非饱和上海软土的土-水和变形特性

使用压力板法和滤纸法测量非饱和上海软土的吸力,得到第②,③,④层上海原状土和第②,③层上海重塑土的土-水特征曲线,以及土体脱水干燥过程中吸力和孔隙比之间的关系.土-水特性试验结果表明:第②,③,④层上海原状土和第②,③层上海重塑土的进气值分别为150～180,220～250,650～800,260～310,550～600 kPa.干燥收缩试验结果表明:上海黏土的收缩过程可分为3个阶段,即弹性阶段、弹塑性阶段和缩限阶段.当基质吸力较小时,收缩变形较小,土体处于弹性阶段;当基质吸力增大到一定值时,收缩变形明显,土体处于弹塑性阶段;当土体变形基本不随基质吸力变化时,土体处于缩限阶段。

Soil-Water and Deformation Characteristics of Unsaturated Shanghai Soft Clays

Using the methods of pressure plate and filter paper to measure soil suction,the soil-water characteristic curves and shrinkage deformation curves of undisturbed Shanghai soft clays(layers ②,③ and ④) and reconstituted Shanghai soft clays(layers ② and ③) are obtained from drying tests.It is found from the soil-water characteristic tests that the air-entering values of undisturbed Shanghai soft clays(layers ②,③ and ④) and reconstituted Shanghai soft clays(layers ② and ③) are 150~180,220~250,650~800,260~310,and 550~600 kPa,respectively.The process of soil shrinkage can be divided into three stages: elastic stage,elastoplastic stage and stage of shrinkage limit.When the imposed matric suction is small,the soil is at the elastic stage.When the large suction is applied,the shrinkage deformation becomes noticeable,and the soil is at the elastoplastic stage.At the stage of shrinkage limit,almost no deformation occurs during the increase of matric suction.