Research On Seismic Behavior Of Huge Underground Structure For Urban Underground Space Development

Since the begin of 21 century, with the sustained and rapid development of economic, and the continuing expansion of urban construction scale in our country, the number and growth of urban underground spaces have been rapid developed. To develop and utilize urban underground will be the only way for sustainable development and function of cities. The reasonable exploitation and utilization of urban underground space, that has attracted the whole society's attention.Historical earthquake damages showed that, once the underground structure was destroyed in earthquake, it would be very difficult for the work of earthquake emergency and post-earthquake recovery, such as Kobe earthquake in 1995. On the other hand, China is a multi-earthquake-prone country, with earthquakes widely distributed, and there were multiple strong earthquakes in history, such as Tangshan earthquake in 1976 and Wenchuan earthquake in 2008. So we should pay attention to research on seismic behavior of huge underground structure for urban underground space development.Because underground structure is completely buried deep in soil, soil-structure interaction will be affect the dynamic response of underground structure, which shows obviously different seismic behavior of underground structure and ground structure. This thesis dealed with Construction Ministry's scientific research project"Research and Application on the Key Technologies of the Underground Space of Zhujiang Newtown Core". It focuses on the research of large underground structure space of Zhujiang Newtown Core, and presents a three- dimensional finite element model. The main work of this paper are as follows:(1) Based on the conclusion of common structural form and function characteristics of underground structure, it analyzes the function characteristics and structural new technology adopted in Zhujiang Newtown Core.(2) Considering the effect of soil-structure interaction on structure dynamic response characteristics, it adopts viscoelastic soil spring to simulate the impact of foundation soil on underground structure, and builds a three-dimension dynamic model, and carries out the elastic-plastic analysis of large underground structure on shallow buried soft soil field. This paper mainly researches on the dynamic characteristics of underground structure under an earthquake. It calculates the horizontal relative displacement responses, inter-story shear magnitude and the overall structural damage status of understructure, and analyzes the change rule of relative displacement of underground structure roof.(3) Using software "MIDAS/Gen", considering different supporting conditions of underground structure, with and without considering the soil-structure interaction, we compared the calculated results of this mode to the calculated results which considered soil-structure interaction, analyzing the different reasons of seismic behavior between underground structure and superstructure. (4) Considering different soil material parameters, structure burial depths, floor slab thicknesses(stiffness) of underground structure, this paper analyzes the influence of structure burial depth and floor slab thickness (stiffness) on seismic responses of underground structure. Finally some advices for structure seismic optimal design of city underground structure are given.