Numerical simulation of the propagation process of a rapid flow-like landslide considering bed entrainment: A case study

Abstract

Bed entrainment plays an important role in the run-out process of a flow-like landslide. A limited number of studies have investigated the influence of entraining loose materials on the mechanical properties of a landslide, and some of them have considered bed entrainment either by mechanical or empirical methods. In this paper, a modified finite difference model was used to analyze the propagation process of a typical flow-like landslide with bed entrainment that occurred in the Jingyang loess tableland, China. In this model, the mechanical parameters of the sliding mass were modified according to the local entrainment depth. Triaxial Consolidated Undrained (CU) tests and ring shear tests were conducted to obtain the mechanical parameters needed in the numerical simulation. The triaxial CU tests were conducted on three intact loess samples taken at the back scarp of the landslide, and the ring tests were conducted on gravelly sand samples taken from the first terrace of the Jinghe River, which includes the landslide deposit. The results show that both the simulated run-out distance and final covering area agreed well with the field data. The modified model revealed the propagation process of this landslide. A major contribution of this study is that entraining the saturated gravelly sand contributed to the flow-like movement of the landslide. The case study investigated here is helpful for better an understanding of the flow-like transformation mechanism. In addition, the numerical model adopted in this paper can be effectively used to assess or predict the propagation processes of similar landslides.