The Study Of Frost Heaving Model On Water-Heat-Deformation Coupled Fields Of Canal Slope In Seasonally Frozen Area

In the seasonal frozen soil area, the frost heaving of water conservancy project has been a topic of concern.. The freeze-thaw damage problem has been a great impact on agricultural and industrial production while the explosive developing of dryland soil is reclaimed into paddy soil. In this paper, we established the mathematical model of canal slope on coupling deformation-water- heat through theoretical analysis; then the prediction regression model is established under the closed system through the indoor experimental study, and the freeze-thaw deformation characteristics of channel slope frost heave was simulated; Finally the couple of water-heat-deformation model was simulated and analyzed using the multiphysics coupling software Comsol. Conclusions were followed:(1) Frost heaving deformation was main affected by soil moisture and soil dry density. Within the appropriate range, frost heave increases with the water content and dry density,and was more determined by the soil moisture.(2) The unidirectional freezing and bidirectional melting characters of the soil freezing and thawing process in the indoor channel model test canal matched the freezing and thawing process of the field soil. There produced different degrees soil moisture of water transfer in the process of freezing and thawing beneath the variation of temperature gradient, different position and different periods of the channel. The more close to the channel surface,the larger water transfer amount is;the more close to the bottom plate,the smaller water transfer amount are, finally reduce to zero.(3) Channel soil freezing process occurred in the large deformation of frost. The temperature dropped quickly at the beginning of the test, the water transfer amount was few, sometimes none. The channel soil freezing occurred. As the temperature continues to decrease, water continued to the freezing front migration and freezed into ice,soil began to heave and varied in different parts of channel slope. The frost heave followed by the order of: canal bottom<canal top<1/7 slope height<fixed foot height<3/4 slope height <1/3 slope height<1/2 slope height. After the temperature began to rise, the ice melts into water lead to volume decreased and began to thawing settlement frost heaving amount greater than the amount of thaw settlement, resulted in a residual deformation.(4) Numerical simulation results of the channel by using multi physics coupling software COMSOL on the moisture, temperature field and deformation field were in accordance with the laws of nature, which can be applied for frost heave damage prediction in engineering practice.