Estimation of hydraulic conductivity based on HK (hydro-kinetic) and EHK (Electro-hydro-kinetic) coupled mechanisms

The main objective of this study is to develop new techniques to estimate the hydraulic conductivity of soils based on two coupled mechanisms. The first is the HK (Hydro-Kinetic) coupled mechanism formulated by Biot (1956 a, b). The second is the EHK (Electro-Hydro-Kinetic) coupled mechanism formulated by Pride (1994).;Based on the HK coupled mechanism for dynamic behavior of soils, a characteristic frequency is a specific frequency at which the viscous coupling and inertial damping is about the same. Dynamic excitation causes the dynamic flow between solid particles and pore water; therefore, the characteristic frequency has information to estimate the hydraulic conductivity of saturated soils. In this experimental study, attenuation-based and velocity-based measurements are conducted to obtain the characteristic frequency using two sandy soils, (QUIKRETE and Ottawa sand) and two sand/bentonite mixtures (QUIKRETE sand/bentonite and Ottawa sand/bentonite mixture). From the saturated specimens, the distinct characteristic frequency is measured from the 1/Q versus frequency and the velocity versus frequency curves. The computed hydraulic conductivity based on Biot's (1956 a, b) simplified macroscopic equation using the acoustic techniques shows comparable results with the conventional laboratory test results.;In addition to the HK coupled mechanism, a new method of dynamic measurement to estimate the hydraulic conductivity is studied using the EHK (Electro-Hydro-Kinetic) coupled mechanism. The potential of direct estimation of hydraulic conductivity using EHK was proposed by Pride (1994), Haartsen and Pride (1994), and Haartsen (1995). Using the dynamic impact force, the seismoelectric conversion is induced, which is measured by two electrodes. Using two sandy soils, (QUIKRETE and Ottawa sand), and five different soil mixtures, the relations between the general soil properties and amplitudes of the seismoelectric conversion are studied. Finally, a relation between the hydraulic conductivity and measured amplitudes of the seismoelectric conversion is compared to the theoretical predictions addressed by Pride (1994) and Haartsen (1995).;Based on this study, the acoustic technique is a new tool for estimating the hydraulic conductivity of sandy and silt sandy soils. In addition, the EHK coupled mechanism proved to be a possible new testing method to measure dynamic soil properties.