本文選題：立堵截流 + 難度��； 參考：《西華大學(xué)》2014年碩士論文

【摘要】：截流是水利建設(shè)中的一項(xiàng)關(guān)鍵工程，由于截流過(guò)程復(fù)雜，，所以截流工程的成效直接影響整個(gè)工程的投資效益和工期。龍口水力條件是決定合龍能否成功的主要因素，所以在施工前，應(yīng)該通過(guò)物理模型或數(shù)學(xué)模擬，提前研究龍口斷面形狀，對(duì)可能發(fā)生的問(wèn)題，提前做好預(yù)防措施，基于此本文主要從以下幾方面做了探討： 首先主要從立堵截流過(guò)程的水力描述、龍口淹沒(méi)流與非淹沒(méi)流的界定、龍口軸線斷面水深的確定、龍口水力參數(shù)變化規(guī)律及拋投粒徑確定，五個(gè)方面對(duì)立堵截流水力學(xué)問(wèn)題進(jìn)行論述。 然后從提高導(dǎo)流建筑物的泄流能力、雙戧堤截流分配水位落差、增強(qiáng)截流塊體的抗沖穩(wěn)定性、采用寬戧堤降低截流難度、防止堤頭坍塌提高截流安全度等方面，探討減輕立堵截流難度的方法及其特點(diǎn)和適用條件。 最后以利用寬戧堤降低截流難度為例，利用ANSYS CFX進(jìn)行數(shù)學(xué)模擬，通過(guò)改變戧堤頂寬，分析戧堤頂寬改變對(duì)龍口過(guò)流量、水流速度、壓力分布等水力因素的影響，研究戧堤寬度效應(yīng)。模擬結(jié)果表明，在入口流速、出口流量和上游水位相同的條件下，龍口頂部寬度保持不變，戧堤頂寬增大，龍口流量、水流速度和負(fù)壓都逐漸減小，但減小一定量后，戧堤頂寬繼續(xù)增加，減小的趨勢(shì)越來(lái)越慢，最后基本不變。
[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.
【學(xué)位授予單位】：西華大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類(lèi)號(hào)】：TV551.2

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