EH-4电磁成像系统在公路隧道工程勘察中的应用研究

The Application of EH-4 Electromagnetic Image System to Highway Tunnel Engineering Survey

在隧道施工前期使用物探方法对工区地下构造情况进行探测,可以为隧道设计、施工提供依据。EH-4电磁成像系统是一种比较成熟的物探设备,已经得到了广泛的应用,首先通过该系统在大冬树山隧道工程勘察中的实际应用,介绍了利用该系统在野外采集数据时的工作方法和注意事项;然后使用非线性共轭梯度法NLCG(Nonlinear Conjugate Gradient)对野外采集的数据进行了二维反演,并研究了地形因素对二维反演结果的影响。根据数据二维反演结果,确定了已知断裂的深部赋存状态,推测出了未知隐伏断裂的存在,同时判定工区地下局部富水性较强。综合分析该系统在本次隧道工程勘察中的应用效果良好,成功寻找出了断层破碎带、富水带等不良地质构造,可以为隧道设计、施工提供参考。

In the early stage of tunnel construction, we can use some geophysical prospecting methods, which can provide basis for tunnel design and construction, to detect the underground structure of our working area. EH-4 electromagnetic imaging system is a widely- used geophysical exploration device. In this paper, we introduced how to use the system to collect the field data through the actual application to Dadongshu mountain tunnel. And we have done 2D inversion by NLCG （Nonlinear Conjugate Gradient） and discussed how the inversion results to be influenced by the topographic factor. We have successfully found the known faults and deduced the abundant groundwater in local area. EH-4 has got a good result and also it can be helpful in tunnel engineering investigation.