Interaction between tunnelling and bridge foundation-3D numerical investigation

This paper presents the results of three-dimensional numerical investigation on the interaction between conventional tunnelling and a pile supported bridge. A hypothetical tunnelling condition under an existing pile supported bridge was first developed with due consideration of urban tunnelling situation. Various components of the bridge including piers, piles, and pile caps are realistically modeled. Also included in the model is the pile-ground interface to simulate possible slip between the piles and the ground during tunnelling. The results of the analysis indicate that during tunnel driving, piles directly above the tunnel experience significant loss of their supporting capacity due to downward settlements of piles relative to surrounding soil. Piles further away from the tunnel however tend to experience increases in the pile load. Practical implications of the findings are discussed.