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Journal of Sensors
Volume 2018 (2018), Article ID 5185460, 8 pages
Research Article

Dielectric Characteristics of Unsaturated Loess and the Safety Detection of the Road Subgrade Based on GPR

1School of Water Resources and Hydro-Electric Engineering, Xi’an University of Technology, Xi’an 710048, China
2School of Architecture and Civil Engineering, Xi’an University of Science and Technology, Xi’an 710054, China
3Geochemical Exploration Team of Shaanxi Geological Mineral Survey Group, Xingfu Road No. 7, Xincheng District, Xi’an 710043, China

Correspondence should be addressed to Gao Lv

Received 28 July 2017; Revised 16 November 2017; Accepted 26 November 2017; Published 31 January 2018

Academic Editor: Lei Yuan

Copyright © 2018 Gao Lv et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


We present a moisture content and permittivity model to simultaneously detect and estimate defects in loess subgrade. Based on the ground-penetrating radar (GPR) method, the dielectric properties of loess in the northwest of China and the imaging feature of the moisture content of different strata were studied. The relative permittivity of loess with different moisture contents was experimented in the laboratory. It was found that the relative permittivity of unsaturated loess was positively related to moisture content. The relationship between relative permittivity and moisture content in different antenna frequencies of GPR was analyzed. Electromagnetic wave reflection rules in the loess interface were studied using the numerical method with different moisture contents. With the increase in moisture content, the amplitude of GPR was increased. When the above conclusions were applied in the engineering practices, there are good effects to detect the defects of the road subgrade. It is a significant guidance for determining the qualitative research of defects in the roadbed.