本文選題：凍土路基 + 溫度場(chǎng)��； 參考：《長(zhǎng)安大學(xué)》2015年碩士論文

【摘要】：我國(guó)青藏高原地區(qū)的多年凍土約占全國(guó)凍土總面積的60%,修筑在青藏高原上的青藏公路就有連續(xù)550公里位于工程環(huán)境條件極其惡劣的多年凍土區(qū)。青藏公路自1954年通車(chē)以來(lái),凍土路基的變形就在持續(xù)不斷的發(fā)生,凍土路基發(fā)生的變形具有不均勻性,而且路基變形在不同的路段也有不同的形式,因此,針對(duì)青藏公路凍土路基變形的養(yǎng)護(hù)工作也一直在進(jìn)行。本文以青藏公路凍土路基為研究對(duì)象,結(jié)合凍土路基溫度場(chǎng)、水分場(chǎng)分布的變化以及行車(chē)荷載作用來(lái)研究?jī)鐾谅坊L(zhǎng)期變形的特性。1.由青藏公路現(xiàn)場(chǎng)調(diào)查資料分析知,凍土路基發(fā)生的變形是不均勻的而且隨著時(shí)間與空間的變化也在不斷的發(fā)生,本文稱(chēng)之為凍土路基的不穩(wěn)定變形,然后分析凍土路基不穩(wěn)定變形的成因及影響因素。2.在多年凍土地區(qū),凍土路基土體會(huì)隨著季節(jié)的循環(huán)變化而發(fā)生相變。本文根據(jù)伴有相變的非穩(wěn)態(tài)溫度場(chǎng)控制方程,在考慮大氣溫度變化、太陽(yáng)輻射、對(duì)流換熱等因素的條件下,建立凍土路基溫度場(chǎng)有限元模型,對(duì)多年凍土地區(qū)路基溫度場(chǎng)分布長(zhǎng)期變化的特點(diǎn)進(jìn)行分析。3.大氣降雨是凍土路基水分的重要來(lái)源之一,本文根據(jù)水分遷移控制方程,在考慮大氣降雨與蒸發(fā)的基礎(chǔ)上,建立凍土路基水分場(chǎng)有限元模型,對(duì)凍土路基水分場(chǎng)分布長(zhǎng)期變化的特點(diǎn)進(jìn)行分析。4.在溫度場(chǎng)和水分場(chǎng)單場(chǎng)計(jì)算結(jié)果的基礎(chǔ)上,分別建立在凍結(jié)過(guò)程與融化過(guò)程中的凍土路基變形場(chǎng)有限元模型,通過(guò)數(shù)值模擬,對(duì)凍土路基長(zhǎng)期的不穩(wěn)定變形特性進(jìn)行分析。本文的研究成果揭示了凍土路基溫度場(chǎng)、水分場(chǎng)以及不穩(wěn)定變形場(chǎng)的長(zhǎng)期變化規(guī)律,以便為青藏公路今后的病害防治工作提供參考,以及為青藏高速公路的建設(shè)提供參考依據(jù)。
[Abstract]:The permafrost in the Qinghai-Tibet Plateau area accounts for about 60% of the total frozen soil area in China. The Qinghai-Tibet Highway built on the Qinghai-Xizang Plateau has 550 km of continuous permafrost area located in the permafrost region where the engineering environment conditions are extremely bad. Since the Qinghai-Tibet Highway was opened to traffic in 1954, the deformation of permafrost roadbed has been continuously occurring. The deformation of frozen subgrade is uneven, and the deformation of roadbed has different forms in different sections of road. The maintenance of permafrost roadbed deformation of Qinghai-Tibet Highway has been carried out all the time. In this paper, permafrost roadbed of Qinghai-Xizang highway is taken as the research object, and the long-term deformation characteristics of permafrost roadbed are studied by combining the variation of temperature field, water field distribution and driving load of permafrost roadbed. Based on the field investigation data of Qinghai-Tibet Highway, it is found that the deformation of permafrost subgrade is uneven and the change of time and space is also continuous, which is called the unstable deformation of frozen subgrade in this paper. Then, the causes and influencing factors of unsteady deformation of permafrost subgrade are analyzed. In permafrost regions, permafrost subgrade soil changes with seasonal cycle. According to the governing equation of unsteady state temperature field with phase change, the finite element model of temperature field of permafrost roadbed is established under the conditions of atmospheric temperature change, solar radiation, convection heat transfer and so on. The characteristics of long-term variation of subgrade temperature field in permafrost region are analyzed. Atmospheric rainfall is one of the important sources of water in permafrost subgrade. According to the governing equation of water migration and considering the atmospheric rainfall and evaporation, the finite element model of water field in permafrost subgrade is established in this paper. The characteristics of long term variation of water field distribution in permafrost subgrade are analyzed. On the basis of the results of single field calculation of temperature field and moisture field, the finite element model of frozen subgrade deformation field in freezing process and melting process is established, and the long-term unstable deformation characteristics of frozen soil subgrade are analyzed by numerical simulation. The research results of this paper reveal the long-term variation of temperature field, moisture field and unstable deformation field of frozen soil subgrade, in order to provide reference for the future disease prevention and control work of Qinghai-Tibet Highway, as well as for the construction of Qinghai-Tibet Expressway.
【學(xué)位授予單位】：長(zhǎng)安大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類(lèi)號(hào)】：U416.168

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本文編號(hào)：1924495