The reported slope failures during thawing season in Hokkaido involved a large failure of soil mass traversing a length of approximately 50 meters. Typically, two-dimensional plane strain analysis was performed to analyze slope stability, considering the effect of freeze-thaw, snowfall, and rainfall. However, this method is not sufficient for large-scale slope stability issues occurring in Hokkaido. Therefore, a study was initiated to investigate the applicability of 3D analysis, coupled with seepage and thermal analysis, to determine slope stability in a cold region.

The geotechnical researchers applied the 3D equilibrium limit features in PLAXIS to analyze the slope stability using pore water pressures derived from 3D-coupled thermal-seepage analysis. Using Bentley’s application, the analysis proved that the 3D method is effective to simulate slope failure in cold regions and is appropriate for large-scale slope failure problems. The digital solution can be applied to difficult slope issues involving complex geological formations.