Abstract:
This study is aimed at evaluation of the intrinsic properties of
Dhaka clay, their interactions and to develop a model for
predicting undrained shear strength. In this study, the undrained
shear strength (Su) behaviour was investigated for reconstituted
Dhaka clay subjected to Ko, isotropic consolidation followed by a
number of loading and unloading stress history. The intrinsic
parameters of the clay thus obtained were used to predict the
strength of natural Dhaka clay for various stress history and
stress conditions.
For the laboratory investigation, samples of Dhaka clay were
mixed with water (1.5 times the liquid limit) to form a slurry.
From slurry, normally consolidated and overconsolidated samples
of various overconsolidation ratios (OCR) were prepared under
different stress conditions. The slurry was consolidated in a
Rowe Cell. A 210 mm diameter Rowe consolidation Cell and test set
up was developed for this purpose. Four categories of samples
were prepared. For each category, cylindrical samples were
prepared by trimming into size of 38.1 mm diameter and 76.2 mm
height from the soil cake extruded from the Rowe Cell after
consolidation of slurry. The first category of samples (KoNC)
were Ko consolidated and sheared in triaxial compression in
undrained state. The second category of samples (KoOC) were Ko
consolidated and unloaded to a specified OCR value and then
sheared in undrained triaxial compression. The third category of
samples (KoINC) were Ko consolidated, extruded from Rowe cell and
reconsolidated isotropically to a higher pressure and then tested
to undrained compression failure. The fourth category of samples
(KoIOC) were subjected to same conditions as that for third
category but was unloaded to a preferred OCR before undrained
compression failure in triaxial apparatus. Stress-strain
behaviour for each category of samples were recorded --------------------
