Journal of Korean Tunnelling and Underground Space Association (한국터널지하공간학회 논문집)

Korean Tunnelling and Underground Space Association (한국터널지하공간학회)
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A study on the behaviour of single piles to adjacent Shield TBM tunnelling by considering face pressures

막장압의 크기를 고려한 Shield TBM 터널 근접시공이 단독말뚝의 거동에 미치는 영향에 대한 연구

  • Jeon, Young-Jin (Dept. of Civil Engineering, Kangwon National University) ;
  • Kim, Jeong-Sub (Dept. of Civil Engineering, Kangwon National University) ;
  • Jeon, Seung-Chan (Dept. of Civil Engineering, Kangwon National University) ;
  • Jeon, Sang-Joon (Dept. of Civil Engineering, Kangwon National University) ;
  • Park, Byung-Soo (Dept. of Civil Engineering, Kangwon State University) ;
  • Lee, Cheol-Ju (Dept. of Civil Engineering, Kangwon National University)
  • 전영진 (강원대학교 토목공학과) ;
  • 김정섭 (강원대학교 토목공학과) ;
  • 전승찬 (강원대학교 토목공학과) ;
  • 전상준 (강원대학교 토목공학과) ;
  • 박병수 (강원도립대학교 건설지적토목과) ;
  • 이철주 (강원대학교 토목공학과)
  • Received : 2018.09.03
  • Accepted : 2018.10.25
  • Published : 2018.11.30
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Abstract

In the current work, a series of three-dimensional finite element analyses were carried out to understand the behaviour of a pre-existing single pile to the changes of the tunnel face pressures when a shield TBM tunnel passes underneath the pile. The numerical modelling analysed the results by considering various face pressures (25~100% of the in-situ horizontal stress prior to tunnelling at the tunnel springline). In the numerical modelling, several key issues, such as the pile settlements, the axial pile forces, the shear stresses have been thoroughly analysed for different face pressures. The head settlements of the pile with the maximum face pressure decreased by about 44% compared to corresponding settlement with the minimum face pressure. Furthermore, the maximum axial force of the pile developed with the minimum face pressure. The tunnelling-induced axial pile force at the minimum face pressure was found to be about 21% larger than that with the maximum face pressure. It has been found that the ground settlements and the pile settlements are heavily affected by the face pressures. In addition, the influence of the piles and the ground was analysed by considering characteristics of the soil deformations. Also, the apparent safety factor of the piles are substantially reduced for all the analyses conducted in the current simulation, resulting in severe effects on the adjacent piles. Therefore, the behaviour of the piles, according to change the face pressures, has been extensively examined and analysed by considering the key features in great details.

본 연구에서는 Shield TBM 터널굴착이 기 시공된 단독말뚝의 하부를 근접하여 통과할 경우 터널 막장압에 따른 말뚝의 공학적 거동을 파악하기 위해 3차원 유한요소해석을 수행하였다. 이때 터널 막장압의 크기를 터널굴착 이전 springline 위치에서 수평토압의 25~100%로 변화시키면서 그 영향을 고찰하였다. 수치해석에서는 막장압의 변화에 따른 터널굴착으로 유발된 말뚝의 침하, 축력 및 전단응력을 고려하였다. 말뚝의 두부침하는 막장압의 크기를 가장 크게 적용한 조건이 막장압의 크기를 가장 작게 적용한 조건에 비해 약 44% 감소하여 발생하였다. 말뚝의 최대축력은 막장압의 크기를 가장 작게 적용한 조건에서 가장 크게 나타났으며, 이는 막장압의 크기를 가장 크게 고려한 조건에 대비하여 약 21% 큰 것으로 분석되었다. 터널굴착으로 인한 말뚝의 거동은 막장압의 변화에 따른 지반침하의 영향을 크게 받는 것을 알 수 있었으며, 막장압의 크기에 따른 말뚝 및 지반의 거동을 등고선을 이용하여 재분석하였다. 또한 모든 막장압 조건에 대하여 말뚝의 겉보기안전율이 1.0 이하로 산정되어 터널굴착이 인접말뚝에 유해한 영향을 끼치는 것으로 판단된다. 따라서 본 연구를 통해 말뚝의 거동에 영향을 미치는 주요인자를 막장압의 변화에 따라 심도 있게 고찰하였다.

Keywords

TNTNB3_2018_v20n6_1003_f0001.png 이미지

Fig. 1. Sectional view of tunnel crossing bridge foundation (Liu et al., 2014)

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Fig. 2. A representative 3D finite element half mesh used in the current study (D: tunnel diameter)

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Fig. 3. Sectional view of analysis geometry

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Fig. 4. Method used for the tunnel construction using TBM (A = the changes of the tunnel face pressures (0.25~1 in the current work), Z = distance from the surface to the tunnel springline, γ = unit weight of material, K0 = lateral earth pressure coefficient at rest)

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Fig. 5. Relation of axial pile forces and pile head settlements

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Fig. 6. Distributions of normalised pile head and soil surface settlements with tunnel advancement (δgr,max = 16 mm for face pressure of 262.5 kPa)

TNTNB3_2018_v20n6_1003_f0007.png 이미지

Fig. 7. Distributions of normalised tunnelling-induced pile and subsurface soil settlements with depth

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Fig. 8. Distributions of normalised axial pile forces with depth

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Fig. 9. Distributions of normalised tunnelling-induced axial pile forces with depth

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Fig. 10. Distributions of interface shear stresses with depth

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Fig. 11. Distributions of tunnelling-induced interface shear stresses with depth

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Fig. 12. Distributions of tunnelling-induced relative displacements at the pile-soil interface with depth

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Fig. 13. The contour of settlements the pile and subsurface (X-Z Plane)(Y/D = 0)

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Fig. 14. The contour of vertical displacements for the pile and subsurface (Y-Z Plane)(Y/D = 0)

Table 1. Summary of numerical analyses

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Table 2. Material parameters assumed in the numerical modelling

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References

  1. Ahn, C.K., Yu, J.S., Lee, S.W. (2018), "Evaluation of the backfill injection pressure and its effect on ground settlement for shield TBM using numerical analysis", Journal of Korean Tunnelling and Underground Space Association, Vol. 20, No. 2, pp. 269-286. https://doi.org/10.9711/KTAJ.2018.20.2.269
  2. Bolton, M.D. (1991), "A guide to Soil Mechanics", M.D. & K. Bolton, Cambridge, pp. 313.
  3. Brinkgreve, R.B.J., Kumarswamy, S., Swolfs, W.M. (2015), "Reference manual", Plaxis 3D 2015 User's Manual, Delft, pp. 1-284.
  4. Cheng, C.Y., Dasari, G.R., Leung, C.F., Chow, Y.K., Rosser, H.B. (2004), "3D numerical study of tunnel-soil-pile interaction", Underground Space for Sustainable Urban Development, Proceedings of the 30th ITA-AITES World Tunnel Congress Singpore, pp. 1-8.
  5. Cho, W.S., Song, K.I., Kim, K.Y. (2014b), "The study on the effect of fracture zone and its orientation on the behavior of shield TBM cable tunnel", Journal of Korean Tunnelling and Underground Space Association, Vol. 16, No. 4, pp. 403-415. https://doi.org/10.9711/KTAJ.2014.16.4.403
  6. Cho, W.S., Song, K.I., Ryu, H.H. (2014a), "Analysis on the behavior of shield TBM cable tunnel: The effect of the distance of backfill grout injection from the end of skin plate", Journal of Korean Tunnelling and Underground Space Association, Vol. 16, No. 2, pp. 213-224. https://doi.org/10.9711/KTAJ.2014.16.2.213
  7. Davisson, M.T. (1972), "High capacity piles", Proceedings of the Lecture Series in Innovations in Foundation Construction, ASCE, Illinois Section, pp. 81-112.
  8. Hartono, E., Leung, C.F., Shen, R.F., Chow, Y.K., Ng, Y.S., Tan, H.T., Hua, C.J. (2014), "Behaviour of pile above tunnel in clay", Physical Modelling in Geotechnics, pp. 833-838.
  9. Hong, Y., Soomro, M.A., Ng, C.W.W. (2015), "Settlement and load transfer mechanism of pile group due to side-by-side twin tunnelling", Computers and Geotechnics, Vol. 64, pp. 105-119. https://doi.org/10.1016/j.compgeo.2014.10.007
  10. Jacobsz, S.W. (2002), "The effects of tunnelling on piled foundations", Ph.D. Thesis, Dept. of Civil Engineering, University of Cambridge, pp. 1-348.
  11. Jeon, Y.J., Kim, S.H., Kim, J.S., Lee, C.J. (2017), "A study on the effects of ground reinforcement on the behaviour of pre-existing piles affected by adjacent tunnelling", Journal of Korean Tunnelling and Underground Space Association, Vol. 19, No. 3, pp. 389-407. https://doi.org/10.9711/KTAJ.2017.19.3.389
  12. Jeon, Y.J., Kim, S.H., Lee, C.J. (2015), "A study on the effect of tunnelling to adjacent single piles and pile groups considering the transverse distance of pile tips from the tunnel", Journal of Korean Tunnelling and Underground Space Association, Vol. 17, No. 6, pp. 637-652. https://doi.org/10.9711/KTAJ.2015.17.6.637
  13. Jeon, Y.J., Lee, C.J. (2015), "A study on the behaviour of single piles to adjacent tunnelling in stiff clay", Journal of the Korean Geo-Environmental Society, Vol. 16, No. 6, pp. 13-22.
  14. Kaalberg, F.J., Teunissen, E.A.H., Van Tol, A.F., Bosch, J.W. (2005), "Dutch research on the impact of shield tunneling on pile foundations", Geotechnical Aspects of Underground Construction in Soft Ground, Proceedings of the 5th International Conference of TC28 of the ISSMGE Amsterdam, pp. 123-131.
  15. Lee, C.J. (2012a), "Three-dimensional numerical analyses of the response of a single pile and pile groups to tunnelling in weak weathered rock", Tunnelling and Underground Space Technology, Vol. 32, pp. 132-142. https://doi.org/10.1016/j.tust.2012.06.005
  16. Lee, C.J. (2012b), "Behaviour of single piles and pile groups in service to adjacent tunnelling conducted in the lateral direction of the piles", Journal of Korean Tunnelling and Underground Space Association, Vol. 14, No. 4, pp. 337-356. https://doi.org/10.9711/KTAJ.2012.14.4.337
  17. Lee, C.J. (2012c), "The response of a single pile and pile groups to tunnelling performed in weathered rock", Journal of the Korean Society of Civil Engineers, Vol. 32, No. 5C, pp. 199-210. https://doi.org/10.12652/Ksce.2012.32.5C.199
  18. Lee, C.J., Jeon, Y.J. (2015), "A study on the effect of the locations of pile tips on the behaviour of piles to adjacent tunnelling", Journal of Korean Tunnelling and Underground Space Association, Vol. 17, No. 2, pp. 91-105. https://doi.org/10.9711/KTAJ.2015.17.2.091
  19. Lee, C.J., Jeon, Y.J., Kim, S.H., Park, I.J. (2016), "The influence of tunnelling on the behaviour of pre-existing piled foundations in weathered soil", Geomechanics and Engineering, Vol. 11, No. 4, pp. 553-570. https://doi.org/10.12989/gae.2016.11.4.553
  20. Lee, G.T.K., Ng, C.W.W. (2005), "The effects of advancing open face tunnelling on an existing loaded pile", Journal of Geotechnical and Geoenvironmental Engineering, ASCE, Vol. 131, No. 2, pp. 193-201. https://doi.org/10.1061/(ASCE)1090-0241(2005)131:2(193)
  21. Lee, J.H., Lee, J.M., Lee, Y.J. (2012), "Behavior of the superstructure subjected to TBM tunnel excavation sequence", Proceedings of the KSCE 2017 Convention Conference & Civil EXPO, pp. 1334-1337.
  22. Lee, Y.J. (2008), "A boundary line between shear strain formations associated with tunneling adjacent to an existing piled foundation", Journal of Korean Tunnelling and Underground Space Association, Vol. 10, No. 3, pp. 283-293.
  23. Liu, C., Zhang, Z., Regueiro, R.A. (2014), "Pile and pile group response to tunnelling using a large diameter slurry shield - Case study in Shanghai", Computers and Geotechnics, Vol. 59, pp. 21-43. https://doi.org/10.1016/j.compgeo.2014.03.006
  24. Mair, R.J., Williamson, M.G. (2014), "The influence of tunnelling and deep excavation on piled foundations", Geotechnical Aspects of Underground Construction in Soft Ground, pp. 21-30.
  25. Marshall, A.M. (2009), "Tunnelling in sand and its effect on pipelines and piles", Ph.D. Thesis, Dept. of Civil Engineering, University of Cambridge, pp. 1-243.
  26. Mroueh, H., Shahrour, I. (2008), "A simplified 3D model for tunnel construction using tunnel boring machines", Tunnelling and Underground Space Technology, Vol. 23, pp. 38-45. https://doi.org/10.1016/j.tust.2006.11.008
  27. Ng, C.W.W., Lu, H., Peng, S.Y. (2013), "Three-dimensional centrifuge modelling of the effects of twin tunnelling on an existing pile", Tunnelling and Underground Space Technology, Vol. 35, pp. 189-199. https://doi.org/10.1016/j.tust.2012.07.008
  28. Ng, C.W.W., Soomro, M.A., Hong, Y. (2014), "Three-dimensional centrifuge modelling of pile group responses to side-by-side twin tunnelling", Tunnelling and Underground Space Technology, Vol. 43, pp. 350-361. https://doi.org/10.1016/j.tust.2014.05.002
  29. Pang, C.H. (2006), "The effects of tunnel construction on nearby pile foundation", Ph.D. Thesis, Dept. of Civil Engineering, The National University of Singapore, pp. 27-56.
  30. Park, H.K., Chang, S.B., Lee, S.B. (2014), "3-Dimensional numerical modeling of SPB shield TBM tunneling-induced ground settlement considering volume loss processes", Geotechnical Aspects of Underground Construction in Soft Ground, pp. 221-224.
  31. Plaxis (2017), Reference manual, Plaxis 3D User's Manual.
  32. Selemetas, D. (2005), "The response of full-scale piles and piled structures to tunnelling", Ph.D. Thesis, Dept. of Civil Engineering, University of Cambridge, pp. 1-302.
  33. Williamson, M.G. (2014), "Tunnelling effects on bored piles in clay", Ph.D. Thesis, Dept. of Civil Engineering, University of Cambridge, pp. 1-418.
  34. Xu, Q., Zhu, H., Ma, X., Ma, Z., Li, X., Tang, Z., Zhuo, K. (2015), "A case history of shield tunnel crossing through group pile foundation of a road bridge with pile underpinning technologies in Shanghai", Tunnelling and Underground Space Technology, Vol. 45, pp. 20-33. https://doi.org/10.1016/j.tust.2014.09.002
  35. You, K.H., Kim, Y.J. (2017), "A study on numerical modeling method considering gap parameter and backfill grouting of the shield TBM tunnel", Journal of Korean Tunnelling and Underground Space Association, Vol. 19, No. 5, pp. 799-812. https://doi.org/10.9711/KTAJ.2017.19.5.799