 .

[15]  Yit-Jin Chen,et al.  UNDRAINED STRENGTH INTERRELATIONSHIPS AMONG CIUC, UU, AND UC TESTS. DISCUSSION AND CLOSURE , 1993 .

[16]  Richard J. Jardine,et al.  FIELD AND LABORATORY MEASUREMENTS OF SOIL STIFFNESS. PROCEEDINGS OF THE ELEVENTH INTERNATIONAL CONFERENCE ON SOIL MECHANICS AND FOUNDATION ENGINEERING, SAN FRANCISCO, 12-16 AUGUST 1985 , 1985 .

[17]  M Bozozuk.  Effect of Sampling, Size, and Storage on Test Results for Marine Clay , 1971 .

[18]  P. W. Rowe,et al.  Importance of Free Ends in Triaxial Testing , 1964 .