孤岛工作面瓦斯渗透规律与排放宽度研究

孤岛工作面的开采对煤炭资源的利用,在经济层面和国家资源战略方面都有重要的意义。本文以伯方煤矿3205孤岛工作面为研究对象,采用数值模拟、理论分析和现场观测手段,分析研究了孤岛工作面回采期间煤层渗透性变化特征,并确定了工作面瓦斯排放宽度。研究表明:3205孤岛工作面回采期间,工作面塑性应变大小与离回采面距离呈反比,等效塑性应变值呈半弧形分布,前方煤体渗透性分布呈现渗透骤增、部分增加、降低明显以及原始渗透四个阶段,瓦斯卸压区宽度为3~4m,工作面前方应力峰值距工作面8m左右;工作面瓦斯排放宽度随着煤巷暴露时间的增大而增大,当煤巷暴露时间为180d时,瓦斯排放宽度为26m。

Study on Gas Permeation Law and Discharge Width of Isolated Island Face

The exploitation of isolated island working face is of great significance to the utilization of coal resources in economic level and national resource strategy.In this paper,taking the 3205 island working face of Bofang Coal Mine as the research object,using numerical simulation,theoretical analysis and field observation,the change characteristics of coal seam permeability during the mining period of the island working face are analyzed and studied,and the gas emission width of the working face is determined.The results show that during the mining period of 3205 isolated island working face,the plastic strain of working face is inversely proportional to the distance from the mining face,and the equivalent plastic strain value is semi-arc distribution.The permeability distribution of coal body in front of 3205 isolated island working face presents four stages:soaring permeability,increasing permeability,decreasing permeability,and original permeability.The width of gas pressure relief zone is 3-4 m,and the stress peak value in front of working face is about 8 m away from the working face.The width of gas emission increases with the increase of exposure time of coal roadway.When the exposure time of coal roadway is 180 days,the width of gas emission is 26 meters.