Research on Mechanical Properties and Energy Evolution Laws of Sandstone with Two Non-Coplanar Fissures

Taking sandstone-like samples containing two non-coplanar fissures as the research object， uniaxial compression tests and PFC^2D numerical simulations were carried out to study the mechanical properties and energy evolution laws of rock specimens under different fissure dip angles <italic>α</italic>. The results showed that as the fissure dip angle increased， the crack initiation， damage， and peak stress of the sample first decreased and then increased， while the crack fracture zone decreased. By analyzing the internal relationship between the number of microcracks and energy during the loading process of the sample， it was revealed that the failure of the sample was a gradual failure process of bearing capacity. Both the number of microcracks and the energy of the sample first decreased and then increased with the increase of fissure dip angle. The elastic energy dissipation ratio <italic>K</italic> of rock samples was introduced， which confirmed that the mutability of <italic>K</italic> could be used as one of the characteristic parameters of rock instability and failure， and the brittleness index correction coefficient of rock specimens could reflect the brittle failure characteristics and energy release characteristics of rock samples.