Applicability of Elastoplastic Modelling for Simulating Tunnel Excavation in Lightly Overconsolidated Clay

摘要

This paper aims at examining the performance of the material models that are normally adopted in finite-element analyses used to predict the ground deformations associated with tunnelling in lightly overconsolidated clay. The tunnel construction problem is represented by a plane strain finite-element model under an undrained condition. Analyses are performed for a number of overconsolidation ratios representative to lightly overconsolidated clays. Solutions are obtained for ground volume loss percentages that practically represent the ground loss associated with the closed face shield tunnelling. The results of analyses show that the effectiveness of the constitiutive model adopted in the analysis is dependent on the amount of plasticity that is expected to develop.