为研究黄砂岩单轴疲劳加载的特性，开展了不同应力上限和加载速率下的单轴疲劳荷载试验。试验结果表明：黄砂岩的疲劳试验曲线受到单轴压缩应力—应变曲线的控制，疲劳极限变形与峰后对应变形一致；砂岩疲劳过程的不可逆变形和耗散能密度均具有三阶段演化规律，依据倒“S”型损伤模型，验证了黄砂岩疲劳损伤三阶段演化规律；分析认为三阶段规律的本质是砂岩的塑性变形和内部孔隙微裂纹生成以及扩展速度的不同所呈现的结果。研究表明应力上限和加载速率对疲劳寿命有显著影响，根据所得应力—寿命公式，可以估计砂岩在一定条件下的疲劳寿命。

In order to study the characteristics of yellow sandstone under uniaxial fatigue loading and fully understand the deformation and failure mechanism of rock under cyclic loading，uniaxial fatigue load tests under different stress upper limits and loading rates were carried out to systematically analyze the fatigue characteristics of yellow sandstone under cyclic loading from three aspects of deformation，energy evolution and damage characteristics.The yellow sandstone used in the test was collected from Dongchuan District，Kunming City，Yunnan Province，and the uniaxial compressive strength is 50.2 MPa.In different stress upper limit fatigue tests，the stress upper limit of cyclic loading is set as 80%，85%，90% and 95% of uniaxial strength，and the lower limit is fixed as 50%.And four loading rates were set as 600 N/s，700 N/s，800 N/s and 900 N/s for fatigue tests with different loading rates.The test results show that the curves of loading and unloading stage do not coincide，and the fatigue process curve presents a form characteristic of “sparse-intensive-sparse”.The curves show that the fatigue deformation failure of yellow sandstone is controlled by uniaxial compression stress-strain curve，and the ultimate deformation is consistent with the corresponding post-peak deformation.The irreversible deformation development curve of sandstone has three stages：Initial deformation stage，stable deformation stage and accelerated deformation stage.This feature is consistent with the evolution trend of dissipation energy density in fatigue process.The dissipated energy is high in the first few cycles，and then decreases rapidly and tends to be stable.And the dissipated energy increases significantly when the specimen is near failure.Moreover，residual deformation is used to define the damage degree of yellow sandstone，and the inverted “S” model is used to describe the damage evolution process.The results show that the parameter fitting effect of all specimens is more than 95%，indicating that it is reasonable to describe the fatigue damage process of yellow sandstone by inverted “S” model.Finally，the results show that the fatigue life of yellow sandstone decreases with the increase of stress upper limit and increases with the increase of loading rate.The biggest influence on the fatigue life of rock is in the stable deformation stage.The fatigue life of yellow sandstone under certain conditions can be predicted by the stress-life fitting formula，and the results provide reference for judging rock instability failure.

http://www.goldsci.ac.cn/article/2022/1005-2518/1005-2518-2022-30-2-233.shtml