Force chains in a uniaxially compressed static granular matter in 2D

Granular matter is a large assemblage of dense-packing particles. The interparticle forces are transmitted through heterogeneous chain architecture. The force chains would display different responses as external loading varies, and it would be directly related to the macroscopic mechanical properties of the granular system. Therefore, understanding the properties of force chains is fundamental to the study in granular systems. In this work, we firstly analyzed three characteristic time scales involved in processes occurring in granular systems, and proposed three dimensionless numbers to measure their relative importance. Secondly, a series of numerical simulations were conducted on a uniaxial compression system consisting of 12400 polydispersed particles. Our results showed that the shape of force distributions are unaffected by system preparation history and packing fractions in the range from 0.855 to 0.886, but mainly affected by the static surface friction. By defining three conditions for evaluating strong force chain, the probability distribution of force chain length was found in the form of power law with an exponent of 1.72, which is independent of packing fractions and static surface frictions in this static system.