Theoretical And Numerical Research On The Solid-Fluid Coupling Problems In The Process Of Consolidation

Based on the theory of multi-phase continuous medium mechanics, soil is modeled as piled continuous body; further Solid-Fluid coupling mathematics model for permeating and consolidation problem under finite deformation is built up, which reflects Solid-Fluid mutual coupling. The nonlinear finite element equations for Solid-Fluid biphasic medium coupling problem in finite deformation case are built according to the theory of finite deformation. Adopted the automated generating system of the finite element of IFPG, the corresponding computer programs are developed. The differences between finite deformation and small deformation in such aspects as pressure field, displacement field and stress field are analyzed with different soil parameters. The results of numerical stimulation show that under the conditions of not very large load, not very thick soil, higher deformation module and permeability of the soil, the difference between finite deformation and small deformation can be negligible. So adopting the small deformation theory can reach the ideal result. On the contrary, the results of vertical sedimentation, horizontal displacements and pore pressures obtained from the theory of finite deformation are more exact than those got from small deformation. Using two different kinds of soil models, the stress distribution of the soil body caused by large and small deformation is analyzed. The results fully reflect the size effect and the phenomenon of stress concentration. It further indicates that considering Solid-Fluid coupling, the tensile stress occurs in the stress distributing districts, which is apt to leading to the soil's destruction and the foundation's instability because of the permeating of water in the soil.