Experimental Study On Resistivity Characteristics Of Seawater Intrusion And Salt Water Interface

Seawater intrusion is one of the serious geological and environmental disasters in coastal zone.To master the movement(hydrodynamic dispersion theory)and diffusion characteristics of solute saturated zone of groundwater,and determine the wedge evolution and movement process of seawater intrusion in water bearing strata,Monitoring the movement of salt water intrusion in saturated zone can provide important basic data and practical value for environmental control.Based on the numerical model of solute transport and the indoor flume model,this paper studies and explores the comprehensive method that seawater intrusion leads to the change of electrical properties.Seawater is rich in ions and its resistivity is less than5 ?.Therefore,as long as we can accurately measure the resistivity of the underground medium,we can have a general judgment on whether the sea water invades and the range of invasion.Starting from the known salt field,we can convert the conductivity /resistivity into the corresponding salt concentration,COMSOL software is used to establish the forward modeling of mobile solute and solve the elder problem and BUOYANCY FLOW to represent the actual saline intrusion in the field.Then,the RESIPY forward and inverse software is used to establish the time-lapse anomaly simulation device,and the three kinds of arrangement devices are compared.The resistivity distribution is analyzed according to the proportional salt water diffusion stage,and the process and range of salt water intrusion can be reflected.The indoor physical model test of seawater intrusion can reveal the law of seawater intrusion and migration under different hydrogeological conditions or hydrodynamic conditions relatively flexibly.The physical model method is used to measure the resistivity of flume model synchronously(TL-ERT)as an invasive measurement method to establish the relationship between resistivity change and brine intrusion;Finally,the paper compares the profile and distribution characteristics of the dynamic change of resistivity with the dynamic hydrological process of salt water intrusion which changes continuously with time,and verifies the feasibility of using the resistivity eigenvalue to distinguish the situation of seawater intrusion,and puts forward valuable information for the groundwater cultural and geological structure according to the measurement results.It can cooperate with borehole sampling monitoring to play a role in groundwater pollution investigation,which lays a foundation for further quantifying hydrogeological parameters.The occurrence and development of seawater intrusion are affected by many factors.Accurate monitoring and objective evaluation of the seawater intrusion system in this area are supported by long-term monitoring data.