EFFECTS OF LARGE SCALE UNLOADING ON EXISTING SHIELD TUNNELS IN SANDY GRAVEL STRATA

Authors

  • Wu Hao Chang’an University, School of Highway, Xi’an,Shanxi,China
  • Miao Miao Chang’an University, School of Highway, Xi’an,Shanxi,China
  • Zhou Hui CCCC Highway Consultants CO., Ltd., Beijing, China
  • Feng Zhi-hua Bridge and tunnel branch institute, Heibei Provincial Communications Planning and Design Institute, Shijiazhuang, Hebei, China

DOI:

https://doi.org/10.14311/CEJ.2020.04.0046

Keywords:

Shield tunnel, Pit excavation, Sandy gravel statement-floating stability measures, Numerical modelling

Abstract

The influence of large-scale unloading of soil on existing metro tunnels is a difficult problem in the operation of Metro in sandy gravel strata. In order to predict and control the tunnel deformation and ensure the safety and normal operation of the metro, three-dimensional numerical models are proposed in this study. These models based on the line 5 of Chengdu subway engineering and the adjacent unloading projects analyse the deformation and stress characteristics of existing metro tunnels under large-scale unloading of soil. In conclusion, after comprehensive reinforcement measures such as advanced tubal curtains and horizontal beams, anti-floating anchor cables, the elastic modulus of strata is improved to a certain extent, and the rebound of pit bottom soil is effectively reduced. After the excavation of the foundation pits are completed, the maximum longitudinal uplift of left and right tunnel is 8.33 mm and 9.56 mm under reinforced condition, which is less than the control standard value of 10 mm.

Downloads

Download data is not yet available.

References

R. J. Finno, and L. S. Bryson, “Response of building adjacent to stiff excavation support system in soft clay,” Journal of performance of constructed facilities, vol. 16, no. 1, pp. 10-20, 2002.

P. G. Hsieh, and C. Y. Ou, “Shape of ground surface settlement profiles caused by excavation,” Canadian geotechnical journal, vol. 35, no. 6, pp. 1004-1017, 1998.

G. B. Liu, C. W. Ng, and Z. W. Wang, “Observed performance of a deep multistrutted excavation in Shanghai soft clays,” Journal of Geotechnical and Geoenvironmental Engineering, vol. 131, no. 8, pp. 1004-1013, 2005.

M. G. Li, Z. J. Zhang, J. J. Chen et al., “Zoned and staged construction of an underground complex in Shanghai soft clay,” Tunnelling and Underground Space Technology, vol. 67, pp. 187-200, 2017.

C. W. Ng, J. Shi, Y. Hong, “Three-dimensional centrifuge modelling of basement excavation effects on an existing tunnel in dry sand.” Canadian Geotechnical Journal, vol. 50, no. 8, pp. 874-888, 2013.

H. Xu, H. W. Huang, and D.M. Zhang, “Centrifuge modelling of deep excavation over existing tunnels,” Proceedings of the Institution of Civil Engineers-Geotechnical Engineering, vol. 167, no. 1, pp. 3-18, 2014.

C. W. Ng, H. S. Sun, G. H. Lei, J. W. Shi, and D. Mašín, “Ability of three different soil constitutive models to predict a tunnel’s response to basement excavation,” Canadian Geotechnical Journal, vol. 52, no. 11, pp. 1685-1698, 2015.

Y. Tan, X. Li, Z. Kang, J. Liu, and Y. Zhu, “Zoned excavation of an oversized pit close to an existing metro line in stiff clay: Case study,” Journal of Performance of Constructed Facilities, vol. 29, no. 6, Article ID 04014158, 2014.

X. Xiao, J. J. Chen, M. G. Li, and J. H. Wang, “Field Monitoring of an Existing Cut-and-Cover Tunnel between Two Large-Scale Deep Excavations,” Journal of Aerospace Engineering, vol. 31, no. 6, Article ID 04018082, 2018.

H. Liu, P. Li, and J. Liu, “Numerical investigation of underlying tunnel heave during a new tunnel construction,” Tunnelling and Underground Space Technology, vol. 26, no. 2, pp. 276-283, 2011.

M. Doležalová, “Tunnel complex unloaded by a deep excavation,” Computers and Geotechnics, vol. 28, pp. 469-493, 2001.

C. W. Ng, J. Shi, D. Mašín, H. Sun, and G. H. Lei, “Influence of sand density and retaining wall stiffness on three-dimensional responses of tunnel to basement excavation,” Canadian Geotechnical Journal, vol. 52, no. 11, pp. 1811-1829, 2015.

G. Zheng, and S. W. Wei, “Numerical analyses of influence of overlying pit excavation on existing tunnels,” Journal of central south university of technology, vol. 15, no. 2, pp. 69-75, 2008.

O. Kusakabe, T. Kimura, and N. Takagi, “Centrifuge model tests on the influence of axisymmetric excavation on buried pipes,” Proceedings of 3rd International Conference on Ground Movements and Structures, London: Pentech Press, 1985.

Y. KOJIMA, and K. YASHIRO, “Deformation behaviour of tunnel lining due to ground surface loading and unloading above the tunnel,” Quarterly Report of RTRI, vol. 46, no. 2, pp. 143-146, 2005.

J. S. Sharma, A. M. Hefny, J. Zhao, and C. W. Chan, “Effect of large excavation on deformation of adjacent MRT tunnels,” Tunnelling and Underground Space Technology, vol. 16, no. 2, pp. 93-98, 2001.

A. V. Kivi, M. H. Sadaghiani, and M. M. Ahmadi, “Numerical modelling of ground settlement control of large span underground metro station in Tehran Metro using Central Beam Column (CBC) structure,” Tunnelling and Underground Space Technology, vol. 28, pp. 1-9, 2012.

A. V. Kivi,, M. H. Sadaghiani, and M. M. Ahmadi, “Analysis of interaction between tunnels in soft ground by 3D numerical modelling,” Bulletin of Engineering Geology and the Environment, vol. 70, no. 3, pp. 439-448, 2011.

X. Xiao, M. G. Li, J. H. Wang, and J. J. Chen, “Numerical Evaluation of Control Measures for Tunnel Deformation Induced by an Oversized Deep Excavation,” Journal of Aerospace Engineering, vol. 31, no. 6 Article ID 04018109, 2018.

Z. Zhang, M. Zhang, and Q. Zhao, “A simplified analysis for deformation behaviour of buried pipelines considering disturbance effects of underground excavation in soft clays,” Arabian Journal of Geosciences, vol. 8, no. 10, pp. 7771-7785, 2015.

R. Liang, T. Xia, Y. Hong, and F. Yu, “Effects of above-crossing tunnelling on the existing shield tunnels,” Tunnelling and Underground Space Technology, vol. 58, pp. 159-176, 2016.

J. F. Zhang, J. J. Chen, J. H. Wang, and Y. F Zhu, “Prediction of tunnel displacement induced by adjacent excavation in soft soil,” Tunnelling and Underground Space Technology, vol. 36, pp. 24-33, 2013.

G. Zheng, X. Yang, H. Zhou, Y. Du, J. Sun, and X. Yu, “A simplified prediction method for evaluating tunnel displacement induced by laterally adjacent excavations,” Computers and Geotechnics, vol. 95, pp. 119-128, 2018.

J. Qiu, Y. Qin, Z. Feng, L. Wang and K. Wang, “Safety Risks and Protection Measures for the City Wall during the Construction and Operation of Xi'an Metro,” Journal of Performance of Constructed Facilities,2019,in press

Z. Wang, Y. Wang, and W. Cheng. “Investigation into Geohazards during Urbanization Process of Xi'an, China,” Natural Hazards, vol. 92, no. 3, pp.1937-1953, 2018.

Z. J. Zhou, S. S. Zhu, X. Kong, J. T. Lei and T. Liu, “Optimization analysis of settlement parameters for post-grouting piles in loess area of Shaanxi, China,” Advances in Civil Engineering, vol. 2019, Article ID 7085104, 11 pages, 2019.

C. T. Chang, C. W. Sun, S. W. Duann, and R. N. Hwang, “Response of a Taipei Rapid Transit System (TRTS) tunnel to adjacent excavation,” Tunnelling and Underground Space Technology, vol. 16, no. 3, pp. 151-158, 2011.

Y. C. Zheng, K. Liu, Y. Fang, W. S. Zhang and J. Fang, “Rock burst Prediction Model Based on Entropy Weight Integrated with Grey Relational -BP Neural Network,” Advances in Civil Engineering, vol. 2019, Article ID 3453614, 9 pages,2019.

B. Zhao, D. Liu, and B. Jiang, “Soil Conditioning of Waterless Sand–Pebble Stratum in EPB Tunnel Construction,” Geotechnical and Geological Engineering, vol. 36, no. 4, pp. 2495-2504, 2018.

X.Liu, Q. Fang, and D Zhang, “Mechanical responses of existing tunnel due to new tunnelling below without clearance,” Tunnelling and Underground Space Technology, vol. 80, pp. 44-52, 2018.

X. Huang, H. F. Schweiger, and H. Huang, “Influence of deep excavations on nearby existing tunnels,” International Journal of Geomechanics, vol. 13, no. 2, pp. 170-180, 2011.

Published

2020-12-31

How to Cite

Hao, W., Miao, M., Hui, Z., & Zhi-hua, F. (2020). EFFECTS OF LARGE SCALE UNLOADING ON EXISTING SHIELD TUNNELS IN SANDY GRAVEL STRATA. Stavební Obzor - Civil Engineering Journal, 29(4). https://doi.org/10.14311/CEJ.2020.04.0046

Issue

Vol. 29 No. 4 (2020)

Section

Articles

License

Creative Commons License

This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.

Authors who publish with this journal agree to the following terms:

  1. Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a Creative Commons Attribution License that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal.
  2. Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgement of its initial publication in this journal.
  3. Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) prior to and during the submission process, as it can lead to productive exchanges, as well as earlier and greater citation of published work (See The Effect of Open Access).