Effects of Electromagnetic Stimulation on Soil’s Hydraulic Conductivity Farid, A., Rocha, J. Civil Engineering, Boise State University, Boise Idaho, U.S.A. Browning, J. Electrical Engineering, Boise State University, Boise Idaho, U.S.A. ABSTRACT A series of bench top tests were performed to investigate the effects of electromagnetic (EM) stimulation on various soil properties. Exploratory tests on EM stimulation’s effects on hydraulic conductivity were performed on very fine sand and clay (bentonite) samples with very promising results. It was found that EM waves do indeed affect the hydraulic conductivity of soil. An increasing effect on the hydraulic conductivity proportional to the EM wave’s power output was observed for the sandy sample while flow restriction was observed for the clayey sample. RÉSUMÉ Une série de tests dessus de banc ont été réalisées pour étudier les effets des champs électromagnétiques (EM) de stimulation sur les propriétés des sols différents. Tests exploratoires sur les effets de stimulation EM sur la conductivité hydraulique ont été réalisés sur un sable très fin et d'argile (bentonite) des échantillons avec des résultats très prometteurs. Il a été constaté que les ondes EM effectivement influer sur la conductivité hydraulique du sol. Un effet croissant sur la conductivité hydraulique proportionnelle à la puissance de la vague d'EM a été observée pour l'échantillon de sable tandis que la restriction de débit a été observé pour l'échantillon argileux. Keywords: Hydraulic Conductivity, Dipole Oscillation, Electromagnetic Stimulation 1 INTRODUCTION An alternating electric field can make dipole water molecules oscillate. Individual water molecules can be aligned using an electrostatic source and droplets of water can even be levitated by magnetic fields (Ikezoe et al. 1998). It has been shown that when stimulated by an electric field matching the water molecule’s resonant frequency, localized vibrations and flow within a water droplet can be induced which can cause an overall deformation through both direct and alternating currents (Yamada et al. 2003). The research involves the identification of the different effects that EM stimulation has on different soil properties and behaviour such as hydraulic conductivity. Hydraulic conductivity is a measure of the rate at which water moves through a porous material. Hydraulic conductivity is mostly dependent on the viscosity of the fluid, along with the pore and grain size distributions, void ratio, and the level of saturation of the porous medium (Das 2006). The hypothesis is that given an EM wave, individual water molecules can be oscillated and induce a net change in the movement and flow of water through a porous medium without altering the properties of the medium itself. This work could prove to be of importance in furthering understanding of the effects of EM stimulation on the hydraulic conductivity of soil. A correlation between EM stimulation and hydraulic conductivity could have broad applications for geo-environmental and geotechnical applications such as contaminant remediation in soils, aquifer regeneration, landfill lining, and for various geotechnical applications. EM waves can be used to enhance soil and groundwater remediation in a way that only a minute amount of heat is generated, yet the desired mechanisms in soil are stimulated or slowed down. This will eliminate the harmful pH changing or heat creating effects of direct or alternating currents used to enhance soil remediation. 2 EXPERIMENTAL SETUP A customizable permeameter to measure the change in hydraulic conductivity given an EM wave emitted from an antenna was developed for this work. The permeameter was built using plastic materials to avoid metallic parts and the resulting uncontrolled interference with regard to EM waves. The permeameter and its contents were stimulated by an EM wave through an antenna with an impedance matched frequency and various power output levels while the hydraulic conductivity was measured incrementally over time. The EM wave was generated through a coaxial cable via an Agilent E4400B signal generator and amplified using a 100LM8 amplifier manufactured by Amplifier Research. The electrical impedance of the medium within the permeameter, cables, and antennas was first matched to that of the amplifier (50 Ω) using a matching network to minimize the reflection back into the amplifier and maximize the power output into the medium. The measurement of the impedance was performed using an Agilent N9320A network analyzer and a dual directional coupler.