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

Korean Tunnelling and Underground Space Association (한국터널지하공간학회)
권호 표지
DOI QR코드

DOI QR Code

A study on the effect of tunnelling to adjacent single piles and pile groups considering the transverse distance of pile tips from the tunnel

말뚝의 횡방향 이격거리를 고려한 터널굴착이 인접 단독말뚝 및 군말뚝에 미치는 영향에 대한 연구

  • Jeon, Young-Jin (Department of Civil Engineering, Kangwon National University) ;
  • Kim, Sung-Hee (Department of Civil Engineering, Kangwon National University) ;
  • Lee, Cheol-Ju (Department of Civil Engineering, Kangwon National University)
  • Received : 2015.10.22
  • Accepted : 2015.11.11
  • Published : 2015.11.30
Download PDF
⟨ Previous Next ⟩

Abstract

In the present work, a number of three-dimensional (3D) parametric numerical analyses have been carried out to study the influence of tunnelling on the behaviour of adjacent piles considering the transverse distance of the pile tip from the tunnel. Single piles and $5{\times}5$ piles inside a group with a spacing of 2.5d were considered, where d is the pile diameter. In the numerical modelling, several key issues, such as the tunnelling-induced pile settlements, the interface shear stresses, the relative shear displacements, the axial pile forces, the apparent factors of safety and zone of influence have been rigorously analysed. It has been found that when the piles are inside the influence zone, the pile head settlements are increased up to about 111% compared to those computed from the Greenfield condition. Larger pile settlements and smaller axial pile forces are induced on the piles inside the pile groups than those computed from the single piles since the piles responded as a block with the surrounding ground. Also tensile pile forces are induced associated with the upward resisting skin friction at the upper part of pile and the downward acting skin friction at the lower part of pile. On the contrary, when the piles were outside the influence zone, tunnelling-induced compressive pile forces developed. Based on computed load and displacement relation of the pile, the apparent factor of safety of the piles was reduced up to about 45%. Therefore the serviceability of the piles may be substantially reduced. The pile behaviour, when considering the single piles and the pile groups with regards to the influence zone, has been analysed by considering the key features in great details.

본 연구에서는 3차원 유한요소해석을 실시하여 말뚝에 인접한 터널시공으로 인한 말뚝의 거동을 터널로부터 말뚝선단의 횡방향 이격거리를 고려하여 분석하였다. 단독말뚝 및 간격 2.5d인 $5{\times}5$ 군말뚝을 고려하였다. 여기서 d는 말뚝의 직경을 의미한다. 수치해석에서는 순수하게 터널굴착(tunnelling-induced) 으로 인해 유발된 말뚝침하, 전단응력, 상대변위, 축력분포, 겉보기안전율 및 터널굴착 영향권을 고찰하였다. 말뚝이 터널굴착으로 인한 지반침하 영향권 내부에 존재할 경우 말뚝두부의 침하는 Greenfield 조건의 지표면 침하보다 최대 대략 111% 크게 산정되었고, 군말뚝의 경우 단독말뚝과 비교하여 말뚝침하가 크고 축력이 작게 나타났는데 이는 군말뚝내의 말뚝이 인접지반과 함께 블록(block)의 형태로 거동하는 것으로 분석되었다. 또한 말뚝의 상부에서는 상향의 마찰 저항력이 발생하고 말뚝의 하부에서는 하향의 마찰 저항력이 발생하여 순수하게 터널굴착(tunnelling-induced)으로 인해 말뚝에는 인장력을 발생시켰다. 한편 말뚝이 영향권 외부에 존재할 경우 말뚝에는 tunnelling-induced 압축력이 발생하였다. 수치해석을 통해 분석된 하중-침하 관계로부터 말뚝의 겉보기안전율을 계산한 결과 터널굴착 이전에 비해 대략 45% 감소된 것으로 나타났다. 따라서 이는 말뚝의 사용성에 심각한 문제를 유발시킬 수 있는 것으로 나타났다. 본 연구를 통해 지반침하 영향권에 따른 단독말뚝 및 군말뚝의 거동을 심도 있게 고찰하였다.

Keywords

References

  1. Attewell, P.B., Yeates, J., Selby, A.R. (1986), "Soil movements induced by tunnelling and their effects on pipelines and structures", Blackie, Glasgow. pp. 277-279.
  2. 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. Proc. of. the 30th ITA-AITES World Tunnel Congress Singpore, pp. 1-8.
  3. Davisson, M.T. (1972), "High capacity piles. proceedings of lecture series in innovations in foundation construction", ASCE, Illinois Section, pp. 81-112.
  4. Dias, T.G.S., Bezuijen, A. (2014a), "Pile tunnel interaction: Literature review and data analysis', ITA World Tunnel Congress 2014, pp. 1-10.
  5. Dias, T.G.S., Bezuijen, A. (2014b), "Pile-tunnel interaction: A conceptual analysis", 8th International symposium on Geotechnical aspects of underground construction in soft ground, CRC Press, Vol. 1, pp. 251-255.
  6. 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.
  7. 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, pp.105-119.
  8. Jacobsz, S.W. (2002), "The effects of tunnelling on piled foundations", PhD thesis, University of Cambridge, pp. 1-348.
  9. Jacobsz, S.W., Standing, J.R., Mair, R.J., Hagiwara, T., Sugiyama, T. (2002), "Centrifuge modelling of tunnelling near driven piles", In Proceedings of the International Symposium on Geotechnical Aspects of Underground Construction in Soft Ground. Toulouse, pp. 49-56.
  10. 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. https://doi.org/10.14481/jkges.2015.16.6.13
  11. 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 5th International Conf. of TC 28 of the ISSMGE, pp. 123-133.
  12. Lee, C.J. (2012a), "Three-dimensional numerical analyses of the response of a single pile and pile groups to tunnelling in weak weathered rock", Tunnel Underground Space Technolgy, Vol. 32, pp. 132-142. https://doi.org/10.1016/j.tust.2012.06.005
  13. 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
  14. 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
  15. 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
  16. Lee, G.T.K., Ng, C.W.W. (2005), "The effects of advancing open face tunneling 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)
  17. 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
  18. 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.
  19. Marshall, A.M. (2009), "Tunnelling in sand and its effect on pipelines and piles", PhD thesis, University of Cambridge.
  20. 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.
  21. Ng, C.W.W., Lu, H., Peng, S.Y. (2013), "Three-dimensional centrifuge modelling of twin tunnelling effects on an existing pile", Tunnelling and Underground Space Technology, Vol. 35, pp. 189-199. https://doi.org/10.1016/j.tust.2012.07.008
  22. 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
  23. Pang, C.H. (2006), "The effects of tunnel construction on nearby pile foundation", PhD thesis, The National University of Singapore.
  24. Plaxis (2012), "Reference manual", Plaxis 3D user's manual, pp. 122-124.
  25. Selemetas, D. (2005), "The response of full-scale piles and piled structures to tunnelling", PhD thesis, University of Cambridge, pp. 1-302.
  26. Williamson, M.G. (2014), "Tunnelling effects on bored piles in clay", PhD thesis, University of cambridge UK.