The Effects of Bedding and Holes on the Mechanical and Microfracture Behavior of Layered Limestone Based on the CZM Method

The mechanical and fracture behaviours of rocks are largely influenced by the rock structure and existing flaws. To study the effects of bedding and holes on the mechanical and microfracture behaviour of layered limestone, numerical specimens based on the cohesive zone model (CZM) method were first established. The cracks’ initiation, propagation and penetration processes during the entire loading process were used to reveal the fracture mechanism of numerical layered limestone under different conditions. The effects of bedding angle, hole location and hole number on the peak stress, failure pattern, length of total cracks and crack ratio of numerical layered limestone were then deeply studied. The numerical results indicate that the existing holes cause damage to the numerical layered limestone at different bedding angles. The hole has stronger and weaker damage influences on the peak stress at bedding angles = 0° and 30°. The hole location has different damage degrees on the peak stress at different bedding angles. The location and number of holes have no obvious influence on the failure pattern of numerical layered limestone at bedding angle = 60° and have a strong influence on the failure pattern of numerical layered limestone at bedding angle = 30°. Under most conditions, the length of total cracks is smaller than that of the intact numerical specimen. The location and number of holes have a strong influence on the ratio of tensile and shear cracks along the matrix for numerical specimens at bedding angles = 0°, 30° and 90°.