Constitutive modeling approach for estimating1-Dheave with respect to time for expansive soils

Many studies are reported in the literature for estimating the potential heave of expansive soils; however, limited efforts have been directed towards estimating the heave with respect to time. In this Technical Note, a simple approach is proposed for estimation of the one-dimensional (1-D) heave of expansive soils over time. The approach involves integrating semi-empirical and numerical techniques into a unified method to estimate heave in response to the net changes in soil suction within the active zone. The information of the variation of modulus of elasticity with respect to suction is introduced into the soil structure constitutive equation proposed by Fredlund and Morgenstern (1976) to estimate the soil heave over time. The commercial software VADOSE/W, a product of Geo-Studio, is used as a tool to estimate the net changes in the soil suction. The approach is tested using the published results by Vu and Fredlund (2006) for Regina expansive clay. The estimated results of the proposed approach agree well with the published data in terms of both the total heave variations and matric suction changes in the soil. The proposed method is promising and can be used in engineering practice for estimation of the 1-D heave with respect to time.