Strata behavior of high-intensity mining face crossing dipping coal pillar under thick stiff key stratum
厚硬关键层下强采动工作面过倾向煤柱矿压显现规律

摘要

基于上覆倾向煤柱对下伏煤层强采动过程中带来的强矿压、煤壁片帮等风险，通过FLAC3D软件进行工程建模，分析了上覆煤层开挖后底板应力分布特征，获得了工作面过倾向煤柱过程中应力的演变规律。结果表明：（1）22煤开挖后，煤柱正下方出现应力集中，应力最大值约为18MPa，上覆煤柱强影响范围在煤柱两侧各60m左右。（2）42202工作面在过煤柱的过程中，工作面超前支撑压力影响范围与煤柱下方应力集中区逐渐贯通，并形成条带式应力集中区；并随着工作面推进逐渐发生旋转，直至工作面推过煤柱后，两应力集中区逐渐分离。（3）工作面处于煤柱下方时，工作面超前支撑压力峰值最大，约35MPa；工作面进煤柱前次之，约33MPa；工作面出煤柱后最小，约24MPa。工作面进煤柱前，超前支撑压力影响范围最大，约150m~200m；工作面处于煤柱正下方时约80m~100m；工作面过煤柱后的超前支撑压力影响范围最小，约45m~70m。

Abstract

Based on the risks of strong mining pressure and coal wall fragmentation caused by the overlying inclined coal pillar during the strong mining process of the underlying coal seam, FLAC3D software was used for engineering modeling to analyze the stress distribution characteristics of the bottom plate after the excavation of the overlying coal seam, and the evolution law of stress during the process of the working face passing through the inclined coal pillar was obtained. The results showed that: (1) After the excavation of coal seam 22, stress concentration occurred directly below the coal pillar, with a maximum stress value of about 18MPa. The strong influence range of the overlying coal pillar was about 60m on both sides of the coal pillar. (2) During the process of passing through the coal pillar, the pressure influence range of the advanced support of the 42202 working face gradually connects with the stress concentration zone below the coal pillar, forming a strip-shaped stress concentration zone; And as the working face advances, it gradually rotates until the working face passes over the coal pillar, and the two stress concentration zones gradually separate. (3) When the working face is located below the coal pillar, the peak forward support pressure of the working face is about 35MPa; Before entering the coal pillar at the working face, the pressure was about 33MPa; The minimum pressure after the coal pillar exits the working face is about 24MPa. Before entering the coal pillar at the working face, the maximum impact range of advanced support pressure is about 150m~200m; When the working face is directly below the coal pillar, it is about 80m-100m; The influence range of the advance support pressure after passing through the coal pillar on the working face is the smallest, about 45m~70m.