Numerical Simulation of Overlying Strata Caving in the Process of Face Advancing

In order to study the caving situation of overlying strata in the processs of face advancing,and based on the theory of support beam model and the principles of continuous media mechanics and damage media mechanics,the author simulated the whole process from crack being germinated and expanded to roof rocks being fractured by using RFPA2D analysis system,reproducing the weighting of overlying strata in coal mining and changing laws of shear stress and strata subsidence in the process of face advancing.The results showed that the thick roof rock controlled the movement of overlying strata and it was critical layer in rock system.In addition,with the face advanced forward,the area of abutment pressure increased was formed at the coal wall of working face and the subsidence of overlying strata continuously increased.