Abstract: Due to the complexity of fracture distribution in engineering rock mass, the physical modeling of fracture network is one of the key problems in rock mechanics experiments. In this study, a 3D printing method of fracture network model based on water-soluble materials with polyactic acid materials as supporting base is proposed. Based on the water solubility of printing material, a method for preparing rock-like model specimens containing fracture network is established. Through digital image correlation (DIC) method, the deformation and fracturing characteristics of rock-like model specimens during loading process are quantitatively studied, and the influence law of filling material is further analyzed. The experimental results show that 3D printing technology is capable to prepare complex fracture network model with satisfied repeatability of mechanical properties. The stress-strain curve of fracture network rock-like model presents several evident stress reductions before its peak strength, whereas the plastic strain softening is encountered after peak strength. DIC technology can capture the global strain field of fracture network rock-like model during the whole loading process. Moreover, the progressive evolution of strain localization is observed in the process of deformation and fracturing, which reflects the law of crack initiation, propagation and coalescence. The mechanical parameters and strain field distributions of model specimens are influenced by different filling conditions. The advantage of the proposed method is reflected by the fact that the filling material can be filled into the fractures in accordance with the actual engineering condition.

Key words: rock mechanics, fracture network, 3D printing, fracturing, digital image correlation method, strain field