SELECTION OF SOIL CONSTITUTIVE MODELS FOR NUMERICAL SIMULATION OF FOUNDATION PIT EXCAVATION

One of the key points in numerical simulation of foundation pit excavation is to select a proper soil costitutive model. The main stress-path in soil affected by deep excavation has been analyzed. And it is noted that a proper soil constitutive model should be able to consider the deformation characteristics of unloading stress-path and stress-dependent stiffness reasonably. Several soil constitutive models commonly used in geotechnical numerical analysis are discussed. The suitability of these constitutive models used in numerical analysis of deep excavation is examined through simulating some stress path triaxial tests and analyzing some typical excavation projects. The Hardening Soil Model uses a stress-dependent stiffness, different for loading and un-/reloading. Both deformation of the foundation pit support structures and the settlement of ground can be predicted well by using this model, thus it is recommended for use in numerical analyses of deep excavations.