Consolidation behavior for saturated sand-marine clay mixtures considering the intergranular structure evolution

Abstract

Laboratory tests on sand-marine clay mixtures reveal that the effect of sand mass fraction on the overall consolidation behavior is negligible for a sand mass fraction of 20% or less. Further increase of the sand fraction significantly affects the overall consolidation process. To describe this behavior, a consolidation model is proposed within a homogenization framework. The sand-marine clay mixture is divided into two systems: a clay matrix system consisting of the silts, clay particles, and void space in the marine clay matrix; and an inclusion system consisting of sand particles. The volume fraction of sand particles is adopted as the structure variable, representing the intergranular structure evolution of the sand-clay mixtures. Based on some reasonable assumptions, the governing equations are formulated and the consolidation problem is solved using Galerkin's weighted residual method within the finite-element framework. The proposed consolidation model has five principal parameters: four intrinsic ones depending on the behavior of the pure clay matrix and one structure parameter related to the intergranular structure. Only two conventional oedometer tests are needed for the calibration of these model parameters. Comparison between the test data and the model prediction reveals that the model can well reproduce the effect of sand fraction on the overall consolidation behavior of the tested sand-marine clay mixtures.