Shaking table experiments on seismic response of a shield-enlarge-dig type subway station structure in liquefiable ground
AN Junhai1，2，TAO Lianjin1，2，WANG Huanjie1，2，LI Jidong3
(1. Key Laboratory of Urban Security and Disaster Engineering of Ministry of Education，Beijing University of Technology，Beijing 100124，China；2. Center of Cooperative Innovation for Beijing Metropolitan Transportation，Beijing 100124，China；3. China State Construction Technical Center，Beijing 101300，China)
Abstract：A shaking table experiment was conducted on a shield-enlarge-dig type structure in liquefiable ground subjected to the near and far field earthquakes respectively. The lateral deformation，the pore pressure ratio，the earth pressure of soil foundation，the accelerations of soil and structure and the strains of structure of subway station were analyzed. The results showed that liquefiable foundation experienced two physical process in earthquake，the loose sand compacted firstly and then moved upwardly. There were phenomena of sand erupting and water oozing in large area after the high intensity earthquake. The shear deformation occurred in the lateral side of the soil and the peak displacements swing left and right asymmetrically. The acceleration amplification factor of soil foundation increased gradually from the bottom to the surface when the small earthquake(peak acceleration was 0.1 g and 0.2 g) was input while it showed an increasing trend when a moderate or strong earthquake was input from the shaking table. A notable phenomenon of high frequency filtering and low frequency amplification appeared in the process of seismic wave propagation from the bottom to the surface of soil. The pore water pressure experienced mainly two stages，the pore water pressure increased slowly at first， rose sharply then at the second stage. The existence of the underground structure has an inhibitory effect on the growth of the pore water pressure of foundation. The earth pressure increased and the structure itself in the elastic state entered into the plastic state gradually with the increase of input vibration intensity. The difference between the upper and lower ground pressures of the underground structure was the intrinsic factor that caused the model structure to generate an upward movement. The earthquake damage of the underground subway station of shield-enlarge-dig type in liquefiable ground experienced three stages：firstly，a shear failure occurred on the column and a damage on the opening position and spandrel of the tunnel；secondly，the connection parts of the side wall and roof had the tensile damage；finally，the underground structure collapsed.
安军海1，2，陶连金1，2，王焕杰1，2，李积栋3. 可液化场地下盾构扩挖地铁车站结构地震破坏机制振动台试验[J]. 岩石力学与工程学报, 2017, 36(8): 2018-2030.
AN Junhai1，2，TAO Lianjin1，2，WANG Huanjie1，2，LI Jidong3. Shaking table experiments on seismic response of a shield-enlarge-dig type subway station structure in liquefiable ground. , 2017, 36(8): 2018-2030.
孙海峰. 地下结构地震破坏机制研究[博士学位论文][D]. 廊坊：中国地震局工程力学研究所，2011.(SUN Haifeng. Study on earthquake damage mechanism of underground structures[Ph. D. Thesis][D]. Langfang：Institute of Engineering Mechanics，China Earthquake Administration China，2011.(in Chinese))
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