Electric response tests on unsaturated layer thickness in course of seepage of sandstone

By use of the model for seepage-electric tests, the temporal-spatial domain parameters of geoelectric field in the course of seepage are gained. Based on the characteristics of potential and current isochrones, the experiment shows that natural electric field represents the rising trend in the temporal-spatial field of the seepage course. From the test, one can obtain the linear relationship between natural potential electrode and unsaturated layer thickness. When the water level rises to the measuring point, the excitation current suddenly increases to a steady state. From the changes of exciting voltages and currents at different positions, the information of flow direction, seepage velocity and leakage point can be obatained.