Soil liquefaction is a prevalent seismic hazard. However

current indoor and model experiments studying the dynamic characteristics of sand liquefaction struggle to accurately represent the actual soil liquefaction process. The computational fluid dynamics (CFD) coupled with discrete element method (DEM) simulation method can accurately simulate various soil-water coupling problems. The CFD-DEM flow-solid coupling module facilitated the exchange of mechanical information between the commercial discrete element software PFC3D and the open-source computational fluid dynamics software OpenFOAM. The feasibility of this approach was confirmed through particle underwater free settling experiments. Calibration of numerical sand specimens with dynamic characteristics of real saturated sand was conducted using PFC3D software through simulated indoor cyclic triaxial tests. Based on the existing parameter information and the coupled simulation method

a site liquefaction model of saturated sand was established. The simulation results indicate that the discrete element method (DEM) can replicate indoor sand liquefaction experiments

and the calibrated parameters can be applied to site liquefaction simulations. The consistency between the settling velocity of individual particles and theoretical solutions validates the accuracy of the CFD-DEM coupling method. Under a peak acceleration of 0.25g

liquefaction occurs at various depths

and the ratio of excess pore pressure does not exceed 1 during liquefaction. The cumulative excess pore pressure increases from shallow layers to deep layers. After liquefaction

the soil strength gradually recovers from bottom to top

and the soil structure in the re-consolidated site shows a trend of homogenization.