Anomalous dynamic response and micro-zonation of saline sabkha soils of eastern Saudi Arabia using 3D seismic behavior modelling

The available seismic response parameters do not accurately represent the unusual behavior of sabkha soils; the weak soils with high salt content. This study aimed at developing seismic response parameters for sabkha soils in Ras Al-Khair Industrial City, Saudi Arabia. These sabkhas revealed an anomalous response to geophysical and dynamic tests. The methodology involved analysis of extensive available data to come up with micro-zonation based on subsurface strata. Field and laboratory explorations were conducted, and 3-D seismic response was numerical simulated. This study identified an anomalous dynamic response of sabkha soil, as it has higher shear modulus. The spectral accelerations values, for both short-period and long-period, have been found to differ from the values specified in local codes. Scientific contributions include the localized liquefaction potential along the boundary of the contrasting strata. The site-specific seismic response is found to be not only dependent on the structure and fabric of the soil, but also highly affected by the pore fluid. Originality appears in utilizing 3-D modelling/ simulations to produce liquefaction hazard maps. It is concluded that 3-D modelling/simulations lead to a more realistic representation of ground conditions. The seismic parameters are recommended to be revised based on 3-D modelling that considers the type of pore fluids.