音频大地电磁测深法在辽东小罗圈沟水库选址中的应用

Application of Audio Earth Electromagnetic Sounding Method in the Selection of Xiaoluoquangou Reservoir in Liaodong

小罗圈沟地表大部分覆盖第四系砂土层,两侧山岭出露大面积灰岩,急需深部地球物理方法来对拟建坝址区内深部结构进行探测。针对这种情况,在该区开展了音频大地电磁测深工作,完成了6条剖面数据采集、处理与反演工作,并结合地质资料,揭示了拟建坝址风化层厚度在5~45m之间,小罗圈沟谷风化层最厚,向两侧山岭逐渐减薄。深部断裂以NW(F1~F5)和NNE(F6和F7)向为主,切错了震旦纪灰岩层,并且NW被NNE切错近百米,形成网状的断裂格局。拟建坝址深部存在大面积震旦纪灰岩,受溶蚀和断裂构造作用该套灰岩层中存在溶洞、溶穴等不良地质体。以上信息为坝址的选定提供重要依据。

Most of the surface of the Rizogou Gully covers the Quaternary sand layer.Both sides of the ridge expose the large limestone.Deep geophysical methods are urgently needed to detect the deep structures in the dam site.In view of this situation,we carried out the audio and magnetic electromagnetic sounding survey in the area and completed the data acquisition,processing and inversion of six sections.Combined with the geological data,we can see that the thickness of the weathering layer in the proposed dam site is between 5~45 m In between,the Ravine ring thickest weathered layer,to the sides of the mountain gradually thinning.The deep faults are dominated by NW(F1~F5)and NNE(F6 and F7)faults,and the Sinian limestone is cut off.NNE is cut by NW by nearly a hundred meters to form a net-like fault pattern.There is a large area of Sinian limestone deep in the proposed dam site,which is subject to dissolution and fault tectonics.There are karst caves,cavities and other undesirable geological bodies in the limestone layer.The above information for the dam site to provide an important basis for the selection.