滨海软土黏滞系数非线性特性及其表达

通过对滨海软土三轴蠕变相关试验数据进行分析,发现黏滞系数不仅与时间有关,还与土所受到的偏压和围压有关。应变率与时间的关系呈现了非常明显的双对数线性关系,因此,黏滞系数是关于时间的幂函数;黏滞系数线性地依赖于偏压的变化,而与围压呈指数关系。最后建立了黏滞系数与时间、偏应力、围压之间的非线性关系表达式,并探讨了其相关参数的意义及取值范围。建立的黏滞系数表达式适用于描述非线性特征明显、应力水平较高的软土黏滞系数随时间、应力的变化规律,可推广到滨海软土直剪蠕变试验中。研究成果可为建立变黏滞系数的滨海软土及其他地区软土的非线性流变模型奠定基础。

Nonlinear Characteristics and Expression of Viscosity Coefficient of Coastal Soft Clay

Analysis on triaxial creep test data of coastal soft soil reveals that viscosity coefficient is not only related to time, but also to the deviatoric pressure and confining pressure of soil. The relation between strain rate and time is of perfect double logarithmic linear characteristics. Hence, viscosity coefficient is a power function of time. Sensitivity analysis of deviatoric pressure unveils that viscosity coefficient is linearly dependent on deviatoric pressure and exponentially on confining pressure. Last but not the least, the nonlinear relations between viscosity coefficient with time, deviatoric stress and confining pressure are established and applied to the direct shear creep test of coastal soft soil. The proposed expression is applicable to describe the variation of viscosity coefficient of soft soil with apparent nonlinear characteristics and high stress level along with time and stress. In addition, factors affecting the relevant parameters are also put forward. The research findings lay a foundation for building the nonlinear rheological model coastal soft soil