关键词: 冻结红砂岩, 特征应力, 应力阈值, 应变能

Abstract: In order to study the law of the characteristic stress of northern artificial frozen red sandstone, the frozen triaxial compression test system was used in the test of frozen red sandstone under different temperatures (-15℃, -10℃, -5℃ and 10℃) and confining pressures (4MPa, 8MPa and 12MPa) and the stress thresholds of stress-strain curves are statistically analyzed. The study found that: When the temperature increases, the crack initiation stress increases firstly and then decreases, but crack damage stress and peak stress decrease. when the confining pressure increases, the crack initiation stress, crack damage stress and peak stress increase. The ratio of crack initiation stress to peak stress and crack damage stress to peak stress decrease with the increase of confining pressure. The ratio of crack initiation stress to peak stress is widely range from 0.373 to 0.721, and the ratio of crack damage stress to peak strength is concentrated around 0.9. The elastic strain energy accounts for 69.79% ~ 98.51% of the strain energy, and the dissipation energy is small. After the peak point, the failure of the specimen leads the sharp decrease of elastic strain energy and the sharp increase dissipation energy.