上海⑤1层粉质黏土的热传导特性

Thermal Conductivity of Shanghai ⑤1 Silty Clay

摘要:

采用基于热探针法的热传导仪，对上海地区地铁隧道主要穿越的⑤1层粉质黏土的热传导特性进行了试验研究.实验结果表明：饱和粉质黏土试样的孔隙比越大，其热导率越小；随着土样含水率从饱和状态逐渐降低，初期土样会出现明显体积收缩、热导率升高，而后当含水率降到低于塑限的时候，土样体积收缩速率明显变缓，热导率则逐渐降低，热导率总体上呈现出先升后降的规律，最大值出现在塑限左右.此外，还应用若干现有经验公式对上述热传导试验数据进行了拟合，由此验证各经验公式的适用性.

Abstract:

A series of tests were carried out with the heat probe method by thermal properties analyzer to investigate the thermal conductivity of shanghai ⑤1 layer silty clay, the most common type in the metro tunnel engineering. The test results show that the thermal conductivity of saturated silty clay decreases with the void ratio. When the water contents drop down gradually from saturated value to dry value, the soil sample shrinks evidently first and then its thermal conductivity increases. While the water contents drop down near the plasticity limit, the volumetric shrinkage becomes stable and the thermal conductivity reaches its maximum value. After the peak, the thermal conductivity decreases with water contents. Finally, some existing empirical formulas were introduced to fit the test data, and their fitness was verified.