【摘要】 利用声波法对华北地区某典型岩溶水害矿井的4707工作面煤层底板不同深度、不同位置的声波波速进行探测,获得了随工作面推进时的波速变化曲线。结果表明:垂深3.9～12.1m之间的声速曲线出现较大的波动,在钻孔距工作面距离15～5m时声波波速迅速升高,在6～5m处达到最大值,工作面推过钻孔后,波速不断降低。垂深13m以上,声波曲线趋于稳定,说明已不在破坏范围内。声速法判断底板最大破坏深度为12.1m。结合FLAC3D软件,利用4707工作面的实际地质资料数值模拟煤层底板采动破坏过程,得出了煤层底板采动破坏特征:底板破坏区沿采空区四周和底板向下扩散呈现出喇叭形,随工作面的不断推进,破坏区也不断前移。更多还原

【Abstract】 The acoustic method was used to detect the wave velocities of the 4707 working face floor from different depth and locations in a typical karst water disaster mine in North China,and the variation curves of wave velocities along with the advance of the working face were obtained.The results show that the significant fluctuation appears in the variation curves when the vertical depth is between 3.9 m and 12.1 m.The wave velocities rise rapidly when the distance from the drilling to the working face is between 15 m to 5 m,and achieve the maximum value when it is between 6 m and 5 m,but they are reduced gradually when the working face passes the drilling.The variation curves of wave velocities tend to be stable when the vertical depth exceeds 13 m,which reveals that it has not been in the range of damage and that 12.1 m is the maximum damage depth of floor detected by the acoustic method.Combined with FLAC3D software,the mining failure process of the coal floor was simulated by using the actual geological data of the 4707 working face,which is concluded that the failure area presents a horn shape along the goaf around and the floor and that the failure area constantly moves forward along with the advance of the working face.更多还原