Effect of mining-induced abutment pressure on gateroad and grouting-based bolting technology: A case study

Abstract

Longwall roadway suffered from mining-induced abutment pressure caused by the consequent large roof movement is a major concern in underground mining. In this study, a novel grouting-based bolting technique was put forward for Headgate 1404# of Xintian Coal Mine, China. Compared with the traditional support methods of single prop and hydraulic support, the proposed method has the advantages of low labor intensity and high improvement of surrounding rock. The field investigation on the effect of mining-induced abutment pressure on the roadway and calibrated numerical models on parameter verification are the key technical design of the proposed grouting-based bolting method. The field investigation showed that in the range of 0–30 m from the faceline, roof-to-floor convergence and roof fracture of the roadway were significant, which affected the stability of the roadway. In our designed scheme, grouting anchor cable was employed for roof pre-reinforcement through grouting the cement and sodium silicate into the roof; the grouting depth was 8 m, and the grouting position was 30 m ahead of the mining operation. The reliability of this scheme was verified by the comparison of stress field, skin convergence, rock fracture and grouting diffusion via the numerical simulation. The simulation results show that after applying grouting-based bolting, the range of maximum principal stress reduction, deformation and the fractured zone around the roadway is smaller than that of the traditional single support. Compared with the traditional method, the convergence of roof-to-floor and rib-to-rib after the implementation of the proposed method decreases by 64.5 % and 82.0 %, and the fracture depth of the roof and ribs decreases by 66.4 % and 38.2 %, respectively. The proposed grouting-based rock bolting significantly improves the resistibility of roadway surrounding rock to the mining-induced abutment pressure, which is beneficial for roadway retaining after mining.