温度梯度作用下非饱和土水分迁移研究

为了探明非饱和土中的水分在温度梯度作用下的迁移规律，开展了非饱和土在不同温度梯度作用下的气态水迁移试验和混合态水迁移试验。试验结果表明土样内部的温度场在24 h内均能达到稳态且稳定后的温度场沿土样长度方向线性变化。气态水迁移量和液态水迁移量均随着温度梯度的增加而增加，气态水迁移量的增幅显著大于液态水迁移量的增幅。在气态水迁移中，温度效应随着土样初始含水率的增加而显著增加；在液态水迁移中，温度效应与土样初始含水率的关系不大。最后建立了非饱和土在不同温度梯度作用下，当其水分场接近稳态时，土样内部含水率梯度的表达式，该表达式包含温度梯度和初始含水率两个影响因素。

Moisture migration of unsaturated soil due to thermal gradients

In order to obtain the law of moisture migration in unsaturated soil due to thermal gradient effect, experiments of vaporous water migration and moisture migration are carried out under different thermal gradients. Experimental results show that the temperature fields in all soil samples have been achieved steady within 24 h and changed linearly along the length direction of the soil samples. Migration quantities of vaporous water and liquid water both increase with the increase of temperature gradient, however the former is significantly greater than the latter. Temperature effect in vaporous water migration experiments increases significantly with the increase of initial water content of soil sample. By contrast, temperature effect in liquid water migration experiments has little relation with initial water content of soil sample. Finally, a function of water content gradient, which contains temperature gradient and initial water content, is developed.