Model test study on the anti-saline effect of the crushed-rock embankment with impermeable geotextile in frozen saline soil regions

In the road construction in frozen saline soil regions, treatments on both permafrost and saline soils are the main challenges to keep the stability of embankments. The crushed-rock embankment was proved to be an effective cooling measure to protect underlying permafrost layers from thawing. In this paper, as a countermeasure to salt migration and salt expansion, impermeable geotextile was added in the crushed-rock embankment. However, little research work has been done on the cooling and anti-saline effects. Thus, the tests of two embankment models, the crushed-rock embankment with impermeable geotextile and the ordinary filling embankment, were carried out to compare this novel embankment structure with ordinary one. The variation characteristics of temperature, moisture, salt and deformation were investigated, and it was found that their variations were a coupled process. The novel embankment structure showed an efficient cooling effect. Meantime, it can efficiently prevent water and salt from migrating to the upper soil layer. More importantly, it can efficiently alleviate frost heaving and salt expansion, and consequently avoid the appearance of longitudinal cracks. The results will provide a good reference to the widespread application of this novel embankment structure in frozen saline soil regions.