DOI QR코드

DOI QR Code

Investigations of countermeasures used to mitigate tunnel deformations due to adjacent basement excavation in soft clays

  • Jinhuo Zheng (Fujian Provincial Institute of Architectural Design And Research Co.,Ltd.) ;
  • Minglong Shen (Fujian Provincial Institute of Architectural Design And Research Co.,Ltd.) ;
  • Shifang Tu (China Railway 16th Bureau Group 3rd Corporation Limited) ;
  • Zhibo Chen (Department of Geotechnical and Geological Engineering, Zijin School of Geology and Mining, Fuzhou University) ;
  • Xiaodong Ni (Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering, Hohai University)
  • 투고 : 2023.11.27
  • 심사 : 2024.02.27
  • 발행 : 2024.03.25

초록

In this study, various countermeasures used to mitigate tunnel deformations due to nearby multi-propped basement excavation in soft clay are explored by three-dimensional numerical analyses. Field measurements are used to calibrate the numerical model and model parameters. Since concrete slabs can constrain soil and retaining wall movements, tunnel movements reach the maximum value when soils are excavated to the formation level of basement. Deformation shapes of an existing tunnel due to adjacent basement excavation are greatly affected by relative position between tunnel and basement. When the tunnel is located above or far below the formation level of basement, it elongates downward-toward or upward-toward the basement, respectively. It is found that tunnel movements concentrate in a triangular zone with a width of 2 He (i.e., final excavation depth) and a depth of 1 D (i.e., tunnel diameter) above or 1 D below the formation level of basement. By increasing retaining wall thickness from 0.4 m to 0.9 m, tunnel movements decrease by up to 56.7%. Moreover, tunnel movements are reduced by up to 80.7% and 61.3%, respectively, when the entire depth and width of soil within basement are reinforced. Installation of isolation wall can greatly reduce tunnel movements due to adjacent basement excavation, especially for tunnel with a shallow burial depth. The effectiveness of isolation wall to reduce tunnel movement is negligible unless the wall reaches the level of tunnel invert.

키워드

과제정보

This work described in this paper is supported by a research grant from Housing and Urban-rural Development of Fujian, China (Grant No. 2022-K-330), and National Natural Science Foundation of China (Grant No. 52278335).

참고문헌

  1. Brinkgreve, R.B.J. and Broere, W. (2004), PLAXIS 3D Tunnel Version 2, PLAXIS by, Netherlands.
  2. Burford, D. (1988), "Heave of tunnels beneath the shell centre", London, 1959-1986. Geotechnique, 38(1), 135-137. https://doi.org/10.1680/geot.1988.38.1.135
  3. Bu, F.M., Yu, W.R., Chen, L. and Wu, E.R. (2022), "Investigation of three-dimensional deformation mechanisms of box culvert due to adjacent deep basement excavation in clays", Geomech. Eng., 30(6), 565-577. https://doi.org/10.12989/gae.2022.30.6.565.
  4. Chen, W.C., Tang, L.X., Zhao, H.J., Yin, Q., Dong, S., Liu, J., Zhu, Z.H. and Ni, X.D. (2023), "Investigation of three-dimensional deformation mechanisms of existing tunnels due to nearby basement excavation in soft clay", Geomech. Eng., 34(2), 115-124. https://doi.org/10.12989/gae.2023.34.2.115.
  5. Devriendt, M., Doughty, L., Morrison, P. and Pillai, A. (2010), "Displacement of tunnels from a basement excavation in London", Proceedings of the Institution of Civil Engineers-Geotechnical Engineering, 163(3), 131-145. https://doi.org/10.1680/geng.2010.163.3.131.
  6. Forth, R.A. (2004), "Groundwater and geotechnical aspects of deep excavations in Hong Kong", Eng. Geol., 72(3-4), 253-260. https://doi.org/ 10.1016/j.enggeo.2003.09.003.
  7. Ge, X.W. (2002). Response of a shield-driven tunnel to deep excavations in soft clay. Ph.D thesis, Department of Civil and Environmental Engineering, The University of Hong Kong Science and Technology, HKSAR.
  8. Hsieh, P.G. and Ou, C.Y. (1998), "Shape of ground surface settlement profiles caused by excavation", Can. Geotech. J., 35(6), 1004-1017. https://doi.org//10.1139/cgj-35-6-1004.
  9. Huang, X., Huang, H.W. and Zhang, D.M. (2014), "Centrifuge modelling of deep excavation over existing tunnels", Proceedings of the ICE-Geotechnical Engineering, 16(2), 3-18. https://doi-org/10.1680/geng.11.00045.
  10. Khabbaz, H., Gibson, R. and Fatahi, B. (2019), "Effect of constructing twin tunnels under a building supported by pile foundations in the Sydney central business district", Underground Sp., 4(4), 261-276. https://doi.org/10.1016/j.undsp.2019.03.008.
  11. Klar, A., Elkayam, I. and Marshall, A.M. (2016), "Design oriented linear equivalent approach for evaluating the effect of tunneling on pipelines", J. Geotech. Geoenviron. Eng., 142(1), 04015062. https://doi.org/10.1061/(ASCE)GT.1943-5606.0001376.
  12. Leung, C.F., Chow, Y.K. and Shen, R.F. (2000), "Behavior of pile subject to excavation-induced soil movement", J. Geotech. Geoenviron. Eng., 126(11), 947-954. https://doi.org/10.1061/(ASCE)1090-0241(2000)126:11(947).
  13. Li, C.W., Li, W. and Liang, Z.R. (2018), "Design and analysis on synchronous construction of deep foundation pit on both sides of tunnels in soft soils", Chinese J. Undergr. Sp. Eng., 14(S1), 197-203. https://doi.org/10.16285/j.upe.2018.S1.031.
  14. Liang, R.C., Wu, J., Sun, L.W., Shen, W. and Wu, W.B. (2021), "Performances of adjacent metro structures due to zoned excavation of a large-scale basement in soft ground", Tunn. Undergr. Sp. Tech., 117, 104123. https://doi.org/10.1016/j.tust.2021.104123.
  15. Liu, B., Zhang, D.W., Yang, C. and Zhang, Q.B. (2020), "Long-term performance of metro tunnels induced by adjacent large deep excavation and protective measures in Nanjing silty clay", Tunn. Undergr. Sp. Tech., 95, 103147. https://doi.org/10.1016/j.tust.2019.103147.
  16. Liu, H.L., Li, P. and Liu, J.Y. (2011), "Numerical investigation of underlying tunnel heave during a new tunnel construction", Tunn. Undergr. Sp. Tech., 26(2), 276-283. https://doi.org/org/10.1016/j.tust.2010.10.002.
  17. Mahajan, S., Ayothiraman, R. and Sharma, K.G. (2019), "A parametric study on effects of basement excavation and foundation loading on underground metro tunnel in soil", Indian Geotech. J.l, 49, 667-686. https://doi.org/10.1007/s40098-019-00361-x.
  18. Marshall, A.M. and Mair, R.J. (2011), "Tunneling beneath driven or jacked end-bearing piles in sand", Can. Geotech. J., 48(12), 1757-1771. https://doi.org/10.1139/t11-067.
  19. Meng, F.Y., Chen, R.P., Liu, Y., Wu, H.N. and Cheng, H.Z. (2023), "Impacts of reinforced wall on nearby excavation-induced ground and tunnel responses: a centrifugal and numerical study", Tunn. Undergr. Sp. Tech., 132, 104903. https://doi.org/10.1016/j.tust.2022.104903.
  20. Ng, C.W.W, Hong, Y., Liu, G.B. and Liu, T. (2012), "Ground deformations and soil-structure interaction of a multi-propped excavation in Shanghai soft clay", Geotechnique, 62(10), 907-921. https://doi.org/10.1680/geot.10.P.072.
  21. Ng, C.W.W, Shi, J.W. and Hong, Y. (2013), "Three-dimensional centrifuge modelling of basement excavation effects on an existing tunnel in dry sand", Cana. Geotech. J., 50(8), 874-888. https://doi.org/10.1139/cgj-2012-0423.
  22. Ng, C.W.W., Shi, J.W., Masin, D., Sun, H.S. and Lei, G.H. (2015), "Influence of sand density and retaining wall stiffness on the three-dimensional responses of a tunnel to basement excavation", Can. Geotech. J., 52(8), 1811-1829. https://doi.org/10.1139/ cgj-2014-0150.
  23. Powrie, W., Pantelidou, H. and Stallebrass, S.E. (1998), "Soil stiffness in stress paths relevant to diaphragm walls in clay", Geotechnique, 48(4), 483-494. https://doi.org/10.1680/geot.1998.48.4.483.
  24. Sharma, J.S., Hefny, A.M., Zhao, J. and Chan, C.W. (2001), "Effect of large excavation on displacement of adjacent MRT tunnels", Tunn. Undergr. Sp. Tech., 16(2), 93-98. https://10.1016/S0886-7798(01)00033-5.
  25. Shi, J.W., Chen Y.H., Lu, H., Ma, S.K. and Ng, C.W.W. (2022), "Centrifuge modeling of the influence of joint stiffness on pipeline response to underneath tunnel excavation", Can. Geotech. J., 59(9), 1568-1586. https://10.1139/cgj-2020-03601.
  26. Shi, J.W., Fu, Z.Z. and Guo, W.L. (2019), "Investigation of geometric effects on three-dimensional tunnel deformation mechanisms due to basement excavation", Comput. Geotech., 106, 108-116. https://doi.org/10.1016/j.compgeo.2018.10.019.
  27. Shi, J.W., Liu, G.B., Huang, P. and Ng, C.W.W. (2015b), "Interaction between a large-scale triangular excavation and adjacent structures in Shanghai soft clay", Tunn. Undergr. Sp. Tech., 50, 282-295. https://doi.org/10.1016/j.tust.2015.07.013.
  28. Shi, J.W., Ng, C.W.W. and Chen, Y.H. (2015a), "Three-dimensional numerical parametric study of the influence of basement excavation on existing tunnel", Comput. Geotech., 63, 146-158. https://doi.org/10.1016/j.compgeo.2014.09.002.
  29. Shi, J.W., Wang, J.P., Chen Y.H., Shi, C., Lu, H., Ma, S.K. and Fan, Y.B. (2023), "Physical modeling of the influence of tunnel active face instability on existing pipelines", Tunn. Undergr. Sp. Tech., 140, 105281. https://10.1016/j.tust.2023.105281.
  30. Shi, J.W., Zhang, X., Chen, Y.H. and Chen, L. (2018), "Numerical parametric study of countermeasures to alleviate basement excavation effects on an existing tunnel", Tunn. Undergr. Sp. Tech., 72, 145-153. https://10.1016/j.tust.2017.11.030.
  31. Soomro, M.A., Saand, A., Mangi, N., Mangnejo, D.A., Karira, H. and Liu, K. (2019), "Numerical modelling of effects of different multipropped excavation depths on adjacent single piles: comparison between floating and end-bearing pile responses", Eur. J. Environ. Civil Eng., 25(14), 2592-2622. https://doi.org/10.1080/19648189.2019.1638312.
  32. Ye, S.H., Zhao, Z.F. and Wang, D.Q. (2021), "Deformation analysis and safety assessment of existing metro tunnels affected by excavation of a foundation pit", Undergr. Sp., 6, 4211-431. https://doi.org/10.1016/j.undsp. 2020.06.002.
  33. Zaid, M. (2021a), "Three-dimensional finite element analysis of urban rock tunnel under static loading condition: effect of the rock weathering", Geomech. Eng., 25(2), 99-109. https://doi.org/10.12989/gae.2021.25.2.099.
  34. Zaid, M. (2021b), "Preliminary study to understand the effect of impact loading and rock weathering in tunnel constructed in quartzite", Geotech. Geol. Eng., 42, 725-753. https://doi.org/10.1007/s10706-021-01948-z.
  35. Zheng, G. and Wei, S.W. (2008), "Numerical analysis of influence of overlying pit excavation on existing tunnels", J. Central South Univ. Tech., 15(2), 69-75. https://doi.org/10.1007/s11771-008-0438-4.
  36. Zheng, G., Yang, X.Y., Zhou, H.Z., Du, Y.M., Sun, J.Y. and Yu, X.X. (2018), "A simplified prediction method for evaluating tunnel displacement induced by laterally adjacent excavations", Comput. Geotech., 95, 119-128. https://doi.org/10.1016/j.compgeo.2017.10.006.