A Simulation Study of Loess Slope Instability and Damage Under Intensive Seismic Vibration

Abstract The instability and damage of the loess slope under intensive seismic vibration can be a complicated process, involving in sliding, horizontal displacement and rotation, which makes the particle flow code a suitable theory to simulate the instability and damage of the loess slope. In this study, based on both field investigation and indoor experiments, PFC2D program was adopted to simulate the instability and damage process of the loess slope landslide under intensive seismic vibration through the detailed identification of relevant parameters, model building and dynamic input. The analysis has revealed three main findings. Firstly, the volley surface structure dominated in the slope tends to magnify the vibration, resulting in intensive vibration of the soil body on the slide surface and an increased high frequency components of Fourier spectrum. Secondly, under the dynamic forces, the slope first accumulates and damages in the lower part, forming a shear outlet. Under the pulling of the lower particles, the difference between the first principal stress and the third principal stress gradually increases, destroying the inherent cohesive contact between the particles, leading to the instability damage. Thirdly, the upper soil body experiences tensile damage, forming a through slide face which causes the instability damage of the whole slope. The sliding face demonstrates in a oval shape, with a deeper arch as the vibration lasts longer.