淤地坝系风险分析方法及防控措施相关理论问题研究

Check dams for farmland forming play a significant role in ecological benefits of soil and water conservation, however, dam break accidents occur sometimes and cause great suffering for people’s lives and property. This project will obey the overall design idea of “Investigation, Analysis, Test and Application”, and adopt theoretical analysis combined with material and model testing. Taking the check damage system for farmland forming as the research object, a risk analysis method and standard for the check dam will be studied, and meanwhile the theoretical research related to risk prevention and control engineering measures will be carried out. ①The rules of storage capacity of check dam for farmland forming, rainwater harvesting area and rainfall frequency will be generalized, and a fast outburst flood analysis approach suitable for the check dam will be established. ②Based on the analysis of continuous outburst flood of the check dam system for farmland forming, a failure probabilities evaluation method will be set up. ③A qualitative and quantitative risk evaluation criteria of the check dam for farmland forming will be established on the basis of the scale, the failure probability and the losses of the accidents of the dams. ④The mechanism that flexible spillway discharge facilities are able to reduce break risk of the warping dam will be analyzed, and the layout scheme of the flexible spillways will be proposed. The structure stability of compression-resistance and erosion-resistance for the flexible spillway will be researched through compression test, scour characteristic test, centrifuge model test, etc. ⑤Taking the JiuYuan check dam for farmland forming as a pilot project, the proposed risk analysis methods and preventive and control measures will be verified, improved and applied, and the corresponding decision support for the warping dam reinforcement will be provided.

淤地坝在发挥着巨大水保生态效益同时，溃决事故也时有发生。其溃决给人民群众生命财产造成巨大灾难。项目遵循“调研→分析→试验→应用”的整体思路，采用理论分析与材料、模型试验相结合的方法，以淤地坝系为研究对象，开展淤地坝风险分析方法及风险标准研究，同时开展风险防控工程措施相关理论研究。①概化淤地坝库容、集雨面积、降雨频率规律，建立适用于淤地坝的快速溃决洪水分析方法。②以淤地坝系连续溃决洪水分析为基础建立淤地坝失效概率分析方法。③结合淤地坝规模、发生失效概率及灾害造成损失建立淤地坝定性及定量风险评价标准。④分析柔性溢洪道泄水设施降低淤地坝溃决风险作用机理，提出柔性溢洪道布置方案。采用压缩试验、冲刷特性测试试验、离心模型试验等方法对柔性溢洪道关键的抗压、抗冲蚀结构稳定性问题进行研究。⑤以韭园沟淤地坝系为试点，对风险分析方法、防控措施进行验证、改进及应用，并为淤地坝除险加固提供决策支持。

由于近年来极端暴雨事件频发和自身运行状态欠佳，淤地坝水毁溃决事件时有发生且频率增高，这对下游人民群众生命财产安全和生态环境保护造成极大威胁。本项目重点围绕以下三个方面开展研究工作，并取得了预期研究成果。一是，基于典型淤地坝系现场调研和遥感调查，厘清了淤地坝系溃决风险孕育机理，为淤地坝系溃决分析方法和淤地坝防冲加固技术研究奠定基础。二是，建立了淤地坝系溃决洪水分析方法体系，解决了淤地坝系溃决洪水计算中逻辑关系难以表述、溃决流量计算不准确等问题。实现了计算淤地坝系溃决失效概率、临界溃决降雨量、溃决洪水淹没范围的目标。三是，基于自主研发的COMPET土工合成材料，采用材料试验、现场施工工艺试验、实际工程示范应用、现场泄流试验等方法，研发了淤地坝柔性台阶式溢洪道技术。相较于传统刚性溢洪道，该技术具有经济合理、因地制宜、环境友好的显著优势。本项目相关研究成果为淤地坝溃决风险分析及防控提供了理论和技术支撑，在内蒙古鄂尔多斯乌兰沟北小流域、陕西延安三连队淤地坝等实际淤地坝工程得到了示范应用。在本项目执行期间，共发表标注本项目资助的学术论文25篇，其中SCI检索论文8篇(其中EI同时收录6篇)，EI检索论文1篇。出版学术专著1部，授权发明专利3项，授权软件著作权4项。项目组举办国内学术会议2次，项目负责人在国内会议作学术报告7次。