Effect of temperature change on the thaw-induced permafrost slope failure based on thermal-hydro-mechanical coupling

In recent years, the temperature in the permafrost region of the Qinghai-Tibet Plateau has risen, which lead to frequent active layer detachments and retrogressive thaw slumps, which seriously affect the ecological environment and human activities. Clarifying the thermal-hydro-mechanical response mechanism of permafrost slopes driven by temperature changes is of great significance in the prevention and reduction of thaw-induced slope failures. In this study, a generalized numerical model of permafrost slopes was established, to simulate the thermal-hydro-mechanical evolution process of permafrost slopes under the condition of temperature changes. Simulated results indicate that the change rate of total water content at the top and toe of the slope reached the annual maximum from July to October, and the value reaches 0.64% per year. A 15-cm-thick water-rich layer was produced with the temperature rises in summer; at this time, the factor of safety of the slope reaches the lowest value. With the regional climate warming, the permafrost table moves down at a rate of 2.6 cm/a, and the thickness of the water-rich layer may gradually increase. Frost heave and thaw settlement causes the maximum deformation at the toe of the slope, generating a net displacement of 2.5 cm per year. Creep deformation on the slope surface indicates the mechanical property degradation of the soil, leading to the decline of the factor of safety with the increasing freezing and thawing cycles. The results provide the theoretical basis and scientific guidance for the prevention and control of thawing hazards in permafrost regions.