浅埋煤层开采顶板切落压架灾害的突变分析

针对浅埋煤层开采周期来压过程中顶板沿煤壁台阶下沉导致顶板切落压架灾害的问题,根据直接顶岩体在支承压力作用下破坏失稳的非线性变化特征,建立了由基本顶-直接顶-支架-矸石组成的系统力学模型。利用突变理论研究了荷载作用下系统的失稳机制,获得了系统失稳的充要条件及直接顶岩体的变形突跳量表达式,分析了系统失稳的主要影响因素。结果表明:直接顶的失稳破坏,导致了顶板的切落,系统失稳除与支架和直接顶岩体的刚度比及材料参数有关外,还与所受载荷及基本顶周期来压步距相关。结合工程实例,验证了理论推导的合理性,并给出了工程建议。

Catastrophic analysis of support crushing disasters while roof cutting in shallow seam mining

Aiming at the problem of roof cutting support crushing disasters caused by roof step con-vergence along the coal wall during the periodic weighting in shallow seam mining, based on the nonli-near variation characteristics during unstable failure of immediate roof under the abutment pressure, a system mechanics model composed by the main roof-immediate roof-powered support-waste rock was established. In addition, the instability mechanisms of the system under the loads were studied by cata-strophic theory. The necessary sufficient condition for instability failure of the system and the formula of the jump value of displacement of immediate roof were gained, and the main factors for instability failure of the system were analyzed. The results show that the unstable failure of immediate roof leads to the roof cutting, the failure of the system is not only related to the stiffness ratio of the powered sup-port, the immediate roof and the material parameters, but also related to the upper load and the cycle weighting interval. The rationality of the theoretical derivation has been verified by engineering exam-ple, some suggestions were given to the mining face.