A soft particle model for investigating on mode I fracture behaviors of layered slate following the Voronoi tessellation construction

It is well-known that the discrete element method (DEM) based on circular particle shape may not be fully suitable for modeling geotechnical materials due to the lack of frictional resistance after solid bond fracture. In this paper, a two-dimensional (2D) soft particle model based on Voronoi tessellation construction attempts to solve these problems. In terms of experiments, the Muzhailing tunnel layer was taken as the research object, the semi-circular bend (SCB) tests were carried out on the sample to systematically study the mode I fracture properties of layered carbonaceous slate, and a series of numerical simulations were carried out based on this test. Through comparative analysis, it can be seen that the numerical simulation results are in good agreement with the splitting modes and fracture toughness of the indoor layered slate samples. At the same time, the effects of different span lengths, bedding spacings, and the strength ratio between bedding and matrix on the fracture mode and fracture toughness of engineering structures in layered rock mass were explored. On the other hand, the anisotropy of the deformation modulus of the layered rock mass in the numerical simulation is also taken into account. In the selection of span, s/2R = 0.6 - 0.8 is more reasonable.