Mechanical Properties and Energy Evolution of Fractured Sandstone under Cyclic Loading

Affected by fracture distribution, sandstone shows different deformation and energy evolution characteristics under cyclic loading and unloading conditions. Therefore, uniaxial cyclic loading tests were conducted on fractured sandstone with different angles. The deformation characteristics and the evolution law of energy indexes with the peak load and crack angles were obtained under cyclic loading. Studies have shown that: The deformation modulus of sandstone first increases and then decreases, and the lateral expansion coefficient is positively correlated with the peak load. Based on the viscoelastic deformation theory, an energy analysis model considering damping energy and damage energy is established. The dissipated energy can be divided into the damping energy consumed to overcome rock viscoelasticity and damage energy causing damage by viscoelastic deformation theory. Based on this model, the relationship between elastic property, damping energy, damage energy and fracture angle is obtained, and the damage energy increases slowly first and then rapidly. The research results provide a reference for predicting the damage and failure of rock.