Geomechanical evolution model of bedding rock landslides in construction areas: A case study of the Maidiping landslide in Tiefeng Town, Wanzhou

Abstract

Objective Engineering construction is the main cause and risk-bearing object for landslides, where excavation at the foot of a slope has a great impact on the stability of a slope. In the cascading slope areas, the progressive damage of soft inclusions such as mudstone shale under the combined effect of natural conditions and engineering activities has led to the occurrence of landslides on a large scale, which cause irreparable economic losses. Therefore, the destruction process of landslides needs to be analysed and discussed. Methods A geomechanical model of the landslide evolution process under the action of rainfall and engineering activities was established based on the investigation of a typical bedding rock landslide in Tiefeng Town, Wanzhou. The mechanical parameters of the soft muddied layer were obtained by ring shear experiments. FLAC3D was applied to simulate the shear deformation of the landslide under the conditions of manual excavation and rainfall, which was combined with the rigid body limit equilibrium method to analyse the trend of landslide stability and compare with the field survey results. Results The results show that the weak interlayer goes through two stages of natural slow softening and artificial excavation rapid softening and belongs to the strain softening model. The strength decreases continuously with the increasing shear displacement, and the strength decreases rapidly when a critical displacement is reached. The large deformation of Maidiping landslide occurs during the rainfall period after the excavation of the foot of the slope, which is consistent with the experimental results. Conclusion The experimental and simulated results agree with the results of field investigation, which verify the present geomechanical model of the cis-layered rock landslide. The results are of guidance for construction activities and disaster prevention and mitigation of cis-slopes.

Keywords

• bedding rock landslide
• weak interlayer
• geomechanical model
• ring shear test
• maidiping landslide