Measurement and numerical analysis of effect of excavation of foundation pits on metro tunnels

With the rapid development of underground space in large cities in recent years, the design of foundation pits of underground space in urban areas should focus on their safety, especially on their influence on the adjacent buildings. Therefore, it needs to consider the foundation pit and the environment as a whole during design. On the basis of the summary of control standards and protection techniques of metro engineering, taking a deep foundation pit near the metro tunnel in Guangzhou as an example, the effect of its excavation on the metro tunnel is synthetically analyzed through numerical simulation and measurement. The measured results show that excavation doses not always have unloading effect on the tunnel, sometimes, it will increase the confining pressure on the tunnel. The influence relates to the depth of excavation and the site of the tunnel as well as the construction method of supporting structure for the foundation pit. Thus, the actual mechanical transmission path should be considered to determine the unloading or loading influence. The numerical results are close to the measured ones, indicating that the boundary conditions and computational parameters of the numerical model are compared with the actual working conditions. The achievements may provide beneficial reference for the optimal design, construction and similar projects.