The 3D reconstruction of a digital model for irregular gangue blocks and its application in PFC numerical simulation

Particle flow simulation of broken gangue backfill materials can be used to effectively study the bearing-compression characteristics of gangue backfill materials. The 3D reconstruction of the digital model for the real shape of the irregular gangue blocks is crucial for the numerical simulation of particle flow to accurately express the spatial and temporal evolution of its meso-structure and its internal mechanism. To this end, the Computed Tomography (CT) scanning experiments for the random gangue blocks was designed; the MIMICS and 3-MATIC were used to carry out binarization, the 3D reconstruction, interface program optimization and other operations on CT slices; then the 3D digital model of the irregular gangue blocks was obtained, and the shape database of irregular gangue blocks was established. Besides, a numerical model for particle flow in the triaxial compression of broken gangue was proposed based on the real shape of gangue blocks, then the shape, mutual occlusion and crushing of gangue blocks in the bearing-compression process can be well simulated by the proposed method. Through the 3-MATIC, the interface program in the 3D digital model of the irregular gangue blocks was optimized. Compared with those in the unoptimized model of gangue blocks, the number of triangles and nodes in the optimized 3D digital model decreased by 91.17 and 91.15% respectively, which effectively improves the speed and accuracy of numerical simulation of particle flow of broken gangue materials.