Novel anti-frost subgrade bed structures a high speed railways in deep seasonally frozen ground regions: Experimental and numerical studies

To reduce the threat of frost damage to the speedy and safe operation of high-speed railways (HSRs) in deep seasonally frozen ground regions, it is necessary to study the anti-frost subgrade bed structure to improve the long-term service performance of HSRs. First, the thermal-mechanical behaviour and preventative efficacy of the original anti-frost subgrade bed structure with graded-crushed rock filling materials are studied. Then, the general change laws of the thermal-mechanical behaviours for embankment engineering in deep seasonally frozen ground regions are revealed. Finally, a finite element model is developed to investigate the anti-frost effects of six novel subgrade bed structures with differential filling materials. The results show that 1) the initial freezing time, initial thawing time and freezing rate of the embankment are substantially different from those of the natural ground; 2) the deformation of the embankment is closely related to the filling depth and frost depth of the embankment. Furthermore, the deformation process is closely related to the seasonal air temperature change; 3) the seasonal frozen depth of the embankment can be reduced by changing the heat entering the subgrade bed and the heat diffusion in the embankment body; and 4) an asphalt concrete pavement + cement stabilized macadam + insulation board subgrade bed structure can best reduce the frost depth. This research provides important technical guidance for the design of the anti-frost subgrade bed structure of the HSR subgrade in deep seasonally frozen ground regions. (C) 2020 Elsevier Ltd. All rights reserved.

Automated summary

Research shows that the anti-frost subgrade bed structure can effectively reduce frost damage to high-speed railways in deep seasonally frozen ground regions. The filling depth and frost depth are closely related to embankment deformation, and the design of the anti-frost subgrade structure can reduce the seasonal frozen depth of the embankment.