真三轴条件下上海软土的孔隙水压力特性分析

Pore Water Pressure Property of Shanghai Soft Soil Based on True Triaxial Tests

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 development of pore water pressure was analyzed under different intermediate principal stress magnitude b,meanwhile the relationship between the pore water pressure and contraction was explored,and the quantitative relationship between pore water pressure and deviator stress was established. From the point of principal strain,the paper researched the shear property of Shanghai soft soil under the true triaxial tests. Studies show that the dilatancy(or contraction) is closely related to the decreasement(or increasement) of pore water pressure. Besides,the pore water pressure and the deviator stress have a strong linear relationship,which is similar to the results under conventional triaxial tests,while the linear slope changes with the changing in the intermediate principal stress magnitude b. Equations between pore water pressure and deviator stress were established through the regression analysis. The results calculated by the equation presented are in good agreement with experimental data.