Study On Dynamic Response Of Fluid-saturated Porous Media Based On The Precise Integeration Algorithm

In this paper,the time domain method for solving the dynamic problem of saturated two-phase media based on precise time integration is studied,the method is validated,and the method is applied to calculate the seismic responses of saturated two-phase media some main work and conclusions as follows:1.The program of solve fluid-saturated porous media wave motion equation based on the precise integration method is improved through Matlab,and writing the program of matrix integration and mesh generation,got a complete calculate program,so it improved efficiency in the back of the work.The paper calculated and analysised many typical cases based on the program,including the dynamic response of one-dimension saturated soil column in step load and sinusoidal load at different mechanical parameters,and the dynamic response one-dimension saturated soil column in sawtooth load,further clarification the algorithm is valid by comparing the numerical solution and analytical solution.2.Based on the program of solve fluid-saturated porous media wave motion equation and transmitting boundary,the free field dynamic response is analyzed,applied Tianjin seismic loading and Loma Prieta seismic loading by compression wave and shear wave.The displacement time history,velocity time history and pore pressure is got,The calculation results accord with the law of elastic wave theory,to verify the applicability of the method in calculation of seismic response in saturated medium,the feasibility of transmitting artificial boundary method for seismic response of two-phase media in u-p wave equation is also demonstrated.3.Mechanical parameters of soil how to influence the dynamic response of free field is studied after the effectiveness of algorithm is verified.Permeability coefficient,poisson's ratio,elasticity modulus and porosity how to influence the dynamic response of free field is analyzed.The studied result show that:(1)permeability coefficient have little impact on vertical displacement of field,but there is obvious impact on horizontal displacement and pore pressure.The horizontal displacement increase and pore pressure decrease as the permeability coefficient increase.The permeability coefficient have a more obviously impact on pore pressure in the upper of field.(2)Poisson's ratio have little impact on vertical displacement of field,but there is obvious impact on horizontal displacement and pore pressure.The horizontal displacement increase and pore pressure increase as the Poisson's ratio decrease.(3)Elasticity modulus have obvious impact on vertical displacement,horizontal displacement and pore pressure of field,vertical displacement,horizontal displacement and pore pressure increase as the elasticity modulus increase.The elasticity modulus have a more obviously impact on pore pressure at the bottom of the field.(4)Porosity have little impact on vertical displacement of field,but there is obvious impact on horizontal displacement and pore pressure of field,the horizontal displacement and pore pressure increase as the porosity increase.4.The application of Ducan-chang model to describe the nonlinear properties of solid two-phase medium,carry out a preliminary study on the nonlinear dynamic response of saturated porous media,the results accord with the nonlinear dynamic response of two-phase medium.The research work in this paper shows that the time-domain numerical method based on precise time integration can be applied to solve the dynamic problems of complex two-phase media.