Time Domain BEM For Saturated Porous Medium With Drainage And Its Application

The dynamic response of saturated soil with drainage plays an important role in the fields of soil dynamics. It’s involved in many practical problems, such as seismic response analysis, dynamic characteristics of pile foundation and the soil–structure interaction(SSI). For these problems, the boundary element method(BEM) has obvious advantages. Therefore, the research on time domain BEM for dynamic poroelasticity is of great importance both in theory and practice.Based on the Biot’s porodynamic equations and Darcy’s law, we start with a derivation of the Green’s function for stress and flow by using theiu ?p formulation proposed by my supervisor. The physical meaning and value of the relevant parameters are interpreted and demonstrated. Secondly, on the basis of previous work done by other researchers, we establish the time domain boundary integral equation of first kind and second kind for dynamic poroelasticity, respectively.Specifically, and the boundary conditions pertaining to drain and undrained states are introduced.Thirdly, the discretization forms of time domain BEM formulations and its numerical approach are discussed in detail. The corresponding numerical results with dimensionless material parameters are presented. For its actual implementation, the singularity within BEM can be easily treated by referring to the method used in the elastodynamics due to the decoupling of the fast and slow dilatational waves existing in porous medium.Finally, this approach, combined with Duhamel’s integral, is tested to calculate the dynamic response of saturated soil according to the records of strong earthquake.