摘要
以甲西倾倒体为典型实例,从赋存环境、发育特征、形成条件等基础层面上分析雅砻江上游互层斜坡倾倒变形破坏机制及演化过程。研究表明:区内大型倾倒体是斜坡岩体在叠加有残余构造应力的自重应力场中长期演化的产物,软硬相间的岩性组合、陡倾内的岸坡结构,加之垂直层面密集节理的切割是斜坡发生倾倒变形的控制性因素;斜坡倾倒是受节理面和层面控制的复合倾倒模式,即:硬岩发生块状-弯曲倾倒,而软岩发生弯曲倾倒;受河谷演化控制,斜坡变形破坏主要经历了4个演化阶段:卸荷回弹陡倾面拉裂阶段,初始变形阶段,板梁根部折断、剪切面贯通阶段以及破坏阶段,并最终转化为蠕滑-拉裂模式形成滑坡。该滑动面受倾向坡外破裂面控制,而并非沿最大弯折带发育。
The mechanism and evolution of toppling in interbedded rock slopes in upstream of Yalong River are analyzed with the typical case of Jaxi toppling. The analysis covers the aspects of geological background, development characteristics and formation conditions. This comprehensive study points out that the large-scale toppling in research area is developed by the unique structure of slopes in gravity stress field. The slopes are consisted of a pervasive foliation dipping steeply into the slope, have soft layer and hard layer interbedded and a set of well-developed cross-joints. A model illustrates a typical feature of toppling failure of interbedded rock slope. It is recombination of block-flexure toppling in hard rock and flexural toppling in soft rock, respectively. With the evolution of Yalong River, the deformation of the slope experiences four steps u n l o a d i n g a n d r e b o u n d , initial deformation, breaking in flexure, and failure as landslide. The sliding surface can be developed along the cross-joints ,rather than the maximum bending zone.
出处
《工程地质学报》
CSCD
北大核心
2017年第6期1501-1508,共8页
Journal of Engineering Geology
基金
国家自然科学基金重点项目(41230637)
中国博士后科学基金(2016M592411)资助
关键词
雅砻江上游
互层斜坡
倾倒
变形破坏机制
演化
Upstream of Yalong River, Interbedded rock slope, Toppling, Failure mechanism, Evolution
