On water migration and frost heaving characteristics of sand under water vapor recharge

The influences of different initial water contents, cold end temperatures and dry densities on water migration in sand were studied using the self-developed water migration and frost heaving testing equipment. The variations of frost heaving force and frost heaving amount subjected to aforementioned three factors were analyzed and the position of freezing front was determined. The results show that the initial water content and cold end temperature had significant influence on the soil water migration and frost heaving effect. When the initial water content increased from 0% to 10%, the peak water content increased by 6.00 times, the horizontal frost heaving force and frost heaving amount increased gradually, and the freezing front moved up to the position of 2.5 cm in height. When the cold end temperature decreased from −5 ℃ to −15 ℃, the peak water content increased by 4.38 times, the horizontal frost heaving force and frost heaving amount increased gradually, and the freezing front moved up to the position of 2.6 cm in height. Dry density has relatively insignificant influence on water migration and freezing characteristics of samples. Under low dry density, there was an overall trend of slightly larger increases in sample’s water content, horizontal frost heaving force and frost heaving amount, and the position of freezing front was concentrated at the position of 2.2−2.5 cm in height. The prediction formulae of frost heaving force and frost heaving amount were put forward for different influencing factors, and they can provide a reference for understanding the water migration law in sand under water vapor recharge and reasonably preventing frost heave.