多年冻土区高温冻土导热系数试验研究

发布时间：2018-02-24 04:08

本文关键词： 高温冻土原状重塑导热系数瞬态法稳态法相关关系　出处：《中国矿业大学》2015年硕士论文　论文类型：学位论文

【摘要】：随着我国西部工程建设的不断推进,寒区地段的冻土工程也在有条不紊的向前发展。随着气候的变暖,青藏高原年平均气温的升高使得多年冻土地区公路、铁路、管道等生命线工程设施面临着许多新的问题与挑战,特别是在高温冻土地区,由于其物理力学性质极易受到外部环境的影响,具有较强的离散性和不稳定性,所以在冻土工程建设过程中既要保证其热稳定性,又要保证其长期稳定性。而高温冻土导热系数的合理取值是解决高温冻土区热工稳定性评价的前提和基础,因此,研究高温冻土导热系数的性质对优化工程设计,保证工程安全具有重要作用。本文以青藏工程走廊原状高温冻土为研究对象,根据高温冻土物理性质对温度极为敏感的特点,分析了常规瞬态法导热系数测试技术在高温冻土导热系数测试中的不足。根据一维稳态法传热理论,自主研制了高温冻土导热系数的试验系统,制定了试验规程及要求并进行了原状和重塑高温冻土导热系数的大量试验。研究了青藏高原开心岭区域高温冻结粉质黏土导热系数与温度、含水量、干密度的相关关系。结果表明,随着温度升高,高温冻土导热系数接近线性降低;随着干密度和含水量的增加,导热系数逐渐增大,而温度越高,随着含水量的增加,导热系数增加的速率越小。以原状高温冻土的干密度、含水量为标准,采用青藏高原粉质黏土和粉土重塑,测试其高温冻土的导热系数,根据多因素拟合方式建立了原状与重塑高温冻土导热系数之间的的经验公式。本项研究成果将为青藏工程走廊地区后续工程设计和建设提供重要的基础数据,同时对高温冻土热力性质研究具有重要参考价值。
[Abstract]:With the continuous development of the construction in the western part of China, the frozen soil project in the cold region is developing methodically. With the warming of the climate, the annual average temperature of the Qinghai-Xizang Plateau increases the highway and railway in the permafrost region. Lifeline engineering facilities such as pipelines are faced with many new problems and challenges, especially in high-temperature frozen soil areas, because of its physical and mechanical properties are easily affected by the external environment, with strong dispersion and instability. Therefore, the thermal stability and long-term stability of frozen soil should be guaranteed in the course of engineering construction. The reasonable value of thermal conductivity of high temperature frozen soil is the premise and foundation to solve the evaluation of thermal stability in high temperature frozen soil region. The study of thermal conductivity of high temperature frozen soil plays an important role in optimizing engineering design and ensuring engineering safety. In this paper, the raw high temperature frozen soil in Qinghai-Tibet engineering corridor is taken as the research object, and the physical property of high temperature frozen soil is extremely sensitive to temperature. The deficiency of the conventional transient method in the measurement of thermal conductivity of high temperature frozen soil is analyzed. According to the theory of one dimensional steady state heat transfer, the test system of thermal conductivity of high temperature frozen soil is developed. A large number of tests were carried out on the thermal conductivity of undisturbed and remolded high temperature frozen soils. The thermal conductivity and temperature, water content of high temperature frozen silty clay in the Qinghai-Xizang Plateau were studied. The results show that the thermal conductivity of high temperature frozen soil decreases linearly with the increase of temperature, the thermal conductivity increases with the increase of dry density and water content, and with the increase of temperature, the thermal conductivity increases with the increase of water content. The rate of increase of thermal conductivity is smaller. The dry density and water content of undisturbed high temperature frozen soil are taken as standard, and the thermal conductivity of high temperature frozen soil is measured by remolding silty clay and silt in Qinghai-Xizang Plateau. The empirical formula between the original state and the thermal conductivity of remolded high-temperature frozen soil is established according to the multi-factor fitting method. The results of this study will provide important basic data for the subsequent engineering design and construction in the Qinghai-Tibet engineering corridor area. At the same time, it has important reference value for the study of thermal properties of high temperature frozen soil.
【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU445

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