Detection of railway subgrade moisture content by GPR

DOI

10.2991/iceeg-16.2016.74How to use a DOI?

Keywords

ground penetrating radar (gpr), velocity spectrum, velocity analysis, common mid-point (cmp), moisture content

Abstract

In cold regions, heaving of the railway subgrade is an important security risk to high-speed railway. It is necessary to find out the moisture content of the subgrade to secure the normal railway operation. Common Mid-Point (CMP) measurement using Ground Penetrating Radar (GPR) was carried out to estimate the moisture content of railway subgrade. As the subgrade is layered medium typically, CMP method is suitable for moisture content measurement. At first, the CMP data is analyzed through velocity spectrum to obtain the stacking velocity, from which the vertical interval velocity profile can be calculated by Dix's formula. The moisture content can be obtained by Topp's formula from dielectric constant which depends on the velocity. However, the velocity analysis has lots of problem for the shallow and thin layers like rail subgrade. With the help of FDTD simulation by gprMAX, we find that there are many multiples and refracted waves which cause much false results during velocity analysis as the offset is large. Under the guidance of the simulated result, we use optimized data gathers for velocity analysis to the real data. It is found that the final result is good and in accordance with the result of induced polarizability (IP). It is proven that it is indeed feasible to use GPR to detect moisture content of subgrade. This method can be widely applied in subgrade moisture detection.

Copyright

© 2016, the Authors. Published by Atlantis Press.

Open Access

This is an open access article distributed under the CC BY-NC license (http://creativecommons.org/licenses/by-nc/4.0/).

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TY  - CONF
AU  - Sixin Liu
AU  - Jiaqi Cai
AU  - Lei Fu
AU  - Yanqian Feng
PY  - 2016/06
DA  - 2016/06
TI  - Detection of railway subgrade moisture content by GPR
BT  - Proceedings of the 7th International Conference on Environment and Engineering Geophysics & Summit Forum of Chinese Academy of Engineering on Engineering Science and Technology
PB  - Atlantis Press
SP  - 271
EP  - 275
SN  - 2352-5401
UR  - https://doi.org/10.2991/iceeg-16.2016.74
DO  - 10.2991/iceeg-16.2016.74
ID  - Liu2016/06
ER  -