坚硬厚层顶板群结构破断的采场冲击效应

Impact effect caused by the fracture of thick and hard roof structures in a longwall face

采用理论分析、物理相似模拟及现场实测相结合的方法,对坚硬厚层顶板群结构的破断冲击效应进行了分析.研究表明:多分层坚硬顶板群结构的破断冲击载荷在短时间内会产生较大的波动,工作面来压特征受多分层顶板垮断的联合作用;采场冲击来压强度主要与顶板赋存厚度及自身岩性特征有关,对于岩性相近的顶板岩层,厚度越大,对采场的矿压冲击影响也越剧烈,但厚层顶板垮断后的结构对其上覆顶板岩层的冲击载荷强度具有一定的缓冲.以大同矿区坚硬顶板群结构下的煤层开采为例,现场实测分析得到的工作面采场来压特征说明多分层顶板的垮断失稳有一定的随机性,但各分层顶板的单层垮断或多层同步垮断几率在整个煤层开采过程中基本保持不变.

A comprehensive research composed of theory analysis, physical simulation and field measurements was conducted to analyse the impact effect caused by fracture of the thick and hard roof group structure to obtain the main factors influencing impulsion pressure, main roof weighting characteristics and rupture characteristics of the roof group structure. The research shows that impact load caused by fracture of the hard layered roof group structure presents a significant fluctuation over a short period , and the roof weighting on the workface is affected by combined effects resulted from layered roofs group fracture. Impulsion pressure strength is associated to the roof thickness and rock properties. For the similar roof strata, the impact effects are more severe if the roof is thicker, but the thick caving roof will buffer the impact from the upper overburden strata. A field test has been conducted in Datong area which is min- ing under hard roof group structure. , Roof weighting characteristics on the workface was ob- tained according to the test. It shows that the fracture and unstability of the layered roof are random, however both monolayer and roof group have stable probability to break down in terms of entire mining process.