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 x 1.46 x 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 x 250 x 76 mm sandbox was clearly detected. Two foam blocks to simulate voids, measuring 127 x 127 x 51 mm and 254 x 254 x 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.

Meeting Name

Transportation Research Board 95th Annual Meeting (2016: Jan. 10-14, Washington, DC)


Electrical and Computer Engineering

Second Department

Civil, Architectural and Environmental Engineering

Keywords and Phrases

Mechanically Stabilized Earth (MSE) Wall; Void; Nondestructive Evaluation (NDE); Microwave Imaging; Synthetic Aperture Radar (SAR)

Document Type

Article - Conference proceedings

Document Version


File Type





© 2016 American Society for Nondestructive Testing, Inc., All rights reserved.

Publication Date

01 Jan 2016

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