采用不同工况的载荷试验、室内常规土工试验和易溶盐试验,分析了碎石土的荷载-沉降曲线特征,探讨了碎石土的湿陷性与湿陷机理。结果表明:碎石土在200 kPa稳定后浸水,再加荷到400 kPa,载荷试验荷载-沉降曲线呈折线型,明显分为三个阶段:压缩变形阶段,湿陷变形阶段,复合变形阶段。场地中4 m厚碎石土具有湿陷性,且湿陷性不均匀。碎石土湿陷的机理在于其结构是疏松的单粒架空结构。骨架颗粒间存在架空孔隙,且部分架空孔隙由砂质颗粒集合体充填;骨架颗粒间呈点与点接触,或者主要通过黏粒、黏土矿物、易溶盐组成的胶结物而联结在一起;在浸水加荷过程中,黏粒周围薄膜水增厚、粘土矿物自身产生膨胀、易溶盐溶解,导致胶结物的胶结强度丧失,结构失稳,发生湿陷。 The loading test under different working conditions, routine geotechnical test in laboratory and salt-soluble test were used to analyze the characteristics of load-settlement curve of crushed-stone soils, and the collapsibility and collapsible mechanism of crushed-stone were discussed. The results show that the gravel soil is soaked at 200 kPa and re-loaded to 400 kPa. The loading-settlement curve of the gravel soil is in the form of a broken line. There are obviously three stages: compressive deformation stage, collapsible deformation stage and composite deformation stage. 4 m thick crushed rock in the site is collapsible and inhomogeneous. The mechanism by which the gravel soil collapses is that its structure is a loose single-unit overhead structure. There are overhead voids between the skeleton particles, and some overhead voids are filled with the aggregate of the sandy particles; the skeleton particles are in point-to-point contact or are mainly linked together by the cement consisting of clay, clay minerals and soluble salts; and in During the process of flooding and loading, the film water around the clay particles is thickened, and the clay minerals themselves swell and the soluble salts dissolve, resulting in the loss of the cementation strength of cement and the structural instability and collapse.