Experimental study on the effects of complex discrete joints on the mechanical behavior of rock-like material

The strength and failure of rock masses are ambiguous due to their complex structure. Investigating the strength and failure of jointed rock mass remains a persistent concern in mining engineering. This study aims to investigate the effects of joint dip angles of complex discrete joints on the mechanical properties and fracture evolution of rock-like material. Rock-like specimens with complex joints were prepared using 3D printing technology and then tested under uniaxial compression loading. The experimental results reveal the following findings: (1) The anisotropy of rock-like material with complex joints is lower compared to the rock-like material with simple joints. (2) The ratio of long-term strength to uniaxial compressive strength of rock-like material remains consistent despite changes in the dip angle of the joints. (3) Differing from intact rocks, AE events of the rock-like material with complex joints are obvious in the initial loading stage and elastic deformation stage. (4) When the dip angle of the joint sets is 0 and 90°, fractures progressively propagate, and the failure mode of the rock-like material demonstrates tensile failure along the pre-existing joints. Conversely, when the dip angle of the joint sets is 45° and 135°, fractures are simultaneously initiated at various locations within the rock-like specimen, resulting in a failure mode of rotational failure by the newly generated block.