基于上海软土的真三轴试验结果,研究不同中主应力系数b值下,上海软土的孔隙水压力发展规律。探寻孔隙水压力变化与土体剪缩之间的关系,寻求真三轴条件下,孔隙水压力与偏差应力之间的定量关系。从主应变关系的角度,分析上海软土在真三轴条件下的剪切特性。研究表明,土体的剪胀(剪缩)特性与孔隙水压力的减小(增大)密切相关。与常规三轴条件下所得结果相似,孔隙水压力与偏差应力之间呈现线性相关关系,但在中主应力系数b值的影响下,两者的线性斜率发生变化。通过回归分析,建立孔隙水压力与偏差应力之间的定量关系。最后,采用此关系对试验资料进行拟合,拟合结果与试验值吻合度较好。 Based on the true triaxial test results of Shanghai soft soil, the law of pore water pressure development in Shanghai soft soil was studied under b values ​​of different middle principal stress coefficients. Explore the relationship between pore water pressure change and soil shear contraction, and seek the quantitative relationship between pore water pressure and deviation stress under true triaxial conditions. From the point of view of the main strain, the shear properties of Shanghai soft soil under true triaxial conditions are analyzed. The research shows that the dilatancy (shrinkage) characteristics of soil are closely related to the decrease (increase) of pore water pressure. Similar to the results obtained under conventional triaxial conditions, there is a linear correlation between pore water pressure and deviatoric stress, but the linear slope changes under the influence of the b value of the principal stress coefficient. Through regression analysis, a quantitative relationship between pore water pressure and deviatoric stress was established. Finally, using this relationship to fit the experimental data, the fitting result is in good agreement with the experimental value.