Influences on surface structure induced by shield tunneling in Tianjin soft ground area

According to the construction of Tianjin Metro Line 2 passing under a masonry building, the finite element model is established to analyze the influence of tunneling on the ground surface and the surface masonry buildings. The calculated results which adopt the small-strain constitutive model are compared with the field measured data. The results are also compared with the conclusions obtained by the hardening soil constitutive model. The further analysis shows that both the maximum settlement and the width of traverse settlement trough predicted by small-strain model achieved better agreement with the practical project. And both the maximum settlement and the width of traverse settlement trough obtained by the hardening soil model are larger than the results obtained by the small-strain constitutive model. During the tunnel construction, the masonry building tilts to the axis of the tunnel. The rate of inclination obtained by the small-strain model can also consistent with the field data. Therefore, the small strain response of soil should be taken into account during the settlement investigation of buildings and ground surface induced by shield tunneling.