Study On The Impacts Of Existing Buildings By Urban Tunnel Construction And Its Safety Controlling

During the process of urban tunnel construction, passing through or closing to the dense existing buildings can hardly be avoided. Furthermore, these groups of buildings are often so dilapidated with reduced structural strength that can’t resistance the tunnel construction disturbance. In this process, there will be great impacts on the safety and use of these buildings. Therefore, it is very significant to carry out the study on the impact of existing buildings by urban tunnel construction and its safety controlling.In this paper, on the basis of extensive research on domestic and foreign literature, taking JC3tenders in the first phrase of Chenggong Road Project in Xiamen as an example, the research on impacts of existing buildings by urban tunnel construction and its safety controlling is implemented deeply by combining method of theoretical studies, numerical simulation, on-site monitoring data analysis and fuzzy comprehensive evaluation. The main contents and results are as follows:(1) The idea of comprehensive effect by tunnel-soil-superstructure is set up according to the principle of soil-foundation-superstructure in construction engineering. With the application of ABAQUS, a3D model is established to simulate the construction of tunnel so as to analyze the rules of surface deformation law and their similarities and differences in the circumstance that the buildings are above the tunnel as well as that is on the inflect point and the edge of surface settlement trough caused by tunnel construction. The results indicate that there are close relationships between building’s deformation and their distance to tunnel.(2) On the basis of measured data from JC3tenders in the first phrase of Chenggong Road Project in Xiamen, the settling rules on surface and its buildings are analyzed according to the different conditions of tunnel construction methods, the difference on settlements between the building and the closed surface is comparatively studied so as to discuss the distinctions on surface settlement with and without the buildings. The results indicate that the surface and building settlement are different by the different tunnel construction method. The duration on tunnel construction affects the surface and building settlement tremendously also with the restraint from closed buildings. (3) Stratum deformation and movement and its damage to buildings caused by tunnel construction are analyzed which concludes that the three-stage evaluation method is the most effective evaluation method. On the basis of comprehensive analysis of various domestic and international building safety control standards, applicable building safety control indicators set up, and the value of the project control indicators and control standards of key tunnel construction steps are determined according to the JC3tenders in the first phrase of Chenggong Road Project in Xiamen by simulation and measured data, which guide the site construction and ensure the safety of the project and its surroundings.(4) Through the comparative analysis of methods to existing buildings reliability, fuzzy comprehensive evaluation method is a feasible and effective way. Contrasting with static and one-sidedness defects of the traditional existing buildings reliability evaluation method, fuzzy comprehensive evaluation considers the building of its own characteristics, the characteristics of the tunnel project, on-site monitoring results and other factors, which can help to ensure the follow-up tunnel construction program targeted to take the building security measures. The method applied to the JC3tenders in the first phrase of Chenggong Road Project in Xiamen and achieved good results, which proves that this method can effectively, quickly and accurately determine the security status of the building with a good prospect of application.