Cooling effect of crushed-rock revetment as a reinforcement measure for embankment in permafrost regions with massive ground ice

Abstract This study assesses cooling effect of crushed-rock revetment (as a reinforcement measure) for embankments underlain by massive ground ice, using ground temperature monitoring and predictive analysis. Results show the reinforcement suppressed thermal erosion, reducing shallow ground temperature fluctuation amplitude and decreasing deep-layer warming rate by 55.6%. However, the crushed-rock revetment mainly maintains embankment stability by slowing down the rate of heat input to delay or prevent the degradation of the underlying permafrost, rather than restoring the original permafrost table. Ground temperature prediction based on a PINN-LSTM hybrid model confirmed that, after reinforcement, the thermal dynamics of the shallow underlying soil layer tended toward a steady state, while the deep layer exhibited thermal inertia characteristics. In addition, the spatial distribution of the massive ground ice dominates the asymmetry in the reinforcement effect of the crushed-rock revetment. The phase-change latent heat buffer of the massive ground ice, combined with the winter forced convection within the crushed-rock layer, jointly enhances the thermal stability of the soil. When maximum thaw depth penetrates the massive ground ice, weakening of the thermal inertia allows revetment cooling to penetrate deeper soil. This study provide scientific support for the application of crushed-rock revetment for permafrost embankments.