高混凝土面板堆石坝漫顶溃坝过程研究

Utilizing the centrifugal model test system of 100 meters level which is developed basing on the time-space compression effect of the centrifuge by the research team of the applicant, the breaching process of Gouhou concrete-face rockfill dam is reappeared, and the similarity criterion of high earth-rock dam which is deduced according to the similarity theory of geotechnical centrifuge will be verified and improved. In order to reveal the breach mechanism and the influence factors of high concrete-face rockfill dams due to overtopping failure, the dam breach model tests are carried out considering the different dam height and overtopping water head. According to the breach mechanism, integrating the numerical modeling methods of computational fluid dynamics (CFD) and discrete element method (DEM), the CFD-DEM coupling model which can consider the erosion of wide grading under the breach flow is established, and the coupling calculation method for the relationship of erosion amount and stress state of concrete slab is also developed to reasonably determine the break time and length of the concrete slab. Taking the valley shape into consideration, a numerical breach model for high concrete-face rockfill dams which can correctly reflect the breach mechanism and reasonably simulate the breaching process is developed. The visualized and GIS technologies are utilized to compile the computer software which can directly show the dam breaching process. This provides a theoretical and technical supports for improving the level of disaster consequence assessment due to the high concrete-face rockfill dam failures.

利用申请人研究团队基于离心机的“时空压缩效应”研发的100m级高土石坝溃坝离心模型试验系统，重现沟后面板堆石坝溃坝过程，验证完善基于土工离心机相似理论推导出的高土石坝溃坝离心模型试验相似准则；通过开展不同坝高和不同漫顶水头的溃坝模型试验，揭示高混凝土面板堆石坝漫顶溃决机理和溃口发展过程影响因素；基于计算流体力学与离散元法耦合的计算方法，建立能合理反映溃坝水流作用下宽级配堆石料冲蚀的CFD-DEM耦合模型，提出堆石料的冲蚀量与混凝土面板受力状态变化的耦合计算方法，合理确定面板折断时刻和折断长度；考虑河谷的形状，建立正确反映高混凝土面板堆石坝漫顶溃坝机理，合理模拟其溃坝过程的数学模型；利用可视化和GIS技术，编译能直观显示其溃坝过程的计算机软件，为提升高混凝土面板堆石坝溃坝致灾后果的预测精度提供理论与技术支撑。

大坝溃决是一种低概率、高危害的重大灾害，而对高混凝土面板堆石坝溃决机理与溃坝过程的认识尚不明晰。利用申请人研究团队基于离心机的“时空压缩效应”研发的100m级高土石坝溃坝离心模型试验系统，验证完善基于土工离心机相似理论推导出的高土石坝溃坝离心模型试验相似准则；通过溃坝离心模型试验，揭示高混凝土面板堆石坝漫顶溃决机理和溃口发展过程影响因素；基于计算流体力学与离散元法耦合的计算方法，建立能合理反映溃坝水流作用下宽级配堆石料冲蚀的CFD-DEM耦合模型，提出堆石料的冲蚀量与混凝土面板受力状态变化的耦合计算方法，合理确定面板折断时刻和折断长度；考虑河谷的形状，建立正确反映高混凝土面板堆石坝漫顶溃坝机理，合理模拟其溃坝过程的数学模型；利用可视化和GIS技术，编译能直观显示其溃坝过程的计算机软件，为提升高混凝土面板堆石坝溃坝致灾后果的预测精度提供理论与技术支撑。