Investigation on overburden failure characteristic and height of water-conducted fracture zone due to fully mechanized caving mining

In order to study overburden failure characteristics and height of water-conducted fracture zone, the mining overburden failure process was analyzed by numerical simulation.The immediate roof failure mechanical model and the basic roof masonry beam instability mechanical model were established by theoretical analysis.The mechanical model of immediate roof failure and basic roof masonry beam instability was established by theoretical analysis method, and the mechanism of immediate roof failure and basic roof instability was revealed.Based on the mining geological conditions of 15201 fully mechanized caving face in Shengtai Coal Mine, the maximum height of water-conducted fracture zone under different mining height, dip length of working face and coal seam dip angle were studied.The research results show that: the mining height, dip length of working face and coal seam dip angle are positively correlated with the height of water-conducted fracture zone; the numerical simulation results of height of water-conducted fracture zone are within the range of calculation results of the "regular for coal pillar retention and coal pressing in buildings, water, railways and main shafts and lanes"; the rationality of the numerical simulation model and lithology parameters is verified.