Criteria for numerical modelling of very stiff cantilever retaining structures

This paper focuses on the main results obtained from studying, via numerical simulations, three different solutions of very stiff cantilever retaining structures in sandy soil. These structures are usually employed to support deep excavations to minimize soil displacement in urban areas where the use of anchors is often impossible. Structural elements are assumed to be elastic and are simulated by both beam and continuum elements. A simple elastic perfectly plastic constitutive model with Mohr-Coulomb strength criterion and zero dilatancy is used to describe soil behaviour. The stress and displacement fields in structural elements under normal loading conditions for the different solutions and approaches adopted (beam or continuum) are reported and compared. Numerical analyses are also carried out to investigate failure mechanisms. The accuracy of the results is checked by convergence analyses. The study highlights the crucial role played by the shear stresses mobilized at the boundary of structural elements due to excavation. Guidance is offered to develop models to numerically obtain accurate behaviour of these kinds of structures in practice.