Energy characteristics of sandstones with different crack angles under true triaxial cyclic loading and unloading

The effect of crack angle on energy evolution during sandstone failure subjected to true triaxial cyclic loading and unloading is great concern. However, the consumed in initiation compaction process generally referred dissipated energy, which inaccurate. To reveal law breaking sandstone, a complex test carried out precast angled samples by employing system. area integral methodology exploited evaluate total density, elastic plastic density rock different angles. variations these four levels terms number cycles upper limit stress are explained discussed. obtained results that entire cycle unloading, above-mentioned factors sample fairly do not rely angle. increases with cycles, significantly increase faster than consumption mode. growth rate dissipative greater density. Additionally, aforementioned quantities grow quadratic manner as function stress. releasable gradually magnifies increasing plasticity first decreases then increases, reflecting change irreversible deformation caused newly developed cracks sample. fitting coefficient employed define characteristic coefficients storage dissipation. indicate larger angle, stronger weaker dissipation capacity. It also explains how strength becomes higher increases.