地下洞穴在孔间电磁波法CT上的反映特征及洞径计算公式

电磁波法CT技术是利用大量的电磁波能量信息,进行专门的反演计算,得到测区内岩土体吸收系数分布规律。与其它方法相比,使用这种方法探查地下洞穴的分布、形态及连通性,分辨率较好、效率较高、空间位置准确。在岩溶发育地区进行工程勘察,采用常规钻探与电磁波法CT成像相结合的方法,可消除工程隐患。目前,对异常的认识和定量解释还停留在看图识字阶段,准确地进行解释是非常困难的。通过模拟计算,得出了地下空洞和充填洞穴在电磁波CT图像上的反映特征及洞径计算公式,经过多个工程的应用和钻探检验,效果较好,对实践具有指导意义。

IMAGE CHARACTERS AND CALCULATION FORMULA OF DIAMETER OF UNDERGROUND GROTTO BY CROSS-WELL ELECTROMAGNETIC WAVE CT TECHNIQUE

Using cross-well electromagnetic wave CT technique,one can computes the distribution of absorptive coefficient of the rock and soil body with energy information of electromagnetic wave by special methods,which can be used to detect the formation and the distribution of underground grotto and is more efficient and accurate than other conventional exploration methods.The combined application of drilling and electromagnetic wave CT method may eliminate the probability of potential disaster during engineering survey in Karst region.By calculating of the cross-well electromagnetic wave CT model,the image characters and the diameter of underground inanition and filling grotto are determined and results show that the new method is feasible and of significance in the practice.