堰塞坝全寿命过程对全流域影响的时空演化分析与风险管控

Landslide dams pose high risks to their drainage basin during their life cycle, which involve a large influence area, a long period of time, and complex disaster mechanisms. Considering damage degree of different causes of landslide dams, the temporal and spatial evolution law of landslide dams blocked by avalanches and slides in their life cycle is studied in this research project to achieve a holistic, systematic, effective and dynamic risk management. Firstly, a model for predicting the formation of landslide dams blocked by avalanche and slide will be proposed based on an in-depth study of the initiation, runout and river-blockage mechanisms of different types of landslides. Secondly, failure and breaching analysis models will be developed through model tests and numerical analysis of the sliding, erosion and seepage failures of landslide dams. Thirdly, the influences of landslide dams on the hydrologic, and geologic environment will be analyzed by studying the soil mass movements caused by landslide dam failures. Finally, a quantitative dynamic risk management system will be developed by considering the uncertainties in occurrence probabilities and consequences of landslide dam disasters, and in corresponding engineering and non-engineering measures. The project will provide theoretical basis and practical tools for emergency management, utilization of dams lake as resources, enhanced safety of human lives and properties, urbanization and transportation planning, and sustainable development in landslide-dam prone basins.

堰塞坝在全寿命过程中对全流域会产生不同程度的影响，呈现影响范围广、持续时间长、潜在风险大和灾变机理复杂等特点。考虑到不同成因堰塞坝的危害程度，本项目将研究崩滑型堰塞坝全寿命过程对全流域影响的时空演化规律，以实现对堰塞坝的全面、系统、有效、动态风险管控。从崩滑体启动运行和堵江成坝机理出发，建立流域内堰塞坝预测模型；通过堰塞坝渗流、滑移、冲刷破坏的模型试验和数值分析，建立崩滑型堰塞坝失稳和溃决机理分析模型；通过堰塞坝全寿命过程水土物质运移的时空演化规律，分析其对全流域水文、地质环境的影响；考虑堰塞坝灾害发生概率和损失的不确定性，以及工程和非工程措施的控制效应，提出定量化动态风险管控体系。本项目的开展对堰塞坝易发区域的应急管理、堰塞湖的资源化利用、流域范围的生命财产安全的有效保障、城镇和交通规划和可持续发展具有重要的理论及现实意义。

堰塞坝致灾影响贯穿全寿命过程和全流域范围，具有影响范围广、持续时间长、潜在风险大、致灾机理复杂的特点。项目在堰塞坝堵江成坝特征、失稳溃决机理、水土物质耦合运移规律、危险性快速评估方法、全寿命过程风险评估及管控等方面取得了如下研究成果：（1）基于全球堰塞坝大型案例数据库建立了流域尺度成坝预测方法；研发了崩滑型堰塞坝形成-溃决过程模型试验装置，揭示了不同影响因素下崩滑碎屑体堆积成坝的形态、结构和材料特征，建立了崩滑型堰塞坝坝体特征参数预测模型。（2）厘清了堰塞坝宽级配材料非饱和持水特性和抗剪切、渗流和冲刷特性；揭示了坝体形态、材料和结构等内因和冲刷、渗流、余震、涌浪等外因对堰塞坝稳定性和溃决过程的影响机理；提出了堰塞坝溃坝程度和寿命阶段概念和预测方法；考虑堰塞坝非均匀结构特性建立了三维溃坝模型，考虑上下游溃坝洪水演进影响建立了堰塞坝多坝连续溃决分析模型。（3）揭示了溃决洪水与河床间相互作用机制，厘清了不同溃决模式下堰塞坝溃决洪水对下游河道的冲淤机制，揭示了堰塞坝消亡过程泥沙输运规律，建立了考虑冲刷-沉积动态转化的堰塞坝溃坝-消亡水土物质运移分析模型。（4）提出了考虑材料特性的堰塞坝稳定性和寿命快速评估模型；构建了数据易获取的堰塞坝溃决参数计算公式和溃坝过程分析模型；提出了堰塞坝全流域溃坝洪水演进快速分析方法，建立了堰塞坝全寿命过程对全流域影响快速评估的地理信息平台。（5）建立了耦合力学原理及统计数据的溃坝生命损失风险定量评估模型；提出了考虑溃坝概率和损失的时间效应的动态风险预警决策方法；建立了堰塞坝全寿命过程对全流域影响的风险评估模型；构建了堰塞坝泄流槽优化设计准则和堰塞坝泄洪流量柔性控制技术。研究成果已成功应用于唐家山、红石崖、白格、川藏铁路洛隆站上游冻错曲等多座堰塞坝的溃坝参数预测、定量风险评估和资源化开发利用，具有重要的理论指导价值和推广应用前景。