The Main Controlling Factors And Influence Laws Of The Gas Drainage Effect Of The Long Hole In The Roof

Mining fracture field in roof is a mining space good channel for the unloading of gas pressure.It is an effective way to control the gas by using the mining fracture field in the working face and the goaf.High-level drainage roadway is a more mature technology,and it has significant gas drainage advantages in the mined-out area and adjacent to solve the upper corner of the gas overrun or other issues,which also was criticized because of the high cost and long cycle.In recent years,with the development of drainage equipment and drainage technology,long boreholes in roof gradually become popular,not only greatly reduce the amount of work,reduce costs,and construction and mining operations can be carried out at the same time to avoid the mining from taking over tension.The influenced rule of the main controlling factors of the long boreholes in roof has an effect on the guidance of the on-site drainage practice.Therefore,it is of great significance to study the influence rule of the main control factors in this paper.Aiming at the influence rule of the main factors of long boreholes in roof and the feasibility of replacing high-level drainage roadway,the study work of this paper mainly includes the following three aspects:(1)Analysis of gas drainage model from long boreholes in roof and influenced radiusTo further study the mechanism of gas flow roof long boreholes drainage,the mathematical model of long boreholes drainage in roof is derived,and through theoretical analysis and numerical simulation of different main controlling factors for gas drainage effect of mining,putting forward the top plate fracture field drainage is different from the pre-drainage coal seam drainage of the effective influenced drainage radius the determination method.(2)Analysis of numerical simulation of long boreholes gas drainage in roofBased on the COMSOL software,the numerical model of the long boreholes gas drainage is established,and the influenced rule of the main controlling factors of the long boreholes gas drainage is analyzed,and a new determination methods of the gas drainage radius based on the fracture field of the roof is put forward,the method of determining the effective drainage radius of the roof fracture field are validated,and the influenced rule of the radius of extraction on the drainage spacing is analyzed.(3)On-site test analysis of long boreholes drainage instead of high-level drainage roadwayAiming at the feasibility study of the long boreholes drainage instead of the high-level drainage roadway,the coal mining experiment of the long hole in the Xinji No.2 Mine is carried out,and compared with the high-level drainage roadway in the mining effect and the engineering cost.The economic formula and geology and economic applicable conditions for replacing high-level drainage roadway is obtained.