综放面单侧采空煤柱稳定性研究及实测

在使用留煤柱护巷的长壁采煤工作面中,单侧采空煤柱的稳定是后采工作面安全顺利回采的保障.近年来随着煤矿开采强度加大,对采对掘情况比较普遍,形成的护巷煤柱将经历两次工作面回采动压影响,对煤柱的稳定产生较大影响,对巷道围岩控制带来困难,特别是在综放开采的矿井尤为明显.因此,对厚煤层放顶煤工作面及相邻巷道对采对掘形成的区段煤柱在单侧采空状态下煤柱内支承压力分布规律进行了理论计算和现场实测分析.以东坡煤矿922和923综放工作面间20m护巷煤柱为例,分析和研究了煤柱形成后各阶段支承压力演变过程,得到了单侧采空煤柱采空区侧和巷道侧极限平衡区范围计算公式、煤柱最小宽度公式;通过钻孔应力计对现场煤柱内支承压力进行实测,得到了本工作面回采超前压力的影响范围和峰值,并说明现场20m宽煤柱内存在稳定弹性核区,煤柱可进一步优化以提高采出率.

Stability study and field observation of coal pillar between goaf and unmined top-coal caving face

The stability of coal pillar between goaf and unmined mining face is the guarantee of safety and success in long wall mining.In recent years,with increasing high-intensity production,the opposite mining and excavation is commonly found in coal mining,which results in twice mining dynamical influences of section coal pillar.It impacts the pillar stability and bring challenges to roadway ground control,especially in top-coal caving face.This paper gives theoretical derivation and field observation of abutment pressure distribution law of section pillar between goaf and unmined thick coal seam top-coal caving face.Taking the 20 meters coal pillar between 922 and 923 mining face in Dongpo coal mine for engineering background,firstly,the evolution process of abutment pressure is analyzed after the formation of section coal pillar,the limit equilibrium zone formulas of gob-side and roadway-side of pillar are deduced and the minimum width of stable pillar is calculated; secondly,with the field observation,the area and peak data of pillar abutment pressure before present mining face are found.The data shows that there is an elastic core in 20 meters coal pillar which helps to keep roadway stable.The discovery also help to propose the possibility of coal pillar size optimization and recovery rate improvement.