Abstract: The behavior of a tunnel and the underground structure above it are considered as an integral system in this paper. The effect of the tunnel underpass excavation on the ground settlement as well as the stress in the above underground structure is analyzed. The mitigations of the ground settlement and the increased buoyancy induced by the tunnel excavation are also presented in the paper.  The induced ground settlement can be minimized by the increased steel support frames and through the construction optimization. The increased buoyancy can be counterbalanced by the ground anchors that welded to the steel support frames. The construction monitoring results indicate that the numerical analysis predicted ground settlement magnitude is reasonable and the increased supporting frames and the optimized construction have a significant impact on the ground settlement reduction. The ground anchors can improve the buoyancy capacity of the underground structure.

Key words:  , Underpass Tunnels； Settlement Control； Buoyant Mitigations； Settlement Monitoring