饱和黏性土的结构性本构模型

Structured constitutive model for homogeneous saturated clay

将Liu等提出的土的结构性本构模型与三剪强度准则相结合,提出了均质饱和黏性土的三剪结构性本构模型。该模型既保留了原结构模型的特点,又考虑了应力状态对土特性及土的拉压强度差异的影响。另外,利用该模型对均质饱和黏性土在常规三轴试验、K_0压缩试验、以及真三轴试验中土的变形特性、孔隙水压力特性、中间主应力效应特性进行了模拟。结果表明在常规三轴试验中,孔隙水压力随着中间主应力影响系数的增加而减小,解构指数对孔隙水压力影响不大;K_0压缩试验中,在偏应变一定时,中间主应力影响系数对体积应变的影响较小,而体积应变随着解构指数的增加而增加;真三轴试验中,中间主应力影响系数越大,偏应力越大,土体强度越大。该本构模型能够反映均质饱和黏性土的强度变形规律及结构性对土的变形规律的影响。

Combined the triple-shear failure criterion with the soil structured constitutive model proposed,the triple-shear structured constitutive model for homogeneous saturated clay was deduced.This new model not only remained the features of the original structured model,but also considered the influences of stress states on deformation properties and tensile-compressive strength difference for clay.Otherwise,the numerical simulation were completed in representing the properties of soil deformations and the pore water pressures and the influences of the intermediate principal stress and decomposition parameter under the conventional tri-axial tests,the K_0 compression and the true tri-axial tests.The results showed that the pore water pressure decreased with the intermediate principal stress effective factor,while the decomposition parameter has little effect on the pore water pressure.In the K_0 compressive tests,the intermediate principal stress has little effect on the volume strain when the deviator strain was certain,but the volume strain increased with the decomposition parameter.In the true tri-axial tests,the deviator stress increased with the intermediate principal stress.