Analysis on mechanical properties and evolution of mesostructure of debris flow from complex network perspective

In order to analyze the meso-structure of debris flow, the debris flow model with different inter-particle friction coefficients and slope angles is established here by the CFD–DEM coupled approach. The simulated results demonstrate that the drag forces caused by the inflow velocity of the fluid will drive the shallow particles to be unstable initially, and gradually disturb the deep particles. This perturbation changes the properties of the contact network, preventing it from forming stable force chains. In this process, the number of particles with a low coordination number in the network gradually increases, and it is easier to form contacts between particles with a high coordination number. Based on the evolving rule of the correlation of the degree/coordination number, we propose a criterion in terms of the correlation for the initiation of debris flow. Eventually the SIS model (susceptible-infected-susceptible epidemic model) is used to establish the movement equation of debris flow, which is beneficial to build the bridge between macro and micro parameters.