LARGE-STRAIN CONSOLIDATION OF FOUNDATION WITH SAND DRAINS BASED ON HANSBO'S FLOW ¹⁾

Based on Gibson's theory for the large-strain consolidation, the governing equations for the void ratio and the excessive pore pressure for the large-strain consolidation of foundation with sand drains are derived by introducing the Hansbo's flow model with consideration of the sedimentary effect of the soil layer. By comparing with the existing research results, the reliability of the proposed method and the equivalence of the two description methods of the large deformation consolidation equation of the sand well foundation are verified. The numerical solutions of the equations are obtained by using the FlexPDE software, then the differences of the consolidation behaviors among the large-strain, the small-strain and the Barron's consolidation are investigated. And the effect of the parameters (m and I_1) of the Hansbo's flow model on the consolidation behaviors is analyzed in detail. Finally, the consolidation behaviors of the axisymmetric consolidation, the radial consolidation and the 1D vertical consolidation are compared. The results show that the large-strain consolidation rate with the Hansbo's flow is smaller than that of any other consolidation models, and the average degree of the consolidation of the consolidation models with the Hansbo's flow tends to be the same with a comparatively long time. And the consolidation rate decreases with the increase of the parameters m and I_1 and of the Hansbo's flow. Moreover, the difference of the average degree of the consolidation between the axisymmetric consolidation and the radial consolidation increases with the increase of the influence radius of the sand drains, and during the early stage of the consolidation, the consolidation rate of the 1D vertical consolidation is larger than those of the axisymmetric consolidation and the radial consolidation.