An Elastoplastic Analysis of 3-D Ground Movements

Abstract

This paper describes numerical modelling of the deformation of sand caused by the reduction of pressure at tunnel face. This study refers to a laboratory test carried out on a centrifuge with measurements of surface settlements and displacements in soil mass. A series of 3D finite element calculations using three elastoplastic stress-strain constitutive models (Mohr Coulomb, Vermeer and Nova models) is performed. The results of this analysis are compared with experimental findings. If numerical results show good conformity with displacements observed at tunnel face, we note some limitations of the physical modelling and the numerical calculation when achieved in a standard way. These limitations in the two approaches are due to simplifications inducing different deformation mechanisms and show that experimental tests and numerical modellings are highly connected and should be carried out simultaneously.