Research on the three-dimensional spatio-temporal dynamic evolution and kinematic characteristics of loess landslides induced by strong earthquakes

Based on the discrete element method (DEM), a numerical simulation of the Xiamadazi landslide caused by the Haiyuan earthquake in 1920 was conducted in this study. The three-dimensional space–time dynamic evolution process of the loess landslide was reproduced, and its motion characteristics were analyzed, which laid a theoretical foundation for the effective prevention of loess landslides caused by strong earthquakes. The parameters are calibrated through multiple triaxial compression tests to ensure consistency between microscopic and macroscopic strength characteristics of loess, establishing a solid foundation for analyzing the landslide’s failure process and motion characteristics. Additionally, the contour line generated by digital elevation model ( DEM) is used to construct the landslide surface, which accurately reflects the terrain and truly reproduces the evolution process of Xiamadazi landslide under seismic action. The results show that the Xiamadazi landslide is a thrust-type landslide with shoulder cracking, the maximum average velocity of the landslide is 11.1 m/s, and the maximum average displacement is 534 m. The whole movement process reflects the characteristics of a fast sliding velocity, long sliding distance and wide disaster range. The Xiamadazi landslide is a loess landslide. In the process of landslides, many weak cements of loess are destroyed, and the destruction of weak cements of loess increases the impact energy and disaster range of landslides. This destruction is also an important factor in high-velocity loess landslides. The results of this study provide a reference for disaster prevention and mitigation in similar areas in the future.