电磁波CT技术在济南地铁岩溶勘察中的应用

随着城市化进程的加速,济南城市轨道交通近年来发展迅速,地铁成为济南未来交通主要建设方向之一。作为泉城,岩溶是济南泉水补给、径流的重要通道,在济南地区普遍发育,但同时岩溶问题也是地铁施工的难点,因此,查明地铁线路下岩溶的发育程度至关重要。与南方岩溶的“大尺寸”相比,济南地区的岩溶尺寸要小得多,且多成蜂窝状、裂隙状,在空间上也无明显规律可循,这对物探工作的分辨率就提出了较高的要求。该次研究区域是地铁2号线任家庄站到腊山站沿刘长山路区间段。经初步探查,该区间段存在多处岩溶且线路地处闹区,车流量大,管线复杂。为了研究该区岩溶发育情况,该次采用电磁波CT技术对区内岩溶进行了探测,通过对区域内地质介质电磁波吸收系数差异的研究,结合钻探资料进行对比,推断出岩溶区吸收系数的取值区间;最后对推断的岩溶区进行钻探取样,验证了物探与钻探的吻合程度。该方法在岩溶勘察中取得了良好的效果,为济南地铁设计及施工提供可靠的依据。

Application of Electromagnetic Computerized Tomography in Karst Detection along Ji'nan Subway

Accompanying with the acceleration of urbanization, urban rail transit has developed rapidly in Ji''nan city in recent years, and subway has become one of the main directions of future traffic construction . As a spring city, karst is an important channel for spring water recharge and runoff. It is widely developed in Ji''nan area, but it is also a difficult problem in subway construction. Therefore, it is very important to identify the degree of karst development under Metro lines. Comparing with the "big size" of karst in south China, the karst size in Ji''nan area is much smaller. It is mostly honeycomb-like and fissure-like, and there is no obvious rule to follow in space. Thus, higher requirements have been put forward in the resolution of geophysical prospecting work. The research area is the section from Renjiazhuang Station to Lashan Station along Liuchangshan Road on Metro Line 2. After preliminary exploration, there are many karsts in this area and the line is located in the downtown area, with large traffic flow and complex pipelines. In order to study the karst development in this area. In this paper, electromagnetic wave CT technology has been used to detect the karst in this area. By studying the difference of electromagnetic wave absorption coefficient beta of geological medium in this area, and comparing with drilling data, the value range of absorption coefficient in karst area is deduced. Finally, the deduced karst area is drilled. The coincidence degree between geophysical prospecting and drilling is verified. This method has achieved good results in karst exploration, and provides a reliable basis for the design and construction of Ji''nan Metro.