Impact of stress path on hydraulic and mechanical behavior of compacted Al-Qatif clay

Expansive soils may naturally exist or used as a compacted material and its behavior should be examined under conditions simulating real field conditions. In field, there are two possible loading/wetting conditions may be experienced by expansive soils. One is that it may be flooded after finishing of structure construction, while the other possible condition is that where flood come first and followed by staged construction for the structure. This study simulates the probable field loading/wetting conditions and examined the impact of their sequence on the hydraulic and mechanical behavior of expansive soils at saturation. Results of the experimental program indicates that stress path sequence has an uneven influence on the hydraulic and mechanical behavior of expansive soils. Moreover, volume change potential, swell pressure (σ_s), hydraulic conductivity (k), as well as shear strength (τ_f) is dependent on applied axial stress (σ_a), however, the key variable of all these characteristics is the void ratio (e). Finally, impact of level of loading is more pronounced on hydraulic conductivity (k) than other investigated characteristics.