Disturbance Deformation Influence and Field Measurement Study of Metro Shield Under-passing High Building Foundation

Abstract

Objective With an increasing number of cases involving metro shield tunneling through or in proximity to high buildings in urban rail transit projects, the shield tunneling method inevitably causes disturbances to the ground due to its unique construction process. In several cases, it may impact the structural safety of existing buildings. Therefore, an in-depth study of the force characteristics on both the tunnel and high buildings during shield tunneling is necessary. Method Leveraging the tunnel construction project of Shengchan Road Sta.-Lihuang Road Sta. interval on Jinan Metro Line R2, a 3D finite element numerical method is employed to simulate the construction process of double-line shield tunnels asynchronous oblique angle under-passing a group of high buildings with pile and raft foundations. Combining with field-monitored data, the law of ground displacement, deformation characteristics of building settlements, and the control effectiveness of shield tunneling parameters during construction are analyzed. Result & Conclusion When the double-line shield tunnels successively pass beneath the building pile group, the land subsidence caused by leading tunnel excavation is relatively significant, while the disturbance to the ground from subsequent tunnel excavation is relatively small. The maximum subsidence occurs when the shield tunnel is directly beneath the building, and as the shield tunnel moves away, the subsidence gradually decreases and tends to stabilize. Due to the framed structure of the high buildings, partial subsidence occurres on the building area adjacent to the tunnel side, while the part far away from tunnel exhibits an upheaving trend. However, the differences in subsidence amount between the two scenarios remain within a manageable range.

Keywords

• metro
• shield tunnel
• under-passing pile group
• stratum deformation characteristics
• numerical simulation