综放面覆岩运动诱发冲击矿压机制研究

 基于砌体梁理论提出综放面覆岩运动的双向发展模式，分析综放面冲击矿压的能量来源和力源，利用微震监测技术对综放面覆岩运动的矿震效应进行监测。结果表明：覆岩运动的矿震活动呈周期性，冲击发生前矿震能量持续增大，冲击发生时达最大值，之后产生突降；冲击发生前，矿震频次先增大后有一定程度减小，冲击发生在频次下降沿，之后急剧下降；平均标高能够反映覆岩运动的空间形态，冲击发生前，平均标高逐渐增大，冲击发生或临近发生时，达到最大值，之后产生突降；矿震活动周期内，矿震空间分布先逐渐向上层位发展，冲击发生前，矿震空间分布达到最大值，工作面近距离岩层矿震活动强烈。指出综放面冲击矿压主要发生在覆岩运动下发展过程，可通过覆岩运动上发展过程的监测预防冲击矿压。

MECHANISM STUDY OF OVERLYING STRATA MOVEMENT INDUCING ROCKRURST ON TOP-COAL CAVING FACE

Based on the voussoir beam theory，the bi-directional(up and down wards) movement model of top-coal caving face was promoted. Accordingly the energy and stress sources of rockburst were analyzed. By the seismic observation technology，the microseism(MS) effect of the overlying strata movement was observed and the achieved results are as follows：(1) the MS activity is periodic，before rockburst，the total energy continuously gets larger，and when rockburst happens，it gets up to the largest，and then it drops extraordinarily；(2) before rockburst happens，the events firstly get higher and then drop. The rockburst happens during the process of events reducing；(3) the average elevation can reflect the development state of the movement of overlying strata. Before rockburst happens，the average elevation gets higher，and when or pre of the rockburst，the elevation gets up to the largest value，while it drops abruptly after rockburst happening：(4) during the MS activity cycle，the spatial distribution of seismcities gets higher in elevation and vast in space before rockburst. When rockburst happens，it gets up to the peek values and the strata near the working face active strongly. As a result，the rockburst mainly happens during the overlying strata moving downwards，hence it?s possible to observe and prevent rockburst by monitoring the upward movement of the overlying strata.