三峡水库蓄水运行之后,库水位每年都在145 m的防洪水位和175 m的蓄水发电水位之间或缓慢或快速地升降变化,岸坡消落带区域岩土体长期处于干湿循环状态,其力学参数的劣化规律将直接影响岸坡的变形稳定。基于此,设计并进行了典型岸坡消落带土体的干湿循环作用试验。结果表明:(1)在干湿循环作用过程中,土体抗剪强度参数劣化幅度非常明显,其中,前4次干湿循环作用导致的抗剪强度参数劣化幅度占总劣化度的75%左右,4次干湿循环作用之后,劣化趋势逐渐趋于平缓;(2)在干湿循环作用下,土样内部的微观裂纹、裂隙反复张开闭合,逐渐发育、汇集,土样由密实状态逐渐变为内部裂纹发育的松散状态,土样内部的损伤是导致其抗剪强度参数逐渐劣化的根本原因;(3)考虑干湿循环作用下消落带土体参数劣化时,岸坡消落带区域局部安全系数劣化趋势明显,总体趋势与消落带土体抗剪强度参数劣化规律一致,而且岸坡消落带区域附近的局部滑动迹象明显,这与现场踏勘所见到的该区域明显发育的裂缝、下挫现象是一致的。研究成果对库水作用下岸坡的长期变形稳定评价具有较大的参考意义,相关分析方法也可以为类似试验提供参考。 After the Three Gorges Reservoir is impounding, the reservoir water level changes slowly or rapidly between the flood control water level of 145 m and the water-storage and power generation level of 175 m each year. The rock and soil mass in the area where the bank slips and falls over a long time is in a dry- Degradation of mechanical parameters will directly affect the deformation stability of the bank. Based on this, a wet and dry cycle test of soil in a typical bank of slope-dip zone was designed and carried out. The results show that: (1) The degradation range of shear strength parameters of soils is very obvious during the process of wet-dry cycles. The degradation range of shear strength parameters caused by the first four wet-dry cycles is about 75% of the total degradation , The trend of degeneration tends to be gentle gradually after 4 cycles of wetting and drying. (2) Under the action of the wetting and drying cycle, the micro cracks and crevices in the soil sample repeatedly open and close, gradually develop and converge, The internal damage of the soil sample is the root cause of the gradual deterioration of the shear strength parameters. (3) When the soil parameters in the ebb and flow belt are deteriorated under wet-dry cycling, The trend of regional safety factor is obvious, and the overall trend is consistent with that of soil shear strength parameters in the ebb and zone, and the local slip signs near the zone are obvious, which is consistent with the obvious development in this area The cracks, the phenomenon of the drop is the same. The research results have great reference significance for the long-term stability assessment of bank slope under the effect of reservoir water, and the relevant analysis methods can also provide reference for similar tests.