基于FLAC3D的季节冻土路基冻融变形分析

为了研究季节冻土路基温度场及变形场的动态变化规律,利用FLAC3D软件及内嵌的FISH语言,编写了路基计算参数随温度变化的程序,对兰新二线典型冻土路基的冻融变形问题进行了更准确的模拟分析。通过建立路基计算模型,对路基温度场与实测资料进行了对比分析,验证了模拟方法的有效性与可靠性;通过模拟不同高度的路基在冬、夏季时的冻融变形情况,得出路基高度H是影响冻土地区路基热稳定性的重要因素。研究表明:路基高度H不同,路基上各点的冻融变形随时间的变化规律相同,而变形量均不相同;冻融引起的路基表面和内部沿深度方向各点的变形差别很大;最后通过比较得到既符合路基稳定性又符合工程经济性的最佳路基高度,对冻土路基的设计和施工有一定指导意义。

Analysis of Freezing and Thawing Deformation in Seasonal Frozen Soil Subgrade Based on FLAC3D

In order to study the dynamic changing regularity of the temperature and the deformation field in seasonal frozen soil subgrade, in this paper the FLAC3D software and embedded FISH language are used to analyze frozen deformation problems of representative frozen roadbed at the second line of the Lan-Xin railway more exactly, by compiling programs of subgrade parameters changing with temperature. Through establishing computing model of the subgrade, the temperature field of roadbed and the measured data are compared and analyzed, and the method is proved effective and reliable. Through simulating the freezing and thawing deformation condition of different heights of roadbed in winter and summer, the height is an important parameter influencing the heat stability of embankment in permafrost regions. The results show that the freeze-thaw deformation regularity of each point on the roadbed with time is the same, and the amount of deformation is different for various heights of subgrade. The deformation of each point of the surface and the interior in the depth direction is quite different, which is caused by freezing and thawing. Finally, comparing different heights of the roadbed, the best height of roadbed is obtained, which is consistent with the roadbed stability and engineering economy and has a certain guiding significance to design and construction of roadbed.