冻土路基边坡稳定性计算程序开发

Development of Slope Stability Evaluation Process of Permafrost Embankment

寒区边坡稳定性评价的特殊性在于其土体内部温度场的不均匀性。针对寒区边坡特点,提出以冻土物性参数随温度变化作为温度场和应力场的耦合纽带。考虑温度分布对土体力学性质改变及冻融交界面的影响,开发了耦合温度场的冻土边坡稳定性评价程序;并对非圆弧滑面稳定性系数求解中取矩中心的求解做了相应改进。利用开发的冻土路基稳定性计算程序,对坡度为1∶1.5的4 m路基进行了不同地温条件下的工况计算。计算结果表明在评价冻土路基正融期滑坡的稳定性时,采用折线滑面的方法来评价更为科学、严谨。此外计算结果还表明,冻土路基年度最小稳定性并非出现在融深最大的10月份,而是出现在暖季的早期从而形成热融滑塌现象;且年度最小稳定性出现的时间随地温的降低而向后推移。

The slope stability analysis in cold region is special for its non-uniform temperature field. Considering the special characteristic of the cold region slope, the physical parameters of frozen soil are treated in this paper as the connection between temperature field and stress field. The temperature influences mechanical properties of frozen soil and forms freezing-thawing interface in the slope, which make great influence on the stability of slope. The critical slip surface searching algorithm for cold region is developed and the moment center solution method in the computation of slope’s stability coefficient is also improved. The critical slip surface and stability of 4m subgrade with 1： 1.5 slopes under different soil temperature condition is computed using the developed frozen subgrade stability computation program. The results shows that the line segment type slip surface is more accuracy than circle type slip surface in cold region slope stability analysis; moreover, the minimum stability coefficient of frozen subgrade does not happen in tenth months when the thawing soil goes to deepest, but show in the early time of warm season, forming the phenomenon of thaw slumping. And it is also found that the occurring time of yearly minimum landslide stability coefficient postpones as the decreasing of soil temperature.