岩土热导率测量和温度影响研究

利用QTM-D2常温导热系数测定仪测定了典型砂、黏土、岩石的导热特性,探讨了室内外试验、试样饱和程度对测量结果影响,通过试验结果和数值模拟研究了不同试样导热系数的尺寸差异,为现场岩土材料导热系数的测定提出了可行的解决方案。热线法测量时,试件尺寸影响范围不大,不同几何尺寸边界的测量结果很接近。根据国内外对导热系数的温度影响问题的研究实际,通过大量的实测数据和数值理论计算,总结了常温条件范围内各类岩土材料导热系数与温度之间的经验关系以及它们的温度变异影响系数β。各类岩土材料的β值普遍较小,大多在10-3的数量级上,导热系数与温度关系曲线近线性。该系数和这些经验公式的导出对中国北方地区岩土材料导热性能的理解及温度场模拟工作均具重要意义。

Measurement of thermal conductivity and temperature effect of geotechnical materials

The thermal conductivity (TC) of the sand, clay and rock is measured by QTM-D2. And the effects of different experiment sizes and different conditions of saturated samples are discussed. The size error of TC among different samples is found out through experimental results and numerical simulation, which offers a solution to the measurement of TC of the geotechnical materials in site. During the measurement of TC by use of the heat line, the effect of sample size is limited, and the measured results of samples with different geometric sizes are similar. According to the domestic and international studies on empirical relation between TC and temperature, the empirical relation between the temperature and TC at the condition of normal temperature is obtained, and the thermal variance coefficient β is also obtained, based on a large number of measured data and numerical calculations. The values of β of geotechnical materials are small, mostly with magnitude 10-3, and the curves of TC and temperature is approximately linear. These coefficients and the experimental relationships are important to the understanding on the TC of the geotechnical materials in north China and to the temperature simulation programming as well.