考虑采空区压实效应的沿空掘巷煤柱设计方法研究*

为建立1种相对科学的沿空掘巷煤柱尺寸设计方法，采用理论与数值试验研究、现场试验等手段，基于采空区压实效应，分析各尺寸煤柱沿空掘巷掘采全过程围岩应力分布与变形。研究结果表明:采空区压实效应模拟研究方法能够模拟采空区应力恢复；掘巷过程中，煤柱内应力由小到大依次为:工作面倾向水平应力、工作面推进方向水平应力、垂直应力，在小尺寸煤柱内呈偏向采空区一侧的单峰分布，小尺寸煤柱逐渐向大尺寸煤柱过渡期间，内部应力量值开始比原岩应力小，随后逐渐增加至出现一定的应力集中，而实体煤帮中峰值应力不断降低，位置逐步向巷帮转移；受超前采动作用后，更大面积的煤柱会受高应力作用，大尺寸煤柱内垂直及水平应力集中系数逐步提高，工作面倾向的高应力区范围更广，当煤柱宽度不超过一定数值时，内部应力大小均低于掘巷过程中相应数值，大煤柱则具有相反的规律，实体煤帮中应力集中系数与掘巷时相比更大，峰值点向围岩深处进一步转移；研究结果通过工程实践检验，可为合理煤柱尺寸设计提供1种新的方法。

Study on coal pillar design method of gob-side entry driving considering gob compaction effect

In order to establish a relatively more scientific design method of coal pillar size for the gob-side entry driving,the stress distribution and deformation of surrounding rock during the whole process of excavation and mining in the gob-side entry driving with coal pillars of various sizes were analyzed by using the theoretical and numerical experiment study,field tests and other methods based on the gob compaction effect.The results showed that the simulation research method of gob compaction effect could simulate the gob stress recovery.During the process of entry driving,the internal stress of coal pillars in ascending order were: horizontal stress in the dip direction of working face,horizontal stress in the advancing direction of working face,and vertical stress.In the small-sized coal pillar,it had a unimodal distribution biased toward the gob side.During the transition from small coal pillar to large coal pillar,the internal stress value was smaller than the original rock stress in the beginning,and then gradually increased until a certain stress concentration occurred,while the peak stress in the solid coal bank continued to decrease,and the position gradually shifted to the entry bank.Under the effect of advanced mining,the coal pillars with larger area would be subjected to high stress,the vertical and horizontal stress concentration coefficients in the large coal pillars would gradually increase,and the range of high stress areas in the dip direction of working face was wider.When the width of coal pillar did not exceed a certain value,all the internal stress were lower than the corresponding value in the process of entry driving,while the large coal pillars had the opposite law.The stress concentration coefficient in the solid coal bank was larger than that of the entry driving,and the peak point transferred further toward the deep surrounding rock.The research results were tested by the engineering practice,and it provides a new method for designing reasonable coal pillar size.