Abstract:The plastic deformation characteristics of permafrost are the key to understand the stress response state and the degradation of overload. The topic is also an active research area in the field of permafrost engineering and geotechnical engineering in recent years. Based on a triaxial test, the physico-mechanical parameters of soil layers, such as -1℃ and -2℃ permafrost soil elastic modulus; cohesion; and internal friction angle under 9%, 12%, and 15% water content conditions, were used to establish a typical railway embankment. The plastic deformation law of the railway subgrade in the permafrost region subjected to natural earthquake loads under temperature increase and strength degradation was analyzed. The results show that with increasing temperature, the frozen soil degraded. At the foot and subgrade center, plastic deformation at -1℃ was greater than that at -2℃. The plastic deformation of the left and right slopes followed a symmetric distribution law. The soil temperature of the typical railway subgrade was raised from -2℃ to -1℃. In 9% moisture content, the plastic slope of the soil layer was 3.5 times larger in the left slope and 4.9 times in the right slope. Moreover, the 12% water content test showed that the plastic strain in the soil layer was 1.6 times larger in the left slope and 2.5 times in the right slope. The tested soil layer with 12% moisture content under permafrost degradation showed good stability, and under the same stress conditions, the plastic deformation increased minimally.
