Numerical Impact Assessment of Axially Loaded Piles and Their Seismic Effects on an Existing Bored Subway Tunnel - NAT2024

Transportation tunnels are highly sensitive to ground movements and are required to be stable and secure for safe operation. In urban areas, the interaction between tunnels and adjacent piles, which are widely used to support buildings and other structures, requires careful consideration. The seismic response of tunnels may vary depending on the lateral stiffness and strength of the tunnel walls, while the axial loading and seismic impact of adjacent piles may cause soil displacement and stress changes that can damage the tunnel lining. As a result, tunnel owners often impose strict limits on the design of new piles lying close to existing tunnels including maximum allowable tunnel deformation, stress change limits, and minimum tunnel to pile separation distances. This paper describes a numerical analysis of the in􀃀uence of the axial loading and seismic impact of bored pile foundations on subway tunnels, underta􀁎en using the 􀂿nite element software 􀀳laxis 􀀖D. 􀀥ased on the results of the numerical analysis, the paper suggests a more realistic and less conservative approach for designing piles in close proximity to transportation tunnels. INTRODUCTION The interaction between tunnels and adjacent piles can cause stress changes and displacements in the soil and structures which may adversely impact structural performance and tunnel safety. It is therefore important to take account of relative load transfer and piling con􀂿guration when designing new piles in