Dry-wet cycle and fatigue loading both severely affect the stability of hydraulic engineering. In this paper, the deterioration process of red sandstone under coupled dry–wet cycle-fatigue loading was investigated from three aspects of deformation, energy, and damage. And the variation law of crack propagation mode of the samples was revealed. The results showed that the elastic modulus and the deformation modulus had a negative correlation with the number of dry–wet cycles, while the maximum strain and the residual strain were the opposite. Coupled damage variable was defined based on porosity and dissipated energy density, and a damage evolution model was established. With the increase of dry–wet cycles, the failure characteristics of the samples evolved from predominantly wing cracks to anti-wing cracks.

干湿循环和疲劳载荷都会严重影响水利工程的稳定性。本文从变形、能量和损伤三个方面研究红砂岩在干湿循环-疲劳耦合载荷作用下的劣化过程。揭示了试样裂纹扩展模式的变化规律。结果表明，弹性模量和变形模量与干湿循环次数呈负相关，而最大应变和残余应变则相反。基于孔隙率和耗散能量密度定义耦合损伤变量，建立损伤演化模型。随着干湿循环的增加，样品的失效特征从以机翼裂纹为主演变为反翼裂纹。