A constitutive model for the simulation of temperature-, stress- and rate-dependent behaviour of frozen granular soils

Abstract

An elastic-viscoplastic model is developed to simulate the rate-, stress- and temperature-dependent mechanical behaviour of frozen soils under nearly monotonic shearing. The main characteristics of the behaviour of frozen soils are analysed by means of confined and unconfined creep and constant-strain-rate compression tests. The novel model approach extends an existing model proposed by R. Cudmani in 2006 to account for the influence of the confining pressure on mechanical behaviour and to differentiate between compressive and tensile strength and creep. After describing the model and determining its parameters, the model performance is assessed by comparing the results of experimental and numerical element tests. In spite of its simplicity, the proposed model can realistically capture essential features of the rate-, stress- and temperature-dependent behaviour of frozen soils observed in the laboratory, including quasi-monotonic confined and unconfined creep, compressive and tensile strength. A distinguishing feature of this model is the ability to predict creep failure and, related to it, the ‘lifetime’ of the frozen soil, which is the time at which creep failure starts. This novel constitutive model proves to be a powerful numerical tool for predicting the stability and evaluating the deformations of frozen soils in engineering applications.