Desiccation Theory for Soft Cohesive Soils

Abstract

A new desiccation theory is developed that provides a rational framework for the consolidation and desiccation analysis of soft fine-grained waste soils. The theory includes four consecutive segments that correspond chronologically to the phases that a soft soil layer undergoes in the field after deposition: consolidation under one-dimensional compression; desiccation under one-dimensional shrinkage; propagation of vertical cracks and tensile stress release; and desiccation under three-dimensional shrinkage. A general form of the finite strain governing equation of the overall consolidation and desiccation process is formulated. It includes the cracking function and the nonlinear constitutive relations. The experimentally obtained consolidation and desiccation characteristics for soft china clay, which are needed for the overall analysis of a given field problem, are presented. The predictions of this theory for the response of a hypothetical soft china clay layer undergoing self-weight consolidation, seepage consolidation, and desiccation due to lowering of the ground-water level or surface drying are presented and discussed.