Interaction between tunneling and bridge foundation – A 3D numerical investigation

This paper presents the results of a three-dimensional numerical investigation into the interaction between conventional tunneling and a pile supported bridge. Hypothetical tunneling conditions under an existing pile supported bridge were first developed in consideration of an actual urban tunneling situation. Various components of the bridge, including piers, piles, and pile caps have been replicated from the areas in question within this model. Also included in the model is the pile-ground interface to allow for possible slip between the piles and the ground during tunneling. The results of the analysis indicate that during tunnel driving, piles directly above the tunnel can experience significant losses in their shaft loads due to downward settlements of piles relative to surrounding soils. Piles within the same system, but farther away from the tunnel tend to experience slight increases in the pile loads. Practical implications of the findings are discussed.