Analysis Of The Seismic Response Of Two Horizontally Contacted Underground Structures

In order to meet the needs of urban development, in recent years, subway construction is developed rapidly, which leads to urban underground space is becoming increasingly tense. The phenomena that underground structures next to each other are increasing cause many uncertain factors on the underground structure seismic safety. In addition, the research of underground structure seismic is insufficient, there is still no a independent codes of underground structure seismic. Therefore, it is quite necessary to study the characteristics of response of adjacent underground structures to earthquakes.In this paper, the seismic response of two horizontally contacted underground structures, a subway station structure to be constructed, and a road tunnel structure immediately beneath, is simulated by using the finite element software MIDAS-GTS. The major studies and achievements in this thesis are as following:1. In order to study the reasonable range of the finite element model, the different calculation models are analyzed comparatively, calculations show that the width of seven times the underground structure in the visco-elastic boundary conditions for the reasonable calculation of the model.2. The seismic response of road tunnel structure with or without subway station structure is calculated, and displacement time history, acceleration time history and the Mises stress of road tunnel are analyzed comparatively. Research shows that new subway station structure exists will influence the seismic response of road tunnel structure, and endanger the road tunnel structure seismic safety.3. In addition, the influence of the contact properties of the horizontal interface between the two structures on the seismic response of the road tunnel structure is also studied, the shear stiffness of the interface between the two structures acts as the major factor of influence to the seismic response of the road tunnel structure, and with the increase of the contact shear stiffness, the dynamic stress of the tunnel base slab within the bounds of the interface is reduced, but the dynamic stresses of the tunnel base slab on both sides of the interface are increased significantly.4. The seismic response of road tunnel structure in different distance between subway station structure and road tunnel structure is studied. As the distance between two structures increase, the effect of the subway station structure on the road tunnel structure seismic response decrease, but when the two underground-structures contact immediately, the influence of the metro station structure buried depth on the seismic response of the road tunnel structure is most remarkable.5. The study of the influence of seismic wave incident angles on the seismic response of the road tunnel structure is performed. The tunnel structure dynamic stress maximum in wave inclined incidence conditions larger than that in wave normal incidence. Therefore, if only consider the normal incident seismic wave in practice design, the structure is unsafe.