Investigating the Complex Resistivity (0.01-1000 Hz) Response to Saturation State for Unconsolidated Sediments

0073680 slater该奖项支持对松散、欠饱和沉积物的低频（0.1-1000 Hz）电学特性的研究。之前的研究已经确定了复杂电阻率（CR）测量在预测饱和介质中的粒度分布、水力导电性和碳氢化合物污染物方面的价值。然而，欠饱和对颗粒-流体界面极化机制的影响尚不清楚。这项工作将研究CR对饱和度的依赖，从而确定其在渗流带水文地质和农业评价中的应用。探地雷达和电阻率法可以提供水分含量的信息。将确定利用CR提供额外的水文信息，如毛细电位、孔隙流体分布和干湿循环中的滞后效应。这项工作开启了堪萨斯城密苏里大学应用电地球物理学的研究。PI将在排水和润湿循环过程中测量一系列松散沉积物的复杂电阻率、饱和度和毛细电位。重要的结构参数，包括粒度分布、比表面积、孔隙度、真实地层因子和矿物学将对所有样品进行评估。由于结构性质控制极化作用的表面积，因此在所调查的松散沉积物范围内，CR对饱和度的响应预计会有很大变化

0073680SlaterThis award supports research on the low frequency (0.1-1000 Hz) electrical properties of unconsolidated, under-saturated sediments. Previous research has identified the value of complex resistivity (CR) measurements for predicting grain size distribution, hydraulic conductivity and hydrocarbon contaminants in saturated media. However, the influence of under-saturation on polarization mechanisms occurring at the grain-fluid interface is not well understood. This work will investigate the CR dependence on degree of saturation and will hence determine its application in hydrogeological and agricultural assessments of the vadose zone. Ground penetrating radar and electrical resistivity methods can provide information on moisture content. The use of CR for providing additional hydrological information, such as capillary potential, pore fluid distribution and hysteresis effects in a drying-wetting cycle, will be determined. This work initiates research in applied electrical geophysics at the University of Missouri, Kansas City. The PI will make measurements of complex resistivity, degree of saturation and capillary potential on a range of unconsolidated sediments during a cycle of drainage and wetting. Important structural parameters, including grain size distribution, specific surface area, porosity, true formation factor and mineralogy will be evaluated for all samples. As structural properties control the surface area over which polarization acts, the CR response to saturation is expected to vary considerably for the range of unconsolidated sediments investigated.***