多年冻土地区公路路基不稳定变形研究

发布时间：2018-05-23 11:13

本文选题：冻土路基 + 温度场　；参考：《长安大学》2015年硕士论文

【摘要】：我国青藏高原地区的多年冻土约占全国冻土总面积的60%,修筑在青藏高原上的青藏公路就有连续550公里位于工程环境条件极其恶劣的多年冻土区。青藏公路自1954年通车以来,冻土路基的变形就在持续不断的发生,冻土路基发生的变形具有不均匀性,而且路基变形在不同的路段也有不同的形式,因此,针对青藏公路冻土路基变形的养护工作也一直在进行。本文以青藏公路冻土路基为研究对象,结合冻土路基温度场、水分场分布的变化以及行车荷载作用来研究冻土路基长期变形的特性。1.由青藏公路现场调查资料分析知,冻土路基发生的变形是不均匀的而且随着时间与空间的变化也在不断的发生,本文称之为冻土路基的不稳定变形,然后分析冻土路基不稳定变形的成因及影响因素。2.在多年冻土地区,冻土路基土体会随着季节的循环变化而发生相变。本文根据伴有相变的非稳态温度场控制方程,在考虑大气温度变化、太阳辐射、对流换热等因素的条件下,建立冻土路基温度场有限元模型,对多年冻土地区路基温度场分布长期变化的特点进行分析。3.大气降雨是冻土路基水分的重要来源之一,本文根据水分迁移控制方程,在考虑大气降雨与蒸发的基础上,建立冻土路基水分场有限元模型,对冻土路基水分场分布长期变化的特点进行分析。4.在温度场和水分场单场计算结果的基础上,分别建立在冻结过程与融化过程中的冻土路基变形场有限元模型,通过数值模拟,对冻土路基长期的不稳定变形特性进行分析。本文的研究成果揭示了冻土路基温度场、水分场以及不稳定变形场的长期变化规律,以便为青藏公路今后的病害防治工作提供参考,以及为青藏高速公路的建设提供参考依据。
[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.
【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U416.168

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