分层冻胀量的观测方法研究

Study on the Observation of Delamination Frost-Heave Amount

当前使用的分层冻胀量观测方法有单体冻胀尺法、叠合冻胀尺法和磁环法,分析了这3种方法各自的优缺点,从冻胀的机理出发,在正冻土中的水分迁移和成冰规律的基础上,提出了表面冻胀量和冻深对比法.依据内蒙古永济冻土试验场、内蒙古巴林左旗二龙灌区冻害试验场和大庆地区等3个季节冻土区的分层冻胀量观测结果,分析了该方法在季节冻土区不同地下水位和不同土质条件下的适用性;同时,还据青海江仓的资料,对在多年冻土地区的应用性进行了评估.结果表明,对比法只可以用于近似确定季节冻土区的分层冻胀量,要确定多年冻土区的分层冻胀量,该方法是失效的.

Observation of delamination frost heave is of significance in the study of foundation frost damage. There are three main methods of observing delamination frost heave: single frost-heave ruler method, spliced frost-heave ruler method and magnetic-loop method. They are briefly introduced in this paper at first. Then, their advantages and disadvantages are analyzed respectively. The key problems of the single ruler method and their solutions are pointed out. And then, according to the mechanism of frost heave and the law of water migration and ice forming in the freezing soil, comparing surface frost heave and frost-depth brings a new approximate indirect method of observing the delamination frost heave forward. Based on the observation of three proving grounds, located in Yongji and Erlong Irrigation Area of Inner Mongolia and Daqing, the applicability is analyzed from three aspects under different groundwater level and soil property in seasonal frozen area. Simultaneously, the applicability in permafrost is also verified by virtue of data from Jiangcang of Qinghai. Finally, it is pointed out that antitheses can be used only in seasonal frozen area. The method is invalidated in permafrost.