شبیه‌سازی پاسخ GPR مدل‌های مصنوعی جهت شناسایی ناهمگنی‌های زیرسطحی مسیر حفر تونل انتقال تاسیسات برقی اصفهان

نوع مقاله : مقاله پژوهشی

نویسندگان

1 دانشگاه محل تحصیل: دانشگاه تهراندانشگاه محل کار: دانشگاه صنعتی اراک

2 دانشگاه صنعتی اصفهان

چکیده

در مطالعه حاضر از روش رادار نفوذی به زمین (GPR) برای مقاصد مهندسی ژئوتکنیک (حفر تونل)، جهت شناسایی ناهمگنی‌های زیرسطحی مسیر حفر تونل انتقال تاسیسات برقی اصفهان استفاده شده است. برای این منظور ابتدا پاسخ GPR دوبعدی مدل‌های مصنوعی به شکل استوانه افقی، منشور دوبعدی مربعی و چندضلعی دلخواه متناظر با اهداف ژئوتکنیکی متداول (ساختارهایی نظیر تونل‌ها، قنات‌ها، انواع لوله‌ها و کانال‌ها)، با استفاده از برنامه مدل‌سازی پیشرو به روش اختلاف محدود دوبعدی بهبودیافته، شبیه‌سازی گردید. سپس پاسخ GPR سه‌بعدی مدل‌های مصنوعی به شکل استوانه قائم و کره (معرف شکل عمومی فضاهای خالی)، با استفاده از نرم‌افزار GPRMAX3D مدل‌سازی شد تا در تفسیر نگاشت‌های راداری واقعی GPR مورد استفاده قرار‌گیرند. به‌منظور آشکارسازی ناهمگنی‌های زیرسطحی اعم از انواع تاسیسات مدفون، فضاهای خالی، نشست‌ها، گسیختگی‌ها و چاه‌های مدفون در راستای مسیر حفر تونل انتقال تاسیسات برقی کلان‌شهر اصفهان، تعداد 14 پروفیل GPR در امتداد یکدیگر به‌صورت یک خط برداشت طولانی به طول کلی بیش از 1200 متر برداشت شد. برداشت داده‌ها توسط یک سیستم GPR پوشش‌دار با فرکانس مرکزی 250 مگاهرتز انجام گرفت. بررسی نتایج حاصل از تفسیر نگاشت‌های راداری، پس از اعمال فیلترهای مختلف حاکی از قابلیت بسیار بالای روش GPR در تعیین موقعیت و شناسایی انواع ناهمگنی‌های زیرسطحی است. به منظور صحت‌سنجی نتایج بدست آمده، بر روی یکی از ناهمگنی‌های تصویر GPR تفسیر شده به عنوان یک چاه مدفون، چال قائمی حفر شد و اعتبار نتایج به اثبات رسید.

کلیدواژه‌ها


عنوان مقاله [English]

Simulation of GPR response for 2-D and 3-D synthetic models for geotechnical applications, case study: detection of subsurface along Isfahan main power line tunnel

چکیده [English]

In this research, the GPR method has been employed to identify subsurface in-homogeneities along Isfahan main power
line  tunnel  as  an  application  in  geotechnical  engineering  practices.  To  this  goal,  the  GPR  response  of  common  2D
synthetic models including horizontal cylinder, 2D prism and arbitrary polygon corresponding to targets encountered
in  usual  geotechnical  practices  were  simulated  first.  To  achieve  this  objective,  an  improved  2D  finite  difference
algorithm  developed  for  forward  modeling  in  frequency domain,  was  used  in  MATLAB  programming  environment.
Next,  the  GPR  response  of  3D  synthetic  models  containing  vertical  cylinder  and  sphere  (representing  usual  form  of
cavities)  was  produced  by  means  of  GPRMAX3D  software  for  more  detailed  and  realistic  interpretations.  To  detect
probable subsurface in-homogeneities including different types of manmade buried installations, subsidence and buried
wells along the Isfahan main electric power line tunnel, 14 longitudinal GPR profiles covering more than 1200 meters
along  the  tunnel  axis  were  surveyed.  The  data  were  collected  using  a  250  MHz  GPR  system  equipped  with  shielded
antennas.  The  interpretation  of  final  radargrams  after  applying  different  filters  revealed  that  the  GPR  method  is
capable  of  detecting  the  location  and  type  of  subsurface  in-homogeneities.  In  order  to  verify  the  performance  and
ability of GPR method in solving geotechnical problems encountered in real geological conditions and in particular the
results  obtained  in  current  case  study,  a  vertical  borehole  was  drilled  at  one  of  in-homogeneities  found  on  the
radargrams which had been interpreted as a buried abandoned well. The result was in agreement with the respective
interpreted radargram.
 

کلیدواژه‌ها [English]

  • Ground Penetrating Radar (GPR)
  • Hyperbolic response
  • Numerical modeling
  • Geotechnical targets
  • Isfahan main power line tunnel
  • Sub-surface in-homogeneities
[1]      Clemena, G.G., “Short pulse radar methods”, Chapter 11 in Handbook on Non-Destructive Testing of Concrete, 1991.##
[2]      Bungey, J.H., Millard, S.G. and Shaw, M.R., “The use of sub-surface radar for structural assessment of insitu concrete”, A.C.I., SP128/31, 2, 497-514, 1991.##
[3]      Grandjean, G., Gourry, J.C. and Bitri, A., “Evaluation of GPR techniques for civil-engineering applications: study on a test site”, Journal of Applied Geophysics, 45, 141–156, 2000.##
[4]      Singh, K.K.K. and Ghouhan, R.K.S., “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, 2002.##
[5]      Rashed, M., Kawamura, D., Nemoto, H., Miyata, T. and Nakagawa, K., “Ground penetrating radar investigations across the Uemachi fault, Osaka, Japan”, Journal of Applied Geophysics, 53 (2–3), 63–75, 2003.##
[6]      Lunta, I.A., Hubbardb, S.S. and Rubin, Y., “Soil moisture content estimation using ground-penetrating radar reflection data”, Journal of Hydrology, 307, 254–269, 2005.##
[7]      Giannopoulos, A., “Modelling ground-penetrating radar by GprMax”, Construction and Building Materials, 19, 762-775, 2005.##
[8]      Lai, W.L. and Tsang, W.F., “Characterization of pore systems of air/water-cured concrete using ground penetrating radar (GPR) through continuous water injection”, Construction and Building Materials, 22, 250–256, 2006.##
[9]      Xingxin, X., Qiaosong, Z., Dong, L., Jin, W., Xiangan, W. and Jinyin, S., 2010, GPR detection of several common subsurface voids inside dikes and dams, Engineering Geology, 111, 31–42.##
[10]   Ahmadi, R., Fathianpour, N. and Norouzi, G.H., “Geotechnical applications of Ground-Penetrating Radar (GPR) to identify physical and geometrical parameters of subsurface inhomogeneities”. The first Iranian Conference on Electromagnetic Engineering (ICEME), Iran University of Science and Technology, 26-27 Dec, Tehran, 2012. ]in Persian[.##
[11]   Jack, R. and Jackson, P., “Imaging attributes of railway track formation and ballast using ground probing radar”, NDT&E International, 32, 457-462, 1999.##
[12]   Saarenketo, T. and Scuillion, T., “Road evaluation with ground penetrating radar”, Journal of Applied Geophysics, 43, 119-138, 2000.##
[13]   Benedetto, A., and Benedetto, F., “GPR experimental evaluation of subgrade soil characteristics for rehabilitation of roads”, Ninth International Conference on Ground-Penetrating Radar, Koppenjan, S.K., Lee, H. (eds.), Proceeding of SPIE, 4758, 708-714, 2002.##
[14]   Loken, M., “Current state of the art and practice of using GPR for Minnesota roadway applications”, Minnesota local road research board office of research services, 22p, 2005.##
[15]   Gobel, C., Hellmann, R., and Petzhold, H., “Georadar model and in-situ investigations for inspection of railways tracks”, Proceedings of Ground Penetrating Radar Conference, Kitchener, Canada, June 12-16, 1994.##
[16]   Huston, D., Pelczarski, N. and Esser, B., “Damage detection in roadways with Ground Penetrating Radar”, Proc. Eighth International Conference on GPR, Gold Coasts, Australia, 2000.##
[17]   Manacorda, G., Morandi, D. and Sarri, A., “A customized GPR system for railroad tracks verification”, Ninth International Conference on Ground Penetrating Radar, Koppenjan, S.K., Lee, H. (eds.), Proceedings of SPIE, 4758, 719-722, 2002.##
[18]   Geraads, S., Charachon, B., Loeffler, O. and Omnes, G., “Applying a wave number notch filter to remove interferences caused by railway sleepers from a GPR section”, Ninth International Conference on Ground-Penetrating Radar, Koppenjan, S.K., Lee, H. (eds.), Proceedings of SPIE, 4758, 715-718, 2002.##
[19]   Karlovsek, J., Scheuermann, A.W. and David, J., “Investigation of voids and cavities in bored tunnels using GPR”, 14th International Conference on Ground Penetrating Radar (GPR), proceedings Shanghai, China., 496-501, 2012.##
[20]   Ahmadi, R., Fathianpour, N. and Norouzi, G.H., “Estimation of geometrical parameters of buried water and waste-water pipes using mathematical model and simulation of Ground-Penetrating Radar (GPR) data”. National Conference on water and waste-water engineering sciences, Post-graduate University of Kerman, 2012. ]in Persian[.##
[21]   Ahmadi, R., Fathianpour, N. and Norouzi, G.H., “Geotechnical investigation of 33 pole bridge structure in Isfahan using Ground- Penetrating Radar method”. National Conference on architecture, civil and modern urban development, Tabriz, 2014. ]in Persian[.##
[22]   Ahmadi, R., Fathianpour, N. and Norouzi, G.H., “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, 2014. ]in Persian[.##
[23]   Annan, A.P., “GPR for infrastructure imaging”: International Symposium (NDT-CE 2003), Non-Destructive Testing in Civil Engineering, 2003.##
[24]   Annan, A.P., “Ground-penetrating radar workshop notes”, Sensors and Software Inc., Mississauga, ON, Canada, 192 pages, 2001.##
[25]   Sadiku, M.N.O., “Numerical techniques in electromagnetic”, second edition, Boca Raton London New York Washington, D.C. CRC press, 2001.##
[27]    www.geophysical.com/whatisgpr.htm##
[28]   Yee, K.S., “Numerical solution of initial boundary value problems involving Maxwell’s equations in isotropic media”: IEEE Transactions on Antennas and Propagation, AP-14, 302–307, 1966.##
[29]   Irving, J. and Knight, R., “Numerical modeling of ground penetrating radar in 2-D using MATLAB”. Computers & Geosciences, 32, 1247–1258, 2006.##
[30]   Ahmadi, R., Fathianpour, N. and Norouzi, G.H., “Improving Ground-Penetrating Radar (GPR) forward modeling approach using the numerical finite difference method”. Iranian Journal of Geophysics, 8(3), pp 114-130, 2013. ]in Persian[.##
 
[31]   Ahmadi, R., “Developing an intelligent algorithm to detect geometrical and physical parameters of geotechnical targets using GPR responses”, Ph.D thesis, Mining engineering department, College of engineering, University of Tehran, 2015. ]in Persian[.##
[32]   Kohl, Ch., Krause, M., Maierhofer, Ch., Wöstmann, J. and Wiggenhauser, H., “3D-visualisation of NDT-data using data fusion technique”, Non-Destructive Testing in civil engineering, NDTnet, Vol. 8, No. 10, 2003.
[34]   Jol, H.M., “Ground-Penetrating Radar theory and applications”, First edition, Elsevier Science, 543 Pages, 2009.##
[35]   Young, R.A., Deng, Z. and Sun, J., “Interactive processing of GPR data”, The Leading Edge, pp. 275–280, 1995.##
[36]   Nobes, D.C., “Geophysical surveys of burial sites: A case study of the Oarourupa”. Geophysics, Vol. 64, No. 2, 357–367, 1999.##
[37]   Olhoeft, G.R., “Maximizing the information return from ground penetrating radar”. Journal of Applied Geophysics, Vol. 43, pp. 175–187, 2000.##
[38]   Annan, A.P., “Practical processing of GPR data”: Proceedings of the Second Government Workshop on Ground Penetrating Radar, Columbus, Ohio, 1993.##
[39]   Gerlitz, K., Knoll, M.D., Cross, G.M., Luzitano, R.D. and Knight, R., “Processing ground penetrating radar data to improve resolution of near-surface targets”, Proceeding of the Symposium on the Application of Geophysics to Engineering and Environmental Problems, San Diego, California, 1993.##
[40]   Dougherty, M.E., Micheals, P., Pelton, J.R. and Liberty, L.M., “Enhancement of ground penetrating radar data through signal processing”. Proceedings of the Symposium on the Application of Geophysics to Engineering and Environmental Problems (SAGEEP ‘94), Boston, USA, pp. 1021–1028, 1994.##
[41]   Fisher, C.S., Stewart, R.R. and Jol, H.M., “Processing ground penetrating radar data”. Proceedings of the 5th International Conference on Ground Penetrating Radar (GPR’94), Canada, pp. 661–675, 1994.##
[42]   Kim, J.H., Cho, S.J. and Yi, M.J., “Removal of ringing noise in GPR data by signal processing”. Geosciences Journal, Vol. 11, No. 1, pp. 75–81. RADPRO/GPR V.3.0 User’s Guide, 2007.##
[43]   Ahmadi, R., Fathianpour, N., and Norouzi, G.H., “Detecting physical and geometrical parameters of some common geotechnical targets through their effects on GPR responses”, Arabian Journal of Geosciences, DOI 10.1007/s12517-014-1517-5, 2014.##