Electrical Effects and the Movement of Water in Soils

摘要

The study deals with electrical streaming potential effects on water movement in the soil. For saturated conditions, the only response was the step change in electrical potential at initiation or cessation of hydraulic flow. The direction and magnitude of this 'E step' were consistent with those of the streaming potential phenomenon. The magnitude of the 'E step' was essentially proportional to the hydraulic gradient. For unsaturated flow, electrical potentials measured during upward entry of water into columns of initially air-dry sand kaolinite showed that as the wet front moved past an electrode, characteristic negative peaks were observed. Electrical potential, water flux, and hydraulic gradient were also studied for saturated water flow through plugs of sodium bentonite at concentrations ranging from 11.5 to 35.1% clay. At the lowest caly content, the relationship between electrical potential and hydraulic gradient, and between water flux and hydraulic gradient were both less than proportional, while at 28.4% clay both relationships were strictly proportional and at 35.1% clay the relationship was more than proportional. (WRSIC abstract)