为了进一步探究涉水堆积体岸坡变形-破坏模式,自主设计制作了模型试验平台,选取三峡库区碎石土样,测定了土样基本力学特性,开展了水位升降作用下堆积体岸坡的物理模型试验。依据试验现象,重点分析了不同坡度的岸坡模型在不同水位作用条件下的破坏模式。结果表明:坡度对岸坡变形-破坏特征影响显著,坡度较大(50°及60°)时,在水位上升期间便发生大规模塌岸现象,变形-破坏模式表现为水位上升→剥蚀、淘空↔塌岸→下错平台→整体滑塌→次稳定状态;坡度为40°时,在水位下降期间发生了较大规模的滑动破坏,对应变形-破坏模式为水位上升→坡体沉降→贯穿裂隙形成→水位下降→贯穿裂隙扩展↔滑面形成→整体滑移;岸坡坡度较小(35°)时,多次升降循环中并未出现明显的变形-破坏迹象。

In the aim of investigating the deformation and failure modes of water-involved accumulation slope,physical model test on accumulation slope was conducted under the action of reservoir water level fluctuation.A model test platform with the base plate adjustable was designed and manufactured independently. And the basic mechanical properties of soil samples collected from Three Gorges Reservoir were determined. Results show that slope gradient has significant influence on the characteristics of slope deformation and failure: large-scale bank collapse occurrs during the rise of water level when slope gradient is large (50° and 60°), and the deformation failure mode is water level raising→denudation and tunneling↔ bank collapse→sinking platform→integral sliding→metastable state; whereas when the slope gradient is 40°, large sliding failure occurs during the water level drawdown, and the corresponding deformation failure mode is water level raising→slope settlement→ crack penetration→drop of water level→propagation of crack penetration↔ formation of slip surface→global slip; when the slope gradient is small (35°), there is no obvious deformation and failure in many times of water level fluctuation cycle.