从高密度电阻率成像法到三维空间上的包气带水文学

Three-dimensional vadose zone hydrology based on high-density electrical resistivity tomography

高密度电阻率成像法是新近出现的通过测定介质电传导特性的地球物理勘探方法。它方便、快速和多尺度,可对探测对象进行无损的、三维的和动态的监测。由于包气带中发生的各种物理、化学、生物和水文过程不可避免的都会引起介质电阻率的变化,通过高密度电阻率成像法可以对这些过程进行三维的动态监测,从而为我们在三维空间上认识各种包气带过程创造了条件。本文首先介绍了高密度电阻率成像法在半无限的介质表面上应用时的电极布置、测定和反演计算方法,然后介绍了影响介质电阻率的因素。最后,从电阻率空间分布的差异性和时间上的变化性方面,介绍了目前高密度电阻率成像法的应用领域和研究方向,以期能促进高密度电阻率成像法的广泛应用和推动三维空间上的包气带水文学的研究。

Highdensity electrical resistivity tomography, which bases on the measurements of material resistivity, is one of the geophysical prospecting methods recently developed. With its convenient, fast and usable in multiscale advantages, the technique can be used to conduct noninvasive monitoring in threedimensions. Since the physical, chemical, biological and hydrological processes occurred in the vadose zone unavoidably would result in changes in the material resistivity, electrical resistivity tomography is helpful in understanding these processes. In this paper, first, the electrode array, measurement method and inversion algorithm for the method were introduced. Then, factors that affect the material resistivity were discussed. Finally, several applications that base on the spatial heterogeneity and temporal variations in resistivity were reviewed, including process monitor and parameter estimation in water pollution, unsaturated zone water flow, solute and heat transport, and material structure change under stress. Applications of the method in the performance evaluation of engineering projects were also introduced. By these reviews, we hope that the researches in threedimensional vadose zone hydrology could benefit from the electrical resistivity tomography well.