Deformation mechanism and medium- and long-term landslide prediction model of Xinpu Xia'ertai landslide

Abstract

Due to the influence of reservoir water level, rainfall and geological conditions, the Three Gorges Reservoir area is a landslide hazard-prone area, and the landslide genesis mechanism and evolution process are also extremely complex.By taking the Xinpu Xia'ertai landslide as an example, this paper summarizes and analyses the resurgence law of large palaeo-landslides based on multiple sources of data, such as GPS displacement monitoring data, fracture data, rainfall and reservoir water level, and through a geotechnical creep compression model. The paper also verifies the mechanism of fracture formation on the trailing edge of the displaced landslide.The results show the following: ①Rainfall is the dominant factor of landslide deformation. Landslide deformation causes the landslide body to produce cracks and form rainfall infiltration channels, which intensifies rock fragmentation and weak layer mudification and reduces landslide stability; besides, concentrated and continuous rainfall can destabilize landslides. ②By comparing the predicted value of the model with the surface monitoring data, it is feasible to take annual rainfall as the controlling factor in the medium- and long-term landslide prediction model and help to improve the prediction accuracy of landslides. ③Pushing landslide trailing edge cracks consist of landslide pushing displacement and geotechnical body compression. In this paper, the compression creep model is introduced to calculate the crack width and compare it with the monitoring data. This shows that the compression creep model is suitable for this type of slope, and the average deformation modulus of the geotechnical body is obtained by applying the backpropagation of the geotechnical body creep compression model. Thus, we judge the degree of rock fragmentation, which provides a reference for landslide stability analysis and subsequent engineering management.

Keywords

• xinpu xia'ertai landslide
• deformation mechanism
• rainfall driven landslide
• landslide prediction
• creep compression model
• tensile crack