重复采动停采边界关键层失稳诱发灾害研究

Study of disasters induced by key strata instability near stopping boundary in the process of repeated coal mining

基于岩层控制的关键层理论,分析了重复采动过程中上覆巨厚关键层岩块形态特征、冒落和移动规律.结果表明:重复采动停采边界矿震机理归结为2种形式:1)采高增加引起顶板冒落高度增加,造成高位关键岩块铰接平衡结构失稳诱发矿震;2)重复采动引起顶板岩层移动线外扩,导致采场边界顶板活动范围增加,造成高位关键层破断诱发矿震.依据此机理,提出了降低推采速度(低扰动)、优化开采边界(低应力)等防控动力灾害的技术方法.通过3下510工作面实施运用与开采实践,达到了采场边界矿震及动力灾害的防控目的,保证了工作面安全和地面稳定.

The morphological characteristics, caving and movement regularity of super-thick overlying key strata were analysed in the process of repeated mining based on the key strata theory. The results show that the mine-quake mechanism near the stopping line is concluded as the following two forms. 1） The increase of roof caving height resulting from the increase of mining height causes the instability of articulated balance structures in highstand key rock stra- ta, which can induce mine quakes. 2） The outward extension of roof strata movement line due to repeated mining results in the increase of roof movement scope near the stope boundary, which can break the highstand key strata and then induce mine quakes. Several prevention and control methods of dynamic disasters such as lowering the mining speed to lower the influence scope, and optimizing mining boundary to lower the stress according to the mechanism of mine quakes were proposed. The mining practice in Longwall Panel 3 lower 510 shows that mine quakes and disasters near the stope boundary are prevented and controlled, and workface safety and surface stability are guaranteed.