地球物理联合探测在识别岩溶地面塌陷精细结构中的应用——以武汉市为例

Application of the Integrated Geophysical Methods in the Fine Exploration of Karst Collapses:A Case Study of Wuhan City

岩溶地面塌陷是隐伏岩溶区典型的地质灾害类型之一,查明其精细地质结构对城市地下空间开发利用和地质灾害防治都具有重要意义。本文以武汉市为例,梳理了以覆盖层厚度与结构、岩溶发育程度和地下水为核心的岩溶塌陷探测地质要素特征,开展了三维高密度电阻率法、多源面波勘探和地面核磁共振方法等地球物理联合探测方法研究。结果表明:三维高密度电阻率法可用于圈定塌陷体边界;多源面波勘探对岩土体界面识别效果明显;地面核磁共振方法可量化地下含水量,划定含水层顶底板埋深,对岩溶发育程度和含水层孔隙度有一定指示作用;三种方法联合探测对提升岩溶塌陷体结构精细度具有重要意义。本文研究成果可为隐伏岩溶区地质结构精细探测方法选择提供参考。

Karst collapses are one of the typical geological hazards in hidden karst areas.Detecting the fine geological structures of karst collapses is of great significance to the development of urban underground space and the prevention and control of geological disasters.Taking Wuhan City as an example,this work analyzed the geological factors of karst collapses including the overburden thickness and structure,the karst development,and groundwater,and conducted integrated three-dimensional high-density resistivity method,multi-source surface wave exploration and ground nuclear magnetic resonance method.Results show that the three-dimensional high-density resistivity method can be used to delineate the boundary of collapsed bodies.Multi-source surface wave exploration can significantly identify the rock-soil interface.The surface nuclear magnetic resonance method can quantify the underground water content,and determine the burial depths of aquifer roof and floor,which will indicate the karst development and the porosity of aquifers.As a result,the joint detection of the three methods can improve the detection accuracy of karst collapses.Therefore,the research can provide helpful methodological significance for fine geological structure detection in karst areas.