Research On The Law Of Air Leakage In The Goaf Of Fully Mechanized Coal Mining Face In Deep Thick Hard Roof Thick Coal Seam

With the continuous deepening of coal mining depth and the increasing promotion of roof-cutting technology,there are large differences in the law of air leakage in the goaf.Therefore,it is of great significance to study the law of air leakage in the goaf of the cut-top roadway in the thick coal seam with deep thick and hard roof.In this paper,the method of combining theoretical analysis,numerical simulation and field experiment is used to study the law of air leakage in the goaf of "Y"ventilation mode in the 1613A working face of Zhangji Coal Mine.This article first elaborates on the overlying rock characteristics of the cutting roof technology,and then conducts a detailed analysis of the rock mass distribution range and characteristics of the "three vertical zones" and "three zones of horizontal" in the mined-out area,and then according to the corresponding experience of the physical characteristics of different overlying rocks The formula calculates the height range of the caving zone and the fracture zone,and uses the UDEC numerical simulation software to simulate the overburden and fracture distribution range and characteristics of the mined-out area.Compared with the calculation result of the empirical formula,the height range of the caving zone is 0?22m,the height of the fracture zone ranges from 22 to 70m.The development of the cracks in the goaf conforms to the "O" ring theory in the horizontal direction.Enter the voltage stabilization area.According to the height range of the caving zone and fracture zone in the mined-out area,a three-dimensional physical model of the mined-out area of the corresponding size is established,and the air leakage range of the mined-out area in the 1613 A working face is numerically simulated by the Fluent fluid mechanics numerical simulation software,and the 1613A working face is obtained.The air flow line diagram of the air leakage area in the goaf,the air volume leaking to the goaf from the roadway section is 160m3/min.Along the direction of the working face,there are two serious air leakage areas in the goaf.The first air leakage area is 70m away from the lower corner.The flow of the road section is within 120m of the goaf in the upper corner,and the second area of air leakage is the flow direction of the cut-off hole at a distance of 70m from the lower corner of the road.Using dual tracer gas measurement technology to measure the air leakage range in the goaf of the 1613A working face,measure the air volume and pressure of the working face,the air inlet,return airway and the retaining section,and calculate and analyze the air leakage range in the goaf Integrating the tracer gas measurement results and energy level calculation results to obtain the air leakage range distribution in the goaf,and comparing the results obtained from the field measurement with the results obtained from the numerical simulation,it is concluded that the air leakage distribution ranges of the two are basically the same,so It also verifies the accuracy of the numerical simulation results.According to the actual situation of the air leakage area in the goaf of the 1613 A working face,specific measures such as hanging air tents along the return air trough along the reserved road wall and spraying to block air leakage have been formulated.Figure[25]table[10]reference[90]...