Abstract
In numerical analysis of frost heave phenomenon, elastic models for soil may overestimate stress more than nonlinear models. It is one opinion that the overestimation of stress is safe for structures subjected to frost heave. However, when simultaneously considering frost heave, according to Takashiʼ s equation, a large constraining stress reduces the frost heave. This underestimation of deformation may threaten the safety of structures in cold regions since a small frost heave will lead to a lower stress level. It becomes a paradox. Therefore, the objective of this research is to construct a nonlinear frost heave estimation model and then confirm the influences of the nonlinear Youngʼs modulus when considering the stress distribution and amount of frost heave. This paper proposes a numerical model that couples the heat transfer process with nonlinear stress analysis. The frost heave ratio is estimated by Takashiʼs equation, which was originally a one-dimensional practical equation widely applied in Japan. However, we expand Takashiʼs equation into multi-dimensionality by using an anisotropic parameter. This parameter distributes frost heave ratio in different directions. The model adopts Fourierʼs law for thermal analysis and latent heat is seriously evaluated by equivalent heat capacity method. More importantly, this paper includes the temperature and stress-dependent Youngʼs modulus, which requires the adoption of a nonlinear mechanical analysis. This is a critical characteristic of soil and a significant improvement to the linear frost heave model. Finally, for discussion, simple examples, simulations and experimental results are provided to clarify the difference between linear and nonlinear models.
