应用GPR获取多孔介质水力参数研究进展

Advances in estimation of hydrogeological parameters of porous media with ground penetrating radar

获取多孔介质水力参数,精细刻画野外含水层水力特征,描述含水层空间变异性,一直是水文地质学、土壤学、园艺学等研究的热点.传统的诸多方法或耗时费力,或数据量少,难以在不同尺度上监测含水介质特征的时空变化.由于探地雷达(GroundPenetratingRadar,简称GPR)电磁波的传播速度主要决定于多孔介质的介电常数,而影响多孔介质介电常数的主要因素是其孔隙度和含水率,这为电磁波方法确定多孔介质含水率、孔隙度、渗透系数等创造了条件.GPR快速、便捷、无损、多尺度、数据量大,能够精细刻画含水介质水力参数的空间变异性.为此,简要介绍了GPR的工作原理、探测方式及其应用条件,探讨了GPR获取水力参数的物理机制,综述了GPR获取水文地质参数的研究进展,指出了尚未解决的问题,并对用GPR获取水文地质参数方法今后的发展进行了展望.

Seeking a method to obtain the hydrogeological parameters of porous media and to give a detailed description of the heterogeneous properties and hydrogeological characteristics of aquifers in the field is always a hotspot in hydrogeology, agrology, and horticulture. Owing to some disadvantages of the conventional methods in the aspects of time consumption, great workload, and small amount of data obtained, it is difficult for them to detect the temporal-spatial variation of hydrogeological characteristics of water-bearing media on different scales. The fact that the electromagnetic wave penetrating velocity of Ground Penetrating Radar (GPR) is mainly affected by the dielectric permittivity of porous media, and the fact that the dielectric permittivity is mainly affected by the water content and porosity of the media make it possible for the electromagnetic wave method to determine the water content, porosity, and hydraulic conductivity of porous media. Owing to such advantages as high speed, convenient operation, nondestructiveness, multi-scale, and great amount of data obtained, GPR is regarded as a more promising geophysical method to provide high-resolution information of aquifers. In this paper, an introduction is given to the principle and method of GPR as well as its application conditions, and the mechanism of the method for obtaining the hydrogeological parameters is also discussed. Moreover, the advances in the technique and some problems to be solved in future studies are reviewed.