The Effect Of Anti-frost Heaving And Boiling On New Enclosed Water-proof Embankment

Frost heaving and boiling is a common disease in seasonal frozen soil areas. In this paper, we propose a new enclosed water-proof embankment after studying the mechanism of frost boiling and heaving and main factors which impacting frost boiling and heaving, evaluating the advantages and weaknesses of regular anti-frost heaving and boiling methods.Model test was used to study this subject, the general embankment and new anti-frost heaving and boiling embankment was constructed in the same frost lab-box at the same time. The date of temperature, water and displacement of these two embankments was recorded steadily during three freeze-thaw cycles and then validating the efficiency of the new embankment in dealing the damage of frost heaving and boiling. The main contents of this paper can be divided into two dominate parts.Firstly,the variation of temperature, moisture migration and displacement was studied based on the general model of embankment under freezing and thawing cycles. The study shows that: moisture migration was occurred during the freezing period in embankment, resulting in the increase of water content in the frozen part of the general embankment and the decline of water content in the unfrozen areas of the embankment, the embankment's soil water content was increased dramatically in the process of being frozen. The displacement of the pavement in the course of heaving and thawing was approximately equal without the dynamic vehicle loads, and the magnitude of the displacement was influenced seriously by the frequency of the freeze-thaw cycles. Embankment slope's displacement is larger than the pavement during freezing period, yet smaller when it is thawing, thence, the overall displacement of the embankment slope was increased.Secondly, we evaluate the effect of anti-frost heaving and boiling on new enclosed water-proof embankment after comparing the new and the general embankment's temperature, water content and displacement variation. The study shows that: the amount of temperature change at different depths of new enclosed water-proof embankment is smaller than general embankment. The new enclosed water-proof embankment's temperature variation was reduced by 20% while comparing to the general embankment during the freeze-thaw cycles, which illustrates that the new enclosed water-proof embankment can reduce the natural heat entering to the internal of the embankment. The radiating of new enclosed water-proof embankment is less than the general embankment, which delaying the occurrence of frost heaving and thawing, so we can say that the new embankment possess thermal insulation property. The new enclosed water-proof embankment can cut off the route of moisture migration, leading to the water content of the new embankment less than the general embankment, at the same time, it also can prevent the rainfall and the groundwater from entering into the embankment. new roadbed can prevent rain and groundwater into the inside of embankment. New enclosed water-proof embankment can effectively reduce the displacement of the pavement and the slope. Comparing to the general embankment, the displacement of the pavement is about 20% lower than the general one, and is about 50% lower at the slope, which indicating that the new enclosed water-proof embankment possess good anti-frost heaving boiling performance.The study shows that the new enclosed water-proof embankment can lead to an ideal effect when being used in seasonally frozen ground, providing a new and effective measures to prevent frost heaving and boiling in seasonally frozen ground.