Force Networks Analysis on the Mesoscale Mechanisms of 2D Arching Effect Development and Degeneration.

The arching effect, which relates to load transfer and stress redistribution, is relevant in various aspects of the engineering field. However, understanding of the development and degeneration mechanisms of the arching effect in mesoscale remains limited. This paper presents discrete-element modelling (DEM) simulations of the 2D trapdoor test to investigate the arching effect in 2D granular materials with different porosity. Complex network theory is adopted for the analysis of mesoscale mechanisms of the development and degeneration of the arching effect. The results show that the variation of arching ratio with trapdoor displacement can be attributed to the evolution of arched force chains and particle contact force in a specific zone (where the vertical displacement of particles is larger than 0.1δ but <0.9δ). In this zone, the normal contact force between particles increases rapidly and robust force chains with large normal contact force are generated during the development process of the arching effect. This evolution of normal contact force and force chains becomes more obvious as the sample porosity decreases. During the degeneration process of the arching effect, the robust force chains in this zone are degenerated gradually, leading to the decrease of normal particle contact force at the microscale and the increase of arching ratio at the macroscale. [ABSTRACT FROM AUTHOR]