Principle Of Landfill Leakage Detection Based On High-voltage Direct Current Method

According to the structure and electrical properties of landfill, the leakage detection principle of landfill based on high voltage direct current method was studied. Firstly, A direct current circuit model for landfill was set up. In this model, three parts of resistance was involved, namely, the resistance between the power supply electrode and the leak, the leak resistance and the soil resistance under the geomembrane liner. The resistance expression between the power supply electrode and the leak was derived. Factors that affect the circuit resistance also were analyzed and validated by experiments. Then, a new leak detection model was advanced. The electric potential in the medium above and under the geomembrane liner was forward deduced. The potential above the liner was determined by the power supply current and the current inflow in the leak, whereas, the potential under the liner was related with the current outflow from the leak. The liner thickness and the soil resistivity under the liner had no impact on the potential above the liner. The power supply current also did not affect the potential under the liner. In addition, a leak current model for double-lined landfills was put forward. The potential expression in the detection layer was deduced.