Abstract:Taking the similar material specimen of layered rock containing interface cracks as the research object, combined with high-speed camera and DIC analysis method, the three-point bending test under different offset distances of interface cracks is carried out. The corresponding numerical simulation study is also carried out using the FEM-CZM method to explore the specimen fracture mode, crack extension process and evolution mechanism, stress intensity factor and the characteristics of fracture strength, fracture toughness and fracture energy of the laminated rock. The results show that the overall fracture process of interface-containing prefabricated cracked specimens undergoes three stages, including the up-concave stage, the elastic stage, and the nonlinear damage. The crack extension mode is significantly affected by the amount of lithological interface bias. The peak load of Type B specimens is more affected by the bias than that of Type A specimens, and the fracture energy and fracture toughness of Group B specimens are larger than those of Group A specimens under the same bias. FEM-CZM numerical simulation is an effective method for fracture analysis of interface crack-containing laminated rock bodies, where the concentration of tensile stress in interface defect-containing laminated rock bodies under three-point bending conditions leads to crack initiation and extension. However, the values of tensile stress on the crack tip and crack extension paths of prefabricated cracks in specimens of different types and offset distances differ.