Investigation of the dynamic behavior and fracturing mechanism of granite

In examining the dynamic behavior and fracturing mechanism of granite using numerical simulation methods, many studies assume a random distribution of minerals, which fails to accurately represent the actual distribution. The primary objects of this study are therefore to combine digital image processing (DIP) method with the discrete element method (DEM) to develop a more accurate granite model that matches the real mineral distribution of the granite specimen. The DEM is then used to simulate the Split Hopkinson Pressure Bar (SHPB) test, exploring how mineral properties like mineral content, grain shape, grain size, and loading conditions such as strain rate and confining pressure, affect the dynamic behavior and fracture pattern of granite. The results demonstrate that granite models, despite differing grain shapes and sizes, display similar dynamic strength (varying by 4.8%) when they have comparable mineral contents. Feldspar content significantly affects stress variations, while quartz and biotite have minor impact. Stronger minerals like quartz and feldspar show similar fracture patterns, whereas biotite leads to a larger damage area and denser fracture distribution. Loading conditions, such as strain rate and confining pressure, significantly influence the fracture behavior of granite specimens. Fracture propagation is primarily characterized by tension cracks, with shear cracks following, and their distribution varies based on mineral properties and loading conditions.