Research Of Interaction Between A New Project And Its Neighboring Existing Subway

With the rapid development of urban rail transit, more subways run through the downtown, the problems of interaction between other urban buildings and subway tunnel and during its operation are increasing. Because of less urban land, it is inevitable that more buildings have to be constructed over the existing subway structure to make full use of land resources. On the one hand, construction of new buildings can exert the significant influence on safety of nearby subway structure. On the other hand, long-period operation of subway can cause the continual vibration on the buildings. The long-term repeated influence of the loading train vibration would affect the life of the building, seriously can cause damage to the building structure, it also affects the physical and mental health of people who have been living and working in these buildings for a long period.This paper takes a large building build above the existing Beijing Subway for the first time as background to study the interaction between this building and existing subway, and the major contents studied include:(1) AN SYS is adopted to establish the three-dimensional numerical model to carry out the analog simulation of the effect of new foundation pit excavation on the subway. Based on the numerical simulation results, the corresponding measures to reinforce the pit bottom are proposed to reduce the resilience of soil mass on it and heave of tunnel. The safety of subway structure and train operation can be guaranteed.(2) ABAQUS is adopted to establish the two-dimensional model of tunnel, soil mass and upper building structure, with which to study and analyze the propagation pattern of subway vibration on the soil layer and its effect on the upper buildings. This paper proposes that the vibration isolation measures should be adopted under the foundation of new buildings. The study results show that the vibration acceleration and its magnitude on buildings have been reduced greatly after the vibration isolation measures are taken.This paper carries out the study and analysis of interaction between the new buildings and existing subway from two aspects, they are the excavation of foundation pit on heave deformation of subway, and vibration of subway train load on the upper buildings respectively, and then proposes the corresponding control measures. It can be achieved the expected effect that guarantees the safety of train operation and make the vibration of the building meet environmental standards for vibration, and it will provide the reference for design and construction of similar projects.