电法勘探新技术在隧道工程地质勘察中的运用实践

Application of New Electrical Prospecting Technology in Tunnel Engineering Geological Survey

隧道由于地质条件复杂、不良地质体发育等特点,一直是工程地质勘察中的一大难题。因此,查明隧道轴线穿越的岩溶、断层破碎带、滑坡堆积体等不良地质体,划分隧道轴线附近围岩级别,对隧道选线及钻孔布设具有重要的指导意义。而电法勘探是地球物理勘探中的重要手段之一,本文分析了电法勘探新技术(高密度电法-分布式、等值反磁通瞬变电磁法、音频大地电磁法、全航空大地电磁法、广域电磁法)对于不良地质体探测的电性异常特征,判释了隧道轴线附近的围岩级别。研究结果表明:充分利用电法勘探新技术,研究隧址区范围内不良地质体与地球物理电性异常特征之间的关系,可有效查明不良地质体的产状、规模及性质,划分围岩级别是有效可行的,可为隧道设计提供科学的地质资料。

Tunnels have always been a major challenge in engineering geological exploration due to their complex geological conditions and the development of unfavorable geological bodies.Therefore,identifying the unfavorable geological bodies such as karst,fault fracture zones,and landslide deposits that the tunnel axis passes through,and dividing the surrounding rock level near the tunnel axis,has important guiding significance for tunnel route selection and drilling layout.And electrical exploration is one of the important means in geophysical exploration.This article analyzes the electrical anomaly characteristics of new electrical exploration technologies(high-density electrical method distributed,equivalent anti magnetic flux transient electromagnetic method,audio magnetotelluric method,all aviation magnetotelluric method,wide area electromagnetic method)for the detection of unfavorable geological bodies,and interprets the rock level near the tunnel axis.The research results indicate that by fully utilizing new electrical exploration technologies and studying the relationship between unfavorable geological bodies and geophysical electrical anomalies within the tunnel site area,the occurrence,scale,and properties of unfavorable geological bodies can be effectively identified,and the classification of surrounding rocks is effective and feasible.This can provide scientific geological data for tunnel design.