中俄原油管道多年冻土导热系数测试方法及比较研究

发布时间：2018-02-11 17:42

本文关键词： 多年冻土导热系数比较法线性回归分析　出处：《吉林大学》2015年硕士论文　论文类型：学位论文

【摘要】：中国快速的工业化进程造成了油气资源的大量消耗，中俄原油管道工程对于保障我国油气资源供给具有重要意义。但管道途径大兴安岭及嫩江河谷约965km2冻土区，管道油温及气候的变化引起的热传递及热积累导致了管道下伏土体温度升高、多年冻土融化，给管道的安全性与稳定性带来了不利影响。冻土融化问题的重点在于对其热力场及热流传递的研究，2014年中俄原油管道复线工程筹划建设，吉林大学建设工程学院冻土实验室对管道区域多年冻土热学性质进行了深入研究。导热系数是热力学参数中极其重要的基本指标，它是影响冻土温度变化及冻土内热流传递的重要因素。吉林大学建设工程学院冻土实验室自2007年以来运用热流计法、热线法及正规状态法对中俄原油管道上百种冻土试样进行了冻土比热、导温系数及导热系数的测试，取得了丰硕的研究成果。比较法属于导热系数测试稳态法中的一种，为了进一步丰富导热系数测试方法，也为了通过室内试验途径得出更为接近原状土的导热系数值，本文第一部分根据比较法测试导热系数的原理及研究思路自主研制了比较法测试试验仪器，解决了研制过程中的若干技术难点，实现了该方法保证热流一维传导、热扩散极少、可控性强的优点。第二部分对取自中俄原油管道工程区的2#粉质粘土进行了比较法导热系数测试，并将其结果与有关规范、热流计法、热线法和正规状态法测试结果进行对比分析，发现比较法与热流计法测试结果与正规状态法测试结果最为接近，而正规状态法是对2#粉质粘土的原状样进行测试，即比较法与热流计法导热系数测试结果更接近土样导热系数真实值。第三部分对取自中俄原油管道多年冻土区5种典型土（1#粉质粘土、2#粉质粘土、3#粉土、4#砂土、5#碎石土）进行了比较法导热系数测定，同时以数理统计分析软件SPSS作为辅助工具，得出5种土体导热系数与其影响因素的线性回归模型，从土样干密度、含水量、冻融状态及土质条件四个方面探讨了导热系数随上述影响因素的变化规律。研究得出：比较法导热系数测试结果较为接近原状土导热系数值；除5#土外，大兴安岭多年冻土区4种典型土质的导热系数与干密度及含水量呈正相关，并具有较好的线性拟合关系；同一土体在绝大部分状态下冻土比融土状态导热性能更强；相同条件下，导热系数由高到低排序为砂土、粉土、粉质粘土，这与土体的粒径大小关系一致；5#土由于颗粒粗大且不均匀，上述规律性较弱。本次研究为导热系数试验方法的选取提供了参考，对多年冻土区管道结构整体性和稳定性及冻土区其他工程建设具有重要意义。
[Abstract]:The rapid industrialization process in China has resulted in a large consumption of oil and gas resources, and the Sino-Russian crude oil pipeline project is of great significance for ensuring the supply of oil and gas resources in China, but the pipeline route is about 965 km ~ 2 in the permafrost region of Daxing'anling and the Nenjiang River valley. The heat transfer and heat accumulation caused by the change of oil temperature and climate in pipeline resulted in the increase of soil temperature and the thawing of permafrost. The key point of the thawing problem of frozen soil lies in the study of thermal field and heat flux transfer of the pipeline, and the planning and construction of the Sino-Russian crude oil pipeline double line project from 2014 to 2014. The thermal properties of permafrost in pipeline area were studied in the permafrost laboratory of Jilin University. Thermal conductivity is one of the most important basic parameters of thermodynamics. It is an important factor to influence the temperature change of frozen soil and the heat flux transfer in frozen soil. Since 2007, the thermometer method has been used in the frozen soil laboratory of the School of Construction Engineering of Jilin University. The hot wire method and the normal state method have been used to measure the specific heat, temperature conductivity and thermal conductivity of hundreds of frozen soil samples in Sino-Russian crude oil pipeline. The comparison method belongs to one of the steady-state methods for the measurement of thermal conductivity. In order to further enrich the test methods of thermal conductivity, and to obtain the value of thermal conductivity closer to that of undisturbed soil through indoor test, In the first part of this paper, according to the principle and research idea of the comparison method, the author has developed the test instrument of comparison method, solved some technical difficulties in the process of development, and realized this method to ensure the one-dimensional conduction of heat flux, and the heat diffusion is very little. The advantage of strong controllability. In the second part, the thermal conductivity of the silty clay obtained from the Sino-Russian crude oil pipeline engineering area is measured by comparative method, and the results are compared with the results of relevant specifications, heat flow meter method, hot wire method and normal state method. It is found that the results of comparison method and heat flow meter method are most close to those of normal state method, while the normal state method is used to test the original samples of silty clay. That is to say, the results of comparison method and heat flow meter method are closer to the real value of soil sample thermal conductivity. In the third part, the comparison method is used to determine the thermal conductivity of five kinds of typical silty clay from permafrost region of Sino-Russian crude oil pipeline. At the same time, the mathematical statistical analysis software SPSS is used as the auxiliary tool. The linear regression models of five kinds of soil thermal conductivity and its influencing factors are obtained. The variation of thermal conductivity with the above factors is discussed from four aspects: dry density of soil sample, water content, freezing and thawing state and soil quality condition. The results show that the results of comparison method are close to that of undisturbed soil, except for soil, the thermal conductivity of four typical soils in permafrost region of Daxing'anling is positively correlated with dry density and water content. Under the same condition, the thermal conductivity of the frozen soil is stronger than that of the thawed soil. Under the same condition, the thermal conductivity is ranked from high to low to sandy soil, silty soil, silty clay. This is consistent with the relationship between the particle size of the soil and the size of the soil, because of the coarse and uneven particle size, the above regularity is weak. This study provides a reference for the selection of test methods of thermal conductivity and is of great significance to the integrity and stability of pipeline structure in permafrost regions and other engineering construction in permafrost regions.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P642.14

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