Simulation of tensile failure problems by improved three-dimensional discontinuous deformation analysis with multi-spring face-to-face contact model

Abstract

Discontinuities remarkably dominate in jointed or blocky media, yielding an assemblage of blocks, and the mechanical properties of joints can greatly affect the behavior of a blocky system. Discontinuous deformation analysis (DDA) is promising method to analyze the failure process of a blocky system. In three-dimensional (3-D) blocky systems, face-to-face contact between adjacent blocks is common, especially for an ideal rock block system at the very early stage. The accurate modelling of the face-to-face contact is critical. The original 3-D DDA adopts the concentrated spring face-to-face contact model, in which a face-to-face contact is simply converted as the combination of several dominant contacts each with a couple of normal and shear springs. However, such simplification is not always accurate and can yield unreasonable results when simulating the progressive tensile failure between blocks under asymmetrical tension conditions. To overcome this problem, a multi-spring face-to-face contact model incorporated into 3-D DDA is proposed. In the proposed model, multiple couples of normal and shear springs are applied for a face-to-face contact to simulate the distributed force induced between contacting blocks. Several verification examples involving tensile failure are studied to show the advantages of the improved 3-D DDA. The simulated results obtained from the improved 3-D DDA converge to the theoretical solutions or experimental results while the original 3-D DDA gets unreasonable results. Thus, the improved 3-D DDA can provide more reasonable results when analyzing the tensile failure problems. • Improved 3-D DDA by incorporating a multi-spring face-to-face contact model. • Showed limitations of the original concentrated spring face-to-face contact model. • Presented the advantages of the proposed contact model in 3-D DDA. • Improved 3-D DDA can more reasonably simulate tensile failure problems.