Detection of Buried Water Lines and Determining the Depth of Water Tables Using Forward Modeling of Ground-Penetrating Radar Data

Document Type : Research Paper

Author

Faculty Member of Arak University of Technology

Abstract

Ground-Penetrating Radar (GPR) is a high-resolution non-destructive geophysical method which detects buried objects and subsurface heterogeneities using transmitting high-frequency (generally in the range of 1 MHz up to 1 GHz) electromagnetic pulses and receiving reflected pulses. In the current study the possibility of employing this method to detect buried water lines and mapping groundwater for water engineering purposes was studied. To achieve this goal, the GPR response of synthetic objects corresponding to targets common in water engineering affairs containing horizontal cylinder and layered earth, was produced using numerical forward modeling by the 2-D finite-difference method modified in the frequency domain to be used for interpreting the real GPR radargrams. The GPR method was also employed to detect underground water lines in Shahin-shahr plain, Isfahan province as the case study of the present research leading to some heterogeneities in the obtained radargrams, interpreted using the results of the forward modeling as probably buried qanat semi filled by fresh water. The validity of the results was also proved through trenching on one of the surveyed profiles. Based on the results of this research, GPR method is capable of detecting all underground water lines, assessing material type (metallic or nonmetallic) of buried pipes, identification of kind of water content (fresh or saline) of nonmetallic pipes, determining depth of water table, estimating thickness of water containing layer (about waters with low conductivity) and distinguishing fresh and saline water interface.

Keywords


احمدی ر، فتحیان­پور ن و نوروزی غ­ح، 1391الف. کاربردهای ژئوتکنیکی روش رادار نفوذی به زمین (GPR) در شناسایی پارامترهای فیزیکی و هندسی ناهمگنی­های زیرسطحی. اولین کنفرانس مهندسی الکترومغناطیس ایران، دانشگاه علم و صنعت ایران، 6 و 7 دی ماه، تهران.
احمدی ر، فتحیان­پور ن و نوروزی غ­ح، 1391ب. تخمین مشخصات هندسی لوله­های انتقال آب و فاضلاب مدفون با استفاده از مدل ریاضی و شبیه­سازی پاسخ داده­های رادار نفوذی زمین (GPR). همایش ملی علوم مهندسی آب و فاضلاب، 8 و 9 اسفند، دانشگاه تحصیلات تکمیلی کرمان.
احمدی ر، فتحیان­پور ن و نوروزی غ­ح، 1393الف. مطالعه ژئوتکنیکی بنای تاریخی سی­و­سه­پل اصفهان با استفاده از روش ژئوفیزیکی رادار نفوذی زمین. همایش ملی معماری، عمران و توسعه نوین شهری، 31 اردیبهشت، کانون ملی معماری ایران، تبریز.
احمدی ر، فتحیان­پور ن و نوروزی غ ح، 1393ب. کاربردهای ژئوتکنیکی رادار نفوذی به زمین در شناسایی ناهمگنی­های زیر سطحی مسیر حفر تونل انتقال تاسیسات برقی اصفهان. اولین همایش ملی رادار نفوذی به زمین، کرمان، دانشگاه شهید باهنر کرمان، کرمان.
احمدی ر، فتحیان­پور ن و نوروزی غ­ح، 1393ث. بهبود مدل‌سازی پیشرو داده‌‌‌های رادار نفوذی به زمین (GPR) به روش عددی تفاضل متناهی. مجله ژئوفیزیک ایران، جلد 8، شماره 3، صفحه­های 114 تا 130.
اویسی مؤخر م، 1386. روش­های مغناطیسی و رادار در تشخیص غارهای زیرزمینی در شهر قصرشیرین در ایران. مجله فیزیک زمین و فضا، جلد 34، شماره 2، صفحه­های 1 تا 11.
Ahmadi R, Fathianpour N and Norouzi GH, 2014. Detecting physical and geometrical parameters of some common geotechnical targets through their effects on GPR responses. Arabian Journal of Geosciences 8(7): 4843-4854.
Annan AP, 2001, Ground-penetrating radar workshop notes, Sensors and Software Inc., Mississauga, ON, Canada, 192 pages.
Annan AP, 2003. GPR for infrastructure imaging: International Symposium (NDT-CE 2003), Non-Destructive Testing in Civil Engineering.
Bakker MAJ, Maljers D and Weerts HJT, 2007. Ground-penetrating radar profiling on embanked floodplains. Netherlands Journal of Geosciences 86: 55–61.
Daniels DJ, 2004. Ground Penetrating Radar, 2nd edition, Radar, Sonar, Navigation and Avionics Series 15, Institute of Electrical Engineers, London, UK.
Davis JL and Annan AP, 1989. Ground penetrating radar for high-resolution mapping of soil and rock stratigraphy. Geophysical Prospecting 37: 531-551.
Geraads S, Charachon B, Loeffler O and Omnes G, 2002. Applying a wavenumber notch filter to remove interferences caused by railway sleepers from a GPR section. Pp. 715-718, In Proceedings of SPIE: 4758. Ninth International Conference on Ground Penetrating Radar.
Gobel C, Hellmann R and Petzhold H, 1994. Georadar model and in-situe investigations for inspection of railways tracks. Pp. 12-16. Proceedings of Ground Penetrating Radar Conference. June, Kitchener, Canada.
Huston D, Pelczarski N and Esser B, 2000. Damage detection in roadways with Ground Penetrating Radar. Pp. 91-95. Proceeding of Eigth International Conference on GPR, Gold Coasts, Australia.
Irving J and Knight R, 2006. Numerical modeling of ground penetrating radar in 2-D using MATLAB. Computers & Geosciences 32: 1247–1258.
Jol HM, 2009. Ground Penetrating Radar Theory and Applications. First edition, Elsevier Science. 543 P.
Manacorda G, Morandi D and Sarri A, 2002. A customized GPR system for railroad tracks verification. Pp. 719-722. Proceedings of SPIE: 4758. Ninth International Conference on Ground Penetrating Radar.
Sadiku O and Matthew N, 2001. Numerical Techniques in Electromagnetics. Boca Raton London New York Washington, D.C., CRC Press.
Stern W, 1929. Experiment of an electrodynamic thickness measurement of glacier ice, Gerl. Beitr. zur Geophysik 23: 292-333.
Stern W, 1930. Basics, methodology and previous results of electrodynamic thickness measurements of glacier ice, Z. Gletscherkunde 15: 24-42.
Zeng X and McMechan GA, 1997. GPR characterization of buried tanks and pipes. Geophysics 62: 797–806.