Abstract:Uniaxial tensile experiments are conducted to study the influence of 3D internal crack dip angle on tensile mechanical properties and fracture features of rock-like material. Special mortar sample of which physical and mechanical parameters are closed to those of sandstone is prepared;and spatial location device for 3D crack is designed. Some improvements are performed for direct tensile experimental methods with rocks;and location equipment for rock-like material bonding tensile experiment is also presented. Experimental results indicate that the tensile loading and deforming process of mortar samples with preexisting crack can be divided into four stages:flaws opening stage,elastic deformation stage,elastoplastic deformation stage,and failure stage,among which elastic stage takes up the most proportion;and the abrupt failure stage is obviously different between tensile and compressive failure. Change of crack dip anglea has much influence on mortar mechanical properties. As a grows (0°<a<90° ,the peak strength,sP,of sample reduces gradually,and when a is around 45°,the sP change amplitude is the largest. Under uniaxial tensile stress,the wrapping wing crack and secondary crack initiate sequentially near the long axis front of internal crack;and the kink region also initiates near the short axis front of internal crack. Finally,the tensile propagation of cracks leads to sample fracture. The change of dip angle has great effects on crack propagation track and sample failure mode.