巨厚火成岩下采动覆岩应力场-裂隙场耦合演化机制

针对杨柳煤矿主采10煤层诱导上覆巨厚火成岩运移破断引发剧烈地表沉陷、瓦斯喷井以及工作面压架等动力灾害的难题,基于巨厚火成岩破断特征,采用物理模拟、数值模拟与理论分析相结合的方法研究了巨厚火成岩下覆岩裂隙发育规律与采动应力分布规律,得到火成岩破断前后裂隙发育高度、支承压力峰值和应力集中区最大高度等指标随工作面推进的变化特征,从而揭示了巨厚火成岩下采动应力场-裂隙场耦合演化致灾机制,即煤层采动→应力重新分布→应力集中→裂隙发育→覆岩破断→应力转移→裂隙扩展→"弧形"离层→火成岩破断→动力灾害。从控制应力集中与裂隙发育两方面提出了"采空区充填技术—离层注浆充填技术—保护层开采技术"的防灾技术体系。

Coupling evolution mechanism of mining-induced overlying strata stress field and crack field under extremely thick igneous rock

In order to solve the problem of dynamic disasters like severe surface subsidence，gas drainage well outburst and supports crushing accident induced by overlying extremely thick igneous rock breaking at No.10 coal seam in Yangliu coal mine，on the basis of crack property analysis of extremely thick igneous rock，this paper investigates the crack development law and mining stress distribution under extremely thick igneous rock by using physical simulation，numerical simulation and theory analysis method.And then some indexes data with working face advancing like the crack development height of igneous rock before and after its breaking，the peak abutment pressure and the maximum height of stress concentration area are obtained.In this research the coupling evolution mechanism of mining-induced stress field and crack field under extremely thick igneous rock is revealed.It can be summarized as coal mining→stress redistribution→stress concentration→crack development→overburden strata break→stress transfer→crack extension→“arc” separation layer→igneous rock break→dynamic disaster.Thus the “gob backfilling technology-separation layer grouting technology-protection layer mining technology” technical system of disaster prevention is proposed based on stress concentration and crack development control.