The microstructure of particulate mixtures in one-dimensional compression: numerical studies

The current paper documents a series of numerical experiments conducted to study the microstructure evolution experienced by mixtures created with particles of contrasting size and stiffness, subjected to one-dimensional compression. Emphasis is placed on quantifying the effects of mixture fraction and relative size ratio on macroscale and microscale responses. The results indicate that force percolation (specifically through the network of high-stiffness grains) controls system mechanical response at the macroscale. The mixing fraction and size ratio of the particles significantly affects (1) force percolation and (2) the strain-dependent evolution of the void space. The latter is of particular relevance to the stress-dependent hydraulic conductivity evolution of the mixture.