高频电磁法在排洪遂道溶洞勘察中的应用研究

溶洞是遂道施工中的安全隐患,利用高频电磁法沿遂道规划线进行了张量电磁法勘探。研究表明测区灰岩区电阻率呈高阻,电阻率大于4000Ω·m,浮土和砂岩区电阻率呈低阻,电阻率在800~4000Ω·m之间。获得了测区的电阻率分布特征及浮土、灰岩和砂岩的分布规律。通过对电阻率异常特征的分析指出了测区的构造分布及溶洞可能存在的位置。测区岩洞并不发育,但由岩体破碎所引起电阻率异常则较多。岩溶发育区位于48号点标高310m的区域,电阻率异常主要位于17~18、30~31点,标高320m区域。

The application of high-frequency electromagnetic method in the detection of karst caves

Karst cave is a kind of potential safety hazard to tunnel construction. High frequency electromagnetic tensor is introduced in this paper for the cave investigation along the proposed tunnel. The study shows that limestone area appears high resistance exceeding 4000Ω. m while facial soil and sandstone zone appears low resistance ranging from 800Ωm to 4000Ω. m. Resistivity distribution characteristics in the surveying area and the distribution rules of facial soil, limestone and sandstone are obtained. The tectonics distribution and possible karst caves location in surveying area is obtained by analysising the anomal resistivity features. There are few karst caves found in the surveying area but there are a lot of abnormalities caused by fractured rock are detected. The karst development area located at the ground level of 310m at surveying point No. 48 and the resistivity anomalies area locate at the level of 320m at the point No. 17 -18 and No. 30 -31.