In the present study, ten cylindrical solid samples with some imitative fractures and veins are investigated by the technique of resistivity tomography. The samples with diameter of 200mm contain 2~3 anomaly-volumes in a linear scale of 2-15mm which axes are parallel to that of the cylinder. 108 electrodes are evenly arranged at the circumference in middle part of the cylinder with certain buried depth. Wenner and Pole-pole observational figurations are adopted. Through a linear iterative inversion, the distribution of electric resistivity in the samples is reconstructed then.
At the beginning the dry sample is measured. Its 2-D resistivity image indicates that the areas of high resistivity in the image exactly coincide with the positions of the fractures and the high-resistivity imitation buried in the sample beforehand. Then salt water is filled into the fractures, and following the water-diffusion process, the tomographic measurements are conducted in the electrode array. A series of resistivity images show that the previous high-resistivity areas at the positions of fractures became low-resistivity areas and the previous high-resistivity imitative area imitating a vein remains. Comparing these images, the temporal change of the images reveals the process of the water diffusion. The repeat tests of same sample and the tests for different samples show similar results.
The experiment indicates that the resistivity image of solid model obtained from the present observational system and imaging method has certain resolution to the fractures, water bearing fractures and veins . This technique can be easily extended to the application in geotechnical explorations.