Failure and mechanical behavior of layered slate under Brazilian splitting test: laboratory experiment and beam-particle model

In order to reveal the influence of bedding angle on the fracture mode and mechanical response of carbonaceous slate, Brazilian split tests were carried out on a disc specimen with bedding, and the systematic numerical study was carried out based on beam-particle model (BPM). The results show that the bedding angle has an important influence on the tensile strength and microscopic failure mode of slate. Compared with our published work, the main differences lie in the following points: (1) The Divider type is added on the basis of the five bedding inclination samples, which fully shows the load-displacement response and rupture of the samples under different bedding angles. (2) In terms of modeling methods, through the mesh size function, the physical model composed of multiple parallel lines under different bedding conditions is constructed. (3) Through parameter calibration, the critical strain and critical rotation angle of the beam in the BPM solver are obtained. Moreover, the number of bedding and the ratio of bedding to matrix strength have a greater impact on the failure mode and peak load of engineering structures in rock mass. With the gradual increase in the number of bedding, the corresponding peak load generally shows a gradual decrease trend, and cracks are more likely to occur along the bedding surface; as the strength ratio of the bedding to the matrix increases, the peak load generally shows a gradually increasing trend, and cracks are more likely to occur cleavage tensile failure through the matrix. Through comparative analysis of test load-displacement response and failure mode with numerical simulation, the BPM solver can better reproduce the split evolution process of layered slate under different bedding angles.