考虑运动学特征和流固耦合作用的滑坡成坝机理研究

The formation and analysis of landslide dam is of great importance due to the huge damage and high risk of the hazard. To date, majority studies on the dam formation are restricted on their geomorphological features, while lacking of the consideration of kinematic characteristics (i.e. landslide velocity, travel distance, flow velocity and discharge) and solid-fluid interaction. For this reason, this study aims to analyze the effect of kinematic characteristics and solid-fluid interaction on the formation mechanism. Firstly, a database of historical landslide dam events is built, aiming to figure out the key geomorphological features by statistical analysis. Then, a filed investigation of typical dam sites will be conducted to study the mechanism that material component and structure affect the solid-fluid interaction. Importantly, a new and typical physical experiment will be designed and implemented to quantitatively analyze the effect of kinematic characteristics and solid-fluid interaction on the formation mechanism by using a series of comparative tests. Moreover, a coupled DDA (Discontinuous Deformation Analysis)-SPH (Smoothed Particle Hydrodynamics) method will be developed to deal with the solid-fluid problem, and thereby fulfill the dynamic simulation of landslide dam. Finally, on the basis of theoretical analysis of dam formation mechanism, quantitative criteria and a comprehensive method will be proposed to evaluate the possibility of dam formation. The research will provide solid foundation and a practical solution for forecasting the possibility of landslide dam in the hillslope-channel region.

滑坡成坝机理是滑坡灾害评估的关键科学问题。当前滑坡成坝机理大多基于对成坝单元地貌特征的分析，而缺乏对滑坡和河流运动学特征（如滑速、滑距；河流流速、流量等）以及二者耦合作用的考虑。针对这一问题，本项目从运动学特征和流固耦合作用为切入点，分析其对滑坡成坝机理的影响。首先，进行滑坡坝灾害的数据库编目，统计分析成坝的关键地貌、运动学因素；其次，进行典型实例的工程地质调查，分析滑坡物质组成、结构对流固耦合作用的影响；然后，设计实施物理模型试验，通过变化运动学特征和滑体物质结构的多组试验，分析其对成坝机理的影响；再者，开发耦合DDA-SPH数值方法和计算程序，实现滑坡成坝过程的动态模拟；最后，理论分析滑坡成坝机理，基于运动力学特征和流固耦合作用定量化地提出滑坡成坝各过程的判据，最终提出一套实用且适用的滑坡成坝评价方法。本研究成果将为高山流域滑坡堵江成坝预测、灾害风险评估提供坚实的理论基础和科学支撑。

滑坡堵江是山区的一种典型地质灾害。当前滑坡成坝机理大多基于对成坝单元地貌特征的分析，而缺乏对滑坡和河流运动学特征（如滑速、滑距；河流流速、流量等）以及二者耦合作用的考虑。针对这一问题，本项目从运动学特征和流固耦合作用为切入点，分析其对滑坡成坝机理的影响。首先，本课题制定了滑坡坝编录数据库的基本格式和要求，通过广泛收集调研形成了中国主要滑坡坝灾害的数据库编目，并统计分析成坝的关键地貌、运动学因素。其次，设计了能够考虑河流运动学特征的明渠流数值实验模型，并定量确定了需求流速恒定流的产生方法，为滑坡坝的数值实验提供基础。再者，验证了基于NonNewtonian-SPH以及SPH-Chrono的耦合模型，并运用到滑体与水体的相关作用过程中，为滑坡坝的数值实验提供了解决方案。本研究成果将为高山流域滑坡堵江成坝预测、灾害风险评估提供坚实的理论基础和科学支撑。