【作者】 杨敏；

【导师】 练继建； 崔广涛；

【作者基本信息】 天津大学 ， 水利水电工程， 2003， 博士

【摘要】 高坝消力塘作为防护下游河床的结构，其自身在高速水流冲击下的安全性是实现消能和防冲目的的关键所在，国内外都不乏破坏的实例。近年来，我国拟建和在建的一批具有世界级水平的300m量级高坝，消能问题十分突出。消力塘防护结构的稳定性是当前水工水力学学科的前沿课题之一，也是实际工程所面临的亟待解决的课题。本文首先从模型相似准则、材料特性、模型布置、水动力荷载的成因和测试方法、失稳机制和分析方法等方面阐述了模型中研究水垫塘安全性的基本准则。结合溪洛渡、拉西瓦、锦屏一级、糯扎渡、向家坝等大型工程消力塘水工模型试验研究，通过同步测量各种水力参数以及理论分析，提出消力塘底板整体荷载预测及反拱形底板的稳定性分析方法。在此基础上，对防护结构安全控制指标以及评估体系等方面进行了系统研究。主要成果包括：（1）导出满足板块间缝隙水流流动的相似条件并阐述了模型研究消力塘底板稳定性的基本相似准则。（2）提出的平底板和反拱形底板整体荷载的预测经验公式可对类似工程底板最大上举力进行稳定性评估和确定防护水平和防护范围。初步分析了板块失稳的频率特征。（3）用“随机拱”的概念，建立了反拱形底板整体和局部稳定分析的结构力学分析模型并进行实验验证。从板块极限平衡角度，得出了反拱形底板优于平底板的量化指标。（4）根据反拱底板的结构特性，提出用非连续介质数值方法来分析反拱底板的稳定性，并建立了一种新的数值方法—块体弹簧元方法，进一步揭示了防护块体—锚固—锚固的相互作用机制，结果令人满意。（5）基于大量的试验数据，分析了冲击压强和整体荷载(上举力)之间以及点脉动压强与冲击压强之间的量化关系。建议用脉动压强均方根作为稳定控制指标。（6）研究了底流消能消力池作用于底板上整体荷载(上举力)特性并给出了预测方法，同时提出了以脉动压强为参数的控制指标。最大上举力可以用底板表面的脉动压强来表征并作为底板安全的控制指标。（7）研究了水垫塘边坡衬砌块上的水动力荷载特性，得出的最大上举力与脉动压强的关系可作为边坡安全控制指标。 <WP=4>（8）通过某工程消力池隔墙水力学模型试验研究，结合动力有限元计算，对脉动压强沿水流方向的分布规律以及频谱特性进行了分析。采用独特的测量装置研究了整体荷载特性并提出消力池不同位置隔墙段的稳定控制参数。更多还原

【Abstract】 The safety of protecting structure in high dam plunge pool is the key to success or failure of energy dissipation. In recent years, a batch of high dams is under construction in China. The problem of energy dissipation is critical, and it is also the problem that needs to be solved in practice. The basic criterion of safety for the protecting structure is analyzed in this dissertation from the similarity law, material property, test method, the cause of hydrodynamic load, layout of model etc.. Based on the study of plunge pool in Xiluodu, Laxiwa, Jinping, Nuozhadu, Xiangjiaba projects, the predicting method of load and the stability analysis method of counter-arch slab are proposed by the synchronous measure of hydraulic parameters. Fore more the controlling factor and safety evaluating system of protecting structure are studied. The main achievements of this dissertation include as follows:The similitude condition of the flow in gaps between apron slabs is derived. The basic principle is proposed, which is used to study the stability of the plunge pool slab in the model test. The empirical formulas of the load acting on the flat slab and counter-arch slab that put forward in the paper can be used to evaluate the stability and to determine protecting range and protecting standard. Using the concept of “random arch”, a mechanical analysis model of the counter-arch slab is developed and a physical model is built up to verify the analysis model at the same time. From the aspect of limit balance, the quantified safety index for the comparison between the counter-arch slab and the flat slab in stability is carried out. In terms of the stability of whole structure, the central angle of counter-arch structure is appropriate in the range from 30°to 70°. But when it refers to local stability, the ratio of central angel between single slab and the whole counter-arch structure will be suitable under 0.2. On the basis of structure characteristic of counter-arch slab, a new method to analyze the stability of counter-arch slab by using non-continuous numerical method is advanced. The calculating result by using this new kind of numerical method named block-spring is satisfactory. Based on a large number of test data, the quantified relationship between the impact pressure and the uplift on slab is described as well as the relationship between fluctuating pressure and impact pressure. The root mean square of <WP=6>fluctuating pressure is recommended as the control factor in this paper. The characteristics of the uplift acting on the slab in stilling basin are studied, and the predictive method is put forward. The fluctuating pressure as the parameter of safety control factor is suggested. The test data indicates that time-average pressure appears to be unfavorable characteristics to stability on the whole slab. The fluctuating pressure plays the main effect to the slab stable. The fluctuating pressure can express the maximum uplift that can be used as the safety control factor for evaluating stability of the slab. The hydrodynamic load acting on the lining structure on the slope increases with the declination of the water depth in plunge pool, and the fluctuating pressure on the bottom is larger than that of above. The fluctuating pressures on the slab and slope are almost equal in magnitude, and its positions of peak value are approximately the same. The proportion of time-average value in whole load is large. The relationship between maximum uplift and fluctuating pressure can be used as the factor of safety control. Based on the hydraulic model experiment of the guide wall in stilling basin of a large engineering project, relating to the calculation of dynamic finite element，the main conclusions can be gained as follows：The distribution of fluctuating pressure declines along the distance and the peak value occurs at the front of jump. The distribution of integer load acting on the guide wall is the same with fluctuating pressure. The transfer coefficient of point-area fluctuating pressure on both sides of更多还原