Evolution of the Mesoscopic Parameters and Mechanical Properties of Granular Materials upon Loading

Biaxial tests of granular materials under different lateral pressures were numerically simulated to study both the macromechanical behavior and evolution of mesoscopic parameters, including the coordination number, degree, clustering coefficient, and average shortest path length, which can provide information bridging mesoscale to macroscale of the mechanical properties of granular materials in a different and new way. The analysis results demonstrate that, with the increasing lateral pressure, there is a higher coordination number for denser granular material, and the coordination number of the samples eventually tends to the similar value at critical state with the same lateral pressure for different initial porosities; the distribution of the degree is very similar for samples with different initial porosities at critical state; the evolution of the clustering coefficients with axial strain is almost the same as that of the coordination number. At critical state, the clustering coefficients of all samples are almost identical, which means that the internal structures of samples with various initial porosities are similar; the average shortest path decreases with increasing lateral pressure and tends to be stable in the critical state. Additionally, the diameter of the contact network of granular material hardly changes at different lateral pressures at critical state.