The physical and mechanical characteristics of saline soil are significantly influenced by salt content, with macro- and mesoscopic mechanical properties closely correlated. This study investigates the strength and deformation behaviors of saturated saline sand through indoor triaxial shear testing under varying confining pressures and salt contents. The key innovation lies in developing a coupled finite element and discrete element analysis model to simulate the mesoscopic behavior of saline sand under triaxial shear stress state. Flexible boundary conditions were applied, and appropriate contact models for salt-sand interactions were selected. By adjusting mesoscopic parameters, stress-strain curves and variations in porosity, coordination number, particle displacement, and contact force chains were analyzed. The study further explores shear band development and shear failure mechanisms by examining relative particle displacement and the breaking of contact force chains. Additionally, the influence of salt particle size on the overall strength of the DEM model was assessed. The findings provide valuable insights into the internal structural changes of saline sand during shear deformation, contributing to a better understanding of its mechanical behavior in engineering applications.

In light of its complicated makeup and fluctuating states of ice and salt crystals, it is challenging to forecast the strength of sodium sulfate saline sand. To examine the strength and deformation properties of sodium sulfate saline sand with various salt levels, many indoor triaxial shear tests were conducted at -2 degrees C, -5 degrees C, -8 degrees C, and 25 degrees C. The strength of sodium sulfate saline sand was found to be affected by temperature and the salt content, and the probable corresponding processes were then demonstrated. The introduction of the linear comparison composite (LCC) approach and homogenization theory led to the development of an upscaling strength model for sodium sulfate sand. Each phase's mechanical characteristics and the interactions between different components were taken into consideration. The triaxial tests of both unfrozen and frozen saline sand served as a basis for the developed strength prediction model's validation. It is believed that the findings of this study would shed light on how saline sand gains its strength from macroscopic and mesoscopic viewpoints.