A systematic 3D simulation method for geomaterials with block inclusions from image recognition to fracturing modelling

Abstract

A systematic hybrid modelling approach for heterogeneous geomaterials with irregular block inclusions is creatively developed based on a deep learning technique, computational geometry algorithms, and a 3D finite-discrete (or discrete-finite) element method; the approach includes the following three major steps: (1) the deep learning-based image identification technique and the computational geometry algorithm are employed to establish a 2D geometry library of realistic rock blocks; (2) 3D block inclusions with desired block shapes are regenerated by a surface morphing technique and then randomly allocated to the specimen domain based on the overlapping detection algorithm; and (3) the finite-discrete element method is developed by integrating cohesive elements with a solid mesh based on a finite element code to simulate the progressive fracture and interface behaviours of heterogeneous geomaterials. To validate the proposed hybrid approach, a series of synthetic specimens with Brazilian split tests are prepared and implemented from 2D to 3D. The results verified that the finite-discrete model can be easily established through images, and the consequent simulation performance is validated through comparisons between observations and numerical results regarding failure patterns and stress-strain relations. Using the calibrated and verified approach, we further numerically discuss the influence of the block-matrix strength ratio and interface strength on the mechanical responses of bimrocks. All results demonstrate that the proposed hybrid approach has a powerful ability to dealing with heterogeneous composite materials that maintain the characteristics of both continuity and discontinuity.