煤体压剪破裂震源模型及远场震动特征

A coal shear fracture source model and its far-field seismic characteristics

为了研究工作面煤体破裂造成的震动破坏效应,根据位错震源理论与动态断裂力学,建立了煤体压剪破裂震源模型,推导了煤体压剪破裂引起的震动位移场远场表达式.数值计算结果表明:随着煤体破裂速度的升高,远场P波、SH波和SV波的振幅逐渐增大.震动位移场远场空间分布特征显示P波分量主要集中在与破裂面成45°夹角的平面内,SH波和SV波分量主要集中在破裂面及其正交面内.在平行和垂直于破裂面的传播方向上,P波的衰减速度大于SH波和SV波且幅值小于SH波和SV波.工程实践中,需要注意防范P波对工作面巷帮造成层裂破坏和SH波、SV波对工作面两巷与顶底板结合处造成剪切破坏.

In order to study the vibration damage caused by coal fracture in mining face, based on the dislocation source theory and dynamic fracture mechanics, a source model of coal shear fracture and the analytical expression of far-field seismic displacement caused by coal shear frac- ture were presented. The results show that the amplitudes of P-wave, SH-wave and SV-wave get larger with the increase of coal fracture velocity. The spatial distribution of far-field seismic displacement demonstrates that P-wave is mainly concentrated on the two planes inclined at 45° to the crack plane, whereas SH-wave and SV-wave are mostly concentrated on the crack plane and its orthogonal plane. On both of the horizontal and vertical direction of the crack plane, the decay speed of P-wave is larger than that of SH-wave and SV-wave, and the magnitude of P- wave is smaller than that of SH-wave and SV-wave. The spallation caused by P-wave on road- way surface deserves significant attention in field application, as well as the collapse induced by SH-wave and SV-wave on the junctions between roadway and both roof and floor.