色拉哈断裂及邻区音频大地电磁三维阵列探测

为了能在川藏铁路色拉哈段隧道选址过程中最大限度地规避地质灾害体，本文针对色拉哈断裂及邻区开展了音频大地电磁三维阵列探测研究，获得了研究区可靠的三维精细电性结构.结合地表活动断裂调查结果，对区内三维电性分布特征进行了综合解释.研究表明，色拉哈断裂及邻区地表至500 m，整体表现为高阻特征，局部受断裂控制的区域为低阻特征；500 m以下电阻率下降显著，推测是断裂带在500 m以下的深部构造富含水体所致；此外，位于色拉哈断裂北侧的木格措南阶区以及南侧的断裂交汇区东侧发育两处高导体C1和C2，推测为区内含水的构造软岩，在设计隧道路线的过程中，应尽量避让. 

3-D AMT Array Exploration in the Selaha Fault and Adjacent Area

In order to avoid the geological hazards to the greatest extent in the processing of tunnel routes in the Selaha segment of the Sichuan-Tibet Railway line, we use audio magnetotelluric (AMT) data and obtain a reliable 3-D electrical structure model in the Salaha fault and adjacent area. The 3-D electrical resistivity model is comprehensively interpreted with the investigation of active faults. There is a large-scale high resistivity body at the depth from surface to 500 m, where the local area controlled by the faults is of low resistivity. Beneath the shallow 500 m, the resistivity decreases significantly, which results from the fault zone rich in aqueous fluids. In addition, there are two high conductors C1 and C2 in the study region; one is in the Mugecuo south stage area at the northwestern side of the Salaha fault, and the other is in the eastern side of the fault intersection area. These high conductors are presumed to be structural soft rocks. Therefore, it should be avoided as far as possible in designing the tunnel route.