Simplified Shear Deformation Method for Analysis of Mechanical Behavior of a Single Pile in Expansive Soils

Abstract

Seasonal volume changes associated with wetting and drying conditions due to infiltration and evaporation of water significantly influence the mechanical behavior of expansive soils. For this reason, rational design of foundations in expansive soils has been a challenge for the geotechnical engineers. Pile foundations have been found to be more suitable in carrying loads from the superstructure to the expansive soil below alleviating stability and deformation problems in comparison to other types of foundations. However, there is a lack of simple procedures in the literature to estimate how the load transfers from pile to the soil, which is the key information required in the rational design of pile foundations in expansive soils. In this paper, the conventional shear deformation method is modified to estimate the load transfer mechanism from pile to expansive soil taking account of the influence of infiltration and evaporation of water. The proposed approach is based on the mechanics of unsaturated soils and can be extended for single pile considering the influence of volume change behavior in expansive soils. In addition, parametric analysis undertaken in the present study suggests that the pile diameter and pile length significantly influence the mechanical behavior of piles in expansive soils. Geotechnical engineers can use the proposed method in routine design of foundations for expansive soils as the complexity associated with the estimation of pile mechanical behavior in expansive soils is significantly reduced.