Processing Research For The Data About The Underground Pipeline Acquired By GPR

Underground pipeline is an important infrastructure of the city,and it is one of the indispensable important data for urban operation and development.Therefore,it is very important to detect the underground pipeline effectively and obtain the underground pipeline information quickly and accurately.In this paper,GPR method,numerical simulation and physical experiment are used to study the data processing of underground pipeline,so as to suppress the linear interference in GPR and extract the pipe diameter and buried depth information of underground pipeline.The main contents and achievements of this study are as follows:(1)The suppression method of linear jamming in GPR is studied,and the conventional F-K filtering method is improved in filtering area and filtering mode.Compared with the conventional F-K filtering method,the improved F-K filtering method can suppress linear interference more effectively,(2)Through numerical simulation of underground pipeline,the influence of single factor change on GPR imaging characteristics of underground pipeline is analyzed under different pipeline types,different buried media,different pipeline radius,different buried depth and other factors.The results show that when other parameters are the same,the type of pipeline does not affect the hyperbolic shape of the pipeline in the radar profile.The larger the difference of dielectric constant between the pipeline and the buried medium is,the stronger the reflected signal energy is,and the clearer the hyperbola is;The smaller the dielectric constant of the buried medium is,the wider the hyperbolic opening is,the larger the curvature radius is,and the higher the time domain position is;The larger the pipe diameter is,the stronger the reflection signal is and the larger the curvature radius of hyperbola is;The larger the buried depth of the pipeline,the weaker the reflected signal,the narrower the hyperbolic opening,the smaller the curvature radius,and the lower the time domain position of the hyperbola.(3)The identification method of pipeline diameter and buried depth is studied.In this method,the characteristic hyperbola of pipeline is extracted according to the composition of echo signal of underground pipeline,and the optimized least square hyperbola fitting method is used to fit the characteristic hyperbola to obtain the required parameters a,B,T0,so as to obtain the pipeline diameter and buried depth,The feasibility and effectiveness of the proposed method are verified by numerical simulation and physical experiments.The research shows that the error of the underground pipeline diameter obtained by this method in practical application is about8.68% ? 13%,and the average error is 10.19%;The apparent error of buried depth is about 8.71% ? 19.04%,and the average apparent error is 14.96%.