孤岛工作面不同推进度对下伏大巷围岩稳定性影响研究

摘要

为了掌握孤岛残留煤体回采工作面推进速度对下伏大巷稳定性的影响展开研究,首先通过室内实验发现,提高试件围压加、卸载速度可显著提高其极限承载能力,结合东欢坨矿井下实际进行分析,认为工作面推进速度加快可减小极限平衡区的范围,也即对下伏大巷高应力持续影响时间降低.随后,通过对不同开采速度影响下大巷围岩应力分布与塑性破坏情况进行计算机数值模拟实验研究,发现工作面循环进尺从1m增加至3m,应力值降低,但增加至4m以后,该应力值增加,也即循环进尺为3m、4m时对围岩承载较为有利;从大巷围岩塑性破坏方面分析,工作面循环进尺增加至3m,大巷围岩塑性破坏范围降低,随后破坏范围增加,从而确定孤岛煤体回采工作面循环进尺保持3m较为合理.%In order to master effect of advancing rate in island working face on the underlying roadway stability,firstly,indoor experiment was carried out,the result shows that the improved specimen confining pressure,and loading-unloading speed can significantly improve the ultimate bearing capacity,which indicated that,combining with the actual conditions of underground mining,the increasing advancing speed of working face will reduce the range of limit equilibrium area,and reduce the continuous high stress influencing period on underlying roadway.Then,according to the practical engineering background,numerical simulation for stress distribution and plastic damage of roadway surrounding rock is carried under different mining speed.And the result shows that,the stress falls when the cyclical footage increases from 1m to 3m,while it rises when the footage is beyond 4m,indicating the 3m and 4m cyclic footage is beneficial for the rock bearing;meanwhile,the range of surrounding rock plastic damage range reduces in main roadway,when the cyclical footage increases to 3m,so 3m is reasonable cyclical footage the island coal mining face.