摘要
地震是触发边坡失稳、滑动形成堰塞湖的重要因素,以云南鲁甸"8·03"地震引发红石岩滑坡为例,应用连续-离散耦合分析方法(FDEM),模拟了三维滑坡体从变形破坏至堆积形成堰塞体的全过程。采用双轴压缩数值试验率定各岩土层的FDEM模拟参数,以对应实际岩土体物理力学参数。建立了滑坡体和河谷的三维有限元模型,滑坡体部分采用较小的网格密度,并在实体有限单元之间插入无厚度界面单元模拟。随着滑坡体的失稳和滑动,失效界面单元不断增加,导致滑坡体由连续体向非连续体转换,并最终形成松散的堆积体。三维FDEM数值模拟表明,地震引发边坡岩体内部损伤和变形累积,结构面贯通,滑坡体高速下滑并伴随破坏、解体、撞击对岸、堆积河道、不断密实,形成堰塞体。最终形成的堆积体形态与现场情况比较接近。
Slope instability triggered by earthquake causing sliding is the main factor of the inducement of a barrier lake. Taking Hongshiyan landslide triggered by Ludian earthquake on August 3 in Yunnan Province for example, the three-dimensional （3D） instability process of the landslide is simulated by using finite-discrete element method （FDEM）. The necessary rock parameters are calibrated by using numerical experiments of biaxial compression corresponding to the physico-mechanical parameters. The 3D finite model is established by concluding landslide and valley, smaller grid density being applied to the landslide part. And zero-thickness interface elements are inserted into elastic finite elements. The invalid interface elements are increasing with the collapse and sliding of landslide, causing the transition of landslide from continuum to non-continuum and finally forming loose deposit. The 3D numerical simulation results show that the mechanical principle of barrier dams can be described as follows： the interior damage and deformation accumulation of rock masses are induced by earthquake. Finally, the river is blocked with density, forming the landslide dam. The final formed accumulation state of landslide is close to the field situation.
出处
《中国农村水利水电》
北大核心
2017年第9期156-163,共8页
China Rural Water and Hydropower
基金
国家自然科学基金面上项目(51379161)
中国博士后科学基金面上资助(2016T907272)
