Yvon Riou

Modélisation des sols et des ouvrages avec le modèle Cam-Clay modifié

ABSTRACT A data base on confrontation of finite elements calculations and in situ measurements was developed with the Laboratoire Central des Ponts et Chaussées (LCPC). This base called MOMIS gathers more than 160 cards concerning of the ground works and the underground works. Its constitution rests on a technological survey in the field of modeling by finite elements. Each card is the result of the analysis of study (paper, communication or report). A specific exploitation of this data base made it possible to draw up an assessment about the use of “Cam-Clay modified” model for the compressible soils: statistical analysis values of the parameters and quantification of the gap between the numerical results and the measurements carried out on the real works.

Resolution of elastoplastic constitutive relations application to the fiber reinforced sand

Abstract The aim of this paper is to introduce a new formulation for the resolution of elastoplastic constitutive relations. A variant of the initial stress method is proposed to reduce the number of increments and iterations and avoid a drift of results. A validation of this new algorithm is performed in two homogeneous tests : unreinforced sand and fiber reinforced sand in triaxial compression. For the sand, the basic elements used in the study are a double yield surface with isotropic hardening and a non-associated flow rule. Then, in order to check our computer program and the mechanical principle of superposition of the two continua (sand and fibers), a finite element simulation of the construction of a wall under gravity forces is presented.