Unsaturated and Saturated Soil-Structure Interface Effect on Cracking Behavior of Soil

Soil-structure interfaces occur at the contact surfaces between the soils and the engineering constructions, such as retaining wall, foundations, and others, where reciprocal transition of stresses takes place at interfaces. An intrinsic motivation of this work stemmed from observations of problematic behavior of natural deposited soils and engineered soils during drying-wetting processes due to variations in annual thermal conditions. In response to variations in environmental conditions, unsaturated soils may experience different hydraulic, and mechanical behavior under wetting and drying processes due to hysteresis. This may cause evolution and propagation of cracks in the soil. In this study, four drying tests (shrinkage tests) were performed using identical circular plates. Two plates were fabricated; one with smooth-base and the other one with circular-grooved-base. The smooth plate was employed to allow the soil sample to shrink freely without crack formation, while the groove plate was used to provide restraints during shrinkage where cracks may develop during drying process. Furthermore, soil samples were tested under saturated and unsaturated in order to investigate the influence of initial moisture conditions of soils on the initiation and propagation of cracks during one drying and wetting cycle. Crack patterns were quantitatively obtained using image analysis techniques. The results of the drying tests refer to the important impact of soil-interface and the initial saturation conditions on the initiation and propagation of cracks during wetting and drying cycle.