大型逆冲断层区域冲击地压频发地质原因分析

Geological Causes of Frequent Rock Burst Events in Large Scale Thrust Fault Area

为了厘清义马煤田南部F16大型逆冲断层区域冲击地压频发的地质原因,分析了义马盆地和F16逆冲断层的演化过程,研究了F16逆冲断层的构造应力场,并通过建立义马煤田数值模型,计算了煤田竖向应力、剪应力和水平应力等,构造应力场分析和数值计算结果表明,义马煤田地应力以水平应力为主,最大主应力方向为南北向,南北向的水平应力导致义马煤田南部F16逆冲断层和义马向斜轴部区域坚硬岩层发生错断、弯曲变形,积聚了大量弯曲弹性能,煤岩体应力高度集中,加之“两硬夹一软”的特殊的煤岩体结构,在采掘扰动作用下,顶底板坚硬岩层中所积聚的应力在煤层、煤矸互叠层等软弱区域释放,导致该区域冲击地压事件频发。

Calculated the vertical stress,shear stress and horizontal stress of coalfield through establishment of Yima coalfield numerical model.Tectonic stress field analysis and numerical calculation results showed that the maximum principal stress of Yima coal field is horizontal stress in SN,which lead to hard rock strata dislocation and deformation near F16 thrust fault and the area of Yima synclinal axis.Rock burst accidents occured frequently in these areas because elastic energy accumulation and stress concentrated.In addition to the special structure of coal and rock mass,one soft coalseam clamping by two hard rock strata,under the action of mining disturbance,the stress accumulated in the hard rock strata of roof and floor is released in the weak areas such as coal seam and coal-gangue interlamination,resulting in many rock burst events in this area.