基于变换应力方法的各向异性模型三维化

Generalization of anisotropic constitutive models using transformed stress method

各向异性模型的三维化较各向同性模型更加复杂,如果采用g(θ)方法进行各向异性模型的三维化,会出现诸如屈服面不连续、内凹的现象。但如果采用变换应力方法,既能保证各向异性屈服面的连续光滑,又能使各向异性模型的临界状态面与强度准则相一致。采用基于SMP准则的变换应力方法,实现了初始应力各向异性化的修正剑桥模型的三维化,确定了三维化模型的塑性因子和塑性流动方向,并给出了应用于有限元计算的切线刚度矩阵。通过试验数据和预测结果的对比,表明变换应力方法三维化的各向异性模型能够较合理地反映K0固结土的强度和变形特性。

The generalization of anisotropic constitutive models is more complex than that of isotropic constitutive models.Using the g（θ） method to generalize the anisotropic constitutive models will result in the discontinuousness and concavity of yield surfaces.But the yield surfaces can be continuous and the critical state surfaces can consist with the adopted failure criterion if the transformed stress（TS） method is used.The modified Cam-clay model with initial stress-induced anisotropy is generalized using the TS method as an example.The proportionality constant and the stress gradient of the generalized model are defined,and the tangent stiffness matrix used in finite element analysis is given.It is seen from the comparison between the test data and the model predictions that the generalized anisotropic constitutive model using the TS method can reasonably describe the strength and deformation characteristics of the K0-consolidation soils.