拉槽侵蚀型泥石流物源补给演进过程及动储量的实验研究

After the Giant Wenchuan Earthquake an increasing number of debris flows were triggered by the precipitations damaged and invalided the debris flow engineering protection projects.The debris flow disasters demonstrated that debris flow in seismic zones have significant differences in distribution, forming conditions,scales,moving styles as well as other disaster modes.Erosion and cutting was the mainly moving mode for the debris.The reason of this phenomenon is the types, volume and supplement mechanism of the debris reserves undergoes a dramatic change, so that the calculation of reserve volume was out of technical standard for disaster mitigation. the erosion and cutting gullies is formed on the landslides and fracturewd slopes in the formation areas and upstreams in the catchments of watersheds in earthquake hit region.Which offer largely amount of debris for debris flows.this makes the erosion and cutting style of reserve supplement became the typical style ofdebris supplement.The study area is in Baishahe River Basin, Wenchuan earthquake region. The slopes was eroded and cut into gullies and providing the solid debris for the debris flows, experimental tests will be used to exploring the mechanism, correlation and process of the erosion mode debris flow reserve, after the correlation of debris supplement process and precipitation is revealed, the micro terrain characteristics, soil mechanism parameters of the debris reserve source are combined to determine the threshold of the debris transition and construct the calculation formula of moveable reserve volume. This project is about to explore on the key scientific issues of the process, threshold and calculation of the moveable reserve for the erosion based mode debris flows reserve, which can contribute great significance for the disaster mitigation and reduction in Wenchuan earthquake regions.

汶川地震灾区震后降雨条件下发生大规模泥石流灾害，导致已治理泥石流防治工程出现大量满库翻（毁）坝等失效现象。其根本原因是震后泥石流物源类型、规模和补给方式同震前具有较大的差别,因其物源量计算无规范可借鉴，导致泥石流物源计算方法不能满足震后泥石流工程设计和预警预报的需要。本项目以极震区白沙河流域为靶区，针对震后泥石流物源区出现拉槽侵蚀型泥石流物源补给的典型模式，主要通过物理模型实验分析拉槽侵蚀型泥石流物源补给的重力侵蚀过程和流水侵蚀过程的交互作用、控制因素和演进过程，揭示物源补给转化过程与降雨激发条件的耦合关系，再结合泥石流物源区沟道岸坡的微地貌特征和坡体力学参数等条件开展实验和理论分析，从而确定物源补给转化的临界条件，并建立定量预测可参与泥石流活动的物源动储量的预测模型，以期解决拉槽侵蚀型泥石流物源补给过程、临界条件和动储量计算的关键科学问题，为震后泥石流防治工程设计和预警预报提供技术支撑。

汶川地震灾区震后降雨条件下发生大规模滑坡并转化为泥石流灾害，震后泥石流物源类型、规模和补给方式同震前具有较大的差别，因其物源量计算无规范可借鉴，导致泥石流物源计算方法不能满足震后泥石流工程设计和预警预报的需要。本项目以极震区白沙河流域为靶区，针对震后泥石流物源区滑坡堆积体出现拉槽侵蚀型泥石流物源补给的典型模式，主要通过物理模型实验分析震后滑坡拉槽侵蚀型泥石流物源补给的水-力的交互作用、控制因素和演进过程，及其转化过程与降雨激发条件的耦合关系，确定物源补给转化的临界条件，并建立定量预测模型，以期解决地震滑坡堆积体拉槽侵蚀型泥石流物源补给过程、临界条件和动储量计算的关键科学问题。主要取得了以下成果（1）揭示了典型震后滑坡拉槽型泥石流物源地貌时空演化规律；（2）揭示了泥石流物源区滑坡堆积体失稳转化为泥石流的渗流特性及水-力耦合机制；（3）量化了基于渗流侵蚀的拉槽侵蚀型物源多物理场耦合演进过程；（4）构建了基于双渗流模型的泥石流物源区滑坡堆积体失稳水-力耦合模型；（5）构建了基于优先流特性的物源区堆积体水-力耦合机制及水-土特征本构模型；（6）建立了基于实测大数据的拉槽侵蚀型物源失稳机理及预警多元指标体系。获取了银洞子沟观测示范点4个水文年现场水-力实测数据和水-力耦合机制试验研究的大量实验数据。研究成果目前出版专著1部，发表科研论文16篇，其中SCI检索5篇，EI或者ISTP检索3篇，国内核心刊物6篇，授权发明专利3项，软件著作权3项。本研究成果可为震后泥石流防灾减灾和预警预报提供技术支撑。