Influence due to urban tunnel excavation on ground buildings and its countermeasures

With the rapid development of urban tunnel construction, increasing attention has been paid to urban environment safety due to urban tunnel excavation in recent years because no matter what kind of construction method is adopted, it will influence environment inevitably and bring safety risks. It is inevitable to harass the stratum during the construction of urban shallow tunnels, incurring the subsidence, sloping and even crack of buildings on the ground, which will influence the safety and the routine use of buildings. Therefore, it is significant to analyze the deformation character and movement mechanism of buildings to minimize the impact on existing structures induced by tunnel construction. Based on the practice of Xiamen Airport Road Tunnel going through complex building blocks under the ground, by using in-situ measured data, numerical simulation and theoretical analysis method, the deformation mechanism of ground buildings and its failure modes are then expounded; and subsequently the control standard involving differential subsidence and crack space of buildings and the three-class management method of “early warning, warning and utmost warning” for building deformation are proposed, and the relationship between building crack space and differential subsidence is presented. By numerical simulation, the deformation of #34 house, a key to the success of this project due to shallow and large span tunnel construction, is predicted, and then the excavation method and support parameters are optimized. Finally, some countermeasures are put forward. The research results can provide references to the future construction of Xiamen Airport Road Tunnel and other similar projects such as urban tunnels and subway tunnels passing through existing structures.