多运行方式协同作用下的长距离输水渠系冰塞冰坝风险防控机制与技术

The safety and efficiency of long distance canal system water transportation have been a hot research issue of related disciplines. This study will break the conventional mode that the canal system pools adopted the same operation mode in winter, so the superiorities of different operation are used to control and reduce the ice jam/dam hazard probability, to improve the water safety and performance of long distance canal system. In this study, the main contents include: based on the formation mechanism of ice jam/dam, the risk factors of ice jam/dam are identified, and the assessment system and mechanism of ice jam/dam hazard probability are established; through the flume experiment and numerical experiment, the relationships among characteristics of canal pool, operation mode and ice jam/dam risk probability will be revealed, and the optimization mechanism of single canal pool operation mode will be established; through the flume experiment and numerical experiment, the coupling response characteristics of ice evolution-hydraulic process-sluice under different operation modes are revealed, and the restriction requirements and rules of different operation modes connected to each other are analyzed, and the operation modes optimization mechanism of canal system will be established; the operation mode real-time adjustment will be used to improve the water conveyance efficiency, then a ice jam/dam risk controller is need to make the operation status switch safely-stablely-fastly; finally, a set of ice jam/dam risk prevention and control technology will be got under the synergism of different operation modes in canal pools.

渠系冰期输水面临冰塞冰坝风险。运行方式具有通过改变水力条件而可能影响冰塞冰坝风险概率和冰期输水能力的优势，但运行方式多样化对冰塞冰坝风险的作用机制尚未明确，因此长距离输水渠系在时空上常采用统一运行方式，限制了其冰期输水安全性、灵活性和效益性。本项目突破常规，从渠系冰塞冰坝形成机理出发，辨识冰塞冰坝风险因子，建立冰塞冰坝风险概率定量评估体系与机制；揭示风险因子与冰塞冰坝风险概率间的作用关系，提出风险防控能力和安全输水能力，建立单渠池冰期运行方式优选机制；基于单渠池运行方式自主优化，剖析不同特性的渠系在不同运行方式组合作用下的冰情-水力-闸门耦合响应规律，探求运行方式最优组合的衔接限制要求与规则，建立渠系冰期运行方式优选机制；研发冰塞冰坝风险控制器，实现不同运行状态安全、平稳、及时切换与优化，最终形成整套长距离输水渠系多运行方式动态协同作用下的冰塞冰坝风险防控技术，可明显改善渠系冰期输水性能。

调水渠系面临的冰塞冰坝风险是威胁冰期输水安全、限制冰期输水效益的重要原因，如何进行风险防控，实现安全高效灵活的冰期输水，成为学术探讨的焦点。研究按照计划书安排，以南水北调中线干线工程为背景，探讨沿线冬季气温特征；揭示冰花下潜临界条件；建立冰情模拟与调度模型；提出调水工程冰塞综合风险评估方法；提出冰坝风险评估方法；提出冰塞/坝洪水风险保险应对措施；优选基于冰塞风险防控的运行方式；设计专用控制器，形成调水工程冰塞冰坝防控实时调控模式。.结果表明，工程沿线地区冬季气温具有显著升温趋势，强冷冬全线同步比例约8%，同步冷暖冬比例共约43%；建立了南水北调中线干线工程冰期输水调控仿真模型，且推荐水面热交换系数hwi取18 W/(m^2·℃)，冰面热交换系数 hwai 取26 W/(m^2·℃)为参数较优取值；提出了冰塞综合风险评估方法，包括考虑工程设计方案和运行管理两个视角的基本风险度确定法和考虑串联渠系水力耦合的次生风险度确定法；采用故障树法确定了气象条件、水温升高、底坡变缓、控制建筑物、桥墩阻挡、渠道运行方式等6个冰坝主要风险因子，确定案例渠道冰坝风险概率为0.002029，属于三级风险；工程管理单位、沿线周边利益主体和保险企业三方演化博弈最优演化稳定策略为（投基本险，投附加险，承保）；认为上游常水位运行造成的冰塞风险最小，下游常水位运行在封冻时闸门调控及时，等体积运行方式中庸；封冻渠池在封冻时，由下游常水位切换为等体积所造成渠系的水位偏差、最大流速等指标分别较始终保持下游常水位减小50%和6.5%，表明运行方式切换更有利于维持渠系在封冻时的稳定和减小冰塞风险；设计了常规PI+寻优双层反馈控制器，建立了封冻期渠系闸门群优化调度模拟模型，寻优控制器能使下游最大水位偏差减小近40%，且系统恢复稳定时刻提前近3 h，表明所建模型对抑制封冻期水力响应过大有一定的效果。.研究成果对完善调水工程冰期输水理论和提高工程冬季运行安全与效益等具有重要支撑意义。