泥石流沟岸冲蚀演绎及动力学研究

我国位于泥石流沟岸的公路里程累计800km左右。沟岸冲蚀是公路泥石流研究的主要方面之一，是泥石流冲蚀能、岸坡抗蚀能耦合作用的表像。应用地貌学方法将泥石流沟岸冲蚀演绎过程分为4个阶段，即冲蚀槽形成阶段、泥石流顶托底部拉裂阶段、自重顶部拉裂变形阶段和坍塌阶段．核心是悬岸的产生及失稳。大量调查发现，沟岸坍塌失稳均主要发生在泥石流暴发期间．其主要原因是泥石流对岸坡的冲蚀作用使得岸坡产生纵向振动，增加荷载效应。减小了悬岸岩土体的刚度。进而诱发了悬岸体的坍塌。运用动力学方法建立了悬臂体系的纵向振动位移方程。据此应用牛顿第二定律便可求解获得泥石流振动对岸坡破坏的诱发荷载，并对护岸结构关键技术进行了探讨。

Research on Evolution Process and Dynamic Effect of Banks of Debris Flow Valleys Under Both Impact and Erosion

Total mileage along banks of debris flow valley is 800 kilometers in China. Impact and erosion of debris flow to banks of debris flow valley is one of key studies for debris flow along highways, the impact and erosion to banks is a macro-feature of coupling action of impact and erosion energy of debris flow as well as anti-impact and anti-erosion energy of the banks. The evolution process of impact and erosion of banks of debris flow valley is divided into four stages by geomorphology principle, i.e. formation stage of trough of impact and erosion, tension stage of bottom of cantilever banks supported by debris flow, tension stage of top of cantilever bank under gravity force of banks, and avalanche stage of cantilever banks. The key problem of the evolution process is that cantilever banks occur and are unstable. According to vast investigations, it is identified that avalanche of banks takes place usually during breaking out time of debris flow, whose reasons are that the vertical vibration of bank from the impact and erosion occurs and dynamic effect increases while the rigidity of banks decreases. Deformation equations of vertical vibration of cantilever bank are established by dynamics principles, which can calculate triggering loads to cause fracture of the banks by Newton's second law. In the end some key techniques about bank revetment are approached in the paper.