近距煤层群开采在不同宽度煤柱中的传力机制

Mechanism of Load-Transfer Between Coal Pillars with Different Widths in Mining the Short-Range Seams

以目前汾西矿区近距煤层群开采为背景,分析了煤层回采后煤柱及附近煤岩体应力重分布影响因素,并采用FLAC3D有限差分程序计算研究了近距煤层群上部煤层回采在不同宽度煤柱内部及下部煤岩体中的传力机制.结果表明:煤柱内部集中应力对底板应力重分布影响大于对顶板应力重分布的影响;不同宽度煤柱内部及顶底板煤岩体应力集中系数不同,随着煤柱宽度的增加,煤柱内部最大主应力呈现先增加后逐渐减小的现象;随着煤柱宽度的增加,煤柱下部煤岩体的应力影响扩散角减小,并逐渐趋于一个稳定数值.水峪煤矿10#～11#合并煤层应力重分布受上部9#煤层工作面回采影响明显,通过对9#煤层煤柱应力影响扩散角的计算,以下部煤层巷道布置于应力降低区为主要原则对10#～11#合并煤层巷道布置进行了设计.现场监测结果显示,变形量不大,整体支护效果良好.

Aiming at the situation of mining short-range coal seams in Fenxi mining area,we analyze the factors affecting the re-distribution of stress of coal-rock mass near the coal pillar and its adjacent area.In addition,we study the mechanism of load-transfer between coal pillars and in coal-rock mass using the finite difference program FLAC3D.The result indicates that the effect of stress concentration in coal pillars on the re-distribution of floor stress is greater than that on the roof stress;the stress concentration factors of coal and rock within the coal pillars with different widths is different from those in the roof and floor,and as the increase of width of the coal seam,the maximum principal stress in the coal seam increases first and then decreases;as the width of the coal seam increases,the stress influence diffusion angle of the coal and rock under the coal pillar decreases and gradually reaches a constant.The stress re-distribution in the 10#~11# coal seams at the Shuiyu coal mine is obviously affected by the 9# coal seam mining.Based on the calculation of the stress influence diffusion angle of the coal pillars in the 9# coal seam,the layout of the roadways in the 10#~11# coal seams is designed following the main principle that the layout of the roadways should be in the area with a relatively low stress.And the in-situ monitoring results show that the deformation is not severe and the supporting effect is good.