An advanced constitutive model for AGF design: From calibration to application

Abstract

The significance of ground freezing is becoming ever more germane, because the design of new urban tunnel systems requires more complex geometries and higher strength of the improved subsoil, which are limited with conventional construction methods. Therefore, advanced constitutive models for frozen soils need to be developed and implemented in finite element analysis (FEA) codes for ground freezing designs under such complex conditions. This study presents a recently proposed elastic-viscoplastic model describing the rate-, stress-, and temperature-dependent mechanical behaviour of frozen granular soils under compressive and tensile loading along with its implementation in a FEA code. After calibrating and validating the model for frozen Manchester fine sand based on single-element tests, we demonstrate the geotechnical and practical advantages of the model by simulating a tunnel excavation supported by a frozen soil body and compare the numerical results with experimental data from the literature. The good agreement highlights the model’s ability to predict the stability and evaluate the deformations of frozen soils in AGF scenarios.