Abstract:

Numerical analysis has become the most important method for analyzing deep excavations in close proximity to sensitive properties. One of the key problems in a numerical analysis is to select proper soil constitutive models and their corresponding parameters. The possibilities and limitations of a limited number of soil constitutive models frequently used in geotechnical numerical simulations were discussed. The suitability of these constitutive models applied to numerical analysis of deep excavations in close proximity to sensitive properties was compared. As ground movement control is a key design consideration in excavations adjacent to sensitive properties, the constitutive model must be able to predict realistic distributions of movement around retaining structures. It was recommended to use strain hardening plastic constitutive models such as modified Cam clay (MCC) model and Plaxis Hardening Soil (HS) model to simulate excavations in close proximity to sensitive properties because they can reflect many important features of soil which are important in excavation simulations. These features include plasticity, strain hardening difference between loading and unloading stiffness, and stress dependent stiffness. The results of the simulation of a deep excavation illustrate the capabilities of the strain hardening plastic constitutive model in the numerical analysis of deep excavations.

Key words: excavations, sensitive properties, numerical analysis, constitutive model