Mechanical behavior of frozen soils: Experimental investigation and numerical modeling

摘要

The mechanical behavior of frozen soils plays a central role in the design, construction, and maintenance of buildings and infrastructure in cold regions. We present and discuss the main results of an experimental campaign focused on the mechanical behavior of frozen soils from Alaska. The data set is unique because it involves natural frozen soils and covers a wide range of temperatures (i.e., from-6 degrees C up to-26 degrees C) and confinements (i.e., from unconfined conditions up to a cell pressure of 54.6 MPa). An elastoplastic model for frozen soils is presented and validated based on the test results. The elastoplastic model accounts for the effects of temperature and cryogenic suction on key properties associated with frozen soil behavior, namely, increase of preconsolidation pressure, stiffness, and strength with the decrease of temperature. Other aspects such as the volumetric behavior of frozen soils at different temperatures and the smooth transition between elastic and plastic states are also qualitatively well captured by the model. We implemented the constitutive model in a fully coupled thermo-hydro-mechanical simulator and we analyzed the behavior of a foundation in a thawing ground. The proposed approach is able to capture the main feature of frozen soil behavior.