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为了研究天然沉积结构性软黏土的屈服特性,采用大直径PVC管取样器获取连云港地区地表下2.5m处的不扰动样,进行一维固结和应力路径三轴试验.一维固结试验结果表明,天然沉积连云港软黏土具有较强的结构性.GDS三轴的不同应力路径试验结果表明,无论以体积变形还是剪切变形为主的应力路径下,连云港软黏土的应力应变曲线都有明显的屈服特征.根据试验各应力路径得到的屈服点,可以得到连云港软黏土的初始屈服轨迹大致呈倾斜的椭圆形状,与Nakano等人模型的屈服面比较吻合.沿各应力路径屈服后塑性应变方向与该模型屈服面法线方向的夹角在-22°～33°范围之内变化,表明屈服后塑性流动方向可简单采用相关联流动法则来描述.
In order to study the yield characteristics of natural sedimentary structural soft clay, a large-diameter PVC pipe sampler was used to obtain undisturbed samples 2.5m below ground surface in Lianyungang area, and the one-dimensional consolidation and stress path triaxial tests were carried out. The results show that the natural sediment Lianyungang soft clay has a strong structural.The experimental results of different stress paths of GDS triaxial indicate that the stress-strain curves of Lianyungang soft clay are obvious both in the stress path of volume deformation and shear deformation . According to the yield point obtained from each stress path in the experiment, the elliptical shape of the initial yielding trajectory of Lianyungang soft clay can be obtained, which is consistent with the yield surface of Nakano et al.According to the plastic strain after yielding of each stress path And the normal direction of the yield surface of the model changes within the range of -22 ° ~ 33 °, indicating that the plastic flow direction after yielding can be simply described by the associated flow law.