巨厚砾岩作用下底板冲击地压诱发机理及过程

以千秋煤矿21141工作面下巷冲击地压发生的地质和采掘情况为基础,建立煤层巷道底板冲击地压诱发机理模型。水平应力的大小是影响巷道底板岩层稳定性的最主要因素,并确定最大水平应力的计算方法。采场上覆巨厚砾岩层断裂所产生的动载扰动能使巷道底板水平应力瞬间积聚升高。数值模拟分析得出,随着动载应力和加载时间的增加,巷道底板变形量、变形速度和加速度都明显的大幅度增加;同时巷道围岩塑性区也逐渐扩大。研究表明采场上覆巨厚砾岩层断裂、垮落对煤层巷道所产生的动载扰动会诱发规模较大的冲击地压,巷道底板由于缺少有效支护会成为冲击破坏的突破口。

Induced mechanism and process of floor burst under the action of hugely-thick conglomerate layer

Based on the geological and mining conditions of rock burst occurrence in headentry of coal face 21141, the induced mechanism model of floor burst in coal seam roadway was established. The horizontal stress was the major factor influencing the stability of roadway floor strata, and the calculation method of the maximum horizontal stress was determined. The dynamic load disturbances caused by fracture of overlying hugely-thick conglomerate layer could lead to a rapid increase of horizontal stress in the roadway floor. Numerical simulation analysis showed that, with increase of dynamic load stress and load time, the deformation quantity, velocity and acceleration of roadway floor increase greatly and obviously; and the plastic zone of roadway surrounding rock also expands gradu- ally. It showed that the dynamic load disturbance to coal seam roadway caused by fracture, collapse of the overlying hugely-thick conglomerate layer could induce large rock burst. Therefore if roadway floor is not supported effective- ly, it would become a breakthrough of burst damage.