Lessons Learned from Construction of Shanghai Metro Stations: Importance of Quick Excavation, Prompt Propping, Timely Casting, and Segmented Construction
Publication: Journal of Performance of Constructed Facilities
Volume 29, Issue 4
Abstract
Four metro stations with similar supporting systems and pit geometries in Shanghai soft clay were excavated using different soil removal procedures, which led to distinctly different pit behaviors. Through analyzing and comparing the well-documented field data from these four bottom-up excavations, the significances of quick excavation, promptly propping, timely casting of floor slabs, and segmented construction in control of pit deformations were identified and their influences were comprehensively quantified. As to these four pits, the measured time-dependent wall deflections and wall heaves in 20–35 days at relatively deep excavation levels were up to 47–94% the magnitudes at completion of excavation to the final depths. The measured postexcavation wall deflections in about 20–30 days were up to 36–45% the maximum wall deflections at completion of excavation and the corresponding postexcavation deflection rates were up to twice those during excavation. The poorly excavated pits, which featured long excavation duration, long wall exposure lengths, or delay in propping struts or casting floor slabs, experienced wall deflections and ground settlements times greater than the appropriately excavated pit. The wall deflection rates of the poorly excavated pits were up to and those of the appropriately excavated pit during and after excavation, respectively. Compared with the countermeasure of increasing supporting system stiffness by casting rigid concrete struts and/or bracing double steel pipe struts at one level, the approach of quick excavation, promptly propping, and timely casting of rigid floor slabs in combination with a segmented construction procedure was demonstrated to be much more efficient in controlling excavation-induced deformations.
Get full access to this article
View all available purchase options and get full access to this article.
Acknowledgments
The financial supports from the Innovation Program of Shanghai Municipal Education Commission (No. 13ZZ027) and the Program for Changjiang Scholar and Innovative Research Team (PCSIRT, IRT1029) in University are gratefully acknowledged. The great comments and suggestions from the two anonymous reviewers and the Editor are sincerely appreciated.
References
Clough, G. W., and O’Rourke, T. D. (1990). “Construction induced movements of in-situ walls.” Geotechnical special publication: Design and performance of earth retaining structures (GSP 25), ASCE, Reston, VA, 439–470.
Finno, R. J., and Roboski, J. F. (2005). “Three-dimensional responses of a tied-back excavation through clay.” J. Geotech. Geoenviron. Eng., 273–282.
Fu, Y. B., Zhu, H. H., and Yang, J. (2009). “Experimental study of time-dependent properties and pore water pressure of soft soil under unloading.” Chin. J. Rock Mech. Eng., 28(Supp. 1), 3244–3249 (in Chinese).
Hashash, Y. M. A., Osouli, A., and Marulanda, C. (2008). “Central artery/tunnel project excavation induced ground deformations.” J. Geotech. Geoenviron. Eng., 1399–1406.
Hsieh, P. G., and Ou, C. Y. (1998). “Shape of ground surface settlement profiles caused by excavation.” Can. Geotech. J., 35(6), 1004–1017.
Koutsoftas, D. C., Frobenius, P., Wu, C. L., Meyersohn, D., and Kulesza, R. (2000). “Deformations during cut-and-cover construction of muni metro turnback project.” J. Geotech. Geoenviron. Eng., 344–359.
Liao, S. M., Fan, Y. Y., Shi, Z. H., Shao, W., and Kong, X. P. (2013). “Optimization study on the reconstruction and expansion of an underground rail transit center in Shanghai soft ground.” Tunnell. Undergr. Space Technol., 38, 435–446.
Liao, S. M., Liu, J. H., Wang, R. L., and Li, Z. M. (2009). “Shield tunneling and environment protection in Shanghai soft ground.” Tunnell. Undergr. Space Tech., 24(4), 454–465.
Liao, S. M., Peng, F. L., and Shen, S. L. (2008). “Analysis of shearing effect on tunnel induced by load transfer along longitudinal direction.” Tunnell. Undergr. Space Tech., 23(4), 421–430.
Liu, G. B., Jiang, R. J., Ng, C. W. W., and Hong, Y. (2011). “Deformation characteristics of a 38 m deep excavation in soft clay.” Can. Geotech. J., 48(12), 1817–1828.
Liu, G. B., Ng, C. W. W., and Wang, Z. W. (2005). “Observed performance of a multipropped excavation in Shanghai soft clays.” J. Geotech. Geoenviron. Eng., 1004–1013.
Liu, J. H. (1999). “Time-space-effect theory and practice for excavations in soft clays.” Chin. J. Rock Mech. Eng., 18(Supp. 1), 763–770 (in Chinese).
Long, M. (2001). “Database for retaining wall and ground movements due to deep excavations.” J. Geotech. Geoenviron. Eng., 203–224.
Ma, L., Xu, Y. S., Shen, S. L., and Sun, W. J. (2014). “Evaluation of the hydraulic conductivity of aquifer with piles.” Hydrogeol. J., 22(2), 371–382.
Mana, A. I., and Clough, G. W. (1981). “Prediction of movements for braced cuts in clay.” J. Geotech. Eng. Div., 107(6), 759–777.
Peck, R. B. (1969). “Deep excavation & tunneling in soft ground. State-of-the-art-report.” Proc., Int. Conf. of Soil Mechanics and Foundation Engineering, Int. Society for Soil Mechanics and Geotechnical Engineering, London, 225–281.
Peng, F. L., Wang, H. L., Tan, Y., Xu, Z. L., and Li, Y. L. (2011). “Field measurements and FEM simulation of a tunnel shaft constructed by pneumatic caisson method in Shanghai soft ground.” J. Geotech. Geoenviron. Eng., 516–524.
Poh, T. Y., Wong, I. H., and Chandrasekaran, B. (1997). “Performance of two propped diaphragm walls in stiff residual soils.” J. Perform. Constr. Facil., 190–199.
Shen, S. L., Ma, L., Xu, Y. S., and Yin, Z. Y. (2013). “Interpretation of increased deformation rate in aquifer IV due to groundwater pumping in Shanghai.” Can. Geotech. J., 50(11), 1129–1142.
Shen, S. L., Wu, H. N., Cui, Y. J., and Yin, Z. Y. (2014). “Long-term settlement behaviour of metro tunnels in the soft deposits of Shanghai.” Tunnell. Undergr. Space Technol., 40, 309–323.
Tan, Y., and Li, M. W. (2011). “Measured performance of a 26 m deep top-down excavation in downtown Shanghai.” Can. Geotech. J., 48(5), 704–719.
Tan, Y., and Wang, D. (2013a). “Characteristics of a large-scale deep foundation pit excavated by the central-island technique in Shanghai soft clay. I: Bottom-up construction of the central cylindrical shaft.” J. Geotech. Geoenviron. Eng., 1875–1893.
Tan, Y., and Wang, D. (2013b). “Characteristics of a large-scale deep foundation pit excavated by the central-island technique in Shanghai soft clay. II: Top-down construction of the peripheral rectangular pit.” J. Geotech. Geoenviron. Eng., 1894–1910.
Tan, Y., and Wang, D. (2013c). “Structural behaviors of large-sized underground earth retaining systems in Shanghai. I: Unpropped circular diaphragm wall.” J. Perform. Constr. Facil., 04014058.
Tan, Y., and Wang, D. (2013d). “Structural behaviors of large-sized underground earth retaining systems in Shanghai. II: Multipropped rectangular diaphragm wall.” J. Perform. Constr. Facil., 04014059.
Tan, Y., and Wei, B. (2012a). “Observed behaviors of a long and deep excavation constructed by cut-and-cover technique in Shanghai soft clay.” J. Geotech. Geoenviron. Eng., 138(1), 69–88.
Tan, Y., and Wei, B. (2012b). “Performance of an overexcavated metro station and facilities nearby.” J. Perform. Constr. Facil., 241–254.
Tan, Y., Wei, B., Diao, Y. P., and Zhou, X. (2013). “Spatial corner effects of long and narrow multi-propped deep excavations in Shanghai soft clay.” J. Perform. Constr. Facil., 04014015.
Wong, I. H., Low, B. K., Pang, P. Y., and Raju, G. V. R. (1997). “Field performance of nailed soil wall in residual soil.” J. Perform. Constr. Facil., 105–112.
Xu, Y. S., Ma, L., Shen, S. L., and Sun, W. J. (2012). “Evaluation of land subsidence by considering underground structures penetrated into aquifers in Shanghai.” Hydrogeol. J., 20(8), 1623–1634.
Xu, Y. S., Shen, S. L., Du, Y. J., Chai, J. C., and Horpibulsuk, S. (2013). “Modelling the cutoff behavior of underground structure in multi-aquifer-aquitard groundwater system.” Nat. Hazards, 66(2), 731–748.
Information & Authors
Information
Published In
Copyright
© 2014 American Society of Civil Engineers.
History
Received: Nov 12, 2013
Accepted: Feb 21, 2014
Published online: Feb 24, 2014
Discussion open until: Jan 20, 2015
Published in print: Aug 1, 2015
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.