Laboratory study on the frost-proof performance of a novel embankment dam in seasonally frozen regions

Abstract

In construction and maintenance of embankment dams in seasonally frozen regions, frost-proof is a key factor to keep the stability of embankment dams, and the water-heat-mechanics process is the basis to reveal the evolution of frost damage for embankment dams in cold regions. In this paper, a novel embankment dam with two-phase closed thermosyphons (TPCTs) for reducing frost heave in seasonally frozen regions was presented. Two embankment dam cases with and without TPCTs during freeze–thaw processes under different reservoir water levels were tested in laboratory. The variations of temperature, volumetric unfrozen water content and deformation were monitored. It is found that, to some extent, the frozen depths at the downstream sides of the two dam cases were larger than those at the upstream sides because of the different thermal properties among the concrete slab, soil materials and reservoir water. Meanwhile, during the cold periods, the frozen depths and vertical deformations at the upstream sides of the embankment dam case 1 with TPCTs were far less than those of the embankment dam case 2 without TPCTs. Furthermore, the volumetric unfrozen water contents for the embankment dam case 1 with TPCTs were larger than those for the embankment dam case 2 without TPCTs at the same freezing position. This is from the fact that, after the TPCTs begin to work during the cold periods, the TPCTs are transferring the heat in the dam from below the reservoir water levels to above it, which effectively reduces the freezing of the embankment dam. Therefore, the embankment dam with TPCTs could be applied as an effective measure to alleviate the frost heave in seasonally frozen regions.