Discrete element analysis of deformation and failure characteristics in a slope affected by corrosion deterioration and underground mining: a case study of the Jiweishan landslide, China

Abstract

The present study uses the Jiweishan landslide in Wulong District, Chongqing City, China, as an example to design a numerical simulation technique to examine two environmental consequences: corrosion deterioration and underground mining. A shear strength prediction model for the corrosion rate of the structural plane was thus proposed by mimicking the time-dependent weakening characteristics of structural planes by using strength reduction. The discrete element simulation method was applied to reproduce the complete process of dangerous rock body movement and slope instability under the effects of these two factors to clarify the influence of environmental and engineering effects on slope deformation behaviour. This was intended to clarify the overburden movement process, fracture evolution law, and rock formation subsidence characteristics of karst mountains affected by mining from the perspective of geomechanics, and the results showed that the deformation evolution process of the Jiweishan landslide can be divided into two stages: the slow chronic deformation caused by long-term corrosion deterioration and the more severe acute deformation caused by short-term underground mining. The overburden movement and fracture evolution seen under corrosion deterioration and underground mining thus represent a progressive evolutionary process with full spatial and temporal continuity. Corrosion is a long-term synchronous process that creates the transformation of numerous structural planes around a dangerous rock body. Underground mining, in contrast, is typically a short-term trigger factor that can nevertheless easily cause significant differential adjustment of the movement characteristics of different parts of a dangerous rock body that result in distinct spatial differentiations of dangerous rock body movement. Further, the subsidence deformation characteristics of the rock formation plane mainly depend on the spatial position and scale of the goaf created by such mining. Analysing the stress characteristics of the relevant inclined rock strata helps clarify the control mechanism of a mountain’s spatial structure’s adaptive adjustment. The simulation results in this case were also compared with the results of centrifuge tests and physical model tests to verify the rationality of the simulation scheme, and the conclusions thus remove provide an important reference for the study of landslide development processes and instability mechanisms under multi-factor coupling conditions.