Different solutions of retaining strucutres in stiff clay

The paper reports the main results obtained studying via numerical simulations two different solutions of cantilevered retaining structures in overconsolidated stiff clay. The behaviour of simply T shaped retaining structure is compared to the behaviour of a retaining structure made up of two diaphragm walls connected at the head by a rigid beam. This class of frameworks are used suitably for supporting deep excavations in order to minimize soil displacements in urban area where the use of anchors is often not possible. Structural elements are assumed elastic and are simulated both by beam and continuum elements. A simple elastic perfect plastic constitutive model with Mohr-Coulomb strength criterion and zero dilatancy is adopted for describing soil behaviour. The soil-structure interface is assumed purely frictional. The accuracy of all presented results are checked by convergence study. Field of displacements and stresses in structural elements under operating conditions for the two different solutions and for the different approaches adopted (beam or continuum) are reported and compared. Failure mechanisms are investigated also. The study going to provide a guidance to develop models to describe accurately the behaviour of this kind of structures.