Effect of loading-induced stress history on the volume change behavior of a compacted highly expansive soil

Compacted expansive soils in situ are subjected to a variety of stress, boundary, and wetting conditions as well as different states of stress history. Investigating the volume change (VC) behavior of compacted expansive soils under conditions that replicate stress states and wetting conditions prevailing in the field is therefore essential to reducing the undesirable impacts of unrealistic assessment for such parameters from both an economic and safety perspective. This study presents a comprehensive investigation of the influence of loading-induced stress history on strain and stress states, in either the axial or lateral direction, during wetting under one-dimensional loading condition. The loading-induced stress history was found to influence wetting strain and axial and lateral swell pressure. Subjecting compacted expansive soil to higher stress history resulted in an increase in swell potential and a reduction in collapse potential, but with a unique void ratio state after wetting. The compression and swell indices (C_c and C_s, respectively) were found to be independent of pre-wetting loading-induced stress history. Finally, an enlargement of yield surfaces depicted in either (σ_a–s) or (p–q) space was observed.