Experimental and numerical investigation on temperature characteristics of high-speed railway's embankment in seasonal frozen regions

By analyzing temperature characteristics of tested embankments at the Changchun site of Harbin to Dalian Passenger Dedicated Line (HDPDL). we found that the temperature changing process is different in parts of the roadbed and foundation under seasonal freeze-thaw cycles. In cold seasons, the temperature under the reinforced concrete component was higher than that under the shoulders. This difference decreases with the depth of roadbed. In warm seasons, these phenomena appear as a reverse trend, and also the temperature difference decreases with the depth of roadbed as usual. In different parts of the roadbed, the maximum seasonal frozen depths were all higher than that in the natural ground, because of the roadbed materials, that changed the heat exchange process between the air and the ground surface. It should be multiplied by an appropriate correction factor for the standard depth of seasonal freezing to allow the setting design of the anti-frost layer thickness of the roadbed. By changing the roadbed filling materials, a series of computer simulations were carried out. The thermal states of roadbeds were simulated 50 years under the climate warming. It was indicated that the modified common A/B group fills do not improve the thermal state, though the filled layers were designed to increase the roadbed bearing capacity. The maximum frozen depth was 1.5-1.6 m under the track plates, and 1.7-1.8 m under the shoulders. The reinforced concrete component made the isothermals appear as a saddle shape, and change to be flatter with the depth of roadbed. (C) 2012 Elsevier B.V. All rights reserved.