In-situ investigation on coal mine overburden dump slope and its seismic stability considering heterogeneity

Abstract

Stability of the coal mine overburden (OB) dump slopes is many times compromised owing to the lesser availability of the in-situ characteristics of the OB dump materials and their spatial heterogeneity. In this study, multi-channel analysis of surface waves (MASW) investigation was carried out for the characterization of OB dump materials of Jambad opencast coal mine of India and the variation of heterogeneous in-situ characteristics has been reported in terms of statistical parameters. Next, the stability of a two-bench OB dump slope against seismic forces was investigated through finite element limit analyses coupled with random field theory utilizing Karhunen-Loeve expansion method for the spatial heterogeneity of the OB dump material. The effects of spatial heterogeneity of the OB dump material on the probability of failure and the critical pseudostatic seismic coefficient of the slope were investigated through Monte-Carlo simulations. The influence of spatial heterogeneity of OB dump materials were investigated with both isotropic and anisotropic correlation lengths. Finally, seismic slope stability analyses were also carried out using the discrete element method for the size heterogeneity of the OB dump materials. This study summarizes the effects of heterogeneity of material property and size on the seismic stability of OB dump slope.

Keywords:

• Coal mine overburden dump slope
• discrete element method
• finite element limit analysis
• Multi-channel analysis of surface waves (MASW) test
• random field theory

Acknowledgement

The first author acknowledges the financial support provided by MHRD, Govt. of India. The second author acknowledges Coal India Limited for providing financial assistance for the research (Project No. CIL/R&D/01/73/2021). The third author acknowledges the partial financial support provided by the Ministry of Human Resource Development, Government of India, under SPARC project titled “Geoenvironmental and Geotechnical Issues of Coal Mine Overburden”. Authors are also thankful to the anonymous reviewers for their comments to improve the manuscript.

Disclosure statement

No potential conflict of interest was reported by the authors.

Data availability statement

Some or all data used in the study are available from the corresponding author on reasonable request.