A Study of the Failure Mechanism of Braced Excavations Using 3D Finite-Element Analysis
Publication: International Journal of Geomechanics
Volume 22, Issue 7
Abstract
This study aims to investigate the failure mechanism of structural support systems in braced excavations. The three-dimensional finite-element method (FEM) was used to model the complexity of real geometry by considering the elastoplastic structural support system. Because failure could occur at the connection between walls and struts, a new model of a strut–wall connection was considered in the analysis to represent the actual condition of excavation failure. Three failure case histories were studied to investigate the performance of strut–wall connections by calibrating their strength parameters until the factor of safety was close to unity. It was found that a good result of stability analysis could be obtained in the FEM by considering this model. The yielding of the strut–wall connection model initiated the collapse of the bracing system in all case histories, followed by the yield of struts and failure of soils. A robust failure mechanism was also obtained, in which the yielding of the structural support system at failure initially developed at the middle section toward the corner of excavation geometry.
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References
Blackburn, J. T., and R. J. Finno. 2007. “Three-dimensional responses observed in an internally braced excavation in soft clay.” J. Geotech. Geoenviron. Eng. 133 (11): 1364–1373. https://doi.org/10.1061/(ASCE)1090-0241(2007)133:11(1364).
Brinkgreve, R., and H. Bakker. 1991. “Non-linear finite element analysis of safety factors.” International Association for Computer methods and advances in geomechanics. Rotterdam, Netherlands: A.A. Balkema.
Brinkgreve, R., E. Engin, and W. Swolfs. 2013. “PLAXIS 3D 2019 reference manual.” Delft, Netherlands.
Chen, R. P., Z. C. Li, Y. M. Chen, C. Y. Ou, Q. Hu, and M. Rao. 2015. “Failure investigation at a collapsed deep excavation in very sensitive organic soft clay.” J. Perform. Constr. Facil. 29 (3): 04014078. https://doi.org/10.1061/(ASCE)CF.1943-5509.0000557.
Choosrithong, K., and H. F. Schweiger. 2020. “Numerical investigation of sequential strut failure on performance of deep excavations in soft soil.” Int. J. Geomech. 20 (6): 04020063. https://doi.org/10.1061/(ASCE)GM.1943-5622.0001695.
Chowdhury, S. S., K. Deb, and A. Sengupta. 2013. “Estimation of design parameters for braced excavation: Numerical study.” Int. J. Geomech. 13 (3): 234–247. https://doi.org/10.1061/(ASCE)GM.1943-5622.0000207.
COI (Committee of Inquiry). 2004. Report of the committee of inquiry into the incident at the MRT circle line worksite that led to the collapse of Nicoll Highway. Singapore: COI.
Corral, G., and A. J. Whittle. 2010. “Re-analysis of deep excavation collapse using a generalized effective stress soil model.” In Proc.,Earth Retention Conf. 3, 720–731. Reston, VA: ASCE.
Do, T. N., and C. Y. Ou. 2020. “Factors affecting the stability of deep excavations in clay with consideration of a full elastoplastic support system.” Acta Geotech. 15 (7): 1707–1722. https://doi.org/10.1007/s11440-019-00886-8.
Do, T. N., C. Y. Ou, and R. P. Chen. 2016. “A study of failure mechanisms of deep excavations in soft clay using the finite element method.” Comput. Geotech. 73: 153–163. https://doi.org/10.1016/j.compgeo.2015.12.009.
Do, T.-N., C.-Y. Ou, and A. Lim. 2013. “Evaluation of factors of safety against basal heave for deep excavations in soft clay using the finite-element method.” J. Geotech. Geoenviron. Eng. 139 (12): 2125–2135. https://doi.org/10.1061/(ASCE)GT.1943-5606.0000940.
Endicott, J. 2013. “Case histories of failure of deep excavation examination of where things went wrong: Nicoll highway collapse, Singapore.” In Proc., 7th Int. Conf. on Case Histories in Geotechnical Engineering. Rolla, MI: Missouri University of Science and Technology.
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).
Goh, A. T. C. 1990. “Assessment of basal stability for braced excavation systems using the finite element method.” Comput. Geotech. 10 (4): 325–338. https://doi.org/10.1016/0266-352X(90)90021-M.
Goh, A. T. C., F. H. Kulhawy, and K. S. Wong. 2008. “Reliability assessment of basal-heave stability for braced excavations in clay.” J. Geotech. Geoenviron. Eng. 134 (2): 145–153. https://doi.org/10.1061/(ASCE)1090-0241(2008)134:2(145).
Goh, A. T. C., W. G. Zhang, and K. S. Wong. 2019. “Deterministic and reliability analysis of basal heave stability for excavation in spatial variable soils.” Comput. Geotech. 108: 152–160. https://doi.org/10.1016/j.compgeo.2018.12.015.
Hsiung, B.-C. B., K.-H. Yang, W. Aila, and C. Hung. 2016. “Three-dimensional effects of a deep excavation on wall deflections in loose to medium dense sands.” Comput. Geotech. 80: 138–151. https://doi.org/10.1016/j.compgeo.2016.07.001.
Huang, M., Z. Tang, and J. Yuan. 2018. “Basal stability analysis of braced excavations with embedded walls in undrained clay using the upper bound theorem.” Tunnelling Underground Space Technol. 79: 231–241. https://doi.org/10.1016/j.tust.2018.05.014.
Karlsrud, K., and L. Andresen. 2005. “Loads on braced excavations in soft clay.” Int. J. Geomech. 5 (2): 107–113. https://doi.org/10.1061/(ASCE)1532-3641(2005)5:2(107).
Khoiri, M., and C.-Y. Ou. 2013. “Evaluation of deformation parameter for deep excavation in sand through case histories.” Comput. Geotech. 47: 57–67. https://doi.org/10.1016/j.compgeo.2012.06.009.
Lee, F. H., S. Hong, Q. Gu, and P. Zhao. 2008. “Application of large three-dimensional finite element analyses to practical problems.” Int. J. Geomech. 11 (6): 529–539. https://doi.org/10.1061/(ASCE)GM.1943-5622.0000049.
Lee, F.-H., K.-Y. Yong, K. C. N. Quan, and K.-T. Chee. 1998. “Effect of corners in strutted excavations: Field monitoring and case histories.” J. Geotech. Geoenviron. Eng. 124 (4): 339–349. https://doi.org/10.1061/(ASCE)1090-0241(1998)124:4(339).
Lim, A., and C.-Y. Ou. 2018. “Performance and three-dimensional analyses of a wide excavation in soft soil with strut-free retaining system.” Int. J. Geomech. 18 (9): 05018007. https://doi.org/10.1061/(ASCE)GM.1943-5622.0001165.
Lim, A., C. Y. Ou, and P. G. Hsieh. 2010. “Evaluation of clay constitutive models for analysis of deep excavation under undrained conditions.” J. GeoEng. 5 (1): 9–20.
Lim, A., C. Y. Ou, and P. G. Hsieh. 2019. “An innovative earth retaining supported system for deep excavation.” Comput. Geotech. 114: 103135. https://doi.org/10.1016/j.compgeo.2019.103135.
Lim, A., C.-Y. Ou, and P.-G. Hsieh. 2020. “A novel strut-free retaining wall system for deep excavation in soft clay: Numerical study.” Acta Geotech. 15 (6): 1557–1576. https://doi.org/10.1007/s11440-019-00851-5.
Mesri, G., and N. Huvaj. 2007. “Shear strength mobilized in undrained failure of soft clay and silt deposits.” In Vol. 217 of Advances in measurement and modeling of soil behavior, Geotechnical Special Publication 173, edited by D. J. DeGroot, C. Vipulanandan, J. A. Yamamuro, V. N. Kaliakin, P. V. Lade, M. Zeghal, U. El Shamy, N. Lu, and C. R. Song, 1–22. Reston, VA: ASCE.
Ou, C.-Y. 2006. Deep excavation theory and practice. London: Taylor & Francis.
Ou, C.-Y., D.-C. Chiou, and T.-S. Wu. 1996. “Three-dimensional finite element analysis of deep excavations.” J. Geotech. Eng. 122 (5): 337–345. https://doi.org/10.1061/(ASCE)0733-9410(1996)122:5(337).
Phan, H. K., B. C. Hsiung, and J. Huang. 2020. “Behaviours and mechanism analysis of deep excavation in sand caused by one-strut failure.” In Proc., 16th Asian Regional Conf. on Soil Mechanics and Geotechnical Engineering, 1–5. Taipei, Taiwan: Society of Geotechnical Engineering.
Pong, K. F., S. L. Foo, C. G. Chinnaswamy, C. C. D. Ng, and W. L. Chow. 2012. “Design considerations for one-strut failure according to TR26—A practical approach for practising engineers.” IES Journal Part A: Civil and Structural Engineering 5 (3): 166–180. https://doi.org/10.1080/19373260.2012.700790.
Ukritchon, B., A. J. Whittle, and S. W. Sloan. 2003. “Undrained stability of braced excavations in clay.” J. Geotech. Geoenviron. Eng. 129 (8): 738–755. https://doi.org/10.1061/(ASCE)1090-0241(2003)129:8(738).
Whittle, A. J., G. Corral, L. C. Jen, and R. P. Rawnsley. 2015. “Prediction and performance of deep excavations for Courthouse Station, Boston.” J. Geotech. Geoenviron. Eng. 141 (4): 04014123. https://doi.org/10.1061/(ASCE)GT.1943-5606.0001246.
Whittle, A. J., and R. V. Davies. 2006. “Nicoll highway collapse: Evaluation of geotechnical factors affecting design of excavation support system.” In Proc., Int. Conf. on Deep Excavations. Singapore: Tunneling and Underground Construction Society (TUCSS).
Zdravkovic, L., D. M. Potts, and H. D. St. John. 2005. “Modelling of a 3D excavation in finite element analysis.” Geotechnique 55 (7): 497–513. https://doi.org/10.1680/geot.2005.55.7.497.
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© 2022 American Society of Civil Engineers.
History
Received: Aug 12, 2021
Accepted: Jan 11, 2022
Published online: Apr 20, 2022
Published in print: Jul 1, 2022
Discussion open until: Sep 20, 2022
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