Vol18 No.4: 1034-1048
【Title】Dynamic process analysis of the Niumiangou landslide triggered by the Wenchuan earthquake using the finite difference method and a modified discontinuous deformation analysis
【Author】HUANG Da1, MENG Qiu-jie1, SONG Yi-xiang1*, CUI Sheng-hua2, CEN Duo-feng1
【Addresses】1 School of Civil and Transportation Engineering, Hebei University of Technology, Tianjin 300401, China; 2 State Key Laboratory of Geohazard Prevention and Geoenvironment Protection, Chengdu University of Technology, Chengdu 610059, China
【Corresponding author】SONG Yi-xiang
【Citation】Huang D, Meng QJ, Song YX, et al. (2021) Dynamic process analysis of the Niumiangou landslide triggered by the Wenchuan earthquake using the finite difference method and a modified discontinuous deformation analysis. Journal of MountainScience 18(4). https://doi.org/10.1007/s11629-020-6188-y
【Abstract】The Niumiangou landslide was the largest landslide triggered by the 2008 Wenchuan earthquake, which was significantly affected by the amplification effectof seismic acceleration. The ring-shear experiments indicated that the materials in the source area of the Niumiangou landslide were subjected to friction degradation under a big shear displacement, which may result in rapid movement of the landslide. In order to better understand the landslide movement and study the effect of the friction degradation on movement mechanisms, the dynamic process of Niumiangou landslide was simulated with a new numerical method, which combines the finite difference method (FDM) and the discontinuous deformation analysis (DDA). First, the FDM was used to study the initiation time, amplification effect and velocity of the landslide. Afterwards, these initiation velocities were applied to the blocks in the DDA model by corresponding coordination in the FDM model. A displacement-dependent friction model of the sliding surface was incorporated into DDA code to further understand the kinetic behavior of the landslide. The results show that the displacement-dependent friction strongly decreases the friction coefficient of sliding surface under a big displacement, which can obviously promote the run-out and velocity of landslide. The model output well matches the topographic map formed by the landslide. This implies that the proposed model can be applied to the simulation of earthquake-induced landslides with amplification effect, and the friction degradation model is important to clarify the movement mechanism of high-speed and long-distance landslides.
【Keywords】Wenchuan earthquake; Discontinuous deformation analysis (DDA); Niumiangou landslide; Amplification effects; Displacement-dependent friction model