Monotonic and Cyclic Behavior of Salt-Encrusted Flat (Sabkha) Soil

Abstract

Sabkha (salt-encrusted flat) soils are problematic because they lose strength due to wetting, and they have liquefaction potential. These soils are spread in North Africa, Australia, and most of the Eastern Province of Saudi Arabia. Owing to a lack of experimental studies, the cyclic behavior of sabkha soils is relatively unknown. The monotonic and cyclic behaviors of sabkha soil were studied based on effective stress (50, 100, and 150 kPa) and cyclic stress ratio (CSR) (0.15, 0.35, and 0.65) using cyclic triaxial and bender element tests. Results indicate that the sabkha exhibits ductile behavior with the cohesion value of 9.33 kPa and a friction angle of 33°. The maximum shear moduli are 18,900, 49,500, and 63,500 kPa for effective confining pressures of 50, 100, and 150 kPa, respectively. Furthermore, the shear modulus tended to decrease with shear strain for different cyclic stress ratios. On the other hand, the damping ratio depends on the level of the cyclic stress ratio. At a cyclic stress ratio of 0.15, the damping ratios remained constant with shear strain. For a cyclic stress ratio of 0.65, the damping ratios decreased with shear strain. However, at a cyclic stress ratio of 0.35, the damping ratio varied with shear strain depending on effective stress.