On the role of meso-structures on the instability mechanism of granular soils

The meso-scale structures in the granular system are regarded as the intermediate topological elements which hold the key on understanding the physical mechanism of the local instability and failure of granular soils. It therefore bears high scientific and engineering significance to study the stability characteristics of meso-scale structures of granular materials. In the present study, different meso-structures were firstly identified by decomposing the contact network of a granular system into different n-cycle clusters. A stability index and a degradation index were defined to estimate the survivability of a meso-structure within the granular system. The results indicate that these two stability indices decrease significantly with the increasing order of the meso-structure. Moreover, the localization of the unstable high-order clusters inside the shear band implys the beginning of the local failure of granular soil. © 2015 Taylor & Francis Group.