两层硬厚岩层下采场覆岩裂隙演化特征研究

Study on the Evolution Characteristics of Overlying Rock Fissure under Two Layers of Hard and Thick Strata

针对工作面上覆两层硬厚岩层情况,运用相似模拟试验的方法,研究了采动影响下裂隙演化及分布特征。研究结果表明,覆岩依次经历直接顶初次垮落、基本顶初次破断、基本顶周期破断、下位岩浆岩初次破断、下位岩浆岩周期破断、上位岩浆岩初次破断等阶段;在硬厚岩层的屏蔽作用下,顶板运动具有明显的层位效应,且硬厚关键层破断前后顶板"三带"分布有明显的变异特性;工作面采空区裂隙的分布具有明显的分区特征,即分布明显的裂隙区和压实区。研究结果可为类似地质条件下的工作面支护及防冲设计提供一定的理论指导。

Aiming at the situation that two layers of hard and thick strata are overlying on the working face,the evolution and distribution characteristics of fractures under the influence of mining are studied by the method of similar simulation test.The results show that the overlying rock is in turn through direct top first caving,the initial breakage of the basic top,the basic top period breaking,the initial break of the lower magma rock,the periodic breaking of the lower magmatic rock and the initial rupture of the upper magma,and the roof movement has obvious stratigraphic effect and hard thickness under the shielding of hard and thick rocks.The distribution of the ＂three zone＂distribution of the roof before and after the breaking of the key layer has obvious variation characteristics,and the distribution of the fissures in the goaf of the working face has obvious zoning characteristics,that is,the obvious fractured zone and the compacted area.The research results can provide some theoretical guidance for supporting and punching design of working face under similar geological conditions.