Simulation of static and dynamic liquefaction characteristics of sand based on discrete element method

To investigate the static and dynamic liquefaction characteristics of sand, we established axial compression and dynamic response models for circle sand samples subjected to undrained cyclic loading through discrete element numerical simulations. The dynamic responses of sand under varying densities, confining pressures, and loading amplitudes were analyzed. The findings indicate that the discrete element numerical simulation method effectively replicates both static and dynamic liquefaction behaviors of sand, with results closely aligning with laboratory triaxial test outcomes. Under dynamic loading conditions, an increase in the cyclic stress ratio correlates with a greater strain amplitude in the sand. Specifically, at initial confining pressures of 100kpa, 200kpa, and 300kpa, the number of liquefaction cycles observed was 5, 9, and 14 respectively. Higher confining pressures enhance liquefaction resistance; as pore ratios decrease and particle contact increases within the sand matrix, displacement between particles is more effectively constrained. Consequently, this leads to reduced susceptibility to significant deformation and liquefaction phenomena.