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.