Investigation of Sloped Surface Subsidence during Inclined Seam Extraction in a Jointed Rock Mass Using Discontinuous Deformation Analysis

In this study, the sloped ground subsidence of a jointed rock mass during tilted seam extraction was investigated using a trap-door model and discontinuous deformation analysis (DDA). In the trap-door model, the jointed rock mass was modeled by aluminum blocks. Sloped ground and inclined seams were produced by the rotary motion of the trap-door model around its center of rotation. The downward movement of the trap door simulated seam extraction, inducing subsidence of the sloped ground. A laser displacement sensor attached to the trap-door model during the extraction process recorded the ground settlement in digital data, which were used to plot subsidence profiles. Then, DDA was used to simulate the excavation process with the same geological conditions. The surface subsidence profiles in DDA were compared with those achieved with the trap-door model. Both experimental and computational results show that the change of the inclination angle affected the shape of the subsidence profiles. The surface subsidence profiles from the DDA simulation correlated well with those from the trap-door model. Thus, DDA is a potential method for predicting the sloped ground subsidence induced by mining extraction on inclined jointed rock strata.