本文選題：海底滑坡 + 泥石流��； 參考：《大連理工大學(xué)》2014年碩士論文

【摘要】：長時(shí)間降雨或暴雨過后,在山區(qū)很容易見到泥石流和滑坡�；�、泥石流不僅在陸地上會(huì)發(fā)生,在水面下(海底)也會(huì)發(fā)生。與陸地滑坡不同,在極緩的坡度下(0.5-3°),海底滑坡都能發(fā)生。大規(guī)模的海底滑坡滑移距離往往長達(dá)數(shù)百公里,這會(huì)嚴(yán)重?fù)p壞海洋平臺(tái)、海底管線、電纜等海底設(shè)施,并造成嚴(yán)重的經(jīng)濟(jì)損失。為了避免災(zāi)害和降低經(jīng)濟(jì)損失,研究和預(yù)測(cè)海底滑坡的滑動(dòng)過程及海底滑坡對(duì)海底管線的作用有重要意義。 論文第一部分內(nèi)容為模擬海底滑坡的滑坡過程。運(yùn)用流體力學(xué)基本方程,如邊界層近似理論、連續(xù)方程、動(dòng)量方程、納維-斯托克斯方程等,推導(dǎo)了Herschel-Bulkley及雙線性(Bilinear)流變模型的控制方程及其差分格式。這些方程驗(yàn)證了一維海底滑坡模擬軟件BING程序的準(zhǔn)確性。之后,用ANSYS CFX與BING兩款軟件模擬了海底滑坡的運(yùn)動(dòng)過程,發(fā)現(xiàn)當(dāng)泥漿抗剪強(qiáng)度越大時(shí)兩款軟件模擬的結(jié)果越接近。由于BING計(jì)算速度很快(普通計(jì)算僅需1～2分鐘),對(duì)于抗剪強(qiáng)度大的泥漿,便可用BING模擬,這樣可大大提高工作效率。 第二部分內(nèi)容是研究海底滑坡對(duì)海底管線的作用。準(zhǔn)確的預(yù)測(cè)海底滑坡對(duì)海底管線的作用力是海洋工程師關(guān)心的問題。海底滑坡對(duì)管線的沖擊力通常采用傳統(tǒng)的流體力學(xué)的阻力系數(shù)來描述。Zakeri (2009)使用計(jì)算流體動(dòng)力學(xué)(Computational Fluid Dynamics-CFD)方法,數(shù)值模擬了5種沖擊角度下,富含粘土的海底泥石流對(duì)管線的沖擊。并且,Zakeri提出了任意沖擊角度下,計(jì)算管線所受的法向阻力和縱向阻力的方法。Randolph和White (2012)用土力學(xué)的方法,對(duì)Zakeri(2009)的數(shù)值結(jié)果重新進(jìn)行了分析處理,提出用一條失效曲線來計(jì)算任意沖擊角度管線所受的沖擊力。本文采用CFD數(shù)值分析重新模擬了Zakeri (2009)的計(jì)算工況,并增加了更多工況。根據(jù)模擬的結(jié)果,發(fā)現(xiàn)沖擊角度對(duì)法向阻力系數(shù)影響很大,但對(duì)縱向阻力系數(shù)影響甚微。接著得到了改進(jìn)的近似公式,該公式能更準(zhǔn)確的估算任意沖擊角度懸浮管線受到的法向和軸向沖擊力。用土力學(xué)的方法對(duì)這些數(shù)值模擬結(jié)果也進(jìn)行了重新分析,得到了新的失效曲線。土力學(xué)方法預(yù)測(cè)的力與CFD計(jì)算的力結(jié)果很接近。
[Abstract]:Debris flows and landslides are easy to see in the mountains after long periods of rain or heavy rain. Landslides and mudslides occur not only on land, but also below the surface. Different from land landslides, submarine landslides can occur at a very slow slope (0.5-3 擄). Large scale landslides often slip hundreds of kilometers away, which can seriously damage offshore platforms, pipelines, cables and other submarine facilities, and cause serious economic losses. In order to avoid disasters and reduce economic losses, it is important to study and predict the sliding process of submarine landslide and the effect of submarine landslide on submarine pipeline. The first part of the thesis is to simulate the process of submarine landslide. The governing equations of Herschel-Bulkley and Bilinear rheological models and their difference schemes are derived by using the basic equations of fluid mechanics, such as boundary layer approximation theory, continuum equation, momentum equation, Navier-Stokes equation and so on. These equations verify the accuracy of the one-dimensional submarine landslide simulation software ing program. Then, ANSYS CFX and ing are used to simulate the movement of submarine landslide. It is found that when the shear strength of mud increases, the simulation results of the two software are closer. Due to the fast calculation speed of ing (only 1 / 2 minutes for ordinary calculation), the mud with high shear strength can be simulated by ing, which can greatly improve the working efficiency. The second part is to study the effect of submarine landslide on submarine pipeline. It is the concern of marine engineers to predict accurately the action force of submarine landslide on submarine pipeline. The impact force of submarine landslide on pipeline is usually described by traditional resistance coefficient of hydrodynamics. Zakeri (2009) using Computational fluid Dynamics-CFD method, numerically simulates the impact of clay rich debris flow on pipeline under five kinds of impact angles. And Zakeri proposed a method for calculating the normal and longitudinal resistance of pipelines at any impact angle. Randolph and White (2012) used the method of soil mechanics to reanalyze the numerical results of Zakeri (2009). A failure curve is proposed to calculate the impact force of the pipeline at any impact angle. In this paper, the computational conditions of Zakeri (2009) are resimulated by CFD numerical analysis, and more conditions are added. According to the simulation results, it is found that the impact angle has a great influence on the normal drag coefficient, but has little effect on the longitudinal resistance coefficient. Then an improved approximate formula is obtained, which can more accurately estimate the normal and axial impact forces on the suspension pipeline with any impact angle. The numerical simulation results are also reanalyzed by soil mechanics method, and a new failure curve is obtained. The force predicted by the soil mechanics method is very close to that calculated by CFD.
【學(xué)位授予單位】：大連理工大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類號(hào)】：P756.2;P642.22

【參考文獻(xiàn)】

相關(guān)期刊論文 前3條

1 劉梁華;張世富;;海底管道發(fā)展現(xiàn)狀淺述[J];中國儲(chǔ)運(yùn);2011年11期

2 安培浚;李櫟;張志強(qiáng);;國際滑坡、泥石流研究文獻(xiàn)計(jì)量分析[J];地球科學(xué)進(jìn)展;2011年10期

3 甘華陽,王家生,胡高韋;海洋沉積物中的天然氣水合物與海底滑坡[J];防災(zāi)減災(zāi)工程學(xué)報(bào);2004年02期

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本文編號(hào)：2087426