| In this Ph D dissertation, the granular dynamic effect and fractal characteristic under vibration are studied systematically. The research work is supported by the National Natural Science Foundation of China. The principal item is to study on the propagation and mechanism of elastic wave in the granular media. This dissertation focuses on the granular dynamic effect under vibration, especially, the wave effect. The granular dynamic characteristic, liquefaction property, wave law, vibrating aided flow, vibrating drag reduction, vibrating aided filtration and fractal behavior are studied in detail and in depth. The following are the main research findings:(1) Utilizing the DSA-1 type vibration direct shearing apparatus, the granular dynamic parameters, such as the dynamic shearing strength τ, the cohesion C, and the angle of internal friction ψ have been identified. Moreover, the experimental researches on the factors that will affect the granular dynamic shearing strength, such as the amplitude, the frequency, the moisture content, the excitation method, the vibration velocity, the granular size and the granular flowability, are well experimented.(2) Based on the experiments, the granular dynamic characteristic is studied.The granular dynamic stress-strain relation under the dynamic load is analyzed. The related properties of the granular dynamic strength and the relation between the dynamic strength and cyclical index are described in detail. A granular mechanical model of viscosity and damping is given. On the basis of it the motion equation of the excited response of the granules is established, and an approximate expression of vibrating-displacement by harmonic excitation and the steady effect solution of the coordinate response is deduced. By the stepwise integration method, the recursion relation matrix of the displacement, the velocity and the acceleration of the excited response of the granules are resolved, and a calculating flow chart and a calculating example are also given.(3) By the use of the wave theory, the characteristics of the wave propagation and their dissipation in the elastic granules, the viscoelastic granules and the flowing granules are analyzed. Then the mechanism of the vibrating aided flow is given.1) The deformation of granular materials would be the elastic deformation when the strain number e < 10-4.The expressions of wave equation, propagation velocity and wave energy in the elastic homogenous and anisotropic media have been analyzed. At the same time, an expression of energy passing coefficient was deduced, and the conducted experiment has proved that the attenuation of wave has a relation to the density of layered media. The propagation characteristics of Rayleigh and Love waves are also analyzed.2) In terms of viscoelasticity the related theory in the granular media is analyzed. Three kinds of viscoelasticity models were given: Maxwell model, Kelvin model and standard linear model of solid. The wave equation, the complex number expressions of propagation and attenuation vectors, and the attenuation coefficientIIIexpressions of longitudinal and transverse waves under the conditions of small distortion have been deduced.3) The flowing granular media is regarded as a weak transverse isotropic media, and the phase velocity expressions of waves P, SH and SV are deduced. The propagation specialties of waves in the flowing granular media have been analyzed. It is the first time that the mechanism of the vibrating aided flow is explained creatively as depicted in this Ph D dissertation.(4) The vibrating liquefaction of saturated granules is studied.Firstly, the mechanism of liquefaction is described in detail. Then, the characteristic of wave propagation in saturated granular media is studied in depth. The potential vector equation and the velocity expressions of three kinds of body waves under the conditions of no dissipation, as well as the general equation of potential vector and the attenuation coefficients of waves P and S under the conditions of dissip...
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