地震荷载作用下中–缓倾角顺层开挖斜坡的变形破坏模型试验

在汶川地震灾区,顺层中–缓倾斜坡是地震山地灾害非常发育的斜坡类型,而开挖往往加剧斜坡的地震山地灾害。据调查,顺层中–缓倾斜坡以整体滑动为最主要的变形破坏形式。为重现斜坡的变形破坏过程,分析斜坡在地震荷载作用下的变形破坏规律,选取北川县陈家坝马滚岩滑坡作为顺层中–缓倾角开挖损伤斜坡的典型实例,进行地震荷载作用下斜坡变形破坏的室内物理模型试验。结果表明,开挖加剧斜坡在地震荷载作用下的变形破坏,整体滑动是斜坡最主要的破坏形式,与野外调查结果吻合。同时,斜坡整个变形破坏过程具有阶段性,可以划分为以下几个阶段:(1)地震初始阶段,此阶段坡体沿开挖不连续层面逐渐贯通并微剪出,同时开挖坡顶形成大量裂缝;(2)开挖坡顶浅表崩塌阶段;(3)整体滑动阶段。

DEFORMATION AND FAILUER MODEL TEST OF MODERATE-SLOW DIP EXCAVATION BEDDING SLOPE UNDER ACTION OF SEISMIC LOAD

In the Wenchuan earthquake disaster area,moderate-slow dip bedding slope is a kind of slope that seismic mountain disaster is very developing and the slope earthquake disaster is often exacerbated by the excavation.According to the survey,integral sliding is the main deformation and destruction form of moderateslow dip bedding slope.In order to reproduce the process and analysis regularity of slope deformation and failure under the action of seismic load,Magunyan landslide located in Beichuan County is chosen as the typical example of moderate-slow dip excavation damage bedding slope;and the indoor physical model test of slope deformation and failure under the action of seismic load are carried out.The results show that slope deformation and failure under the action of seismic load is intensified by the excavation.Integral sliding is the main form of deformation and failure;and the results are consistent with field investigation.From the whole process of deformation and failure of bedding slope,the slope can be divided into the three stages:(1) Initial phase of the earthquake.The slope gradually breakthrough and slightly cuts out along the discontinuous bedding plane induced by excavation,and large cracks appear at the top of excavation slope.(2) Shallow landslides phase at top of excavation slope;(3) Integral sliding phase.