Probabilistic stability analysis of geo-structures in anisotropic clayey soils with spatial variability

Theoretical solutions of geotechnical engineering problems are generally based on simplifying assumptions about soil homogeneity and isotropy. In reality, soil masses are usually both anisotropic and heterogeneous in situ and thus, the effects of soil deposition orientation and stratification should be taken into account. In this context, the present paper describes a contribution towards a general probabilistic limit analysis of geotechnical stability problems dealing with clays having inherent spatial variability and anisotropy of the undrained shear strength simultaneously. The static lower-bound theorem in conjunction with the finite element method and mathematical programming are utilized to provide limit analysis approach. Anisotropy of clay is imposed by the application of an iterative scheme and, its spatial variability has been considered via the application of random field theory. Based on the proposed method, the bearing capacity of a strip footing and the stability of a square tunnel have been investigated and the effects of simultaneous consideration of non-homogeneity and anisotropy of soil?s shear strength on collapse load have been studied.