中文摘要：

红层软岩在三峡库区广泛分布,其在水–岩作用下的物理力学特性劣化将直接影响相关库岸边坡的长期变形稳定与安全。基于此,考虑消落带库水位反复升降变化,设计进行红层软岩的浸泡–风干循环水–岩作用试验,研究结果表明：（1）在水–岩作用过程中,红层软岩的强度及变形参数劣化趋势明显,岩样存在逐渐＂变软＂的趋势,而且前3次浸泡–风干循环中的劣化速率较快,5次浸泡–风干循环作用之后,红层软岩的强度及变形参数劣化趋势逐渐趋于缓慢;（2）在水–岩作用过程中,岩样的破坏模式也存在明显的变化,不同围压下岩样的剪切破坏特征逐渐明显,岩样破坏时控制性裂纹数量逐渐减少,次生裂纹的数量逐渐增加;（3）在水–岩作用过程中,水压力的反复升降变化和浸泡–风干循环作用对红层软岩造成了不可逆的渐进累积损伤,红层软岩由相对致密的结构转变成微观裂隙、孔隙发育的松散多孔结构,宏观上就表现为抗压、抗剪强度劣化和破坏模式的变化。相关研究结论可为库岸边坡长期变形稳定分析提供参考。

英文摘要：

Red-layer soft rock is widely distributed in the Three Gorges Reservoir area. The deterioration of physical and mechanical characteristics of red-layer soft rock,caused by water-rock interaction,will directly affect the long-term deformation stability and safety for the slopes of reservoirs concerned. Therefore,considering the fact that the water level of hydro-fluctuation belt is rising up and down repeatedly,the immersion-air dry test for red-layer soft rock is designed and conducted. The results show that：（1） Under water-rock interaction,it is obvious that the strength and deformation parameters of the red-layer soft rock are deteriorating,and the rock samples tend to be soft gradually. At the meanwhile,the first 3 tests have a faster deterioration rate for the parameters,but the rate tends to be slowdown after 5 immersion-air dry circulations;（2） As the number of circulation times increased,the failure modes of the rock samples would also be changed obviously,its shear failure features with different confining pressure would be behaved obviously,and the number of controlled cracks would be decreased gradually while the secondary cracks would be increased;（3） Under water-rock interaction,the repeated change of water pressure and the immersion-air dry circulation would impose irreversible cumulative damage to red-layer soft rock,which would convert to loose and porous structure with micro cracks and developing pores from relatively compact structure. In macroscopic view,it would behave as the deterioration of compressive strength and shear strength,and the change of failure modes. Related research results can provide references for the study of the long-term deformation stability and safety for the slopes of reservoirs.