Abstract:In order to effectively calculate the stress changes of base slab and pile foundation of the bridge before and after the pile foundation underpinning construction of subway tunnel shield crossing viaduct, and ensure the smooth progress of the pile foundation underpinning project, relying on the pile foundation underpinning project of the tunnel shield of Xiamen Metro Line 6 crossing Xinglinwan Road Viaduct, combined with the characteristics of the pile foundation underpinning project and the actual situation of the engineering field, Midas/fea and MIDAS/civil are used to establish the three-dimensional numerical model and beam element model of pile foundation underpinning of the bridge to numerically calculate the pile foundation underpinning project of the bridge in the construction field. The changes in the bearing capacities of the new base slab and pile foundation during the pile foundation underpinning construction are specially analyzed. Based on this, the control measures for the construction quality of pile foundation underpinning are put forward to ensure the quality of pile foundation underpinning project, which provides the theoretical guidance and reference for the smooth construction of similar projects.