Bounding Surface Plasticity. III: Application to Anisotropic Cohesive Soils

Multi-mechanism anisotropic model for granular materials

“…For example, a rotational hardening rule was employed by Hashiguchi (1977), which was originally proposed by Sekiguchi and Ohta (1977). The idea was later adopted for granular materials by Ghaboussi and Momen (1982), and for cohesive soils by Anandarajah and Dafalias (1986) and Kavvadas (1983), among others, in modeling the initial as well as the induced anisotropy. Hashiguchi (1994) and Hashiguchi and Chen (1998) presented a subloading surface model that considered initial and induced anisotropy by using a rotational hardening rule.…”

“…For example, Anandarajah and Dafalias (1986) controlled the maximum rotation of the surface by controlling the hardening function, introducing what was referred to as the "saturation" phenomenon. Hashiguchi and Chen (1998) limited the rotation by introducing what was referred to as the rotational limit surface.…”

“…A modified form of the evolution rule used in Anandarajah and Dafalias (1986) is adopted in the present work, which represents the evolution of fabric anisotropy in terms of the plastic strain, but considers the strong dependency on the rate of stress.…”

“…Hashiguchi and Chen (1998) limited the rotation by introducing what was referred to as the rotational limit surface. In both the models of Anandarajah and Dafalias (1986) and Hashiguchi and Chen (1998), the rate of change of the tensor modeling the rotation was assumed to be a function of the rate of change of plastic deviatoric strain.…”

Efficient Approach to Characterize Strength Anisotropy in Soils

“…The criterion however requires proper stress transformation in many cases, which renders it not particularly convenient. A technique by rotating an isotropic yield surface according to the initially anisotropic stress state was later widely adopted to model strength anisotropy of clays (Sekiguchi and Ohta 1977;Anandarajah and Dafalias 1986;Whittle et al 1994). Because the direction and magnitude of such rotation are typically dependent on the initial stress state, it cannot adequately account for the fabric structure of a soil, for example those features related to particle orientation and void distribution in sand (Kaliakin 2003).…”