Change of critical state lines of reconstituted clays with initial water contents

A series of isotropically consolidated undrained triaxial compression shear tests are performed on two kinds of reconstituted clays with different initial water contents to investigate the effect of the initial water content on the critical states. It is found that the stress-strain curves and the effective stress paths of the reconstituted clays are significantly affected by the initial water content. There exists the critical stress ratio for a given clay at the given initial water content which is not dependent on the confining stress. More importantly, within the theoretical critical state framework, the critical state line is not unique for the given reconstituted clay with an intrinsic nature. The change of the critical state lines with initial water content is discussed in p´-q plane and v-ln p´ plane, respectively. The variation of the critical state parameters with the initial water content is analyzed.