Numerical Simulation of the 2017 Xinmo Catastrophic Landslide Considering Entrainment Effect

Abstract

The mass movement process of the 2017 Xinmo catastrophic landslide was simulated using the discreet element method (DEM). Field investigation indicates that the basal entrainment is a typical feature of this landslide. Hence, the entrained colluvium on the sliding path is considered in the DEM model. According to the terrain elevation data before and after sliding, the slope geometry is divided into three parts: sliding bed, sliding body, and colluvium on the path. The blocks are generated in MATLAB and a fill-remove method has been used to produce the loose colluvium. The key parameter, contact friction angel, which controls the mobility of mass movement, has been obtained through displacement back analysis. The simulated deposit area and main sliding time coincide with actual landslide characteristics. Simulation results indicate that the colluvium is pushed to the bottom of the Songpinggou Valley by the sliding body. The local topography has a significant influence on the sliding direction. Some typical phenomena of substrate entrainment, including frontal plowing, mass spray, shear zones in substrate, thickened substrate, and basal abrasion, are observed in the DEM simulation. During the entrainment process, the frontal plowing, or the thrust, plays an important role in creating the substrate failure compared with basal abrasion. After the failure of the whole colluvium, the magnitude of thrust descends quickly but is still slightly larger than that of shear thrust. Entrainment of dry material on the slope leads to more friction energy consumption and reduces the mobility of mass movement. This work shows a good capability of simulating entrainment of dry materials using a discreet element method and highlights the significance of plowing relative to the basal abrasion under conditions of limited path material supply.

A large frozen debris avalanche entraining warming permafrost ground—the June 2021 Assapaat landslide, West Greenland

“…The latter is dropping sharply below the secondary scarp at the Assapaat frozen debris avalanche as shown by our volume calculation. Also, Chen et al (2020) showed through numerical modelling of the 2017 Xinmo landslide that entrainment of dry material on the slope leads to more frictional energy consumption and a reduction of landslide mobility. We therefore conclude that entrainment of the large dry permafrozen volume inside the secondary scarp together with the low slope gradient consumed a large fraction of the kinetic energy of the frozen debris avalanche.…”

Description and Dynamic Analyses of the 1935 Luchedu Rock Avalanche in Sichuan, China

“…Luchedu landslide is on the eastern edge of the Qinghai Tibet Plateau. A few similar severe slope disasters occurred there, including the Lannigou landslide and Yigong landslide [1][2][3][4], all of which evolved from rock slides or rock falls at the beginning to a disaster chain event of dam building, river blocking, and collapse. Through field investigation, the Luchdu landslide had the characteristics of high speed and fluidization and was full of detritus, feasible to be categorized as a rock avalanches or debris avalanches.…”

Large-Scale Field Test Study on Failure Mechanism of Non-Cohesive Landslide Dam by Overtopping

“…Landslide dam is one of the most devastating natural disasters worldwide, especially in the mountainous areas of Southwest China. As a result of earthquake, rainfall, snow melting and other factors, soil or rock slopes slide and block the valley or river, forming a landslide dam (Costa and Schuster, 1988;Korup, 2002;Dunning et al, 2007;Huang, 2009;Chen et al, 2020;Zhou et al, 2020). As a natural dam, the landslide dam body consists of loose and un-compacted materials, and it is easy to burst in a very short time, resulting in a large number of floods, threatening the safety of life and property in up-and-down stream districts (Zhou et al, 2013;Fan et al, 2014;Zhou et al, 2016;Choi et al, 2018;Liao et al, 2020).…”