基于连续-离散耦合方法的堰塞坝形成机理研究

Landslide and rockfall are main reasons for the formation of landslide dam. The formation process of landslide dam mainly includes the instability, sliding and collapse of the rock material, and the blocking of river channel by the rock landslide or rockfall, which is a transformation process of rock material from continuum to discontinuum state. On one hand, the whole continuous rock collapses to form granular flows with different sized particles; On the other hand, particle fragmentation always occurs during this flowing process. The formation of landslide dam experiences both continuum and discontinuum processes, and therefore only one continuum or discontinuum method cannot describe precisely the whole formation process of landslide dam. Due to this complexity, so far no deep understanding on the mesoscopic mechanism of landslide dam formation has been found. Based on the finite-discrete element method, a deep study on the mesoscopic mechanism of landslide dam formation will be conducted, and the effects of size segregation and particle fragmentation on the kinetic characteristics of granular flows will be analyzed. A new numerical method that can describe precisely the whole formation process of landslide dam will be proposed. According to the findings in this research, the mesoscopic mechanical behavior of granular materials will be well understood. The research will be of great importance to evaluate the possibility for a rock slope to form a landslide dam and the safety of the existing landslide dam.

滑坡和崩塌是形成堰塞坝的主要形式之一，其形成过程主要包括滑坡体失稳、滑动、崩塌以及最终堵塞河道，在这过程中一直伴随着岩石材料从连续到非连续的转化过程：一方面，滑坡体从连续体失稳破坏成大小不一的颗粒流；另一方面，颗粒在滑动过程中不断发生着破碎。无论是连续介质的方法还是非连续介质的方法均无法统一地、精细地描述堰塞坝形成的整个过程。由于堰塞坝形成过程十分复杂，至今国内外对于堰塞坝形成的细观机理尚未有深入的认识。本项目拟基于连续离散耦合分析方法，深入研究堰塞坝形成过程的细观力学机理，分析尺寸分离、颗粒破碎等颗粒细观动力学模式的影响，并提出模拟堰塞坝形成的全过程数值分析方法。该项目的研究不仅可以深化对颗粒材料细观力学行为的理解，而且对于预测可能形成的堰塞坝、评估已形成的堰塞坝安全性尤为重要。

滑坡和崩塌是形成堰塞坝的主要形式之一，其形成过程主要包括滑坡体失稳、滑动、崩塌以及最终堵塞河道，在这过程中一直伴随着岩石材料从连续到非连续的转化过程：一方面，滑坡体从连续体失稳破坏成大小不一的颗粒流；另一方面，颗粒在滑动过程中不断发生着破碎。无论是连续介质的方法还是非连续介质的方法均无法统一地、精细地描述堰塞坝形成的整个过程。由于堰塞坝形成过程十分复杂，至今国内外对于堰塞坝形成的细观机理尚未有深入的认识。本项目基于连续离散耦合分析方法，深入研究了堰塞坝形成过程的细观力学机理，分析尺寸分离、颗粒破碎等颗粒细观动力学模式的影响，建立了一个能够精确描述滑坡体动力学特性的细观数值模型，揭示了堰塞体形成全过程的细观力学机制。通过三维连续-离散耦合数值模型，结合颗粒流滑动-堆积物理试验，研究了能够统一描述滑坡体从连续介质到离散颗粒体再到最终堆积形成堰塞体的力学行为。该项目的研究不仅可以深化对颗粒材料细观力学行为的理解，而且对于预测可能形成的堰塞坝、评估已形成的堰塞坝安全性尤为重要。