音频大地电磁与浅层地震在隧道地质勘查中的应用

Application of audio magnetotelluric and shallow seismic methods in tunnel geological exploration

针对山区长埋深隧洞勘测技术的研究,是近年来我国隧洞地质勘查中的研究热点,然而传统的钻探等手段在多山区域有很大的局限性,因此,近些年来地球物理勘探方法逐渐面向工程勘探,而单一的物探方法往往在异常判断方面存在局限性,鉴于此在工程勘探中往往运用多种地球物探方法相结合,可以在一定程度上减小了单一物探方法的多解性,提高物探解释的质量以及精度.本文以南水北调某工程为例,在某受水段分别布置了大地电磁法、地震浅层反射物探方法,其中大地电磁法主要用于辅助查明隧洞覆盖层厚度、地层岩性、隐伏构造、地下水位等工程地质条件,地震浅层反射用于查明小规模的地质构造(小断层、溶洞等)的勘查,经过这两种方法的结合,有效的查明了工程受水区的基本地质情况.

Recently,The study of surveying technology in longly and deeply buried tunnel is a hot spot in the tunnel geological exploration in China. However,traditional methods such as drilling in mountainous area have significant limitations. So geophysical prospecting methods are gradually applied in engineering exploration in recent years. Because the single geophysical exploration methods often have limitations in terms of abnormal judgment,to some degree,using a variety of geophysical prospecting methods in engineering exploration can reduce the uncertainty which a single geophysical exploration method causes and can improve the quality and precision of the geophysical interpretation. In one project of the South-to-North Water Diversion project, we use the Audio Magnetotelluric method, and The Shallow Seismic Reflection method in exploration area,The Magnetotelluric method is mainly used for finding out tunnel overburden thickness,lithology of layer,concealed structures, underground water level and so on, The Shallow seismic reflection is used to find out the small geological structure such as small fault and karst cave,etc. Through the combination of the two methods,It is effective to find out the geological structure in exploration area.