厚层坚硬顶板逆断层对煤岩动力失稳的力学分析

Mechanical Analysis of Coal and Rock Dynamic Instability by Thick and Hard Roof Thrust Fault

针对厚层坚硬顶板的结构特点,以实际案例为基础,分析了逆断层逆冲滑动的主要影响因素,构建了由水平构造应力影响下逆断层上盘的简化力学模型,研究了水平构造应力以及由其引起附加垂直应力的分布规律,从而揭示逆断层诱发冲击地压及煤与瓦斯突出等煤岩动力灾害的力学原因。研究结果表明:断层上盘中存在大于自重应力的垂直应力,积聚大量的弹性能;距应力边界越远,断层倾角越大,附加垂直应力及水平构造应力下降的速度就越快且其值越小;距边界较近时,水平构造应力变化不大,但附加垂直应力随着断层倾角的增大而递增。

According to the structural characteristics of thick and hard roof,the influencing factors of thrust faults sliding were analyzed based on the actual case. The simplified mechanics model of hanging wall of reverse fault under the influence of horizontal tectonic stress was constructed; and the law of distribution for both horizontal tectonic stress and additional vertical stress induced by the horizontal tectonic stress was studied; And then mechanics reasons of coal and rock dynamic disasters for rock burst and coal and gas outburst were revealed. The research results show that the hanging wall of fault has greater vertical stress than gravity stress. Much elastic energy can be accumulated. If the distance is more far form stress boundary and the fault dip is larger,the descent velocity of both horizontal tectonic stress and additional vertical stress is faster and the value of the both stresses is smaller. If the distance is closer from stress boundary,the horizontal tectonic stress has little change. But the additional vertical stress is incremental with the fault dip rising. And then the mathematical model of the hazard zone of thrust- shear slip of hanging wall was set up.