Comprehensive analysis of dynamic instability characteristics of steeply inclined coal-rock mass

As an important source of energy and strategic commodities, coal is closely related with national economy, social development, and national security. This paper aims at stability control of coal-rock mass in steeply inclined coal seams roadway of Wudong coal mine in Urumqi mining area in Western China. Field survey and theoretical analysis are applied to gain theoretical criterion of dynamic instability of layer rock mass. Numerical calculation, physical simulation, and field monitoring are adopted to comprehensively analyze spatial-temporal evolution characteristics of layer rock mass around roadway influenced by structural anisotropy. Results show that deformation and instability of layer rock mass on the roof side of roadway begins with synthetic bucking, which occurs in the middle position of excavated free face. In addition, deformation and instability on the floor side begins with shearing slip in the bottom corner. Furthermore, numerical calculation shows that horizontal spans of the dynamic instability district on the roof and floor side are 2.1 m and 1.7 m respectively. Physical simulation shows that stress-concentrated areas on the roof and floor side are located in the middle and foot position respectively, the horizontal distance between the stress-concentrated area on the roof and the excavated free face is 1.2 m, and the one on the floor side is 0.8 m. Support modes and parameters are optimized based on analysis. Site monitoring shows that the maximum cumulative convergence of roadway is 39.2 cm, deformation rate is reduced by 82.2%, and dynamic instability disasters of the steeply inclined coal seams are effectively controlled, which has made contribution for energy science and social economy construction.