顶板全垮落法短壁连采煤柱合理宽度研究

The reasonable width of coal pillars in the short-wall continuous mining with full roof falling

针对短壁连采边角煤回收技术,为解决因留设的隔离煤柱连锁破坏,进而诱发关键层大面积失稳运动引发的冲击难题,在分析短壁连采技术覆岩关键层2种破断运动形式的基础上,以控制关键层大面积破断运动诱发冲击为原则,提出了"顶板全垮落短壁连采边角煤回收技术":在首块段和第2块段间留设隔离煤柱,保证煤柱在首块段开采期间保持稳定有效支撑顶板,第2块段开采时煤柱破坏失稳诱发关键层破断充分运动,实现煤柱破坏与关键层破断运动间的耦合协调;其后各块段完全取消隔离煤柱,实现顶板运动沉降连续化。首块段长度应小于关键层初次破断步距,以防止关键层沿边界产生塑性铰接线而处于临界不稳定状态;从煤柱弹塑性分区观点出发,分析了煤柱塑性破坏宽度及保持煤柱稳定的最小临界弹性宽度,建立煤柱合理宽度判据。

In view of the short-wall continuous mining in bound coal recovery,in order to solve the problem of key strata large-area instability caused by chain damage of remaining pillar,based on the analysis of two fracture movement forms of key strata,and with the control of large-area fracture movement of key strata as the principle,the ＂bound coal recovery technology of short-wall continuous mining with full roof falling＂ was put forward：barrier pillar are to be set between the first and second block section to keep the pillar stable during the mining of the first block section;the full fracture movement of the key strata caused by the coal pillar damage and instability during the mining of the second block section helps realize the coordination and coupling between the damage of pillar and the fracture movement of the key strata;the complete cancelation of barrier coal pillars in the subsequent blocks section realizes the continuity of the roof movement and settlement.The length of first block section should be less than the initial fracture step in the key strata to prevent the critical and unstable state of the plastic hinged lines of key strata.From the perspective of elastic and plastic partition of isolated coal pillar,the width of plastic partition and the critical width of middle elastic area of the coal pillar to keep stable were analysed,and the width criterion of isolated coal pillar was establish.