Simulation Analysis And Prediction Research Of Stray Current Interference On Buried Metals Under The Influence Of Multiple Factors

With the rapid expansion of the urban rail transit network in China,the number of subway operating cities is increasing year by year,which brings great convenience to the daily life of the majority of urban residents.However,the potential problems behind urban rail transit have gradually entered people’s lives.For example,because the rail cannot achieve ideal insulation to the ground,some current leaks into the soil,which will accelerate the corrosion of underground metal pipelines and pose a great threat to passengers’travel and daily life.Therefore,it is of great significance to simulate and analyze the stray current generated by the urban rail transit system and its interference to buried metals.In this paper,a three-dimensional finite element simulation model is established according to the influencing factors such as the length of the train,the arrangement of the moving wheels of the train,the local damage of the rail insulation,and the operation mode of the subway train,and the distribution characteristics of the stray current under different influencing factors are studied.divide the cathode and anode areas of buried pipelines at different times,and solve the total corrosion current density and corresponding corrosion areas of buried pipelines in the train running interval.The interference of stray currents on reinforced concrete can not be ignored.Based on the finite element method,the change law of reinforced concrete under the interference of stray current is simulated,and the damage of reinforced concrete is detected by GPR signal,The results show that the surface ground penetrating radar is feasible for the damage detection of reinforced concrete under the interference of stray current,and can accurately detect the damage area and degree.Due to the risk of breakdown of the pipeline insulation layer due to the overvoltage of the buried pipeline,combined with the lightning protection structure of Guangzhou Metro Station A,an equal-scale finite element model was built to study and analyze the process of lightning current flowing to the far end of the earth.The law of electromagnetic interference of pipelines.Taking safety protection measures against the influence of buried pipeline overvoltage,the mitigation effect of improving grounding device,installing shielded wire and protective wire on pipeline overvoltage is compared and analyzed,and suggestions for pipeline overvoltage protection are given.Finally,the partial least squares(PLS)prediction model of rail ground potential and pipeline current density is established.According to the error analysis of determination coefficient(R~2),the optimal principal component fraction is determined,the prediction mean square error(MSEP)and cross-validation root mean square error(RMSECV)is calculated,and the optimal layout position of reference electrode monitoring points is determined,The layout model and optimal layout model of the reference electrode in the actual subway project are optimized.The MSEP and RMSECV of different optimization models are compared to determine the number and layout position of the monitoring points of the optimized reference electrode corresponding to the optimization model,which provides a more powerful theoretical guidance for the actual project.