Assessment of the effects of initial water contents on the pore pressure response of reconstituted clays

Abstract

Isotropically consolidated undrained triaxial compression shear tests were performed on three reconstituted clays to investigate the effects of initial water contents on the pore pressure behaviour. The test results show that during undrained shearing the excess pore pressure normalised by isotropic consolidation pressure has a linear relationship with the effective stress ratio under a given initial water content, and the slope of the linear relationship changes with initial water contents for a given reconstituted clay. The pore pressure coefficient at failure also varies with initial water contents, ranging from .5 to .96 for the reconstituted clays investigated. By comparing the pore pressure response induced by shear stress, the mechanism of decrease in undrained strength with an increase in initial water content is identified from higher shear-induced pore pressure. Finally, a simple equation is also proposed to link the slope of linear relationship between normalized pore pressure and effective stress ratio with undrained strength and effective friction angle.

Keywords:

• clays
• initial water content
• excess pore pressure
• effective stress ratio
• pore pressure coefficient at failure

Disclosure statement

No potential conflict of interest was reported by the authors.