Vibration-Induced Stress Changes in Saturated Soil: A High-Cycle Problem

Numerical modelling of the cyclic deformation of soil can be performed with the use of two types of constitutive models: incremental plasticity models and so-called explicit cyclic models. The present study deals with the application of a model of the second type—the high-cycle accumulation model for sand—to the analysis of vibration-induced stress changes in saturated soil. The application of the model requires the concurrent solution of two coupled boundary value problems: a dynamic problem for the determination of strain amplitude and a quasi-static problem for the calculation of stress evolution. The coupling of the two problems has been implemented in a two-dimensional axisymmetric formulation with the finite-element program Abaqus. The model is applied to the analysis of stress changes near a concrete wall caused by a vibrating pile. The numerical results show that a large-amplitude vibration, e.g. during the installation of vibratory driven piles, may substantially reduce both the effective and the total stresses in front of the wall. The effective stress may be reduced to zero resulting in soil liquefaction.