Pullout Capacity Factor for Cylindrical Suction Caissons in Anisotropic Clays Based on Anisotropic Undrained Shear Failure Criterion

New plastic solutions of the pullout capacity factor for cylindrical suction caissons in anisotropic clays are presented in this paper. These solutions are derived by employing the lower bound and upper bound finite element limit analyses under an axisymmetric condition. In this study, anisotropic clays obey anisotropic undrained shear (AUS) failure criterion with three anisotropic undrained shear strengths obtained from triaxial compression, triaxial extension, and direct simple shear. The solutions of the pullout capacity of cylindrical suction caissons are presented as a series of design charts. The effects of three dimensionless parameters, namely the ratio of depth to width of caissons, adhesion factor, and the ratio of undrained shear strengths obtained from triaxial compression and triaxial extension, on the pullout capacity are demonstrated and discussed. The present solutions can be used as guidance for geotechnical engineers to design a suction caisson by considering the anisotropy effects of undrained shear strengths of clays.