Damage characteristics and energy-dissipation mechanism of frozen–thawed sandstone subjected to loading

Abstract To reveal the energy-dissipation mechanism of the rock deformation and destruction process under the influence of freeze–thaw cycles and investigate the essence of rock freeze–thaw damage, the evolution characteristics of the total strain energy, elastic energy, and dissipated energy in the sandstone failure process are analysed according to the energy principle, number of freeze-thaw cycles, and uniaxial compression. The results reveal that: (1) the evolution behaviours of the total strain energy, elastic energy, and dissipative energy of sandstone under different numbers of freeze–thaw cycles are similar; that is, the total strain energy and elastic energy gradually increase with the increasing strain, and the elastic energy decreases sharply after reaching the peak limit. The dissipative energy gradually increases and thereafter remains stable; finally, it rapidly increases. (2) With increasing freeze–thaw cycles, the growth rates of the total strain energy, elastic energy, and dissipated energy gradually decrease, whereas the energy value at the peak first increases and then decreases. The energy distribution during rock loading is affected by the number of freeze-thaw cycles (defined as N). When N is