关键词: 非饱和土, 基质吸力, 收缩变形, 土-水特征曲线, 重塑土

Abstract: 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.

Key words: matric suction, reconstituted soil, shrinkage deformation, soil-water characteristic curve, unsaturated soil