Impact of drying-wetting cycles on shear properties, suction, and collapse of sebkha soils

Sebkha soils are known as saline formations that was rencontred generally in arid and semi-arid regions. With the alternation of drying-wetting cycles (D-W) these soils present variable morphological and geotechnical properties. These cycles D-W have an important effect on the mechanical behavior of sebkha soils which poses enormous problems for the construction of structures in general. In this study, compacted sebkha soil samples from Ain M'Lila, Algeria were subjected to three D-W cycles based on the natural drying process to reach the targeted water contents of 13, 11.4, 7 and 4%, in a laboratory environment. For each of these water contents, laboratory tests were conducted to study the effect of the D-W cycles on the collapse potential Cp, suction, and shear strength of the soil. The results obtained showed that the three components of suction, i.e., total, matric, and osmotic suctions decreased when the number of D-W cycles increased. Moreover, the collapse potential Cp increased with an increase in the number of D-W cycles. Moreover, the results obtained illustrated that the shear strength parameters were affected by the number of D-W cycles a significant decrease in cohesion and an increase in the internal friction angle were observed when the number of D-W cycles was increased. Finally, a correlation was found between the soil salinity and the three factors studied these were affected by the decrease in salinity under the effect of D-W cycles.