A numerical study on the strata movement induced by mining under a jointed-rock slope

Abstract

With the depletion of mineral resources in recent years, the hanging-wall orebody under the final slope needs to be extracted after opencast working in an open-pit mine. Because of the slope-free face and the special mining position, this process will lead to a significantly different strata movement compared with traditional underground mining. The discrete-element method (DEM) is a common approach to studying mining-induced strata movement considering the influence of the joint. Using DEM, this paper reveals the sensitivity of the strata movement induced by mining under the final slope to the key joint-evaluated parameters (friction angle ϕ and cohesion c) and obtains the strata movement characteristics under different joint strengths. The main conclusions are as follows: (a) the strata movement is more sensitive to ϕ than to c; (b) ϕ is positively associated with the strata movement angle θ, whereas there is no apparent correlation between c and the strata movement angle θ; and (c) there are four primary strata failure modes and three typical strata movement processes under different joint strengths, and the mechanical analysis is given. These conclusions could benefit the back-analysis of strata movement using DEM and understanding the joint impact on the strata movement induced by mining under the final slope.