高坝泄流诱发闸门特殊振动形式的被动减振方法研究

With the development of high dam construction, the vibration problems of hydraulic structures and surrounding environment induced by high dam flood discharge are increasingly prominent, and the adverse effects of vibration on hydraulic gates are especially serious. Based on the theoretical analysis and physical model test, the conventional researches for vibration reduction of hydraulic gates mainly focus on the structural optimization of gate, flume, gate slot and supporting structure. However, the vibration damping effect is not satisfying, and sometimes the structural optimization scheme is difficult to apply. The application of dynamic vibration absorber (DVA) in the control of gate vibration is not reported in published literatures. Recently, the results of prototype test indicate that some kinds of gate vibrations are characterized by centralized distribution of energy and time-invariant dominant frequencies, which provide favorable conditions for the application of DVAs, such as tuned mass damper (TMD). In order to effectively reduce the gate vibration induced by high dam flood discharge, this project mainly focuses on the following research aspects: (1) determining the parameters and layout scheme of TMDs according to the dynamic characteristics and vibration mechanism of hydraulic gate; (2) developing the dynamic analysis method for the gate-TMD system with non-classical coupled damping and nonlinear damping; (3) investigating the feedback influences of TMDs on flow-gate interaction mechanism. This research project aims at providing theoretical basis and feasible technical support for the long-term safety and stability operation of hydraulic gates, which has important theoretical and practical significance.

随着高坝建设的发展，泄流诱发结构和环境振动问题突出，就水工结构而言，以闸门受到的不利振动影响为最。传统研究主要基于理论分析和模型试验，通过优化闸门、流道和门槽等结构体型以减小振动，但其减振效果较差，且减振方案有时不易实施。近期的原型观测表明，闸门的某些振动形式具有能量集中、频率稳定的特点，这为以调谐质量阻尼器（TMD）为代表的被动减振器的应用提供了有利条件。然而，应用动力学减振措施进行闸门减振的研究极为缺乏。本项目首先结合闸门动力特性和振动机制，明确TMD的参数设计和布置方案；然后研究复杂阻尼特性的闸门-TMD系统动力响应计算方法，以准确考虑非经典耦合阻尼和非线性阻尼对系统动力响应的影响；最后，考虑水流作用，研究TMD对水流-闸门耦合机制的反馈影响，以期通过被动减振方法，实现高坝泄流诱发闸门振动的有效衰减。所申请项目兼有理论性和实用性，旨在为保障闸门长期稳定安全运行提供理论基础和技术支持。

随着我国水利枢纽建设的蓬勃发展，高坝泄流诱发的闸门振动问题十分突出，亟需加强研究以满足工程需求。事故闸门承担着动水中紧急落门防止事故扩大的重要任务，然而闸门无法完全落门并伴随爬行振动的问题屡屡发生，在紧急情况下可能造成严重损失。从系统控制理论的基本观点出发，将由动/静摩擦力转换导致的非线性特性作为单独的环节，合理选取被控量与参据量，构建了负反馈控制系统理论模型并进行了合理性验证，阐明了闸门无法闭门并伴随爬振的发生机制。考虑东庄坝身底孔平面事故闸门的具体情况，将实际参数输入理论模型，分析了闸门的受力和运动状态，并对不易确定的参数进行了敏感性分析，与其它研究对比分析了计算结果的合理性。认为东庄坝身底孔闸门不会发生爬行振动，并认为闸门发生无法动水闭门工程问题的可能性较小。结合发生爬振问题的工程实例，针对东庄闸门给出了初步的减振方案。考虑闸门伴生振动机制，采用双调谐TMD减振措施，建立了振动控制方程；基于H∞鲁棒控制设计目标，推导了闸门-双调谐TMD体系参数优化设计的目标函数和约束条件；并对动力特性与实际相似的简化模型进行了参数优化设计；结构动力计算表明该方法可以有效衰减闸门的伴生振动，保障闸门安全和正常运行。针对大石峡放空排沙洞工作闸门的泄流振动问题，设计、建立了相应的水弹性模型，对上下支臂、主横梁、边纵梁腹板的动应力和动位移进行了测试，测试结果表明，闸门结构受力特征良好，其刚度和强度均满足设计要求；脉动应力主频在1Hz以内；测试得到了不同上游水位和闸门开度工况下的振动位移；明确了闸门振动较为严重的不利工况，提出了以减振为目标的优化调度运行方案。