Analysis of Formation Mechanism of Slightly Inclined Bedding Mudstone Landslide in Coal Mining Subsidence Area Based on Finite–Discrete Element Method

Abstract

In this paper, the formation mechanism of a slightly inclined bedding mudstone landslide in the overlying mountain of the coal mining subsidence area of the Tanshan Coal Mine in Ningxia, China, is studied. By means of geotechnical investigation, indoor geotechnical tests, theoretical analysis and other technical means, we find the geological environment background of the study area and obtain the physical and mechanical property indexes of the mining landslide in the Tanshan Coal Mine. By combining the numerical simulation of discrete elements and finite elements, the macro deformation and failure law of the mining mudstone landslide and the displacement and stress nephogram of the failure process are discussed. The results show that the slightly inclined bedding mudstone landslide in the Tanshan Coal Mine is 850 m long from east to west, 500 m wide from north to south and 10,875,000 m3 in volume. It is composed of Jurassic mudstone and is a traction landslide caused by the coal mining subsidence area. The formation of the landslide is affected by internal factors and inducing factors. The internal factors are mainly geotechnical types and engineering geological properties, and the inducing factors are mainly coal mining activities and rainfall. By analyzing and summarizing the calculation process of the slope model prior to the landslide in 2D-Block and GeoStudio numerical simulation software, the sliding process of the slightly inclined bedding mudstone landslide in the Tanshan Coal Mine is divided into four stages: slope creep, slope deformation, landslide movement and landslide accumulation. GeoStudio software is used to calculate the stability of the Tanshan Coal Mine landslide under natural and rainfall conditions. The landslide is in a stable state under natural conditions and is basically stable under rainfall conditions. By comparing the calculation results of the limit equilibrium method and the finite element limit equilibrium method, we find that the calculated stability coefficient is more accurate when the appropriate constitutive model is selected. The research results have important reference significance for the prevention and control of the gently inclined bedding mudstone landslide of the overlying mountain in the coal mining subsidence area of the Loess Plateau.

FDEM numerical study of the influence law of geostress on state and pressure of tunnel surrounding rock

“…The correctness and effectiveness of FDEM have been confirmed through laboratory and engineering scale simulations. FDEM has been widely applied in various fields including tunnel excavation (Lisjak et al, 2014;Lisjak et al, 2015a) and support (Lisjak et al, 2015b), surrounding rock reinforcement (Liu et al, 2019), slope stability analysis (Zhong et al, 2022), hydraulic fracturing (Yan and Zheng, 2017a;Yan and Zheng, 2017b), rock fracture acoustic emission (Lisjak et al, 2013;Zhao et al, 2015), complex rock block modeling (Yan et al, 2015), uniaxial compression (An et al, 2022), triaxial compression (Song et al, 2022), Brazilian splitting (Zhang et al, 2021), direct shear test (Min et al, 2020), rock thermal failure (Yan and Zheng, 2017c) and blasting failure (Trivino and Mohanty, 2015). However, the application of FDEM in studying surrounding rock pressure is still limited.…”