粗颗粒硫酸盐渍土地基盐-冻胀界限深度模型试验

为完善粗颗粒硫酸盐渍土盐胀理论，研究其盐-冻胀力的影响因素及变化机制，人工配制96组粗颗粒硫酸盐渍土试样，通过自主设计的试验装置，进行室内模型试验研究。结果表明：盐-冻胀力的敏感温度区间为-0.2～-1.0 ℃；含盐量不影响盐-冻胀力随温度的增长规律，与含水量共同决定最大盐–冻胀力的大小；对于相同孔隙比的试样，含水量的增加使其发生峰值盐-冻胀力所需的含盐量增加。当含盐量一定时，含水量的增加反而使其峰值盐-冻胀力减小；盐渍土试样在孔隙比为0.55和0.58时峰值盐-冻胀力分别出现极小值和极大值，这与盐分在土颗粒骨架间的结晶位置有关。基于试验结果，运用分层总和法给出工程适用的粗颗粒硫酸盐渍土地基盐-冻胀界限深度表达式，为粗颗粒硫酸盐渍土地基盐-冻胀变形的量化评价和设计提供重要参考依据。

Model Test of Salt-frost Heaving Limit Depth of Coarse-grained Sulphate Saline Soil

In order to perfect the salt expansion theory of coarse-grained saline soil and explore the influencing factors and mechanism of the salt-frost heaving force,96 groups of coarse-grained sulphate saline soil samples are prepared artificially then indoor model tests have been carried out by self-designed test device. Test results showed that the sensitive range of temperature on the salt-frost heaving force is -0.2~-1.0. The salt content had no influence on the rules that the salt-frost heaving force increasing with temperature and determines the maximum salt-frost heaving force together with water content. For samples with same void ratio, the increasing water content led to an increased amount of the salinity which resulted in the maximum salt-frost heaving force. When the salt content kept constant, however, the increase of water content caused the decrease of maximum salt-frost heaving force. The maximum salt-frost heaving force achieved the maximum and minimum values when the void ratio was 0.58 and 0.55, respectively, which was related to the crystallization position of salt in the soil frame. Furthermore, based on the test results, a mathematical expression of frost heaving limit depth of coarse-grained sulphate saline soil is given by the hierarchical synthesis method, which is expected to provide guidance for the quantitative evaluation and design of salt-frost heaving deformation of coarse-grained sulphate saline soil.