Simulation of roof shear failure in coal mine roadways using an innovative UDEC Trigon approach

Shear failure is a common failure mechanism in underground coal mine roadways. This paper presents an innovative numerical approach to simulate shear failure of a coal mine roadway roof. The distinct element code, UDEC, incorporating a proposed Trigon logic is employed for the study. Using this approach, shear failure in the mine roof characterized by fractured initiation and propagation is successfully captured. The results suggest that shear failure of the roadway roof initiates at the roadway corners and then progressively propagates deeper into the roof, finally forming a large scale roof failure. The numerical results confirmed the time sequence of marked microseismic activity, significant stress changes and accelerated displacement during the process of a roof fall. The effect of rock bolting in the control of roof shear failure in a roadway is evaluated using the UDEC Trigon approach. It is found that the installation of rock bolts constrains rock dilation, reduces failure of rock bridges and maintains rock strength thereby leading to a significant decrease in roof sag.