Numerical Simulation For Stability Of Subgrade On Seasonal Frozen Region

Based on research of predecessor and ADINA finite element procedure, the stability of seasonal frozen subgrade is approached. The highway reconstruction project of the State Road 213, which from the Lang Musi to Chuan Zhusi is taken as engineering background.Combining the characteristic of the seasonal frozen subgrade, and comprehensively considering the distribution condition of the subgrade temperature field under the action of atmospheric temperature, thermal convection, thermal radiation, and heat conduction, the temperature field of subgrade is calculated and analyzed. Through calculation adding the temperature of the temperature model as the initial stress to the structure model, the coupling analysis of the temperature field and stress field is realized, and under the temperature condition the distribution of the stress and displacement inside subgrade is gained.According to climate and soil texture condition in northwestern Sichuan region, the stability of subgrade is analyzed under the influence of the setting location of the insulating layer in the seasonal frozen soil subgrade in this the region. In the prior condition of taking insulating layer thickness as 0.1m, choosing insulating layer 0.5m,1.0m,1.5m,2.0m below the pavement, the stability of seasonal frozen soil subgrade is analyzed. The results of the analysis show that the optimal position of the insulating layer is 1.0m～1.5m below the pavement, that is to say, 0.5m～1.0m below the subgrade.Considering the frost heave amount and frost heaving force, stress field distribution of the seasonal frozen soil subgrade in frost-heaving and thaw-subsiding is simulated in the light of frozen soil strength theory and elastic theory. Study shows that the stability of the subgrade is higher in frost heaving than in thaw subsiding, the subgrade begin to damage under the uniformly distributed load, the subgrade completely loses stability under the rated load.