本文選題：連續(xù)橋墩　切入點(diǎn)：通航安全　出處：《長(zhǎng)沙理工大學(xué)》2015年碩士論文　論文類(lèi)型：學(xué)位論文

【摘要】：橋梁建設(shè)在一定程度上影響了河道水流運(yùn)動(dòng),在橋墩周?chē)a(chǎn)生復(fù)雜的三維水流,致使橋墩附近存在不安全的航行區(qū)域。從通航安全考慮,有必要開(kāi)展深入研究。利用flow-3D軟件,針對(duì)不同來(lái)流角度以及連續(xù)墩不同間距,計(jì)算了圓形墩和圓端形墩周?chē)乃髁鲌?chǎng);通過(guò)概化船舶物理模型,研究了船舶通過(guò)單墩和連續(xù)墩時(shí)所受到的總力沿橫向分力,確定了通航安全距離。得到以下主要結(jié)論:1.單橋墩周?chē)嬖趦蓚�(gè)明顯的橫向流速峰值,連續(xù)橋墩周?chē)嬖谒膫�(gè)明顯的橫向流速峰值。橋墩尾部受到橋墩尾流的影響,橫向流速出現(xiàn)正負(fù)擺動(dòng)。隨著連續(xù)墩間距的增加,第一個(gè)橋墩尾流的影響慢慢體現(xiàn)出來(lái)。橋墩附近橫向流速零值,并不是在橋墩中心。第一個(gè)零值在第一個(gè)橋墩邊壁附近,第二個(gè)零值出現(xiàn)在墩尾。橋墩周?chē)牡谝粋�(gè)峰值大小與單墩時(shí)很接近。第一個(gè)峰值和第二個(gè)峰值出現(xiàn)的位置與單墩時(shí)基本一致。當(dāng)連續(xù)墩間距達(dá)到12D時(shí),第三個(gè)峰值和第四個(gè)峰值與第二個(gè)橋墩的相對(duì)位置較單墩時(shí)基本一致。2.當(dāng)水流流向與橋軸線法線方向的交角大于5°,不宜直接用橫向流速為0.3m/s的標(biāo)準(zhǔn)確定橋墩紊流寬度,可采用有無(wú)橋墩橫向流速差值作為紊流寬度的取值標(biāo)準(zhǔn)。水流流向與橋軸線法線方向的夾角和墩長(zhǎng)對(duì)橋墩周?chē)奈闪鲗挾却嬖诿黠@影響。3.船舶經(jīng)過(guò)單橋墩時(shí),船舶所受總力的橫向分力沿縱向分布曲線存在三個(gè)區(qū),兩個(gè)推力區(qū)和一個(gè)吸力區(qū)。當(dāng)船舶經(jīng)過(guò)連續(xù)墩時(shí),當(dāng)連續(xù)墩間距較小時(shí),連續(xù)墩可以看做是一個(gè)整體,與單墩的分布規(guī)律基本相同。當(dāng)連續(xù)墩間距為6D和9D時(shí),吸力區(qū)發(fā)生分離,出現(xiàn)兩個(gè)吸力峰值,當(dāng)連續(xù)墩間距達(dá)到12D時(shí),總力沿橫向分力的分布規(guī)律與單墩相同,可以把連續(xù)墩看做是兩個(gè)獨(dú)立的橋墩。4.以橫向流速0.3m/s為判別依據(jù)判別橋墩周?chē)陌踩ê骄嚯x。橋區(qū)安全通航距離為0.736D。將總作用力的橫向分力峰值減小最明顯的兩斷面中離橋墩較近的斷面作為判別橋區(qū)安全通航的依據(jù),可以得出橋區(qū)安全距離1.0D。兩種依據(jù)判別的結(jié)果只是在數(shù)值上存在差異,但是連續(xù)墩對(duì)安全通航距離的影響規(guī)律一致。
[Abstract]:Bridge construction affects river flow movement to some extent and produces complex three-dimensional flow around the pier, which results in unsafe navigation area near the pier. Considering navigation safety, it is necessary to carry out further research. Using flow-3D software, it is necessary to carry out further research. The flow field around circular pier and round end pier is calculated according to different flow angles and spacing of continuous pier, and the total force of ship passing through single pier and continuous pier is studied by generalizing ship physical model. The main conclusions are as follows: 1. There are two obvious transverse velocity peaks around the single pier and four obvious transverse velocity peaks around the continuous pier. The tail of the pier is affected by the wake flow of the pier. The effect of wake flow on the first pier is slowly reflected with the increase of the spacing between the continuous piers. The zero value of the transverse velocity near the pier is not in the center of the pier. The first zero is near the side wall of the first pier. The second zero value appears at the end of the pier. The first peak value around the pier is very close to that of the single pier. The position of the first peak value and the second peak value is basically the same as that of the single pier. When the spacing between continuous piers reaches 12D, The relative position of the third peak value and the fourth peak value with the second pier is basically the same as that of the single pier. When the angle of flow flow direction to the normal direction of the bridge axis is greater than 5 擄, it is not appropriate to use the criterion of transverse velocity of 0.3 m / s directly to determine the turbulent flow width of the bridge pier. The lateral velocity difference of bridge pier can be used as the criterion of turbulence width. The angle between flow direction and normal direction of bridge axis and the length of pier have obvious influence on the turbulence width around pier .3.When a ship passes a single pier, There are three zones, two thrust zones and one suction zone in the transverse distribution curve of the total force on the ship. When the ship passes through the continuous pier, when the distance between the continuous piers is small, the continuous pier can be regarded as a whole. When the spacing of continuous piers is 6D and 9D, the suction zone is separated and two peak suction peaks occur. When the spacing of continuous piers reaches 12D, the distribution law of total forces along the transverse force is the same as that of single piers. The continuous pier can be regarded as two independent piers. The transverse velocity of 0.3 m / s is taken as the basis for judging the safe navigable distance around the pier. The safe navigable distance in the bridge area is 0.736 D. The section close to the pier in the two sections is used as the basis for judging the safe navigation in the bridge area. It can be concluded that the safety distance of bridge area is 1.0 D. the results of the two discriminations are only different in numerical value, but the influence of continuous piers on the safe navigable distance is the same.
【學(xué)位授予單位】：長(zhǎng)沙理工大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類(lèi)號(hào)】：U442.3;TV135.4

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