Influence of surface undulations on GPR-based underground pipeline detection
ZENG Bo1(), LIU Shuo2, YANG Jun3, FENG De-Shan2(), YUAN Zhong-Ming3, LIU Jie3, WANG Xun2
1. Guangzhou Urban Planning and Design Survey Research Institute,Guangzhou 510060,China 2. School of Geosciences and Info-Physics,Central South University,Changsha 410083,China 3. Guangzhou Municipal Engineering Design & Research Institute Co. Ltd.,Guangzhou 510060,China
As important urban facilities,underground pipelines perform the functions of energy transfer and information transmission,providing convenience and guarantee for urban life.Ground-penetrating radar (GPR),as a high-resolution,high-precision,trenchless,and non-destructive detection technique,has great advantages in pipeline surveys.However,undulating surfaces with complex terrain greatly influence GPR-based detection of underground pipelines.Therefore,this study conducted numerical simulations of the underground pipeline detection using the finite element method,which can be combined with an unstructured grid to fit the undulating surfaces effectively.Furthermore,this study introduced the height correction method to match the obtained geologic sections with terrain,making it easier to analyze the anomaly characteristics.Finally,through numerical experiments,this study analyzed the influence of undulating surfaces on the detection of pipelines with different burial depths,spacings,materials,and fillers,providing a theoretical basis for GPR data interpretation.The experimental results show that waveforms and reflected wave energy,subjected to distortion due to surface undulations,cannot be used as the sloebasis for judging pipeline information.Therefore,height correction is required,and the vertexes of hyperbolas can be used to judge the burial depths and materials of pipelines.
Zhao X, Wang X L, Liu Z Y, et al. Simulation of underground pipelines under complicated condition[J]. Geophysical and Geochemical Exploration, 2014, 38(6):1307-1312.
[2]
Park B, Kim J, Lee J, et al. Underground object classification for urban roads using instantaneous phase analysis of Ground Penetrating Radar (GPR) data[J]. Remote Sensing, 2018, 10(9):1-24.
doi: 10.3390/rs10010001
Yao X C, Yan M, Lyu G, et al. Research on underground pipeline classification and discrimination method based on geological radar detection[J]. Progress in Geophysics, 2018, 33(4):1740-1747.
Han J M, Zhong X, Jing S, et al. The application of geological radar to urban pipeline detection in the loess area[J]. Geophysical and Geochemical Exploration, 2020, 44(6):1476-1481.
[5]
曾昭发, 刘四新, 冯晅, 等. 探地雷达原理与应用[M]. 北京: 电子工业出版社, 2005.
[5]
Zeng Z F, Liu S X, Feng X, et al. Theory and application of ground penetrating radar[M]. Beijing: Electronics Industry Press, 2005.
Xiao M, Chen C Y, Jia H, et al. The study of the interference region around metal pipeline in underground disease detection of urban road[J]. Geophysical and Geochemical Exploration, 2016, 40(5):1046-1050.
Liang X Q, Yang D X, Zhang K N, et al. Application of FDTD numerical simulation of Ground Penetrating Radar in pipeline detection[J]. Progress in Geophysics, 2017, 32(4):1803-1807.
[8]
Yee K. Numerical solution of initial boundary value problems involving maxwell's equations in isotropic media[J]. IEEE Transactions on Antennas & Propagation, 1966, 14(3):302-307.
[9]
葛德彪, 闫玉波. 电磁波时域有限差分法[M]. 西安: 西安电子科技大学出版社, 2005.
[9]
Ge D B, Yan Y B. Finite-difference time-domain method for electromagnetic waves[M]. Xi'an: Xidian University Press, 2005.
Wang S, Yan T L. The extraction of sounding curves from the data of high-density resistivity method for intepretation[J]. Geophysical and Geochemical Exploration, 2016, 40(5):1051-1054.
[11]
Gao L, Song H, Liu H, et al. Model test study on oil leakage and underground pipelines using ground penetrating radar[J]. Russian Journal of Nondestructive Testing, 2020, 56(5):435-444.
doi: 10.1134/S1061830920050058
Li J, Liu J J, Zeng Z F, et al. Study of GPR simulation based on the transformation optics FDTD[J]. Chinese Journal of Geophysics, 2016, 59(6):2280-2289.
Lei J W, Fang H Y, Li Y P, et al. GPR forward model of underground non-metallic pipeline based on parallel conformal symplectic Euler algorithm[J]. Chinese Journal of Geophysics, 2020, 63(8):3192-3204.
[15]
徐世浙. 地球物理中的有限单元法[M]. 北京: 科学出版社, 1994.
[15]
Xu S Z. The finite element method in geophysics[M]. Beijing: Science Press, 1994.
[16]
Jin J M. The finite element method in electromagnetics[M]. John Wiley & Sons, 2014.
Feng D S, Wang X. Convolution perfectly matched layer for the finte-element time-domain method modeling of Ground Penetrating Radar[J]. Chinese Journal of Geophysics, 2017, 60(1):413-423.
[18]
Zhang Z, Wang H H, Wang M L, et al. Non-Split PML boundary condition for finite element time-domain modeling of ground penetrating radar[J]. Journal of Applied Mathematics and Physics, 2019, 7(5):1077-1096.
doi: 10.4236/jamp.2019.75073
Wang H H, Wang M L, Zhang Z, et al. Simulation of GPR in Cole-Cole dispersive media by finite element method based on Pade approximation[J]. Chinese Journal of Geophysics, 2018, 61(10):4136-4147.
Wang H H, Lyu Y Z, Wang M L, et al. A perfectly matched layer for second order electromagnetic wave simulation of GPR by finite element time domain method[J]. Chinese Journal of Geophysics, 2019, 62(5):1929-1941.
Hou J, Liu Y S, Lan H Q, et al. Elastic reverse time migration using a topograpghy flattening scheme[J]. Chinese Journal of Geophysics, 2018, 61(4):1434-1446.
Liu S X, Feng Y Q, Fu L, et al. Advances and numerical simulation of airborne ground penetrating radar[J]. Progress in Geophysics, 2012, 27(2):727-735.
[23]
Taflove A, Brodwin M E. Numerical solution of steady-state electromagnetic scattering problems using the time-dependent maxwell's equations[J]. IEEE Transactions on Microwave Theory and Techniques, 1975, 23(8):623-630.
doi: 10.1109/TMTT.1975.1128640