| 摘要: |
| 黏性土坝漫顶溃决涉及多学科交叉，过程极其复杂，尽管国内外大量物理模型试验成果表明其溃决多以“跌坎式”溯源冲蚀为主要特征，然而对该冲蚀发展形式下的水流-坝体微观作用机制尚不清晰。水流作为漫顶溃决的冲刷主动力，对坝体溃决发展起着主导性作用，采用RNG k-ε紊流模型和VOF自由液面捕捉技术针对黏性土坝漫顶溃决代表性水流结构——溃决跌坎水流开展了三维数值模拟研究，对跌坎水流的水流结构、流态、水力特性指标等进行了细致分析，揭示了不同工况下坝体跌坎上的剪切应力、流速分布规律，进而从水动力学的角度对坝面进行受力分析，初步推断了黏性土坝漫顶溃决过程中各级跌坎的主要合并方式为“台阶水平面刷深下切”。研究成果为进一步掌握黏性土坝漫顶溃决发展演变机理提供了理论基础。 |
| 关键词: 黏性土坝 漫顶 跌坎水流 水动力特性 数值模拟 |
| DOI： |
| 分类号:TV871 |
| 基金项目:国家自然科学基金委青年科学基金项目(51409173)；中央级公益性科研院所基本科研业务费专项资金（Y116009，Y114004） |
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| Numerical study of hydrodynamic characteristics of dam-break headcut flow |
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ZHU Long, ZHOU Donghui, LI Yun, XUAN Guoxiang, WANG Xiaogang
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State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Nanjing Hydraulic Research Institute, Nanjing
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| Abstract: |
| Taking the lower approach channel of the Wuliting navigation lock as a case history. A two-dimensional hydrodynamic model is developed to study regulation measures, such as riverbank excavation, construction of the guild walls, dredging and adjustment of waterway regulation. The gradual optimization of water flow conditions of the typical approach channel is expounded in detail, and the recommended regulation schemes for the downstream approach channel of the Wuliting navigation lock are proposed based on the analyses above. Through the gradual optimization of the schemes, the main conclusions are as follows: ①The optimization process of the comprehensive channel regulations is a gradual process under multi constraints. Both the feasibilities of hydropower generation and flood propagation should be considered before the regulation measures of navigation are adopted, which is usually ignored; ②There should be an optimal length of the guild walls for certain approach channels; ③The construction of a long submerged guild wall is suggested, not only appropriate for the navigation conditions but also for the hydropower generation and flood carrying capacity. It is an effective measure to remedy the poor navigational flow in approach channels of the navigation locks. |
| Key words: clay soil dam overtopping headcut flow hydrodynamic characteristics numerical simulation |
