膨胀土的胀缩变形会对其上的建筑产生危害,研究膨胀土的胀缩变形特征具有重要意义。通过一系列干燥收缩-加湿膨胀试验,研究膨胀土在收缩-膨胀循环过程中孔隙比-含水率的关系及初始干密度对其的影响,结果表明:采用照相法测量土样面积是一种较为理想的非接触测量方法;不同初始干密度下的收缩曲线及膨胀曲线分别相互平行,且随着初始干密度的增加,孔隙比-含水率曲线往下移动;当初始干密度小于临界干密度时,土样的收缩曲线与膨胀曲线相交;随着初始干密度的增加,土样的收缩曲线与膨胀曲线逐渐由交叉状态变为分离状态;在一次干缩-湿胀过程中,随着初始干密度的增大,土样的体积收缩率逐渐减小,体积膨胀率变化不大,即经过一次收缩后,初始干密度对土样膨胀性的影响减弱。 Expansion and deformation of expansive soil will have a detrimental effect on the buildings on it. It is of great significance to study the characteristics of expansive deformation of expansive soils. Through a series of drying shrinkage-humidification expansion tests, the relationship between void ratio and water content and the initial dry density of expansive soils during shrinkage-expansion cycles were studied. The results showed that the area of ​​soil samples was a Ideal non-contact measurement method; the shrinkage curve and the expansion curve at different initial dry densities are parallel to each other, and the pore-water content curve moves downwards as the initial dry densities increase; when the initial dry densities are less than the critical dry densities , The shrinkage curve of soil sample intersects with the expansion curve. With the increase of initial dry density, the shrinkage curve and expansion curve of soil sample gradually change from the cross state to the separation state. In a dry shrinkage-wetting expansion process, With the increase of density, the volumetric shrinkage rate of soil samples decreases gradually and the volumetric expansion rate does not change much. That is to say, after a contraction, the influence of initial dry density on the expansibility of soil samples is weakened.