Relationship between Electrical Resistivity and Matric Suction of Compacted Granite Residual Soil

In this paper, the change of electrical resistivity and matric suction with volumetric water content is investigated using the electrical resistivity measurement and pressure plate test for different densities compacted granite residual soils. The results show that the resistivity value decreases with increasing water content and dry density, and tends to constant at higher values. The shapes of the soil-water characteristic curve (SWCC) and electrical resistivity-water characteristic curve (RWCC) of the investigated soils are very similar. Both curves of RWCC and SWCC can be well described by the van Genuchten model and observed a better correlation i.e., the fitting parameters of RWCC and SWCC are linearly proportional to each other. Based on these two characteristic curves mentioned above, the modification of the van Genuchten model is proposed to develop a direct relationship between electrical resistivity and matric suction for the compacted residual soils. Moreover, the comparison of fitting parameters of the resistivity-matric suction characteristic curve with RWCC and SWCC parameters is also linearly proportional to each other. It can be concluded that the matric suction is strongly depend on the electrical resistivity of the soil, after knowing the fitting parameters of the RWCC, it may be possible to predict the SWCC from the resistivity data.