Conversion Timing of Tunnel Excavation Methods in Upper-Soft and Lower-Hard Stratum Based on Displacement Direction Angle Theory: Case Study
Publication: International Journal of Geomechanics
Volume 19, Issue 4
Abstract
Zi-Zhi Tunnel is a shallow-buried tunnel, and its geological conditions are generally upper soft and lower hard. Therefore, the designed excavation methods are the center diaphragm method and the bench method. For the considerations of safety, cost, and schedule, excavation methods should be converted in advance. When determining the conversion timing of excavation methods, the different positions between the tunnel face and the upper-soft and lower-hard stratum interface need to be taken into consideration. The finite-difference software FLAC3D was used to analyze the rules of three-dimensional deformation and the variation of displacement direction angle of the surrounding rock based on the theory of displacement direction angle under different working conditions. The field-monitoring data of vault settlement before and after the conversion of excavation methods were also compared and analyzed to verify the rationality of the conversion of excavation methods. The results indicated that when the tunnel face passes through 1.5B distance (B is the tunnel width) of the stratum interface, the displacement direction angle of the surrounding rock tended to be stable, and the longitudinal stress concentration of the surrounding rock was decreased, which was conducive to utilizing the self-bearing capacity of the surrounding rock. Therefore, we suggest that the conversion of excavation methods should be carried out after the vault of the tunnel face passes through 1.5B distance of the stratum interface. Engineering experience verified the reliability of the conversion timing.
Get full access to this article
View all available purchase options and get full access to this article.
Acknowledgments
The preparation of the paper received financial support from the National Natural Science Foundation of China (Grant 51378505); the Natural Science Foundation of Hunan Province, China (Grant 2018JJ2519); the Science and Technology Plan Projects of Hunan Province, China (2010GK3173); and the China Railway Tunnel Group Science and Technology Innovation Project (2016-14). All these supports are acknowledged.
References
Chen, D. H., C. Y. Tang, H. B. Xiao, and P. Ying. 2015. “Utilizing electromagnetic spectrum for subsurface void detection—Case studies.” Arabian J. Geosci. 8 (9): 7705–7717. https://doi.org/10.1007/s12517-014-1725-z.
Deng, B., and X. F. Gu. 2012. “Hard rock shield construction technology research.” J. Modern Tunnelling Technol. 49 (2): 59–64.
Diao, Z. G., and C. J. Li. 2007. “Study on construction method of large-section tunnels in upper soft and lower hard layers.” J. Tunnel Constr. 2007 (S): 433–436.
Hu, X. Y., and A. Y. Liu. 2015. “Macro and micro mechanism of surface instability failure of composite stratum mud water shield.” J. Shanghai Jiao Tong Univ. 49 (7): 1067–1074.
Huo, X. L., and S. G. Chen. 2013. “Hard rock excavation of soft in the reliability research.” Chin. J. Underground Space Eng. 9 (4): 854–860.
Liu, S. T., G. A. Zhang, and X. Z. Yang. 2011. “Study on the consturction method of railway tunnel crossing under expressway and built in upper soft and lower hard stratum.” J. Railway Sci. Eng. 8 (5): 35–39.
Liu, T., S. Z. Zhao, and F. F. Sun. 2014. “Security analysis of dismantling temporary supports of large-span shallow tunnel in upper-soft and lower-hard stratum.” J. Rock Soil Mech. 2014 (S1): 306–310.
Lunardi, P. 2000. “The design and construction of tunnels using the approach based on the analysis of controlled deformation in rocks and soils.” Tunnels and Tunneling Int. 5: 3–30.
Ramoni, M., and G. Anagnostou. 2011. “The interaction between shield, ground and tunnel support in TBM tunnelling through squeezing ground.” Rock Mech. Rock Eng. 44 (1): 37–61. https://doi.org/10.1007/s00603-010-0103-8.
Schubert, W., and A. Budil. 1995. “The importance of longitudinal deformation in tunnel excavation.” In Proc., 8th ISRM Congress. Lisbon, Portugal: Int. Society for Rock Mechanics and Rock Engineering.
Wang, W., M. Hu, and H. Zhang. 2018 “Application of displacement direction angle theory on excavation methods conversion opportunity of Zi-Zhi Tunnel.” In Tunneling in Soft Ground, Ground Conditioning and Modification Techniques. GeoChina 2018. Sustainable Civil Infrastructures, edited by W. C. Cheng, J. Yang, J. Wang. Cham, Switzerland: Springer.
Wang, X. D., S. H. Zhou, and J. P. Chi. 2011. “Study on shallow-burid tunnel’s thickness-span ratio in upper-soft lower-hard ground.” Chin. J. Underground Space Eng. 7 (4): 700–705.
Wang, Y. C., H. W. Jing, H. J. Su, and J. Y. Xie. 2017. “Effect of a fault fracture zone on the stability of tunnel-surrounding rock.” Int. J. Geomech. 17 (6): 04016135. https://doi.org/10.1061/(ASCE)GM.1943-5622.0000837.
Wang, Z. W., C. S. Qiao, and C. Y. Song. 2014. “Calculation method of relaxation pressure of shallow large span tunnel in up-soft/low-hard rock stratum.” J. Rock Mech. 35 (8): 2342–2352.
Wu, Q. X., G. F. An, and X. W. Zhou. 2015. “Soft and hard composite formation in shield tunneling feeding disc stress analysis and calculation.” China Civ. Eng. J. (S2): 321–326.
Xiao, J. Z., F. C. Dai, Y. Q. Wei, and Y. C. Xing. 2016. “Comparative analysis of excavation schemes for a tunnel constructed through loose deposits.” J. Perform. Constr. Facil. 30 (4): 04015061. https://doi.org/10.1061/(ASCE)CF.1943-5509.0000813.
Ye, X., S. Y. Wang, J. S. Yang, D. Sheng, and C. Xiao. 2017. “Soil conditioning for EPB shield tunneling in argillaceous siltstone with high content of clay minerals: Case study.” Int. J. Geomech. 17 (4): 05016002. https://doi.org/10.1061/(ASCE)GM.1943-5622.0000791.
Zhang, J. X., F. C. Guo, and L. Gang. 2011. “Study on construction methods of shallow-buried tunnel under condition of upper-soft lower-hard ground by numerical simulation.” Chin. J. Underground Space Eng. S1 (7): 1416–1421.
Zhang, Y., X. J. Wu, and H. E. Chuan. 2007. “Study on application of displacement vector orientation trend line to Wushaoling Tunnel.” Chin. J. Rock Mech. Eng. 26 (7): 1448–1456.
Zhang, Z. G., and M. S. Huang. 2014. “Geotechnical influence on existing subway tunnels induced by multiline tunneling in Shanghai soft soil.” J. Comput. Geotech. 56: 121–132. https://doi.org/10.1016/j.compgeo.2013.11.008.
Zhao, C. H. 2015. “Research on key technology of shallow-buried tunnel construction method conversion in upper-soft lower-hard strata.” J. Railway Sci. Eng. 2015 (6): 1444–1451.
Information & Authors
Information
Published In
International Journal of Geomechanics
Volume 19 • Issue 4 • April 2019
Copyright
© 2019 American Society of Civil Engineers.
History
Received: Feb 8, 2018
Accepted: Oct 4, 2018
Published online: Feb 7, 2019
Published in print: Apr 1, 2019
Discussion open until: Jul 7, 2019
Authors
Metrics & Citations
Metrics
Citations
Download citation
If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.