Modeling the compression behavior of remolded clay mixtures

Clay mixture is a waste material in open pit mining from the excavation of various soil layers. In the present study, a general constitutive framework is proposed for the prediction of compressibility of remolded clay mixtures. First, the resulting structure of a clay mixture is simplified as a composite structure, in which the elements of the constituents are randomly distributed in a representative elementary volume. Afterwards, the initial water contents of the constituents are estimated based on a simplified model for the undrained shear strength of the clay mixture. Then, the representative elementary volume of the mixed soil is divided into separate individual parts and the volume fractions of the constituents are formulated as functions of the overall porosity and those of the constituents. Finally, a homogenization law is proposed based on the analysis of the randomly arranged structure together with a simple compression model for clay mixtures. Parameters required by the model correspond only to the constituents, which are simple to calibrate based on standard laboratory tests. By making comparisons of the predictions with test data, it is shown that the proposed model can well represent the compression behavior of the clay mixtures.