2008 年 11 巻 p. 389-398
The microstructure of soils is, in general, anisotropic in both the “inherent” and “induced” senses described by Casagrande and Carillo, which yield anisotropic responses for both strength and plastic deformation. The undrained shear strength of clayey soils, for example, changes greatly depending on the inclination angle θ of the loading direction with respect to the consolidation plane. In the present study on constitutive modeling, a tensorial quantity called the fabric tensor is incorporated into the classical plasticity framework to simulate the effects of microstructure on the variation of undrained shear strength of Kaolin clay. The effects of inherent and induced anisotropies are considered in terms of an evolution rule of the fabric tensor. It is shown that the proposed model can simulate well the variation of undrained shear strength observed in plane strain experiments of normally consolidated Kaolin clay by Kurukulasuriya.