تحلیل حساسیت پاسخ GPR اهداف ژئوتکنیکی مدفون به پارامترهای هندسی و فیزیکی با استفاده از مدل‌سازی عددی پیشرو

نوع مقاله : مقاله پژوهشی

نویسندگان

1 دانشکده مهندسی معدن دانشگاه صنعتی اراک

2 دانشکده مهندسی معدن، دانشگاه صنعتی اصفهان

3 دانشکده مهندسی معدن، دانشگاه تهران

10.17383/S2251-6565(15)940912-X

چکیده

 
در پژوهش حاضر پاسخ GPRمدل­های مصنوعی مختلف متناظر با ساختارهای ژئوتکنیکی فرضی نظیر استوانه افقی منفرد، منشور دوبعدی، استوانه افقی جفت، چندضلعی دوبعدی دلخواه و زمین لایه­ای، با استفاده از مدلسازی عددی پیشرو به­روش تفاضل محدود دوبعدی حوزه زمان بهبود یافته در حوزه فرکانس، مدلسازی شده است. در این تحقیق براساس پارامترهای ریاضی هذلولی و نتایج مدلسازی پیشرو داده­های GPRهدف استوانه­ای، نشان داده شده که بین نسبت ارتفاع به پهنای هذلولی با پارامترهای هندسی هدف استوانه­ای (قطر و عمق دفن) یک سری روابط خطی وجود دارد. این روابط می­تواند به­عنوان معیارهای کمی مناسب برای شناسایی مشخصات فیزیکی و هندسی اشیاء استوانه­ای مدفون در زیر زمین با تصاویر GPR مورد استفاده قرار گیرد. برای دست­یابی به هدف و تحلیل حساسیت، تأثیر پارامترهای مختلف هدف نظیر شکل هندسی، جنس، اندازه و ابعاد، عمق دفن، نوع و سطح سیالات محتوی (درصد حجمی سیالات) و ویژگی­های فیزیکی محیط میزبان بر روی پاسخ­های GPR، مورد بررسی قرار گرفته است. نتایج حاکی از پتانسیل بالقوه روش GPR برای آشکارسازی انواع اهداف مدفون، شناسایی جنس مدل و ارزیابی ویژگی­های محتوای سیال مدل است. با استفاده از این شبیه­سازی­ها می­توان اهداف استوانه­ای فلزی را از غیرفلزی تشخیص داد و نوع سیال محتوای درون ساختارهای غیرفلزی (نظیر هوا، آب شیرین و آب شور) را تعیین نمود. نتایج تحقیق با مطالعه موردی برای شناسایی قنات واقع در دشت شاهین شهر اصفهان نیز اعتبارسنجی گردیده است، به­گونه­ای که عمق دفن و قطر قنات به­ترتیب با خطای 4/3 درصد و 12 درصد تقریب زده شد.

کلیدواژه‌ها

موضوعات

عنوان مقاله [English]

Sensitivity analysis of physical and geometrical parameters of geotechnical targets on GPR responses using forward modeling

نویسندگان [English]

  • Reza Ahmadi 1
  • Nader Fathianpour 2
  • Gholam-Hossain Norouzi 3
1 Dept. of Mining, Arak University of Technology
2 Dept. of Mining, Isfahan University of Technology
3 Dept. of Mining, University of Tehran
چکیده [English]

In the current research, GPR response of variety of synthetic models encountered with geotechnical applications containing single horizontal cylinder, 2D prism, double horizontal cylinders, 2D arbitrary polygon and layered earth have been produced using forward modeling through the finite-difference time-domain algorithm improved in the frequency domain. In this research by using the parameters of a hyperbola and GPR responses produced for cylindrical objects by means of the forward modeling, it was revealed that there exist some linear relationships between the hyperbola height to width ratio (H/W) with physical and geometrical parameters of the cylindrical objects. These relations can be used as proper quantitative criteria to identify physical and geometrical parameters of buried cylindrical objects on GPR images. To achieve this purpose, the effect of several parameters such as geometrical shape, material type, size and burial depth of the objects as well as type and interface of fluids content and host medium physical properties on GPR responses, have also been studied. The results lead us to the potential of GPR method to detect the kinds of targets; identifying the parameters of cylindrical objects and evaluating characteristics of fluid content, so that one can distinguish metallic from nonmetallic targets as well as type of fluid content of nonmetallic targets (i.e. air, fresh water and salt water). The results of the research were validated by applying for identification of buried qanat in Shahin-Shahr plain, Isfahan province. The burial depth and diameter of the qanat were estimated by 3.4% and 12% erorr respectively.



کلیدواژه‌ها [English]

  • Ground-Penetrating Radar (GPR)
  • Hyperbolic response
  • Numerical forward modeling
  • Geotechnical targets
  • sensitivity analysis
  • Geometrical parameters of cylindrical targets

مراجع

]1[. Stern, W. (1929). Versuch einer elektrodynamischen Dickenmessung von Gletschereis, Gerl. Beitr. zur Geophysik, 23, 292-333.
]2[. Stern, W. (1930). Über Grundlagen, Methodik und bisherige Ergebnisse elektrodynamischer Dickenmessung von Gletschereis. Z. Gletscherkunde, 15, 24-42.
]3 .[Knödel, K., Lange, G., & Voigt, H.J. (2007). Environmental geology: handbook of field methods and case studies-Google Books Result, 1357 pages, Chapter 4, Geophysics.
]4[. Kovin, O.N. (2000). Application of georadar for engineering investigations. Proceeding of scientific session Mining Institute UB RAS, April 9­13, Perm, 198­202 (in Russian).
]5[. Gregoire, C., Halleux, L. (2002). Characterization of fractures by GPR in a mining environment. First Break 20 (7), 467­471.
]6[. Strange, A.D., Ralston, J.C., & Chandran, V. (2005). Near-surface Interface Detection for Coal Mining Applications using Bispectral Features and GPR. Subsurface Sensing Technologies and Applications, 6(2), 125-149.
]7[. Kovin, O.N. (2010). Ground penetrating radar investigations in Upper Kama potash mine, Mining problems and solutions. ISBN: 978-3-8433-5958-0, LAP Lambert Academic Publishing (2010-11-14), 124 pages.
]8[. Grandjean, G., Gourry, J.C., & Bitri, A. (2000). Evaluation of GPR techniques for civil-engineering applications: study on a test site. Journal of Applied Geophysics, 45, 141–156.
]9[. Singh, K.K.K., & Ghouhan, R.K.S. (2002). Exploration of underground strata conditions for a traffic bypass tunnel using ground penetrating radar system- a case study. Geotechnical and Geological Engineering, 20, 81-87.
]10[. Ahmadi, R., Fathianpour, N., & Norouzi, G.H. (2014), Geotechnical applications of Ground- Penetrating Radar to identify subsurface in-homogeneities of Isfahan electric installation transfer tunnel. The first national Conference on Ground Penetrating Radar, Shahid Bahonar University of Kerman, Kerman (In Persian).
]11[. Ahmadi, R., Fathianpour, N., & Norouzi, G.H. (2014), Identification of basement pitfalls of Isfahan- Imam mosque historical- cultural building using Ground- Penetrating Radar. The first national Conference on Ground Penetrating Radar, Shahid Bahonar University of Kerman, Kerman (In Persian).
]12[. Ahmadi, R., Fathianpour, N., & Norouzi, G.H. (2014), Geotechnical investigation of 33 pole bridge structure in Isfahan using Ground- Penetrating Radar method. National Conference on architecture, civil and modern urban development, Tabriz. (In Persian).
]13[. Al-fares, W., Bakalowicz, M., Guerin, R., & Dukhan, M. (2002). Analysis of the karst aquifer structure of the Lamalou area (Herault, France) with ground-penetrating radar. Journal of Applied Geophysics, 51, 97–106
]14[. Johnson, R.H., & Poeter, E. (2005). Iterative use of the Bruggeman–Hanai–Sen mixing model to determine water saturations in sand. Geophysics, 70(5), K33–K38.
]15[. Leucci, G., Cataldo, R., & De Nunzio, G. (2006). Subsurface water-content identification in a crypt using GPR and comparison with microclimatic conditions. Near Surface Geophysics, 4(4), 207–213.
]16[. Grasmueck, M., Weger, R., & Horstmeyer, H., (2004). Three­dimensional ground­penetrating radar imaging of sedimentary structures, fractures, and archeological features at submeter resolution. Geology, 32(11), 933­936.
]17[. Conyers, L.B. (2010). Ground-penetrating radar for anthro-pological research. Antiquity 84, 323, 175–184.
]18[. Rappaport, C., El-Shenawee, M., & Zhan, H. (2003). Suppressing GPR Clutter from Randomly Rough Ground Surfaces to Enhance Nonmetallic Mine Detection. Subsurface Sensing Technologies and Applications, 4(4).
]19[. Santos, R.N. dos, V., Porsani, L.J. & Hirata, S.T.N. (2009). Automatic classification of metallic targets using pattern recognition of GPR reflection: a study in the IAG-USP Test Site, Sao Paulo (Brazil), IEEE Conference Publications, 1-4.
]20[. Moorman, B.J., Robinson, S.D., & Burgess, M.M. (2003). Imaging periglacial conditions with ground-penetrating radar.
]21[. Christopher, W., Stevens, B.J., & Moorman, S.M. (2008). Detection of Frozen and Unfrozen Interfaces with Ground Penetrating Radar in the Nearshore Zone of the Mackenzie Delta, Canada. Ninth International Conference on Permafrost, 1711-1716.
]22[. Jordan, T.E., & Baker, S.B. (2004). Reprocessing GPR data from the CFB Borden experiment using APVO/GPR techniques. Proceedings, Symposium on the Application of Geophysics to Engineering and Environmental Problems, Colorado Springs, Colorado, Paper DNA07.
]23[. Johnson, T.C., Routh, P.S., Barrash, W., & Knoll, M.D. (2007). A field comparison of Fresnel zone and ray-based GPR attenuation-difference tomography for time-lapse imaging of electrically anomalous tracer or contaminant plumes. Geophysics, 72(3), J7–J16.
]24[. Lian, F.Y. & Li, Q. (2011). Recognition method based on SVM for underground pipe diameter size in GPR map. Information and Electronic Engineering. 9(4), 403-408.
]25[. Diamanti, N., Giannopoulos, A., & Forde, M.C. (2008). Numerical modelling and experimental verification of GPR to investigate ring separation in brick masonry arch bridges. NDT&E International, 41, 354–363.
]26[.www.tstengineering.com/en/ground-penetrating-radar.
]27[. Annan, A.P. (2001), Ground-penetrating radar workshop notes, Sensors and Software Inc. Mississauga, ON, Canada.
]28[. Annan, A.P. (2003). Ground penetrating radar: Principles, procedures, & applications. Sensors & Software Inc. Technical Paper.
]29 .[ http://mysite.du.edu/~lconyers/SERDP/GPR2.htm
]30[. Daniels, D.J. (2004). Ground Penetrating Radar, 2nd edition, Radar, Sonar, Navigation and Avionics Series 15, Institute of Electrical Engineers, London, UK.
]31[. Shihab, S., & AL-Nuaimy, W. (2005). Radius estimation for Cylindrical objects detected by Ground Penetrating Radar. subsurface sensing technologies and applications, 6, 151-166.
]32[. Sadiku, M.N.O. (2001). Numerical techniques in electromagnetics, second edition, Boca Raton London New York Washington, D.C. CRC press.
]33[. Irving, J., & Knight, R. (2006). Numerical modelling of ground penetrating radar in 2-D using MATLAB, Computers & Geosciences, 32, 1247–1258.
]34[. Ahmadi, R., Fathianpour, N., & Norouzi, G.H. (2012), Simulation of response of GPR pulses using forward modelling by finite difference. The first Iranian Conference on Electromagnetic Engineering (ICEME), Iran University of Science and Technology, 26-27 Dec, Tehran. (in Farsi).
]35[.Ahmadi, R., Fathianpour, N., & Norouzi, G.H. (2014), Improving Ground Penetrating Radar (GPR) forward modeling approach using the numerical finite difference method. Iranian Journal of Geophysics, 8(3), 114-130. (In Persian)
]36[. Zeng, X. & McMechan, G.A. (1997). GPR characterization of buried tanks and pipes. Geophysics, 62(3), 797–806.
]37[. Davis, J.L., & Annan, A.P. (1989). Ground Penetrating Radar for High-Resolution Mapping of Soil and Rock Stratigraphy, Geophysical Prospecting. 37, 531-551.
]38[. Jol, H.M. (2009). Ground-Penetrating Radar theory and applications. First edition, Elsevier Science, 543 Pages.
]39[. WWW.malags.com

فایل ها

سابقه مقاله

  • تاریخ دریافت: 11 آبان 1394
  • تاریخ بازنگری: 24 آبان 1394
  • تاریخ پذیرش: 11 آبان 1394

هم رسانی

ارجاع به این مقاله

آمار