等值反磁通瞬变电磁法在轨道交通勘探中的应用

The Application of Opposing Coils Transient Electromagnetic Method to Exploration of Rail Transit

西南山区城市轨道交通勘察中,查明地下隐伏岩溶和地质构造的分布情况对于轨道交通的修建及后期运行都具有重大的安全意义。基于等值反磁通原理的瞬变电磁法是一种新的探测地下纯二次场的方法。该方法与传统瞬变电磁法相比,采用收发一体的微型天线,对于地形复杂的地区,施工较方便,而且还具有勘探精度较高,抗干扰能力较强和工作效率较快的优势。本文基于山区城市轨道交通勘察中地形复杂和外界干扰强的特点,将等值反磁通瞬变电磁法应用于城市轨道交通地球物理勘探中,并取得了较好的应用效果。最后将两个应用实例的勘察结果与对应测线的地质资料进行对比,验证了该方法在西南山区城市轨道交通勘察的可行性与有效性。

In the process of prospecting urban rail transit in the southwest mountainous area,it is of great significance for the safety to find out the distribution of underground hidden karst and geological structure for the construction and later operation of rail transit.The transient electromagnetic method,based on the principle of equal and reverse magnetic flux,is a new tool for exploring the pure secondary electromagnetic field.Compared with the traditional TEM,this method adopts the micro antenna with transceiver.For the complex terrain area,this method is more convenient,and also has the advantages of high precision,strong anti-interference ability and quick working efficiency.Based on the complex terrain and strong external disturbance in the construction of rail transit in mountainous cit-ies,this paper applies the opposing coils transient electromagnetic method（OCTEM）to the geophysical exploration of rail transit in two mountainous cities and obtains a good application effect.The good prospecting results of two application examples are compared with the geologic data of the same survey line to verify the feasibility and effectiveness of OCTEM for the exploration of urban rail transit in southwest mountainous area.