A simplified 3D model for existing tunnel response to piles construction

Abstract

The construction and loading of deep foundations (piles) of high-rise buildings causes a considerable effect in terms of stresses and deformation and requires assessing their impact on the response of adjacent tunnels to deformations, particularly for pile foundations, which are often constructed in locations very close to existing tunnels. The execution process for piles structures generates displacements, stresses, and forces, which are transferred through the piles’ soil surrounding a nearby existing tunnel. The research presented in this paper has led to a significantly improved understanding of pile-tunnel interaction problem. It is crucial for the analysis of the impact of the pile construction on an existing tunnel. The treated topic appears in a setting of an urban environment, where we construct numerous profound foundations, sometimes in contact or adjacent to a. In this paper, the response of the existing tunnel under constructed pile process is studied. Numerical modeling was carried out using Plaxis3D software in which the Mohr-Coulomb Model (MC) has been used for modeling, while the piles/ tunnels are modeled as a linear elastic material. Furthermore, a parametric study is conducted, and its cases are investigated. The displacements and the stresses generated on the tunnel lining decreases with the increase in relative distance between pile and tunnel (spacing), the location/length of the pile from the tunnel, the pile diameter, the number of piles. We have also identified two geometrical parameters of the tunnel: shape section and thickness lining which play a prominent role in the interaction between an existing tunnel and a new pile to excavate.

Keywords

• tunnel
• piles
• mohr-coulomb model
• movements
• finite element analyses