A multilaminate constitutive model accounting for anisotropic small strain stiffness

In this paper an extension of existing multilaminate soil models is presented, which can account for inherent and stress-induced cross-anisotropic elasticity in the small strain range and its dependency on the load history. In the multilaminate framework, material behaviour is formulated on a number of local planes in each stress point, and the macroscopic response of the material is obtained by integration of the local contributions. Strain-induced anisotropy, which adds to the stiffness anisotropy inherently present in the material, is therefore intrinsically taken into account. Micro–macro relations between local parameters on plane level and global parameters on macroscopic level are obtained by the spectral decomposition of the global elastic compliance matrix. The model is implemented into a finite-element code, and model predictions are compared with experimental data of triaxial tests on different soils involving small and large load cycles. The importance of cross-anisotropic elasticity within the small strain range for predicting ground deformations in geotechnical boundary value problems is discussed at the example of an excavation problem