随着铁路建设的发展，规模较大的隧道数量越来越多，且隧道在施工过程中经常伴随着塌陷、突泥、涌水等地质灾害的发生，因此探明隧道前方隐藏的地质灾害至关重要。当隧道前方及上方地质异常体达到一定规模时，会对隧道产生多方向的较大压力，而在隧道内部开展的常规预报方法只能探测隧道前方地质异常体。本文为了探究和邢铁路天河山隧道周边地质异常体的空间规模及形态，在隧道上方布置3条音频大地电磁测深剖面，对音频大地电磁数据进行精细化处理、分析和反演，最终获得地下700 m深度范围内电阻率结构模型，发现存在东、西2组低阻异常，结合地球物理和地质资料，认为东部的近直立低阻异常可能为破碎带，而西部向西倾斜的低阻异常可能为与区域大断裂相关的构造或破碎带，且异常规模较大。后期隧道的掘进结果证实了反演结果的可靠性，认为采用音频大地电磁测深方法可以有效探测隧道周边一定深度范围内地质异常体的空间规模和形态，可为有效避免隧道施工过程中重大地质灾害的发生提供参考依据。
With the development of railway construction, there are more and more large-scale tunnels, and a tunnel construction process is often accompanied by geological disasters such as collapse, mud intrusion, water inrush. Therefore, it is crucial to identify hidden geological disasters in front of a tunnel. When a geological anomaly in front of and above a tunnel reaches a certain scale, it will generate a large pressure in multiple directions; however, conventional prediction methods that are carried out inside a tunnel can only detect a geological anomaly in front of the tunnel. In order to explore the spatial scale and shape of the geological anomalies around the Tianheshan tunnel of the He-Xing railway, three audio-magnetotelluric sounding profiles were arranged above the tunnel, and the audio magnetotelluric data were refined, analyzed, and inverted. A resistivity structure model in a depth range of 700 m was obtained, and two sets of low-resistivity anomalies were found. Combined with geophysical and geological data, it is believed that the near-upright low-resistivity anomaly in the east may be a broken zone; it may be a structure or fracture zone related to a large regional fault, and the anomaly scale is large. The subsequent excavation results of the tunnels confirmed the reliability of the inversion results. It is considered that the use of audio-magnetotelluric sounding method can effectively detect the spatial scale and shape of geological anomalies within a certain depth range around the tunnel, and provide a reference for effectively avoiding the occurrence of major geological disasters in the process of tunnel construction.
2022,43（5）: 40-48 收稿日期：2022-08-02
DOI：10.3969/j.issn.1003-3246.2022.05.006
作者简介：邵军尧(1965-),男,河北省保定市望都县人,高级工程师,主要从事铁路工程建设管理工作。E-mail:sjysjy163@163.com
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