Abstract To further investigate the influence of large diameter shield tunnel construction on the surrounding struc? tures, based on a large diameter shield tunnel project of a railway engineering in Chengdu, combined with the characteristics of small spacing and shallow soil crossing highway bridge and culvert, the numerical analysis method is adopted to consider the interaction between pile-soil-tunnel, and a three-dimensional finite element calculation model is established. The displacement trends of ground surface, bridge pile, pedestrian tunnel and isolation pile caused by shield tunnel construction are analyzed, The simulation results show that the excavation unloading of shield tunnel forms an obvious settlement trough on the surface, but the isolation pile can effectively block the soil deformation and reduce the surface settlement; the horizontal surface settlement curve shows a sudden change at the position of the isolation pile, and the surface settlement value before and behind the isolation pile decreases by 27% and 40-50% respectively; the vertical surface settlement curve decreases in the range of the isolation pile and shows a W-shaped distribution. The bridge pile is affected by the tunnel excavation unloading, and produces additional deformation and bending moment to the tunnel side. The value of the tunnel body range increases from the bottom to the top and then decreases, and the vertical influence range of the small diameter shield is tunnel large. At the same time, the additional deformation of the structure floor caused by the shield tunnel under the pedestrian tunnel is large, and the maximum value of settlement is 7.5 mm. The above numerical calculation results are close to the field measured results, which verifies the accuracy and feasibility of the numerical simulation results.
Abstract：
To further investigate the influence of large diameter shield tunnel construction on the surrounding struc? tures, based on a large diameter shield tunnel project of a railway engineering in Chengdu, combined with the characteristics of small spacing and shallow soil crossing highway bridge and culvert, the numerical analysis method is adopted to consider the interaction between pile-soil-tunnel, and a three-dimensional finite element calculation model is established. The displacement trends of ground surface, bridge pile, pedestrian tunnel and isolation pile caused by shield tunnel construction are analyzed, The simulation results show that the excavation unloading of shield tunnel forms an obvious settlement trough on the surface, but the isolation pile can effectively block the soil deformation and reduce the surface settlement; the horizontal surface settlement curve shows a sudden change at the position of the isolation pile, and the surface settlement value before and behind the isolation pile decreases by 27% and 40-50% respectively; the vertical surface settlement curve decreases in the range of the isolation pile and shows a W-shaped distribution. The bridge pile is affected by the tunnel excavation unloading, and produces additional deformation and bending moment to the tunnel side. The value of the tunnel body range increases from the bottom to the top and then decreases, and the vertical influence range of the small diameter shield is tunnel large. At the same time, the additional deformation of the structure floor caused by the shield tunnel under the pedestrian tunnel is large, and the maximum value of settlement is 7.5 mm. The above numerical calculation results are close to the field measured results, which verifies the accuracy and feasibility of the numerical simulation results.
ZHANG Qing1 ZHEN Wenzhan1 FENG Kun2
.Analysis of the Impact of Large Diameter Shield Tunnel Crossing Existing Expressway Bridge and Culvert[J] MODERN TUNNELLING TECHNOLOGY, 2024,V61(1): 137-145
2024, Vol. 61 