中文摘要：

针对一库岸古滑坡进行了水位骤降条件下失稳机制的离心模型试验。离心模型的制作考虑了原型边坡的大尺寸和非均质特征,离心试验过程中进行了上下游水位的实时控制,试验后进行了边坡土体物理特性和强度特性的对比试验。离心试验结果表明：水库蓄水导致坡脚抗滑阻力降低,坡体前缘出现裂缝并随着水位上升出现坡脚坍滑;水位骤降坡体内产生向外的动水压力,加剧坡脚滑动并形成牵引式滑坡趋势;坡脚被加固后边坡变形情况得到明显改善,滑动被阻止,边坡整体稳定性提高。离心试验前后边坡土体的物理力学试验结果揭示：坡脚滑动会造成坡体土密度和含水率重新分布,并导致近滑动区土体强度特性改变、强度指标下降。另外,水下土体随浸没时间增长黏聚力会降低直至消失。

英文摘要：

With regard to an ancient bank landslide near a dam,centrifugal model tests on instability mechanism under reservoir impoundment and rapid drawdown are carried out.The slope models are constructed with the consideration of large-size and heterogeneous characters of the prototype.The centrifuge tests are accompanied with real-time control of water levels,and followed by laboratorial test for physical status and strength of model slope soil.The results of centrifugal tests show that the rising water level in the reservoir leads to decreasing slope foot sliding resistance,as well as leads to edge cracks and slump.Also,the results reveal that the rapid drawdown causes slope body to produce outward hydrodynamic pressure,aggravates slope foot sliding and creates pull-typed landslide trends.When the slope foot is reinforced,the deformation is controlled and stability is improved.The soil tests of model slopes,before and after centrifuge tests,indicate that the slope foot sliding will lead to the redistribution of soil density and moisture,at the same time lead to the strength reduction near slide zone.Moreover,the cohesion of immersed soils will reduce until it vanishes finally.