Research On Seismic Response Of Underground Structures And Its Interacton With Ground Building

The earthquake damage record in the history has showed that if underground construction were destroyed during the earthquake, the earthquake emergency and the post-earthquake repair will subject to great difficulties. In 1995, the Daikai subway station was severely damaged in Kobe in Japan, after which people gradually realized that the anti-seismic performance of underground construction was not as good as being expected. At present, the subway construction has entered the golden era and become an important part of urban lifeline in China, then its anti-seismic problems have also become an important content of city anti-seismic engineering and earthquake preparedness and disaster reduction research. Most subway stations locate close to bustling business districts, venues area and residential area, so there have be existed some structures near the subway station. Because of the existing of large subway station, wave propagation will be changed by scattering and reflection produced when waves pass though the structure interface, so the seismic response of adjacent ground surface building will be influenced; the foundation will be disturbed by wave field and additional stress field caused by vibration of the surface buildings, therefore, the seismic response of the underground structures will also be changed. Therefore, in the dissertation, seismic response characteristics of underground station is studied, and characteristics of dynamic mutual disturbance between underground structures and surface building is also looked into systematically. The major studies are as follows:(1)Firstly, the dynamic nonlinear viscoelastic model, whose skeleton curves is simulated by Davidenkov model, is used to model the characteristics of soils under cyclic loading, and the dynamic plastic damaged model of concrete is selected to model the characteristics of subway station. The dynamic nonlinear viscoelastic model of soil is not built in ABAQUS, so it is developed and incorporated in ABAQUS through its user-supplied subroutines, and the parameters of the model are fitted with differential evolution algorithm. Lastly, single-point seismic wave is generated based on theory of phase spectrum.(2)The two-storey-three-span-island shaped subway station is selected as the research object, and the shaped station is often used in subway construction. Nonlinear seismic response analysis of the subway station is performed subjected to different seismic waves, and response results of station are given, the results include relative displacement, horizontal acceleration, response spectrum and the internal force. The characteristics and laws of subway station seismic response are summarized. Simultaneously, the influence of the factors on seismic response of subway station is looked into, which include characteristics of contact interfaces, soil stiffness and embedded depth.(3)A systematic study of the influence of underground station structures on seismic response of nearby ground building is performed. Firstly, the effect underground space excavation to ground motion of free field in uniform homogeneous elastic space is studied, and the variation law of acceleration at the ground surface points of free field is given. Secondly, the effect underground subway station to seismic response of adjacent ground buildings in three different fields is researched. Thirdly, Assuming the surrounding ground is layered and non-linear, the effect of underground structures to adjacent buildings is studied. Lastly, the influence of the factors on seismic response of adjacent buildings is studied, which include vibration characteristics of building, relative distance, soil stiffness and embedded depth of station., and influence law is summarized.(4)A systematic study of the influence of nearby buildings on seismic response of underground station is carried out. Firstly, the non-linear interaction finite element model is set up, which are composed of nearby buildings, soil and underground structures. The seismic response change of underground station is studied for two cases whether ground nearby buildings exist. Lastly, effect of the factors to seismic response of underground station is also looked into, which include vibration characteristics of building, spectral characteristics of seismic waves, relative distance and soil stiffness, and influence law is also summarized(5)Seismic response of the large space underground station subjected to spatially non-uniform seismic ground motion is analyzed. Firstly, Procedures for artificial simulation of multi-point seismic acceleration histories with consideration of spatially non-uniform seismic ground motion are demonstrated based on code response spectrum in detail. Secondly, seismic response of the three-dimensional model of underground station under spatially uniform and non-uniform ground motion are carried out for three site cases, and the results containing relative displacement and shear force of side wall are given. Lastly, the effect of acceleration peak is studied.(6)According to the difference between blast loading and earthquake, the dynamic response of underground station under blast loading is analyzed. Firstly, a simplified model of overpressure loading in subway station is proposed, and the improved dynamic cam-clay model of soil and the concrete damaged plasticity constitutive model are used for the dynamic analysis of subway station subjected to the simplified loading. Meanwhile, the dynamic response analysis of subway station under surface explosion and measured explosion seismic wave are carried out, respectively.