Prediction of Lateral Swelling Pressure in Expansive Soils

Lateral swelling pressure (LSP) develops in silty or clayey soil when the volume expansion of soil is constrained in the horizontal direction. Determination of LSP is important in designing geotechnical structures in expansive soils. Existing methods for derivation of LSP requires several empirical parameters, which are hard to obtain. Furthermore, the majority of the existing models determine LSP assuming the soil is fully saturated which may lead to an over conservative design. Considering the aforementioned limitations, this paper presents an analytical solution for determination of LSP in unsaturated soils. The proposed method attributes the soil expansion to changes in suction stress during infiltration and uses the effective stress-strain relationship to quantify LSP. The proposed model only needs a limited number of soil properties such as the soil water retention curve (SWRC) and Poisson's ratio along with initial and final soil water contents. The method is compared against an alternative solution and is then used in a set of parametric study to evaluate LSP for four soils. Results suggest that the proposed model can reasonably predict LSP in expansive soils.