Safety Evaluation of Existing Tunnel Nearby Driving Pile Using Two Different Standards

Abstract

Pile driving is a complex dynamic process, which induces ground movement. The generated ground vibrations have considerable potential to damage the nearby structures and could lead to possible disturbance of building occupants. The safety of underground structures during the driven process constitutes a significant concern. In this study, two different standards were adopted to estimate the security of tunnels adjacent to the driven pile site. The continuous pile driving installation from the initial position to the final depth was executed using arbitrary Lagrangian–Eulerian (ALE) adaptive mesh and element deletion methods. Through the elimination of all the simplified hypothesis and the adoption of a three-dimensional model, consistent results compared to field monitoring were obtained. The damage of the adjacent tunnels during the driven pile was evaluated in terms of three criteria, peak particle velocity and distance (Swiss code) and displacement limitations (Chinese code). The effects of tunnel depths (H) relative to pile length (L) were investigated by driving the pile near the tunnel axis and next to and below the pile toe. The results indicated that the peak particle velocity limit value criterion could be adopted for the safety evaluation of an existing structure during pile driving. However, the maximum allowable radial distance from the existing structures to the pile centerline is not always an acceptable criterion to justify the safety of existing structures neighboring the driven pile site. A peak vertical velocity is a convenient approach that can result in a reasonable evaluation of the peak particle velocity.