1D Constitutive Model for Expansive Soils

Modeling the element behavior of expansive soil with cyclic variations of its water content in stress and time dimensions is a challenging topic. In this paper, a one-dimensional (1D) model will be proposed to provide an estimation of soil deformation. To simplify the model, the effect of suction in an expansive soil will be considered indirectly in the values of the model parameters, and the model parameters will be determined via current testing methods. This paper aims to describe the behavior of unsaturated soil in a relatively simple and pragmatic manner, meanwhile, the model parameters will be determined via methods that engineers are familiar with. The performance of the model will be demonstrated and verified against experimental data for two categories of soil behavior: (1) time-dependent swelling behavior, and (2) stress-induced compression behavior. The practical approach used in this paper could be useful and eventually help to find solutions for some complicated practical problems where the influence of both categories of soil behavior need to be taken into consideration.