Abstract
The main objective of the present study is to investigate and evaluate the geo-environmental characteristics of continental Sabkha soil. This type of soil is widespread throughout the world, especially in Saudi Arabia. For the current work, disturbed and undisturbed samples are extracted from a site in Tymaa, Saudi Arabia. The natural geotechnical properties are determined, and chemical analyses are performed. Modified compaction, California bearing ratio (CBR), direct shear, and potential collapse tests are conducted experimentally on the soil, with the obtained results indicating that Sabkha soil is poorly graded sand and contains high concentrations of salts, causing a corrosive environment. Therefore, reinforced concrete foundations of structures built on this type of soil should be protected. In the tests, the compacted samples induce high values of shear strength and CBR. However, the soaked Sabkha soils show very low values of shear strength parameters and CBR compared to those of non-soaked samples. Hence, Sabkha soil indicates collapsible behaviour when soaked in water, which is attributable to the weak salt bonds between the soil grains. Also carried out in this work are numerical simulations of a fuel tank resting on unsaturated and saturated Sabkha soil, utilizing 2D and 3D Plaxis programs. The numerical analyses results show that while unsaturated soil has good performance under tank loads, it collapses under the loads when soaked in water. These outcomes match experimental results. In the limit state, the raft foundation on saturated soil shows greater values of settlement and internal forces compared to those of the raft foundation prior to immersion. Hence, Sabkha soil requires treatment before being built on.