冲击地压矿井采区下山保护煤柱合理宽度研究

留设合理宽度的采区下山保护煤柱是防范采区下山发生冲击地压的关键。为探讨冲击地压矿井采区下山保护煤柱宽度的确定方法,以李楼煤矿采区下山保护煤柱合理的宽度确定为工程背景,运用矿压理论研究了工作面向采区下山推采过程中覆岩运动规律、支承压力演化特征、冲击地压类型及其发生机制,分析了现场工作面推采过程中的微震监测数据和应力动态监测数据,综合确定了李楼煤矿工作面采动影响范围,提出了以防范各类冲击地压为原则的采区下山保护煤柱宽度的综合确定方法,并进行了工程验证。结果表明:①随着工作面向采区下山推进,采区下山保护煤柱宽度逐渐减小,工作面超前支承压力与采区下山侧向支承压力及两翼工作面超前支承压力将发生叠加、集中,震动附加应力与采区下山侧向支承压力叠加程度逐渐增大;②采区下山可能发生静动载叠加型、应力叠加型和蠕变型等3类冲击地压;③工作面超前、滞后采动影响距离为235 m,侧向采动影响距离为105.5 m;④从防范采区下山动静载叠加型、应力叠加型和延后蠕变型冲击地压的角度,综合确定李楼煤矿采区下山一侧保护煤柱宽度应不小于235 m。回采后期现场监测结果与收尾情况初步验证了当前李楼煤矿采区下山一侧保护煤柱240 m的合理性。

Study on rational width of protective coal pillar for district dip in rock burst mine

The key to prevent rock burst in district dip is to reserve a protective coal pillar with a reasonable width.In order to discuss the determination method of protective coal pillar width in mining area of rock burst mine,determining reasonable width of protective coal pillar for district dip in Lilou Mine is taken as an engineering background.Movement law of overlying strata,evolution feature of abutment pres?sure and mechanism of rock burst in the advancing process of working face to the district dip are investigated by using ground pressure the?ory.The microseismic monitoring data and stress dynamic monitoring data in the process of working face advancing are analyzed.The influ?ence range of working face in Lilou Mine is determined comprehensively.A comprehensive method to determine the width of protective coal pillar for district dip based on the principle of preventing all kinds of rock burst is put forward,and the engineering verification is carried out.The results show that:①With the working face advancing to the district dip and the lessening of protective coal pillar width,the ad?vance abutment pressure of working face and the lateral abutment pressure of district dip,or the advanced abutment pressure of two wing working faces,will be superimposed and concentrated,and the superposition degree of vibration additional stress and lateral abutment pres?sure of district dip gradually increases.②Three types of rock burst may occur in the district dip,including static and dynamic load superpo?sition type,stress superposition type and creep type.③The influence distance of advanced and delayed mining is 235 m,and the influence distance of lateral mining is 105.5 m.④From the point of view of preventing three types of rock burst including static and dynamic load superposition type,stress superposition type and creep type,the width of protective coal pillar at one side for district dip in Lilou Mine should not be less than 235 m.The field monitoring results and ending situation in the late mining period preliminarily verified the rationality of 240 m protective coal pillar at one side of district dip in Lilou Mine.