Numerical Simulation of Recent Stress-History Effects on Excavation Responses in Soft Clays

Abstract

A finite element analysis of a hypothetical excavation was conducted to investigate recent stress-history effects on excavation-induced ground movements. The numerical simulations were conducted using a hypoplasticity model for clays which is capable of modeling small strain nonlinearity, soil anisotropy, and recent stress-history effects. The recent stress-history effects noted in previous laboratory experiments were reasonably reproduced by the model. Numerical simulations of the hypothetical excavation made through glacial clays are presented to illustrate the effect of preexcavation recent stress-history on computed ground movements. Lateral wall deformations caused by excavations in these soils with different recent stress histories resulted in computed movements that differed by a factor of two. These results suggest that recent stress-history effects should be considered when serviceability requirements dictate the design of a support system for which deformations must be limited to prevent damage to adjacent structures or infrastructure.