Time-dependent strength behavior of dredged clays at low effective stresses

Abstract

This paper presents an experimental investigation on the effects of initial water content and time during secondary compression on the strength behavior at low effective stresses of dredged clays obtained from two places in China. A suite of vane shear tests was conducted on clay samples consolidated at 16 kPa using the self-developed compression apparatus. Tests results showed that the shear angle corresponding to the peak shear stress almost increases with the decreasing time during secondary compression and the vane shear stress increases with decreasing initial water content at the same shear angle. A significant increase in peak strength with time during secondary compression was observed compared with the insignificant increase in residual strength. The normalized strength increases linearly with log time during secondary compression. The undrained strength of dredged clay specimens with different initial water contents consistently increases with time during secondary compression. The strength and time curve for specimens at lower initial water content lies above that at higher initial water content. A quantitative expression of normalized strength as functions of normalized water content and time during secondary compression was obtained. The proposed equation is verified by comparing the calculated results and measured results for other sources of samples.