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Geomechanics and Engineering
  Volume 36, Number 2, January25 2024 , pages 131-143
DOI: https://doi.org/10.12989/gae.2024.36.2.131
 


Pipeline deformation caused by double curved shield tunnel in soil-rock composite stratum
Ning Jiao, Xing Wan, Jianwen Ding, Sai Zhang and Jinyu Liu

 
Abstract
    Shield tunneling construction commonly crosses underground pipelines in urban areas, resulting in soil loss and followed deformation of grounds and pipelines nearby, which may threaten the safe operation of shield tunneling. This paper investigated the pipeline deformation caused by double curved shield tunnels in soil-rock composite stratum in Nanjing, China. The stratum settlement equation was modified to consider the double shield tunneling. Moreover, a three dimensional finite element model was established to explore the effects of hard-layer ratio, tunnel curvature radius, pipeline buried depth and other influencing factors. The results indicate the subsequent shield tunnel would cause secondary disturbance to the soil around the preceding tunnel, resulting in increased pipeline and ground surface settlement above the preceding tunnel. The settlement and stress of the pipeline increased gradually as buried depth of the pipeline increased or the hard-layer ratio (the ratio of hard-rock layer thickness to shield tunnel diameter within the range of the tunnel face) decreased. The modified settlement calculation equation was consistent with the measured data, which can be applied to the settlement calculation of ground surface and pipeline settlement. The modified coefficients a and b ranged from 0.45 to 0.95 and 0.90 to 1.25, respectively. Moreover, the hard-layer ratio had the most significant influence on the pipeline settlement, but the tunnel curvature radius and the included angle between pipeline and tunnel axis played a dominant role in the scope of the pipeline settlement deformation.
 
Key Words
    double curved shield tunneling; field monitoring; numerical simulation; pipeline deformation; soil-rock composite stratum
 
Address
Ning Jiao, Xing Wan, Jianwen Ding, Sai Zhang and Jinyu Liu: Institute of Geotechnical Engineering, School of Transportation, Southeast University,
No.2, Southeast Road, Jiangning District, Nanjing, 211189, China
 

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