Experimental investigation of rock-shotcrete interface damage under dynamic splitting using digital image correlation and acoustic emission

Interface failure is the main type of rock-concrete structure failure, which affects the stability and safety. To study the interface crack propagation and damage characteristics, this article carried out the rock-shotcrete cube interface splitting test under different loading rates. The rock-shotcrete specimens are composed of four material types. Based on the nondestructive monitoring technology, digital image correlation and acoustic emission (AE) were used to monitor the whole process of splitting failure. The results indicate that, both peak load and critical displacement exhibit significant strain rate effects. The main stage of interfacial microcrack development is between 0.8 P-max and P-max. And the damage evolution of cracks is more sufficient and stable under low loading rate. The splitting damage at the rock-shotcrete interface shows phased characteristics. When the load is near the peak, the surge of the AE signal indicates that the damage is intensified.