Research on the Mechanical Response of Shield Side–Crossing Construction on Surrounding Rocks and Existing Bridges

To investigate the mechanical response of surrounding rocks and existing bridges during shield tunnel construction, this study relied on the Guangzhou Electric Power Shield Tunnel Project. The 1g scaling test and numerical analysis method are employed to examine the variation patterns of surface settlement, surrounding rock pressure, pile displacement, and internal force during the shield tunnel construction, considering the two key factors: the longitudinal slope angle of the tunnel axis and the horizontal distance between the pile and the tunnel. The results signify that the width of the surface settlement trough on the pile side decreases under the influence of the existing pile foundation. The relationship between the maximum surface settlement caused by construction and the tunnel's longitudinal slope angle follows an approximately exponential function. The primary area affected by the construction extends from −2 to 4 times the diameter of the tunnel excavation on both sides of the pile cap. Additionally, the displacement of the pile cap caused by tunnel construction increases. As the shield tunneling transitions from uphill to downhill excavation, the settlement displacement of the pile cap induced by the tunnel construction also increases.