地震作用下黄土边坡震陷破坏的动力离心模型试验研究

为研究黄土边坡地震动响应机制,以兰州地区典型边坡为原型,设计并完成了几何比尺1∶20的原状黄土边坡动力离心模型试验。系统地研究了黄土边坡的地震动力响应特性、黄土边坡的稳定性和震陷变形规律。表明黄土边坡的加速度放大效应随坡高呈非线性增大变化,且在坡体顶部到达最大;边坡坡面的动力放大效应大于坡体内的动力放大效应;边坡断面内坡肩下动力放大效应大于坡中下动力放大效应。强震作用下黄土边坡破坏形式表现为坡顶有明显的震陷下沉,坡顶、坡肩及坡面出现大量的震动裂隙。由于坡肩及破面震陷变形,以及坡体内震动裂缝发展,边坡中下部坡面出现挤出、隆起变形,并向临空面方向产生移动。坡体内震动裂缝发展形成了潜在滑移面,为边坡产生整体滑移提供了条件。

Dynamic centrifugal model tests on seismic subsidence of loess slopes under earthquake action

The dynamic centrifugal model tests on the loess slope samples with geometric scale of 1∶20,which are taken from a typical slope in Lanzhou,are designed and carried out.The characteristics of seismic dynamic response,stability and deformation of the loess slope are studied systematically.The results show that the acceleration amplification effect of the loess slope increases nonlinearly with the slope height and reaches the maximum at the top of the slope.Under the action of strong earthquakes,the failure of the loess slope shows that there is obvious subsidence at the top of the slope,and a large number of fractures and fissures appear at the shallow stratum,shoulder and slope surface.Due to the seismic subsidence deformations at the shoulder and surface of the slope and the development of the fractures and fissures in the slope,uplift deformation appears at the middle and lower parts of the slope,and they move towards the direction of the slope surface.The potential slip surface is formed by the development of fractures and fissures in the slope,which provides the conditions for the overall slip of the slope.