Effect of Piled Structures on the Tunnel Stability for Different Pile-Tunnel Configurations

Abstract

In view of the rapid pace of urbanization, the demand to enhance the capacity of existing transportation infrastructure and construction of alternative modes of transport is escalating. In the recent pursuit of metro trains in India, the focus toward the construction of underground tunnels has substantially increased. The construction of infrastructure on the ground surface is still growing and may potentially influence the stability of tunnel passing underneath it. The situation may become worse when the structure is to be constructed on deep foundation like piles or wells. In terms of sustainable development, it is of paramount importance to understand the influence of piled structures on the tunnel lining in terms of location and load of pile and pile-tunnel configuration in different subsoil profiles. The present study aims to investigate the effect of the piled structure on stability of the tunnel and the surrounding soil. The 2D multiplier elastoplastic analysis has been carried out using the popular Mohr-Coulomb material model on the commercial finite element-based software OptumG2. The stresses on tunnel lining and the surrounding soil mass have been analyzed under different pile-tunnel configurations under varying load and pile eccentricity with respect to the axis of tunnel. Also, a parametric study has been done to evaluate the displacement and stress distribution of surrounding soils and tunnel lining under increasing pile load, length, and different pile-tunnel placements.