Earthquake Dynamic Response Analyses Of Soil-underground Structure And Influence Of Different Site Conditions

Metro is an important way to solve the urban traffic congestion, and the subwaystation is also a public space of great population density, It’s security and stability isdirectly related to the safety of human life and property. A large number of earthquakedamage data indicates that underground structures are not always safe under the action ofstrong earthquake, underground structures seismic performance becomes an importantissue of the city of Earthquake Engineering and disaster prevention and mitigation withmore and more construction of large-scale subway, so it is necessary to study the law ofunderground structure seismic response and soil-underground structure dynamicinteraction. In this paper, in order to analyse the soil-underground structure of seismicdynamic response law, vibration table test of soil-subway structure interaction areconducted in two conditions, including full clay site condition and containing sandinterlayer site condition. Then based on metro station shaking table test, establishingnumerical models to simulate the soil-subway underground structure dynamicinteraction,it provides some conclusions for the optimization and design of subwayunderground structures. The main tasks are as follows:(1) Large vibration table model tests of soil-underground structure interaction areconducted, including subway station model test in simple clay site and subway stationmodel test in containing sand interlayer site. The law of seisimic dynamic response ofstructure and surrounding soil is studied, including the variation of acceleration peakvalue about the different site surface points and points along the depth, includingvariation of Fourier frequency-amplitude spectrum in different depths and differentvibration input conditions, the strain response of underground structures, but also toexplore the pore water pressure in the containing sand interlayer site.(2) Elaborated two constitutive relationship models of soil in detail. Add amulti-layer soil static Duncan Chang EB constitutetive relationship and power equivalentnonlinear viscoelastic model constitutive relationship model for MSC.Marc secondarydevelopment, and one example verified the effection and reliability of the developmentprocess.(3) Finite element model of the soil-underground structure dynamic interaction isestablished by using MSC.Marc. The parameters used finite element is verified accurate by comparison between the clay site soil-underground structure numerical simulation andexperimental results, while also proved the reliability of the shaking table test; explorethe response of soil-underground structure of four different site conditions, including theupper part of the structure with soft soil sandwich, the lower part of the structure withsoft soil sandwich, shallow buried underground structures, deeper buried undergroundstructures. After comparative analysis, prove that more shallow the underground buried,more intense seismic response of the underground structure and the soft soil surroundingit, which also prove that sandwich of soft soil under strong earthquake have an isolationeffect.