Application of slightly overlapped circular particles assembly in numerical simulation of rocks with high friction angles

Brittle rocks show complex mechanical behavior under loading. A promising approach in simulation of rock deformation is the use of interaction of bonded circular particles through normal and shear springs. Each contact bond can break if the applied force is greater than the bond strength. Although the synthetic material obtained with this approach behaves similar to rocks in many aspects, it shows low friction angle compared to actual values. In this paper, a new technique is introduced to obtain a realistic rock friction angle and failure envelope for the synthetic material. The idea is to allow circular particles to overlap slightly with a double force-displacement contact law. In addition, tensile strength of this synthetic model is briefly examined. All numerical computations were conducted using Continuum Analysis, two-dimensional (CA2) program developed by the author which has the capability to model rock deformation using a hybrid explicit finite difference-distinct element method. (C) 2004 Elsevier B.V. All rights reserved.