Numerical Modeling of Excavation in Shanghai Soft Clays Using the New Small Strain Shanghai Constitutive Model

Abstract

AbstractNumerical simulations are employed to predict deep excavations’ performance and the magnitude of the associated wall and ground displacements. Accurate prediction of these displacements is essential to prevent any distress or damage to the adjoining structures. A novel numerical approach is proposed in this paper to predict the wall and ground displacements related to deep excavations in Shanghai soft clays by using a new elastoplastic small strain constitutive model. The small strain Shanghai model incorporates the effects of small shear strain, elucidates both the clays' structure and mechanical properties, and describes the dilatancy characteristics and strain-softening in a three-dimensional state. A deep excavation case study in Shanghai soft clay is simulated on Plaxis 2D. The material parameters and the monitored values of displacements are obtained from the site. A user defined soil model of small strain Shanghai model is made in the form of Dynamic Link Library (.dll) file to be used in this analysis. A comparison of the monitored values of displacements is made with ground and wall displacements' simulated values. The effects of the excavation activity on the adjoining historical buildings are evaluated. The simulated results agree well with the monitored results. The comparison lays out a novel numerical approach for predicting the performance of deep excavation in Shanghai soft clays and the associated displacements by using a new constitutive model.KeywordsConstitutive modelDeep excavationFinite element analysisSmall strainSoft clays