Three-dimensional numerical investigation of rock plate cracking and failure under impact loading

Platy structures are a common geological feature in nature, and rock masses are often subjected to dynamic loadings. However, the dynamic behavior of rock plates has rarely been investigated. Three-dimensional FEM-based numerical modeling is used in this study to understand the cracking and failure characteristic of rock plates subjected to impact loading. First, a numerical plate center impact testing system is established. The impact is simulated by hitting the center of a rock plate with a striker. The rock plate model has a high width-to-thickness ratio, and its heterogeneity is described by the Weibull distribution function for specific physical parameters. During impact, the contact between the striker and the plate is captured by a three-dimensional dynamic contact model, and the damage evolution in the rock plate is analyzed using the equivalent damage method. After comparison with laboratory measurements, the applicability of the proposed numerical method in modeling the cracking and failure characteristics of a rock plate under impact loading is validated. The simulation results indicate that radial cracks first initiate at the center of the rear surface of the rock plate, and these cracks propagate to the boundaries and penetrate to the front surface of the rock plate. The number of radial cracks is dependent on the rock plate thickness: the number of radial cracks decreases with increasing rock plate thickness. In addition, circular cracks are induced when the impact velocity is sufficiently high or the rock plate thickness is sufficiently small. Two types of circular cracks are identified and classified by the initiation time and mechanism. The findings in this study may facilitate a comprehensive understanding of the failure process of rock plates under impact loading.