A Study On Electric Capacitance Response Characteristics And Tomography Monitoring Method Of Solute And Water Transport Processes In Solution And Rock

Resistivity method is one of the most important exploration methods of geophysics, which is widely used in hydrology, environmental, engineering and geological survey. Especially from the1970s with the emerge of aligned array resistivity explorating method, resistivity explorating method became more popular with the development of computer technology, and obtain more attention and apply in many areas.There are many ways to apply capacitance and dielectric constants, but most of them have to base on the theory of electromagnetic wave transmission in medium, to determine capacitance and permittivity directly is rarely to see.In field operation high-density electric methods usually use screw thread electrodes and column electrode, there is no calculating formula for this type of electrodes. Influencing factors of capacitance mainly include dielectric constants and system characteristics. Dielectric constants are depend on temperature, frequency and medium characteristics, mainly focused in this thesis. System characteristics include electrode plate area and interval. In practical application the electrode plate area is a constant, so main influencing factor is electrode interval.In an attempt to discuss the reliability of the capacitance of NaCl solutions using parallel screw thread electrodes, we carried out a pilot study on the effects of temperature factors, electrode interval, measuring frequency and solution concentration by controlling variable method. According to the results, the capacitance of NaCl solutions increased with the temperature rising, and decreased with the temperature decreasing; however, the capacitance of solutions is inversely proportional to the square root of the electrode interval, and the capacitance increases linearly with the concentration increasing. The capacitance and the frequency on the double logarithmic diagram showed a relationship of an approximate linearly decreasing. The results of research provide evidence for the establishment of the capacitance tomography method and the coupling applications with high density resistivity method, which has a very important significance.According to the research of electric capacitance tomography method in one-dimensional piping, solute migration under two-dimensional static water conditions and three-dimensional rock block, we basically established a high-density array electric capacitance tomography method system, which can help us to fast imaging, review the results intuitively, automatic monitoring continuously. Moreover, this method is sensitively to solute transport, thus it is a reliable and has a broad prospect method for testing electrical method.