大定源瞬变电磁法在含水断层构造探测中的应用

针对黄土层及松散砂层覆盖厚度较大地区的三维地震探测断层构造效果欠佳问题,在山西大同煤田右玉矿区进行了瞬变电磁法探测含水断层构造的工程尝试。已知区域的前期试验结果表明:上下两盘存在电性差异或充水断层构造在视电阻率断面图上表现为等值线向下弯曲,电性层错动;不同落差的断层等值线弯曲程度不同,落差越大,等值线弯曲程度越大。基于此,勘探区内推断解释断层49条,目前5条断层在井巷掘进过程中得到验证,揭露结果与推断解释基本一致,方法有效性得到验证。

Application of transient electromagnetic method in the detection of water-bearing fault structure

In areas covered by thick loess and looses sand, 3D seismic is inefficient in detecting fault structure. In view of this situation, an engineering try by using TEM method to detect the fault structure was done in Youyu mine. The grid is 40 m × 20 m and the exploration area is 2.5 km2. The preliminary test result of the area with known fault structures indicates that the fault structure where the up and down sides have electrical difference or are filled with water shows bending-down contour and electrical layer dislocation of electric layer in apparent resistivity section; the contours of fault with different drop bend in different degree, the contours bend more greatly if the drop is bigger. Based on this, 49 faults are interpreted in the exploration area. At present, 5 faults have been proved during the roadway excavation and the revealed result is coincident with interpretation, so effectiveness of the method gets verified.