Comparing frost heave characteristics in cut and embankment sections along a high-speed railway in seasonally frozen ground of Northeast China

Abstract

The Harbin–Dalian Passenger Dedicated Line (HDPDL) is the first high-speed railway in deep seasonally frozen ground in China. Frost heave is among the most difficult problems in roadbed deformation control in such area. In this study, the ground temperatures and frost heave in a road cut section (K865) and an embankment section (K866) along the HDPDL were analyzed based on monitoring data in situ. From 2012 to 2018, the maximum frost heave in the cut section ranged from 4.52 mm to 9.18 mm, while in the embankment section this value ranged from 1.86 mm to 5.28 mm. The data clearly show that frost heave in the cut section was much more serious than that in the embankment section, although the frozen depth of the road cut was approximately 20 cm shallower than that of the embankment. The frost heave ratios of the roadbed filling materials in the well-graded gravel layer (0–0.5 m), non-frost susceptibility A/B group fill layer (0.5–1.5 m), and A/B group layer (1.5–2.7 m) were 1.20%, 0.14%, and 0.08% on average in the cut section and generally higher than 0.63%, 0.04%, and 0.02% in the embankment over six freezing seasons, respectively. The investigation of frost heave in different soil layers at 24 monitoring sites indicated that most frost heave occurred in the top well-graded gravel layer (0–0.5 m), account for averagely 66% of the total deformation. The frost heave of the subgrade along the HDPDL mainly developed during the early period of each freezing season and an abrupt increase typically occurred during the initial period of the thawing process.