Testing Study Of The Unsaturated Sandy Soil Mechanics Characteristic And Its Interaction With Structure Analysis

China is one of those countries that suffer from the disaster of earthquake. Withthe rapid development of society, social wealth and concentration of population, lossresulting from earthquake disasters increases greatly. Consequently, more and moreresearchers gradually realized that it is necessary to take the interaction betweenupper structure and foundation into consideration during the design process. Thisthesis focus on the mechanism performance of the soil under seismic action, Soil-Structure Interaction(referred to SSI). By a series of indoor one-way shear anddynamic cyclic simple shear tests, the static and dynamic characteristics of soil aredeeply studied. At the same time, a1/4large scale bridge pier model’s test areconducted. By this prototype, two finite element models considering the rigidfoundation and the pile-soil-pier interaction under the effect of two kinds of seismicrecords are established. We hope that based on the theoretical analysis andexperimental studies we can have an intimate knowledge about the mechanicalproperty and SSI problem. This thesis is divided into four chapters and the contents asfollows:1.Research situation and level of development at home and abroad ofsoil-structure interaction are summarized. The advantages and the disadvantages ofachievements are described. On this basis, research methods and mentality of thisproblem are proposed in this thesis.2.In order to specializing the influence of moisture content and consolidationpressure on mechanical characteristics of unsaturated soil, a series of one-way andcyclic shear tests are conducted. The regularity of the influence of moisture contentand consolidation pressure on mechanical characteristics of unsaturated soil aresummarized. And the static and dynamic parameters of unsaturated soil in experimentsite are obtained, which will lay a foundation for the following finite elementanalysis.3.Experimental research for contact nonlinear mechanics performance of theinterface of unsaturated soil and steel plate are conducted. And the effects of theroughness and normal pressure of the contact surface on mechanical behaviors arethoroughly studied.4.two bridge pier model tests are conducted, the seismic performance of Pile-Soil-Pier interaction system and bridge pier with completely rigid foundationunder near-field earthquake effect are studied separately, including hystereticproperties of the pier, skeleton curves and so on.Based on the bridge pier model test,two finite element models considering the rigid foundation and the pile-soil-pierinteraction under the effect of two kinds of seismic records are established throughABAQUS finite element analysis software. Based on the contrasting analysis of thesetwo models, the seismic performance of Pile-Soil-Pier interaction system isinvestigated through the displacement, acceleration of pier pillars, and stress of thebottom of the pier.