| Recently,remarkable achievements have been achieved in the development of high-speed railway.However,the vibration of bridge structure and substructure caused by the running of high-speed trains has attracted attentions of more and more researchers.Therefore,how to effectively predict the dynamic characteristics of foundation under dynamic loads and the resulting vibration transfer law of foundation soil around the bridge has become a crucial issue in the research of the vibration and control of the bridge structure.To effectively analyze the dynamic interaction between the foundation soil and foundation,a semi-analytical and semi-numerical TLM-PML-VM method(a combination of the Thin Layer Method,Perfectly Matched Layer and Volumetric Method)is proposed in this paper,and then the method is applied in solving the dynamic interaction between the pile and soil.What’s more,the dynamic characteristics of pile group in layered soil and the vibration transfer law of foundation soil around pile foundations are studied,in which the influence analysis is carried out as well.The main research contents can be summarized as follows:(1)Based on the TLM,the displacement fundamental solution in the frequency-wavenumber domain of three-dimensional layered foundation soil is deduced,and the displacement fundamental solution of the foundation soil under point loads in frequency and space domain is obtained respectively through the application of Fourier-Bessel inverse integral transform.By introducing the boundary conditions,the PML is applied in the TLM so as to analyze the vibration of foundation soil in and out of the two-dimensional plane.The effectiveness of using TLM-PML method to solve the vibration of foundation soil is verified by comparing the calculated results with the analytical solutions.Then the method is applied in studying dispersion characteristics of the three-dimensional foundation soil and the vibration transmission law of the foundation soil.(2)Based on the fundamental principle of VM,a dynamic analysis model of pile foundation-layered foundation soil is established,and the dynamic impedance function of pile cap and pile group foundation is deduced by adopting TLM-PML method.The Matlab software is used to write the calculation program,and the correctness of applying the TLM-PML-VM method in solving the dynamic impedance of pile foundation is proved by the calculation examples,then the dynamic impedance analysis of rigid pile group foundation with pile cap,completely embedded pile foundation and partly embedded pile foundation in layered soil is carried out.(3)The TLM-PML-VM method is applied in solving the dynamic response of foundation soil around pile foundations,and then the vibration transfer function of pile foundation and subsoil is deduced.The vibration transfer law of foundation soil around piles group foundation under point loads and train loads is summarized.The influence factors on the vibration transfer law of the layered subsoil around pile foundations are studied by discussing the shear wave velocity of foundation soil,the density of foundation soil,the spacing of piles and the types of pile group foundation. |
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