非饱和粗颗粒土体的冻结试验研究

按照实际工程中路基填料的级配要求配制试样，在考虑覆盖层和补水条件下进行室内单向冻结试验，开展了土质、温度梯度和温度边界条件对非饱和粗颗粒填料冻胀特性的影响研究。试验结果表明：土质、温度梯度和温度边界对粗颗粒填料的冻胀特性影响显著。其中混合细粒的冻胀量最大、黏质黄土次之、粉质黏土最小，且其对应的试样顶部、冻结锋面处的含水量及外界补水量均具有相同的大小关系。温度梯度越大，冻胀量越大，试样顶部含水量越高，但冻结锋面处的含水量变化比较小，同时外界补水量越小。试样冷端温度边界越低，冻胀量越小，试样冷端含水量越小，但外界补水量越大。

Experimental study on freezing of unsaturated coarse-grained soils

According to the grading standards of subgrade fillings in practical engineering, some test specimens were made for one-side freezing experiments, under the consideration of impervious cover and no-pressure water supply, and for studying the influence of properties of soils, temperature gradients and boundaries on the frost susceptibility of unsaturated coarse-grained soil. The tests results showed that the properties of soils, temperature gradients and boundaries have significant influence on the frost susceptibility of coarse-grained soils. The amount of frost heaving of specimen with mixed fines is largest, following by the specimens with clay loess, and the specimens with silty clay is the minimum. The water contents in the upper position and freezing front of specimen, as well as the external water supply, have the same effect. The larger the temperature gradient, the bigger the frost heaving of specimen, resulting in more water accumulated at the top of the specimen. But the water content is less changing at the freezing front, and the external water supply is smaller. The lower the temperature boundary at the cold end, the smaller the frost heaving. In addition, the water content in the upper position decreases and the external water supply increases. As the water content in the upper position less, the external water supply will increase.