Performance of Strut-Free Retaining Walls for 30 M Deep Excavations in Soft Clay
Article Sidebar
Main Article Content
Strut-free retaining wall systems offer important advantages for deep excavations, including improved construction efficiency, safety, and workspace availability. However, their application in excavations deeper than 20 m in soft clay remains limited. This study investigates the deformation behavior and optimal design parameters of a strut-free retaining wall system for a 30 m deep excavation in soft clay using three-dimensional finite element analysis. The retaining system consists of diaphragm walls, buttress walls, cross walls, and rib walls. A total of sixty-one numerical simulations were conducted to evaluate the influence of the number, thickness, and height of buttress and cross walls on wall deflection and ground settlement. The Hardening Soil model was adopted to represent the nonlinear behavior of soft clay, while structural components were modeled as elastic plate elements. The results indicate that increasing the number of buttress walls in the long excavation direction significantly reduces maximum wall deflection and surface settlement, whereas the effect in the short direction is relatively small. Among the investigated layouts, the configuration with two rib walls in the long direction and one in the short direction provided the most effective deformation control.
Downloads
References
A. Lim and C.-Y. Ou, "Case Record of a Strut-free Excavation with Buttress Walls in Soft Soil," in Proceedings of the 2nd International Symposium on Asia Urban GeoEngineering, 2018: Springer, pp. 142–154.
C. Ou, Y. Lin, and P. Hsieh 2006. Case record of an excavation with cross walls and buttress walls. Journal of GeoEngineering. 1, 2, 79–87.
C.-Y. Ou, F.-C. Teng, R. B. Seed, and I.-W. Wang 2008. Using buttress walls to reduce excavation-induced movements. Proceedings of the Institution of Civil Engineers-Geotechnical Engineering. 161, 4, 209–222.
C.-Y. Ou, P.-G. Hsieh, and Y.-L. Lin 2011. Performance of excavations with cross walls. Journal of Geotechnical and Geoenvironmental Engineering. 137, 1, 94–104.
P.-G. Hsieh, C.-Y. Ou, and Y.-L. Lin 2013. Three-dimensional numerical analysis of deep excavations with cross walls. Acta Geotechnica. 8, 33–48.
C.-Y. Ou, P.-G. Hsieh, and Y.-L. Lin 2013. A parametric study of wall deflections in deep excavations with the installation of cross walls. Computers and Geotechnics. 50, 55–65.
P.-G. Hsieh, C.-Y. Ou, Y.-K. Lin, and F.-C. Lu 2015. Lessons learned in design of an excavation with the installation of buttress walls. Journal of GeoEngineering. 10, 2, 63–73.
P.-G. Hsieh, C.-Y. Ou, and W.-H. Hsieh 2016. Efficiency of excavations with buttress walls in reducing the deflection of the diaphragm wall. Acta Geotechnica. 11, 1087–1102.
A. Lim and C.-Y. Ou 2018. Performance and three-dimensional analyses of a wide excavation in soft soil with strut-free retaining system. International Journal of Geomechanics. 18, 9, 05018007.
C. Ou, A. Lim, P. Hsieh, and S. Chien, "A study of a strut-free excavation system in deep excavations," in Geotechnical Aspects of Underground Construction in Soft Ground: CRC Press, 2021, pp. 365–370.
G. Zheng, X. He, H. Zhou, Y. Diao, Z. Li, and X. Liu 2022. Performance of inclined-vertical framed retaining wall for excavation in clay. Tunnelling and Underground Space Technology. 130, 104767.
S.-H. Wu, J. Ching, and C.-Y. Ou 2013. Predicting wall displacements for excavations with cross walls in soft clay. Journal of Geotechnical and Geoenvironmental Engineering. 139, 6, 914–927.
W. Zhang, A. T. Goh, and F. Xuan 2015. A simple prediction model for wall deflection caused by braced excavation in clays. Computers and Geotechnics. 63, 67–72.
A. Goh, F. Zhang, W. Zhang, Y. Zhang, and H. Liu 2017. A simple estimation model for 3D braced excavation wall deflection. Computers and Geotechnics. 83, 106–113.
G. Zheng, Z.-p. Liu, H.-z. Zhou, X.-p. He, and Z.-y. Guo 2022. Behaviour of an outward inclined-vertical framed retaining wall of an excavation. Acta Geotechnica. 17, 12, 5521–5532.
C. Moormann 2004. Analysis of wall and ground movements due to deep excavations in soft soil based on a new worldwide database. Soils and foundations. 44, 1, 87–98.
Y. Tan, D. Fan, and Y. Lu 2022. Statistical analyses on a database of deep excavations in Shanghai soft clays in China from 1995–2018. Practice Periodical on Structural Design and Construction. 27, 1, 04021067.
C.-Y. Ou, Fundamentals of Deep Excavations. CRC Press, 2021.
P. Vermeer and M. Wehnert, "Beispiele von FE-Anwendungen–Man lernt nie aus," in Tagungsband zum Workshop’FEM in der Geotechnik–Qualität, Prüfung, Fallbeispiele, Hamburg, 2005, pp. 101–119.
C.-Y. Ou, Deep excavation: Theory and practice. CRC Press, 2014.
T. Schanz, P. Vermeer, and P. Bonnier 1999. Formulation and verification of the Hardening-Soil model. Beyond 2000 in Computational Geotechnics Brinkgreveed Rotterdam Balkema. 281–290.
M. Calvello and R. J. Finno 2004. Selecting parameters to optimize in model calibration by inverse analysis. Computers and Geotechnics. 31, 5, 411–425.
M. Bolton 1986. The strength and dilatancy of sands. Geotechnique. 36, 1, 65–78.
A. Lim, C.-Y. Ou, and P.-G. Hsieh 2010. Evaluation of clay constitutive models for analysis of deep excavation under undrained conditions. Journal of GeoEngineering. 5, 1, 9–20.
M. D. James and C. Chin-Yung 1970. Nonlinear analysis of stress and strain in soils. Journal of the Soil Mechanics and Foundations Division. 96, 5, 1629–1653.
A. Lim, C.-Y. Ou, and P.-G. Hsieh 2020. A novel strut-free retaining wall system for deep excavation in soft clay: numerical study. Acta Geotechnica. 15, 6, 1557–1576.
A. Lim and C.-Y. Ou 2017. Stress paths in deep excavations under undrained conditions and its influence on deformation analysis. Tunnelling and Underground Space Technology. 63, 118–132.
American Concrete Institute ACI 318-19, "Building Code Requirements for Structural Concrete," ed, 2022.
Bentley, "Material Models Manual of PLAXIS CONNECT Edition V21.01," ed, 2021.
C.-Y. Ou, J.-T. Liao, and H.-D. Lin 1998. Performance of diaphragm wall constructed using top-down method. Journal of Geotechnical and Geoenvironmental Engineering. 124, 9, 798–808.
L. S. Bryson and D. G. Zapata-Medina 2012. Method for estimating system stiffness for excavation support walls. Journal of Geotechnical and Geoenvironmental Engineering. 138, 9, 1104–1115.
S. Lam, S. Haigh, and M. Bolton 2014. Understanding ground deformation mechanisms for multi-propped excavation in soft clay. Soils and Foundations. 54, 3, 296–312.
This work is licensed under a Creative Commons Attribution 4.0 International License.
All articles published in our journal are licensed under CC-BY 4.0, which permits authors to retain copyright of their work. This license allows for unrestricted use, sharing, and reproduction of the articles, provided that proper credit is given to the original authors and the source.