Role of Rock Sections in Intermittent Joints in Controlling Rock Mass Strength and Failure Modes

Rock sections in intermittent joints are important structures that prevent joints from interconnecting and maintain the stability of the rock mass, and they play a pivotal role in the strength and failure mode of the rock mass. In order to analyze the controlling effect of rock section in intermittent joints, the samples with different rock section angles were prepared and laboratory tests were carried out using Acoustic Emission and Digital Image Correlation (DIC) techniques. The results show that the uniaxial compressive strength of the samples reaches its minimum value when the orientation of the rock section in the intermittent joints coincides with the loading direction. Furthermore, as the angle of the rock section increases, the time share of the sample in the compaction stage increases and the time share in the plastic-yield stage decreases. The samples show the structural characteristics of being difficult to close at the early stage and easy to destroy at the late stage. In terms of the damage mode, the increase in the angle of the rock section reduces the difficulty of the rock section itself being penetrated, and the samples are more easily damaged. Finally, a damage constitutive model considering the compaction stage and initial damage was developed and the effect of rock section angle on the rate of rock damage was analyzed.