Analyses of the Impacts of Climate Change and Forest Fire on Cold Region Slopes Stability by Random Finite Element Method

Increasing number of landslides occurred in the cold regions over the past decades due to rising temperature or forest fires associated with climate change. The instability of thawing slopes caused serious damages to transportation infrastructure, residential properties, and losses of human lives. These types of landslides, however, are difficult to analyze by the traditional limit equilibrium methods due to the coupled thermos-hydro-mechanical multiphysics processes involved. This paper describes a novel microstructure-based random finite element model (RFEM) to simulate the stability of permafrost slope subjected to climate change, including the increasing extent of thawing by warm atmosphere and thermal load due to forest fire. The properties of frozen soil are captured with random finite element model incorporating soil-phase coding. The thermomechanical responses of a permafrost slope are simulated to obtain the temperature, displacement, and stress fields. From these, the local factors of safety are obtained, which predict failure slumps along the slope that are consistent with the field-observed failure behaviors in permafrost slopes. The effects of climate change on the permafrost slope stability are analyzed for the years of 1956, 2017, and 2045. The results demonstrated appreciable amount of effects of climate change on the extent of slope failure zones. Forest fire led to melting of frozen soil and also affects the slope stability primarily in the shallow depth.