底流消力池水动力荷载特性研究

发布时间：2018-05-02 17:04

本文选题：底流消力池 + 脉动压强　；参考：《天津大学》2014年博士论文

【摘要】：底流消能主要通过表面旋滚与底部主流的强烈紊动掺混过程消杀能量,是水电站泄水建筑物常用的水力消能方式。底流消能以其流态稳定、消能效果好、冲刷轻微、雾化范围小、对地质条件适应性强等优点在高坝工程中的应用受到越来越多的关注。但由于其底部主流流速较高、水流条件复杂,到目前为止,水动力荷载与防护结构稳定性之间的内在关系不十分清楚,工程实际中屡屡发生消力池底板泄洪破坏。因此,深入研究底流消能的水动力荷载特性具有重要的理论意义和工程应用价值。本文依托某工程1:50跌坎消力池和某工程1:80宽尾墩消力池两个水工模型对底流消能进行了水动力荷载系统试验研究,主要内容如下:(1)基于模型试验对消力池底板脉动压强和上举力进行研究,得出了脉动压强、单位面积上举力与总水头的关系;对跌坎消力池与传统消力池进行对比,给出了跌坎消力池对脉动压强和上举力的降低幅度。(2)对消力池底板和边墙的脉动压强和整体荷载进行研究,得到了消力池底板和边墙板块的脉动压强点面转换系数以及最大上举力与脉动压强的关系;提出以脉动压强为参数的底流消力池防护结构稳定的评估指标。(3)对消力池中线底板、边墙板块、陡槽板块尺度对上举力的影响进行了研究,在试验范围内建立了消力池底板尺度、脉动压强空间积分尺度与上举力的关系,给出了优选板块尺度的参考指标。(4)针对板块四周止水完全破坏的极限情况,研究了消力池底板下表面与基岩之间缝隙的贯通程度对上举力的影响。(5)对消力池底板块各种止水完好程度对上举力影响进行了研究,以板块四周止水完全破坏时的上举力为基准,给出可能出现的最大上举力的增加幅度;并对以后进行水动力荷载试验时预测可能出现的最大上举力提供参考。(6)基于模型试验研究了宽尾墩对消力池水动力荷载的影响,并给出宽尾墩对不透水底板和透水底板的下表面脉动压强及上举力的影响程度。(7)对透水底板透水孔内的脉动压强特性进行研究,得到透水孔内任意两点脉动压强相关系数的取值范围;从幅值特性和频谱特性两方面就孔内各点的脉动压强与相同位置上表面的脉动压强进行了对比。
[Abstract]:The energy dissipation of the bottom flow is mainly through the strong turbulent mixing process between the surface rotation and the bottom stream. It is a common hydraulic energy dissipation method in the drainage structures of hydropower stations. The application of bottom flow energy dissipation in high dam engineering has attracted more and more attention due to its stable flow state, good energy dissipation effect, slight erosion, small atomization range and strong adaptability to geological conditions. However, due to the high flow velocity at the bottom and complicated flow conditions, the relationship between the hydrodynamic load and the stability of the protective structure is not very clear so far, the failure of flood discharge on the bottom slab of the stilling pool is often occurred in the engineering practice. Therefore, it is of great theoretical significance and engineering application value to study the hydrodynamic load characteristics of bottom flow energy dissipation. In this paper, the hydrodynamic load system test of the bottom flow energy dissipation is carried out based on two hydraulic models of a certain project at 1:50 and a certain project at 1:80 wide tail pier stilling pool. The main contents are as follows: (1) based on the model test, the pulsating pressure and lifting force of the bottom plate of the stilling pool are studied, and the relation between the pulsating pressure, the lifting force per unit area and the total head is obtained. In this paper, the pulsating pressure and integral load of the bottom plate and side wall of the stilling pool are studied by reducing the pulsating pressure and lifting force. The relation between pulsating pressure point conversion coefficient and maximum lifting force and pulsating pressure is obtained, and the evaluation index of the stability of the protection structure of the bottom flow stilling pool with pulsating pressure as the parameter is put forward, and the bottom plate of the middle line of the stilling pool is counteracted by the index of evaluating the stability of the protection structure of the bottom flow stilling pool with pulsating pressure as a parameter. The influence of the scale of sidewall plate and chute plate on the lifting force is studied. The relationship between the scale of the bottom plate of the stilling pool and the integral scale of the pulsating pressure and the upward lifting force is established in the range of the test. In this paper, a reference index of plate scale, I. e. 4), is given for the limit of complete failure of water stop around the plate. The influence of the penetration degree of the gap between the bottom surface of the stilling pool and the bedrock on the upward lifting force is studied. (5) the influence of various watertight intact degrees of the bottom plate of the stilling pool on the uplift force is studied. On the basis of the uplift force when the block is completely destroyed around the plate, the increase range of the maximum uplift force is given. The influence of wide tail pier on hydrodynamic load of stilling pool is studied based on model test. The influence of wide tail pier on the pulsating pressure on the bottom surface of impermeable bottom plate and permeable bottom plate and the influence of lifting force on the characteristics of pulsating pressure in the permeable hole of permeable bottom plate are also given. The range of the correlation coefficient of pulsating pressure at any two points in the pervious hole is obtained, and the pulsation pressure of each point in the hole is compared with that on the surface of the same position from the aspects of amplitude characteristic and spectrum characteristic.
【学位授予单位】：天津大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TV135.2

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