地面核磁共振地下水探测技术在水库大坝渗漏勘查中的应用

The application of the SNMR groundwater detection technology to the detection of reservoir dam leakage

地面核磁共振找水技术是一种非介入探测技术,通过识别水分子中氢原子信号的分布来推测水分子在地层中的分布,进而确定是否有地下水存在,并给出地下水位、富水程度和孔隙率等地层结构信息。以安徽某水库土质大坝为例,采用地面核磁共振方法对大坝渗漏进行勘查,取得初始振幅(E0)、纵向弛豫时间(T1)、横向弛豫时间(T*2)等物理参数,分析物理参数与地质结构的对应关系,判断出坝体存在两处渗漏点,通过地面调查和工程地质钻探,验证了物探勘察结果,为病险水库坝体的治理提供地质依据。

Surface nuclear magnetic resonance（SNMR） technique is a non- invasive detection technology,which,through the recognition of the distribution of hydrogen atom signals in water molecules,infers the distribution of water molecules in the strata,and then determines whether there exists groundwater or not and provides some information concerning the water table,the water-rich degree and the porosity. In this paper,taking a soil dam of a reservoir in Anhui Province as an example,the authors used the SNMR to investigate the dam leakage,and obtained such physical parameters as initial amplitude（E0）,longitudinal relaxation time（T1）,and transverse relaxation time（T＊2）. Through analyzing the correspondence between the physical parameters and the geological structure,the authors determined the existence of two leakage points and,through field investigation and engineering geological drilling,verified the geophysical survey results,thus providing the geological basis for the management of dangerous reservoir dam.