Is Basal Reinforcement Essential for Long and Narrow Subway Excavation Bottoming Out in Shanghai Soft Clay?
Publication: Journal of Geotechnical and Geoenvironmental Engineering
Volume 145, Issue 5
Abstract
Because of its great length, one subway terminal excavation in Shanghai, China, was divided into two pits for sequential construction. Although it featured an adequate earth-supporting system and the field construction followed proper procedure, wall and ground displacements of the first excavated pit were up to 1.8–2.7 times local specifications. Then, basal strata of the second pit were jet grouted. Unfortunately, worse excavation performance was tracked. Technical review of design plans, construction logs, and field data, and postconstruction investigations disclosed that for a long and narrow deep excavation bottoming out in soft clays, reinforcing basal strata prior to excavation is essential and attention should be paid to the adverse effect arising from great wall exposure length, , during excavation. Although both basal treatment and are of decisive importance, lack of suitable basal treatment imposed more adverse effect on excavation performance when , where = final excavation depth.
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Acknowledgments
The financial support from the National Natural Science Foundation of China (41877286 and 41672269) and Natural Science Foundation of Shanghai (16ZR1411900) are gratefully acknowledged. The insightful comments and suggestions from the two anonymous reviewers, associate editor, and editor Professor Timothy D. Stark are sincerely appreciated.
References
Abaqus. 2014. Abaqus Unified FEA, AQAQUS/CEA user manual. Waltham, MA: Dassault Systemes.
Clough, G. W., E. M. Smith, and B. P. Sweeney. 1989. “Movement control of excavation support systems by iterative design.” In Vol. 2 of Proc., Foundation Engineering: Current Principals and Practices, 869–884. New York: ASCE.
Finno, R. J., J. T. Blackburn, and J. F. Roboski. 2007. “Three-dimensional effects for supported excavations in clay.” J. Geotech. Geoenviron. Eng. 133 (1): 30–36. https://doi.org/10.1061/(ASCE)1090-0241(2007)133:1(30).
Hashash, Y. M. A., and A. J. Whittle. 1996. “Ground movement prediction for deep excavations in soft clay.” J. Geotech. Eng. 122 (6): 474–486. https://doi.org/10.1061/(ASCE)0733-9410(1996)122:6(474).
Liu, G. B., C. W. W. Ng, and Z. W. Wang. 2005. “Observed performance of a multipropped excavation in Shanghai soft clays.” J. Geotech. Geoenviron. Eng. 131 (8): 1004–1013. https://doi.org/10.1061/(ASCE)1090-0241(2005)131:8(1004).
Liu, G. B., and W. D. Wang. 2009. Excavation engineering handbook. [In Chinese.] Beijing: China Architecture & Building Press.
Liu, J. H., and X. Y. Hou. 1997. Excavation engineering handbook. [In Chinese.] Beijing: China Architecture & Building Press.
O’Rourke, T. D., and A. J. McGinn. 2006. “Lessons learned for ground movements and soil stabilization from the Boston central artery.” J. Geotech. Geoenviron. Eng. 132 (8): 966–989. https://doi.org/10.1061/(ASCE)1090-0241(2006)132:8(966).
Ou, C. Y., P. G. Hsieh, and Y. L. Lin. 2011. “Performance of excavations with cross walls.” J. Geotech. Geoenviron. Eng. 137 (1): 94–104. https://doi.org/10.1061/(ASCE)GT.1943-5606.0000402.
Ou, C. Y., T. S. Wu, and H. S. Hsieh. 1996. “Analysis of deep excavation with column type of ground improvement in soft clay.” J. Geotech. Geoenviron. Eng. 122 (9): 709–716. https://doi.org/10.1061/(ASCE)0733-9410(1996)122:9(709).
Shen, S. L., Z. F. Wang, J. Yang, and E. C. Ho. 2013. “Generalized approach for prediction of jet grout column diameter.” J. Geotech. Geoenviron. Eng. 139 (12): 2060–2069. https://doi.org/10.1061/(ASCE)GT.1943-5606.0000932.
Shirlaw, J. N. 2003. “Jet grouting soft clays for tunnelling and deep excavations—Design and construction issues.” In Proc., 3rd Int. Conf. on Grouting and Ground Treatment, 257–268. Reston, VA: ASCE.
Tan, Y., W. Jiang, W. Luo, Y. Lu, and C. Xu. 2018a. “Longitudinal sliding event during excavation of Feng-Qi Station of Hangzhou Metro Line 1: Postfailure investigation.” J. Perform. Constr. Facil. 32 (4): 04018039. https://doi.org/10.1061/(ASCE)CF.1943-5509.0001181.
Tan, Y., and M. Li. 2011. “Measured performance of a 26 m deep top-down excavation in downtown Shanghai.” Can. Geotech. J. 48 (5): 704–719. https://doi.org/10.1139/t10-100.
Tan, Y., X. Li, Z. Kang, J. Liu, and Y. Zhu. 2015a. “Zoned excavation of an oversized pit close to an existing metro line in stiff clay: Case study.” J. Perform. Constr. Facil. 29 (6): 04014158. https://doi.org/10.1061/(ASCE)CF.1943-5509.0000652.
Tan, Y., and Y. Lu. 2017a. “Forensic diagnosis of a leaking accident during excavation.” J. Perform. Constr. Facil. 31 (5): 04017061. https://doi.org/10.1061/(ASCE)CF.1943-5509.0001058.
Tan, Y., and Y. Lu. 2017b. “Why excavation of a small air shaft caused excessively large displacements: Forensic investigation.” J. Perform. Constr. Facil. 31 (2): 04016083. https://doi.org/10.1061/(ASCE)CF.1943-5509.0000947.
Tan, Y., Y. Lu, and D. Wang. 2018b. “Deep excavation of the Gate of the Orient in Suzhou stiff clay: Composite earth-retaining systems and dewatering plans.” J. Geotech. Geoenviron. Eng. 144 (3): 05017009. https://doi.org/10.1061/(ASCE)GT.1943-5606.0001837.
Tan, Y., Y. Lu, C. Xu, and D. Wang. 2018c. “Investigation on performance of a large circular pit-in-pit excavation in clay-gravel-cobble mixed strata.” Tunnelling Underground Space Technol. 79: 356–374. https://doi.org/10.1016/j.tust.2018.06.023.
Tan, Y., and D. Wang. 2015a. “Structural behaviors of large underground earth-retaining systems in Shanghai. I: Unpropped circular diaphragm wall.” J. Perform. Constr. Facil. 29 (2): 04014058. https://doi.org/10.1061/(ASCE)CF.1943-5509.0000521.
Tan, Y., and D. Wang. 2015b. “Structural behaviors of large underground earth-retaining systems in Shanghai. II: Multipropped rectangular diaphragm wall.” J. Perform. Constr. Facil. 29 (2): 04014059. https://doi.org/10.1061/(ASCE)CF.1943-5509.0000535.
Tan, Y., D. Wang, Y. Lu, and T. Fang. 2017a. “Excavation of Middle Huai-Hai Road Station of Shanghai Metro Line 13: Challenges, risks, countermeasures, and performance assessment.” Pract. Period. Struct. Des. Constr. 22 (3): 05017003. https://doi.org/10.1061/(ASCE)SC.1943-5576.0000320.
Tan, Y., B. Wei, Y. Diao, and X. Zhou. 2014. “Spatial corner effects of long and narrow multipropped deep excavations in Shanghai soft clay.” J. Perform. Constr. Facil. 28 (4): 04014015. https://doi.org/10.1061/(ASCE)CF.1943-5509.0000475.
Tan, Y., B. Wei, X. Zhou, and Y. Diao. 2015b. “Lessons learned from construction of Shanghai metro stations: Importance of quick excavation, prompt propping, timely casting, and segmented construction.” J. Perform. Constr. Facil. 29 (4): 04014096. https://doi.org/10.1061/(ASCE)CF.1943-5509.0000599.
Tan, Y., H. Zhu, F. Peng, K. Karlsrud, and B. Wei. 2017b. “Characterization of semi-top-down excavation for subway station in Shanghai soft ground.” Tunnelling Underground Space Technol. 68: 244–261. https://doi.org/10.1016/j.tust.2017.05.028.
Wu, Y. X., H. M. Lyu, J. Han, and S. L. Shen. 2019. “Case study: Dewatering-induced building settlement around a deep excavation in the soft deposit of Tianjin, China.” J. Geotech. Geoenviron. Eng., in press. 10.1061/(ASCE)GT.1943-5606.0002045.
Vedantham, R. K., K. Tung, T. S. Lee, and M. L. Fong. 2015. “Lessons learned from ground improvement on BART Fremont Central Park Subway Project in Fremont, California.” In Proc., Int. Foundations Congress and Equipment Expo 2015 (IFCEE 2015), 569–582. Reston, VA: ASCE.
Weatherby, D., and D. Zywicki. 2012. “Deep soil mixed wall and jet grouting for an excavation retention system at Museum of Fine Arts, Boston.” In Proc., 4th Int. Conf. on Grouting and Deep Mixing, 379–388. Reston, VA: ASCE.
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Published In
Journal of Geotechnical and Geoenvironmental Engineering
Volume 145 • Issue 5 • May 2019
Copyright
©2019 American Society of Civil Engineers.
History
Received: Oct 1, 2017
Accepted: Oct 4, 2018
Published online: Feb 21, 2019
Published in print: May 1, 2019
Discussion open until: Jul 21, 2019
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