井下槽波地震勘探——预防煤矿灾害的一种地球物理方法

In-seam seismic exploration techniques——a geophsical method predictting coal-Mine disaster

当在煤层中激发地震波时,由于顶、底板围岩速度明显高于煤层中地震波的传播速度,当地震波入射角大于临界角时会发生全反射,经过多次全反射混合叠加,在煤层中形成槽波.槽波是一种围限波,它最大的特点是频散现象,槽波在煤层中传播时还具有速度低、衰减弱等特点,因此可以用来探测煤层中的采空区、断层等地质构造.本文初步阐述了槽波地震勘探技术的研究现状,槽波的形成,槽波的特点、槽波地震勘探的工作方法以及应用实例等内容,并基于其特点对槽波地震勘探技术作出了展望.

Since the velocities in surrounding rocks of roof and floor are faster than those in coal seam, the total reflection takes place if the angle of incidence is greater than critical angle when the seismic waves are excited in coal seam. After multiple combination and superposition of total reflection, channel wave will generate in coal seam. Channel wave is a confined wave and has the dispersion phenomenon which is the most important feature. Besides, when propagating in coal seam, channel wave has other features including low speed and weak attenuation. So it can be used to detect voids, faults and other geological structures in coal seam. This paper describes the current research situation of In Seam Seismic, the formation of channel wave, channel waves~ features, methods of In Seam Seismic exploration, example of application and so on, and make an expection about In Seam Seismic exploration according to its characteristics.