放炮震动诱发煤矿巷道动力失稳机理分析

发展了J.Litwiniszyn关于震动波诱发巷道动力失稳理论,分析了炮采震动诱发煤层巷道稳定性的影响,从理论上解释了放炮震动诱发冲击地压的根本原因。结合赵各庄矿实际生产情况,利用有限差分软件FLAC2D,对比分析了无支护和两种不同柔性支护条件下,巷道受放炮震动影响后的变形破坏情况。研究表明:放炮震动不仅增加了巷道围岩荷载,同时震动波的传播在围岩内产生了裂纹并在煤层和顶底板间诱发摩擦滑动,从而降低了围岩体的承载能力;柔性支护能有效吸收放炮震动的能量,降低巷道变形量;炮采影响下的防冲柔性支护,“U”型钢可缩支架略优于锚网支护。

ANALYSIS OF BLASTING TREMOR IMPACT ON ROADWAY STABILITY IN COAL MINING

Based on the model for the initiation of coal-gas outbursts developed by J.Litwiniszyn,this paper briefly describes the mining conditions that lead to the coal bumps and a study of the impact on roadway stability caused by dynamic loading of blasting tremor in Zhaogezhuang Coal Mine.A mechanical model is described to analyze the mechanism of coal bumps induced by blasting tremor in deep mining.The FLAC2D is used to analyze the tremor impact on deep excavations and responses of different kinds of support systems in Zhaogezhuang Mine.The material properties are determined by examinations carried out in the mine.The study indicates that the blasting tremor can not only cause the stress redistribution,but also induce decreasing of frictional force between the coal seam and surrounding rock.The results of numerical simulations show that the behavior of the rock mass-support system under the dynamic load and confirm the possible damages to the excavation.The U-shaped steel yielding support system is proved to be efficient to offer superior protection in bursting region to the bolt and net system.