A bonded polyhedral DEM model for irregular cemented granular materials based on energy-conserving contact theory

Cemented granular materials, as unique granular substances possessing both permeability and load-bearing characteristics, have found extensive applications in chemical catalysis and geological engineering, and other fields. Given the significant impact of skeleton particle shape on the mechanical properties of cemented granular materials, this paper proposes a bonded polyhedral discrete element method adaptable to arbitrary skeleton particle shapes. Within this method, the adhesive surface is constructed from the contact geometry, and the interaction between particles of different shapes is described by employing an energy-conserving contact model based on strain energy density. The spring-damping model and bilinear constitutive model are utilized to characterize the elastic behavior and damage fracture behavior of cement, respectively. Moreover, the influence of skeleton particle shape on cemented granular materials is elucidated through both mesoscopic and macroscopic analyses using the proposed model. Mesoscopic results indicate that the area of the adhesive surface is a critical factor influencing the destructive force of bonding units. Variations in particle shape cause particles with identical volume and density to form adhesive surfaces with differing shapes and areas under the same conditions, leading to varied destructive forces in the bonding units. The macroscopic results reveal that both the sphericity and aspect ratio of the skeleton particles impact the strength of the cemented granular material. This effect predominantly arises from the differences in the coordination number of the accumulation bodies formed by skeleton particles of varying shapes.

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