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Microwave Synthetic Aperture Radar Imaging for Nondestructive Evaluation of Mechanically Stabilized Earth Walls

Mechanically stabilized earth (MSE) walls are advantageous over gravity and cantilever retaining walls in terms of cost effectiveness, construction time, and tolerance to differential settlement. However, voids and moisture changes behind mechanically stabilized earth walls have previously led to distress and failure, and effective nondestructive evaluation tools for their detection are yet to be developed. In this study, a wideband (1–4 GHz) microwave synthetic aperture radar imaging technique was employed to generate 2D slice images of a mechanically stabilized earth wall system at various depths. Two 1.52 × 1.46 × 0.178 m reinforced concrete wall panels with backfill sand were investigated. The effects of surface roughness, voids, and moisture change were investigated. The effect of change in moisture content behind the wall and in a 350 × 250 × 76 mm sandbox was clearly detected. Two foam blocks to simulate voids, measuring 127 × 127 × 51 mm and 254 × 254 × 51 mm, respectively, were also successfully located and imaged. The proposed and implemented imaging technique was proven to be robust and a promising technique for detecting voids and moisture changes behind MSE walls.

  • AASHTO, AASHTO Guide Specifications for LRFD Seismic Bridge Design, first edition, American Association of State Highway and Transportation Officials, Washington, D.C., 2008.
  • Allen, T.M., and R.J. Bathurst, “Prediction of Soil Reinforcement Loads Stabilized Earth Walls,” report no. WA-RD 522.1, Washington State Department of Transportation, 2001.
  • Alzamora, D.E., and S.A. Anderson, “Review of Mechanically Stabilized Earth Wall Performance Issues,” Proceedings of the 88th Annual Meeting of the Transportation Board, CD-ROM, 2009.
  • Beckham T.L., L. Sun, and T.C. Hopkins, “Corrosion Evaluation on Mechanically Stabilized Earth Walls,” research report KTC-05-28/SPR-239-02-1F, Kentucky Transportation Center, 2005.
  • Case, J.T., M.T. Ghasr, and R. Zoughi, “Optimum 2-D Non-uniform Spatial Sampling for Microwave SAR-based NDE Imaging Systems,” IEEE Transactions on Instrumentation and Measurement, Vol. 61, No. 11, 2012, pp. 3072–3083.
  • Case, J.T., M.T. Ghasr, and R. Zoughi, “Nonuniform Manual Scanning for Rapid Microwave Nondestructive Evaluation Imaging,” IEEE Transactions on Instrumentation and Measurement, Vol. 62, No. 5, 2013, pp. 1250–1258.
  • Chen, D.H., S. Nazarian, and J. Bilyeu, “Failure Analysis of a Bridge Embankment with Cracked Approach Slabs and Leaking Sand,” Journal of Performance of Constructed Facilities, Vol. 21, No. 5, 2007, pp. 375–381.
  • Chen, D.H., and A. Wimsatt, “Inspection and Condition Assessment using Ground Penetrating Radar,” Journal of Geotechnical and Geoenvironmental Engineering, Vol. 136, No. 1, 2010, pp. 207–214.
  • Hugenschmidt, J., and A. Kalogeropoulos, “The Inspection of Retaining Walls using GPR,” Journal of Applied Geophysics, Vol. 67, 2009, pp. 335–344.
  • Huston, D.R., N. Pelczarski, and B. Esser, “Inspection of Bridge Columns and Retaining Walls with Electromagnetic Waves,” Proceedings of SPIE Smart Structures and Materials 2001: Smart Systems for Bridges, Structures, and Highways, Vol. 4330, Newport Beach, California, 30 July 2001.
  • Kee, S., T. Oh, J. Popovics, R. Arndt, and J. Zhu, “Nondestructive Bridge Deck Testing with Air-coupled Impact-echo and Infrared Thermography,” Journal of Bridge Engineering, Vol. 17, 2012, pp. 928–939.
  • Narsavage, P., “MSE Walls Problems and Solutions,” presented at the Ohio DOT Geotech Consultant Workshop 2006, Columbus, Ohio, 11 April 2006.
  • Richards, T., and D. Thome, “Rehabilitation of a Failing Anchored Retaining Wall,” Ground Anchorages and Anchored Structures in Service, London, United Kingdom, 26–27 November 2007.
  • Sun, C., and C. Graves, “Evaluation of Mechanically Stabilized Earth Walls for Bridge Ends in Kentucky; What’s Next?” report no. KTC-13-11/SPR443-12-1F, Kentucky Transportation Center, 2013.
  • Tarawneh, B., and J. Siddiqi, “Performance Issues of Mechanically Stabilized Earth Wall Supporting Bridge Abutment,” Proceeding of the 8th International Conference on Engineering and Technology Research, Dubai, United Arab Emirates, April 2014.
  • Thome, D., and R. Janke, “Rehabilitation of an Existing Mechanically Stabilized Earth Wall using Soil Nails,” Deep Foundations Institute 30th Annual Conference of Deep Foundations, Chicago, Illinois,
  • September 2005.
  • Tinkey, Y., and L.D. Olson, “Applications and Limitations of Impact Echo Scanning for Void Detection in Posttensioned Bridge Ducts,” Transportation Research Record: Journal of the Transportation Research Board, Vol. 2070, 2008, 8–12.
  • Vankavelaar, D.P., and D. Leshchinsky, “Inspection Guidelines for Construction and Post-construction of Mechanically Stabilized Earth Wall,” Delaware Center for Transportation, Newark, Delaware, 2002.
  • Yen, P.W., G.D. Chen, I. Buckle, T. Allen, D. Alzamora, J. Ger, and J.G. Arias, “Post-earthquake Reconnaissance Report on Transportation Infrastructure Impact of the February 27, 2010, Offshore Maule Earthquake in Chile,” no. FHWA-HRT-11-030, U.S. Department of Transportation, March 2011.
  • Zevgolis, I., and P. Bourdeau, “Mechanically Stabilized Earth Wall Abutments for Bridge Support,” no. FHWA/IN/JTRP-2006/38, U.S. Department of Transportation, April 2007.
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