Vibration response law of existing buildings affected by subway tunnel boring machine excavation

摘要

Excavation of urban subway tunnels through hard rock can induce strong vibration waves, particularly in the soil layer and existing building infrastructure. Such vibrations affect the structural stability of buildings and the safety of occupants. The main factors influencing the transmission of vibration energy produced by tunnel excavation include the engineering properties of the geotechnical medium, tunnel depth, and type of building foundation. In this study, the vibration acceleration and structural stress of existing buildings during tunnel boring machine (TBM) excavation were investigated via numerical simulation using the case of Qingdao Metro Line 1. First, the segment on-site vibration was monitored, and the impact area was evaluated. Then, a three-dimensional fully coupled dynamic model (3DFCDM) of tunnel-hard rock-building was established. Thereafter, the most destructive acceleration obtained from the on-site vibration monitoring was taken as the external load in predicting the building vibrations using the model. Then, various building foundation types and horizontal distances from the tunnel were established to analyze their effects, and relevant vibration control standards were adopted. Subsequently, the ground vibration response was analyzed and the numerical results were compared with the on-site monitoring data to verify its accuracy. The results showed that the main impact distance of the segment vibration caused by hard rock tunnel construction was approximately 9 m. Parametric analysis indicated that excavation of hard rock tunnels may cause building vibrations to exceed the standard limit, and buildings with different foundation types have different sensitivities to such vibrations. Additionally, the existence of buildings on the ground affects the transmission of surface waves and suppresses vibration.