单向冻结黏性土水热特性冻胀试验研究

Experimental Study on Water Thermal Characteristics and Frost Heaving of Unidirectional Frozen Cohesive Soil

冻结过程中对其水–热分布特性及冻胀的研究一直是冻土学研究的热点。本文以新疆南疆阿拉尔市周边黏性土为研究对象,进行土体单向冻结作用下的冻胀试验,设置冷端温度−1℃、−5℃和−10℃,暖端温度、环境温度为3℃,研究土体在单向冻结作用下水–热变化及土体的变形。试验结果表明;土体中水分迁移过程受土体降温的影响,冷端温度越低水分随冻结时间向冷端迁移速度越快。试样冻胀量随冻结时间的增加而增加,且冷端温度越低冻胀量越大。研究结果能够很好的反映在不同温度变化条件下新疆南疆地区黏性土在冻结过程中的温度分布、水分分布及变形规律,从而为后期深入研究路基盐–冻胀变形机理提供一定的理论参考。

During the freezing process, the research on the water heat distribution characteristics and frost heaving has always been a hot spot in permafrost research. In this paper, the cohesive soil around Alar city in southern Xinjiang is taken as the research object, and the frost heaving test of soil under Unidirectional Freezing is carried out. The cold end temperature is −1˚C, −5˚C and −10˚C, the warm end temperature and the ambient temperature are 3˚C, and the water heat change and soil deformation under Unidirectional Freezing are studied. The results show that the moisture migration process in soil is affected by soil cooling, and the lower the temperature of the cold end is, the faster the moisture migrates to the cold end with freezing time. The frost heaving increases with the increase of freezing time, and the lower the cold end temperature is, the greater the frost heaving is. The research results can well reflect the temperature distribution, moisture distribution and deformation law of cohesive soil in the freezing process in southern Xinjiang under different temperature changes, so as to provide a theoretical reference for the later in-depth study of subgrade salt frost heaving deformation mechanism.