Seismic design of pile-reinforced foundations using a multiphase approach

This contribution is based upon the concept of multiphase model aimed at capturing the macroscopic behavior of soils reinforced by linear inclusions, regarded as continuously distributed beam elements. As an illustrative application of this model, the simulation and design of an embankment resting upon a pile-reinforced soft foundation soil and subject to a lateral seismic loading is performed. This simulation is based on the numerical implementation of the multiphase model in the context of a finite element formulation. It is notably shown that the bending stiffness and yield strength characteristics of the reinforcements, which are constitutive parameters of the multiphase model, have a decisive influence on the improved performance of this kind of structure. Furthermore, the computational code thus obtained makes it possible to devise design rules concerning the reinforcement scheme to be adopted, such as for instance optimizing the orientation of the reinforcing piles.