Similar Simulation Test of Overlying Rock Failure and Crack Evolution in Fully Mechanized Caving Face with Compound Roof

In the process of coal mining, the characteristics of overburden failure and the evolution of cracks were of great significance to the prevention and control of mine water and gas by using similar simulation test to study the overlying rock failure and crack evolution law of Yuwu Coal Industry's compound roof and large cutting height fully mechanized caving face. The results show that: the height of the caving zone is 32.6 m and the height of the fracture zone is 64.6 m; The influence of coal seam mining process on the supporting pressure of the roof overlying rock, the near seam was larger, the far seam was smaller; The inclination angle of the overburden mining fissures was medium angle, the width was mainly medium width, and the number of fissures gradually decreases as they move away from the coal seam; During the mining process, the overlying strata of the coal seams at a short distance are the gathering areas of mining cracks, and the density curve of the overlying cracks presents a "wave" shape.