不同土样冻胀融沉特性实验和数值模拟研究

为了研究土样、荷载、吸水量以及温度等因素对冻胀量和融沉量的影响,运用多功能冻胀融沉实验系统,分别以粉细砂、粉质黏土、黏质粉土和杂填土为研究对象,进行在试件周边和底部限制变形条件下顶部施加不同荷载的冻胀融沉实验。研究结果表明:(1)土样冻胀变化趋势主要分为三个阶段:缓慢冻胀阶段、快速冻胀阶段以及稳定冻胀阶段;(2)随着冻结温度的降低,土样冻胀量均逐渐增大,并最终趋于稳定;(3)冻结过程中吸水量和冻胀量成正比,变现出良好的想关性;(4)在试样上部施加荷载对试样的冻胀产生明显的抑制作用,随着荷载的加大,冻胀量逐渐减少最终接近于零;(5)无论土样是否受到载荷作用,粉质黏土的冻胀率均为最大,而杂填土的冻胀率最小,且黏质粉土的冻胀率大于粉细砂;(6)冻胀量对融沉量影响较大,冻胀量越大融沉量也越大,且融沉量大于冻胀量。研究成果对土体冻胀融沉的研究具有重要的指导意义。

Experimental and field measure of frozen heave properties of different soil sample

In order to explore the influence of different soil samples and load on frost heaving and melting, the frost heaving and melting experiments was carried out by the multi-functional frost heaving and melting test system under the condition of limited deformation around the specimen and at the bottom with different loads on the top of the sample. The results show that: (1) The variation trend of soil frost heave can be divided into three stages: slow frost heave stage, rapid frost heave stage and stable frost heave stage. (2) The frost heaving amount of soil gradually increases and finally tends to be stable with the freezing temperature decreases. (3) During the freezing process, the amount of water absorbed is proportional to the amount of frost heave, which shows good correlation . (4) The load applied on the upper part of the sample has obvious inhibiting effect on the frost heave of the sample. With the increase of the load, the frost heave gradually decreases and finally approaches zero. (5) The frost heaving rate of silty clay is the maximum, and that of mixed soil is the minimum, and that of clay is greater than that of fine sand, whether the soil sample is under load or not. (6)The amount of frost heave has great influence on the amount of frost heave. The research results have important significance for the research of soil frost heave and melt.