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结合现场实测、理论分析和数值模拟等方法,系统研究了“三硬”煤层巷道冲击地压发生的机理。现场地应力测量结果表明,大同矿区存在明显的水平构造应力,通过力学分析发现侧压系数与煤壁冲击线性相关;用关键层理论对坚硬底板冲击地压进行了分析,认为其影响因素有:底板关键层的厚度及其与底板表面的距离、水平构造应力以及工作面采动等;由数值分析结果可知:巷帮的水平位移与施加的水平载荷呈线性正比关系,当水平载荷足够大时,若巷帮一定深度范围内存在或产生了垂直裂隙,且顶底板岩层与煤层分离,巷帮将发生煤壁整体推出型冲击地压;底板岩层水平拉应力最大值随着巷道宽度的增加逐渐向底板深处发展并出现离层,导致底板关键层突然断裂,发生底板冲击地压。
Combined with field measurement, theoretical analysis and numerical simulation, the mechanism of rockburst in the “three hard” coal seam roadway was systematically studied. The results of in-situ stress measurement show that there is obvious horizontal tectonic stress in Datong mining area, and the lateral pressure coefficient is linearly correlated with the coal wall impact through mechanics analysis. The impact floor pressure of hard floor is analyzed by the key layer theory, and the influencing factors are as follows: The thickness of the key floor of the floor and its distance from the surface of the floor, the horizontal tectonic stress and the mining of the working face. The numerical analysis shows that the horizontal displacement of the roadway is linearly proportional to the applied horizontal load. When the horizontal load is large enough , If the depth of the lane to help a certain depth of vertical cracks or have occurred, and the roof and floor rock and seam separation, the tunnel will occur as a whole launched coal wall impact pressure; floor rock strata horizontal tensile stress with the width of the tunnel gradually increased Deep to the bottom of the development and the emergence of sub-layers, resulting in a sudden fracture of the key floor, the floor impact pressure.