Advertisement

Ground Penetrating Radar Inspection Experiment on a Shield Tunnel Segment and the Backfill Grouting

Conference paper

Abstract

Defects of the backfill grouting have a strong impact on the shield tunnel engineering and gotten more and more attention from the experts in recent years. To estimate the thickness of the grouting and the position of some objects behind a shield tunnel segment, we conducted a field experiment using Ground Penetrating Radar (GPR). In the paper, a segment was put vertically on the ground with half of its outer surface covered by a wooden box. We injected concrete grout into the box until 80% of the box was filled by it. SIR4000 pulse radar system made by GSSI (Geophysical Survey System Inc.) with 400 MHz center-frequency antenna was used in this experiment. First, static measurements show that the direct wave and the coupling wave were stacked together when the antenna was put on the internal surface of the segment. We, therefore, regard the peak point as the time zero of the signal. Then contrastive analysis reveals that Principal Component Analysis (PCA) performed better than Average Mean Removal (AMR) in eliminating the direct wave and highlighting the effective signals. From the processed radargram of dynamical measurement, we can see that it was easy to distinguish the inner structure and the interfaces of the segment, as well as the grouting and other objects in the back. After a week, we retested it again and found that the travel time of electromagnetic wave passing through the grouting became shorter than the previous one. It may be attributed to the loss of moisture in the solidification process of concrete, which means that the technique we proposed can monitor the change of the grouting layer and provide decision-maker with reliable information of the shield tunnel quality.

Keywords

GPR Backfill grouting Shield tunnel segment Principal component analysis 

Notes

Acknowledgement

This work is partially sponsored by National Natural Science Foundation of China No. 41774124 and No. 41374146. Authors wish to express gratitude to Prof. Xiongyao Xie and Mr. Biao Zhou who offered the technical guidance and experimental sites in College of Civil Engineering, Tongji University.

References

  1. Benedetto, A., Blasiis, M.R.D.: Applications of ground penetrating radar to road pavement: state of the art and novelties. In: Geoshanghai International Conference, pp. 412–419 (2010)Google Scholar
  2. Du, J., Huang, H.W., Xie, X.Y., et al.: Research on the effect of permittivity on the result of GPR detection of grouting material behind shield tunnel segment. In: American Society of Civil Engineers, pp. 120–127 (2006)Google Scholar
  3. Li, C., Miao, L., Yue, J.: Research on detection to moisture content of flexible pavement by GPR. In: Geoshanghai International Conference, pp. 420–426 (2010)Google Scholar
  4. Liu, H., Xie, X., Sato, M.: Accurate thickness estimation of a backfill grouting layer behind shield tunnel lining by CMP measurement using GPR. In: International Conference on Ground Penetrating Radar. IEEE, pp. 137–142 (2012)Google Scholar
  5. Pantoja, M.F., Rodríguez, J.B., Bretones, A.R., et al.: Application of neural network and principal component analysis to GPR data. In: International Workshop on Advanced Ground Penetrating Radar. IEEE, pp. 1–4 (2011)Google Scholar
  6. Qi, W., Tian, T.J., Wu, C.X.: Ground penetrating radar in tunnel backfill grouting quality evaluation research on the application. In: International Conference on Electric Technology and Civil Engineering. IEEE, pp. 6633–6636 (2011)Google Scholar
  7. Xie, X.Y., Chen, Y.F., Zhou, B.: Data processing of backfill grouting detected by GPR in shield tunnel and research on equipment of GPR antenna. In: International Conference on Ground Penetrating Radar. IEEE, pp. 1–5 (2016)Google Scholar
  8. Xie, X., Yao, R., Qin, H., et al.: Study on radargram characteristics of the backfill grouting quality evaluation of a shield tunnel using GPR. In: International Conference on Ground Penetrating Radar. IEEE, pp. 407–412 (2014)Google Scholar
  9. Zhao, Y., Wu, J., Xie, X., et al.: Multiple suppression in GPR image for testing back-filled grouting within shield tunnel. In: International Conference on Ground Penetrating Radar. IEEE, pp. 1–6 (2010)Google Scholar

Copyright information

© Springer Nature Singapore Pte Ltd. 2018

Authors and Affiliations

  1. 1.School of Ocean and Earth ScienceTongji UniversityShanghaiChina
  2. 2.College of Civil EngineeringTongji UniversityShanghaiChina

Personalised recommendations