埋深与形状对土中结构自由冻拔的影响

冻拔破坏是季节性冻土地区土中结构常见的破坏形式。为了探明季节性冻土地区土中结构冻拔位移与结构埋深、结构截面形状的关系，利用挤塑保温板加工成长度不等的圆柱体与长方体，埋置于室外冻胀土中，模拟土中结构，开展一个冻融周期的室外自由冻胀试验。观测气温、地温、冻深及土体、圆柱体、长方体的冻拔位移等参数，对比试件的冻胀位移，分析自由冻拔的影响因素。结果表明：当埋深小于临界埋深时，一个冻融周期后2种截面的残余冻胀位移均随埋深增加而快速增大，而当埋深大于临界埋深时，残余冻胀位移随埋深增加无明显变化；埋深相同的长方体与圆柱体的残余冻胀位移相对差均值为10%，考虑到试验过程中其它偶然因素的影响，截面形状对土中结构的自由冻拔无明显影响。

Effects of embedment depth and section shape on frost heaving of buried structures

In order to evaluate the effects of embedment depth and cross-section shape of buried structures on its frost heaving damage, frost heaving test of one freezing-thawing cycle was conducted at outdoor test site, where cylinders and cuboids with different shapes and dimensions made by extruded polystyrene insulation board were used to simulate buried structures. Air temperature, soil temperature, freezing depth and frost heaving displacements of the buried structures were monitored in test. By analyzing and comparing the test data, it was concluded that in a freezing-thawing cycle, frost heaving displacement of structures buried in certain depth range above maximum frozen depth increased rapidly with embedment depth, and it tended to stable when embedment depth increased to a certain value. The mean relative difference of frost heaving displacements of cylinders and cuboids with the same embedment depth is 10%, in consideration of the accident factors in the test, there was no obvious relationship between the frost heaving displacement and section shape of the structure.