Experimental Research On Landfill Leakage Detection Based On Resistivity Anomaly

Due to the advantages of economic,practical,and mature construction technology,landfills are widely used in solid waste treatment all over the world,especially in developing countries,which still regard landfills as the main method to dispose of harmless solid waste.However,at present,almost all the impervious layers of landfills have leakage problems.Accurate detection of seepage points and long-term monitoring of pollution plumes are of great significance to the treatment and restoration of landfill pollution.In this paper,different landfill models and landfill seepage models are set up outdoors.The In-situ resistivity method is used to detect pollution seepage at the bottom of the models.Visual MODFLOW is used to establish the solute transport model of landfill.The in-situ resistivity data were converted into pollution concentration data,and the in-situ resistivity,groundwater flow model MODFLOW,and multi-component solute transport model MT3 DMS were coupled.Based on this,accurate detection of the leakage point at the bottom of the landfill site was realized,and the variation of pollution plume concentration and diffusion range were simulated and predicted.Through experimental research,the following conclusions are obtained:(1)For in-situ resistivity detection at the bottom of the landfill,a better detection effect can be achieved when the minimum concentration of landfill leachate reaches 80mg/L,and the half-space apparent resistivity calculation formula is used to calculate the calculation methods.(2)From the results of seepage simulation with leachate,it can be concluded that the more distance from the leakage point,the greater the variation of myopia resistivity,and the damage of different sizes and shapes can be well recognized.It can be concluded that the in-situ resistivity difference method can better determine the location of the leakage point and can monitor the leakage plume.(3)Through the Archie formula,linear fitting,polynomial fitting,and nonlinear curve fitting,the optimal resistivity conversion concentration formula was obtained as nonlinear curve fitting.The measured resistivity was converted to the simulated leachate concentration.Characteristic points were selected to establish the pollutant concentration observation well,and the simulated pollution plume was compared and verified.The solute transport model was verified.(4)The permeability coefficient at the bottom of the actual model is somewhat different from that simulated by the model due to various reasons such as porosity and compactness,but in general,the seepage plume of leachate obtained through the measured apparent resistivity contour map is similar to that simulated by Visual MODFLOW.The simulation results show that the combination of in-situ resistivity detection and solute transport numerical simulation can better detect the specific leakage location of the landfill site and monitor the migration direction of the pollution plume.Various formation parameters required by the groundwater model will be measured during the site selection and construction of the landfill site.The specific leakage location and size measured by in-situ detection at the bottom of the landfill will be added to the groundwater model,and the resistivity data will be converted into concentration data to adjust and verify the model.Finally,the groundwater solute migration model will be used to predict the migration path of the pollution plume.It can provide some technical support for the treatment and repair of landfill seepage and can provide a new leakage monitoring method for the same type of engineering such as tailings dams,dams,and other hydraulic structures.