Rock and Soil Mechanics ›› 2021, Vol. 42 ›› Issue (1): 233-244.doi: 10.16285/j.rsm.2020.5763

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Field measurement and numerical analysis for evaluating longitudinal settlement induced by shield tunneling parallel to building

DAI Xuan1, GUO Wang2, CHENG Xue-song3, HUO Hai-feng1, LIU Guo-guang1   

  1. 1. College of Airport Engineering, Civil Aviation University of China, Tianjin 300300, China 2. Tianjin Municipal Engineering Design and Research Institute, Tianjin 300392, China 3. MOE Key Laboratory of Coast Civil Structure Safety, Tianjin University, Tianjin 300072, China
  • Online:2021-01-11 Published:2021-05-26
  • About author:DAI Xuan, male, born in 1988, PhD, Lecturer, mainly engaged in teaching and research in geotechnical engineering.
  • Supported by:
    the National Natural Science Foundation of China (51808548), the Fundamental Research Funds for the Central Universities (3122018C017) and the Tianjin Technical Expert Project (20YDTPJC00750).

Abstract: The transverse settlement induced by the construction of a parallel shield tunnel alongside the building has raised considerable attention, whereas few studies focus on the longitudinal settlement. Therefore, the spatial deformation of ground developed from this tunneling form is investigated. In this study, some field measurements from the shield tunnel section of Tianjin Metro Line 6 parallel to four similar masonry buildings in vicinity are analyzed first, and the deformation pattern is established. Then, a hardening soil model calibrated against field measurement, considering small strain stiffness, is implemented in a three-dimension finite element simulation to evaluate the longitudinal deflection of the buildings, the ground deformation, and the soil stress distribution. Additionally, the effect of building aspect ratio is discussed. The simulation results show that tunneling-induced sagging deformation develops along the longitudinal direction of the building, and the settlement at the middle of a longitudinal wall is twice of that at the corners. Therefore, the study of tunneling parallel to buildings cannot be simplified to a plane strain problem. The building construction and tunneling activity result in the soil above the tunnel crown experiencing a complicated stress history, which can be divided into six stages. In longitudinal direction, compared with the part below the building foundation corners, the soil in the middle initially behaves larger compressive deformation due to building construction, followed by greater unloading deformation caused by tunnel excavation. In addition, the longitudinal sagging is significantly reduced for the buildings with aspect ratio less than 2.

Key words: shield tunneling, parallel tunneling, building settlement, finite element method (FEM), HS-Small model