Abstract

Most existing thermal–hydromechanical (THM) models used to describe the process of frost heave assumed the freezing soil to be elastic. However, an inelastic constitutive model capable of reflecting the viscous constitutive behaviour of freezing soils should be considered. Based on the existing mathematical model, this study presented an improved mathematical model of coupled water, heat, and stress for saturated freezing soil, in which the soil was assumed to be elastic-viscoplastic and its viscoplasticity was modelled by means of a simple (linear) Norton–Hoff’s law. In addition, solid–fluid interface energy was considered to formulate the effective water and ice pressures and liquid–crystal equilibrium condition which can be used to explain the micro-cryosuction mechanism was adopted to replace Clapyron equation which were used in most existing models. To solve the nonlinear governing equations, numerical simulations were performed using COMSOL software. Finally, the improved model was validated by comparing its simulation results with reference model and the distribution curves of frost heave, temperature, water content and flux rate were discussed.

摘要

大多数现有的用于描述冻胀过程的热流体力学 (THM) 模型都假设冻土具有弹性。然而，应该考虑能够反映冻土的粘性本构行为的非弹性本构模型。本研究在已有数学模型的基础上，提出了一种改进的饱和冻土水、热、应力耦合数学模型，假设土为弹粘塑性，采用简单的（线性) 诺顿-霍夫定律。此外，考虑固-流界面能来制定有效的水和冰压力，并采用可用于解释微低温抽吸机制的液晶平衡条件来代替大多数现有模型中使用的克拉皮龙方程。为了求解非线性控制方程，使用 COMSOL 软件进行了数值模拟。最后，将改进后的模型与参考模型的模拟结果进行对比，对改进后的模型进行了验证，并讨论了冻胀、温度、含水量和通量率的分布曲线。