Analysis Of Foundation Vertical Vibration On A Variational Shear Modulus Elastic Half-space And Experimental Study Of Soil Dynamic Property

An integral representation for displacements of a circular footing vibrating vertically with a linear wave velocity on a elastic half-space whose shear modulus changes non-linearly with depth was presented by analysis, dynamic triaxial test on dynamic modulus and damping ratio of soils was also carried out.Soil-structure dynamic interaction is a objective phenomenon.While analyzing the soil-structure dynamic interaction, ti is of first importance to build the translation relationship between the vibration of site and structure.It is a effective way to focus on the analysis of the force and movment of the foundation while building that relationship. In this way the foundation will be effected by the vibration force of the structure. All this force will be formulated with movement of the underside of foundation.so ti is the principal step to confirm the movement of the underside of foundation., sequentially confirm the rigid of foundation.Once the rigid of foundation is found, it can be the reference of the integer movement equation.Otherwise,the meaning of dynamic rigid of foundation to danamic machine foundation is obviously.Based on the research and the practical datum, a site model is presented that the shear modulus is distributed exponentially increasing with depth. The method of integral transform has been introduced for the analysis of a circular footing vibrating vertically with a linear wave velocity on a elastic half-space whose shear modulus changes non-linearly with depth.The dynamic problem could be formulated as a set of dual integral equations. An integral representation for displacements was presented by analysis. The representation can be used to numerical analysis and theory reference. Furthermore, the curve of frequence and response is presented.In dynamic analysis it is important to make clear dynamic behavior of site soils, of which the parameters are necessary for theoretical analysis and numerical analysis. Then one of the problems in the project is how to determine the parameters and their regularity using the test equipments. Therefore dynamic triaxial test is conducted to determine the dynamic modulus and damping ratio of silty clay of the site, where a model test about soil-foundation-structure dynamic interaction will be done. Because the relationship curves of dynamic stress and dynamic strain from the test are approximately hyperbolic, the silty clay regarded as a vis-coelastic body is studied by mears of an equivalent linear model. After two affect-ting factors of consolidation ratio and lateral pressure being studied, the empirical formulas of maximum shear modulus, dynamic modulus and damping ratio are suggested for being applied in theoretic analysis and practical engineering and also supplying the essential parameters for analysis of the seismic response of sites and soil-structure dynamic interaction.