Challenges to properly accounting for cyclic response in transversely isotropic elastic soil idealizations

The way natural soils are deposited gravitationally inherently leads to an anisotropic microfabric. The elasticity of such anisotropic soils has typically been idealized as being transversely isotropic (or “cross anisotropic”). The importance of elastic anisotropy in geotechnical engineering applications has particularly been invoked in conjunction with predicting ground deformations associated with underground structures such as deep excavations and tunnels. The development of elastic constitutive relations for transversely isotropic geomaterials is complicated by the fact that the elastic material parameters are usually not constant. This paper briefly reviews the issue of elasticity in soils. Following a short overview of isotropic elastic idealizations, the more relevant topic of transversely isotropic idealizations is discussed, with emphasis not only on monotonic but also on cyclic response.