减轻立堵截流难度方法及应用研究

发布时间：2018-06-06 01:49

本文选题：立堵截流 + 难度　；参考：《西华大学》2014年硕士论文

【摘要】：截流是水利建设中的一项关键工程，由于截流过程复杂，，所以截流工程的成效直接影响整个工程的投资效益和工期。龙口水力条件是决定合龙能否成功的主要因素，所以在施工前，应该通过物理模型或数学模拟，提前研究龙口断面形状，对可能发生的问题，提前做好预防措施，基于此本文主要从以下几方面做了探讨：首先主要从立堵截流过程的水力描述、龙口淹没流与非淹没流的界定、龙口轴线断面水深的确定、龙口水力参数变化规律及抛投粒径确定，五个方面对立堵截流水力学问题进行论述。然后从提高导流建筑物的泄流能力、双戗堤截流分配水位落差、增强截流块体的抗冲稳定性、采用宽戗堤降低截流难度、防止堤头坍塌提高截流安全度等方面，探讨减轻立堵截流难度的方法及其特点和适用条件。最后以利用宽戗堤降低截流难度为例，利用ANSYS CFX进行数学模拟，通过改变戗堤顶宽，分析戗堤顶宽改变对龙口过流量、水流速度、压力分布等水力因素的影响，研究戗堤宽度效应。模拟结果表明，在入口流速、出口流量和上游水位相同的条件下，龙口顶部宽度保持不变，戗堤顶宽增大，龙口流量、水流速度和负压都逐渐减小，但减小一定量后，戗堤顶宽继续增加，减小的趋势越来越慢，最后基本不变。
[Abstract]:Closure is a key project in the construction of water conservancy. Because of the complexity of the closure process, the effectiveness of the closure directly affects the investment benefit and duration of the whole project. The hydraulic condition of Longkou is the main factor to determine the success of closure, so before construction, the shape of Longkou section should be studied in advance through physical model or mathematical simulation, and preventive measures should be taken in advance for possible problems. Based on this, this paper mainly discusses the following aspects: Firstly, the hydraulic description of the process of vertical interdiction, the definition of submerged flow and non-submerged flow in Longkou, the determination of water depth in the section of Longkou axis, the variation law of hydraulic parameters and the determination of throwing particle size of Longkou are introduced. This paper discusses the mechanics of blocking water in five aspects. Then, from the aspects of improving the discharge capacity of diversion buildings, distributing the drop of water level in the closure of double dike, enhancing the anti-scour stability of the blocking block, reducing the difficulty of closure by adopting the broad embankment, preventing the collapse of the head of the embankment and improving the safety degree of the closure, etc. This paper discusses the methods, characteristics and applicable conditions of reducing the difficulty of vertical interception. Finally, taking the use of broad embankment as an example to reduce the difficulty of closure, using ANSYS CFX to carry out mathematical simulation, by changing the top width of embankment, the influence of the change of the top width of dike on hydraulic factors such as flow rate, flow velocity, pressure distribution and so on is analyzed. The effect of embankment width was studied. The simulation results show that when the inlet velocity, outlet flow rate and upstream water level are the same, the top width of the embankment increases, and the flow rate, flow velocity and negative pressure decrease gradually, but after a certain amount, the top width of the embankment increases. The width of the top of the embankment continues to increase, the decreasing trend is slower and slower, and the final trend is basically unchanged.
【学位授予单位】：西华大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TV551.2

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