基于颗粒物质热动力学理论的非饱和土热水力耦合模型研究

A thermo-hydro-mechanical coupled model for unsaturated soils based on thermodynamic theory of granular matter

基于颗粒物质热动力学理论和混合物理论,结合改进的土水特征曲线(SWCC)模型,考虑温度和饱和度变化引发的颗粒层次能量耗散,提出了一个非饱和土的热水力耦合模型。该模型引入颗粒熵和颗粒温度的概念,通过构建热力学恒等式得出非饱和土非弹性变形的本构关系,并通过迁移系数和能量函数模型将非饱和土体的耗散机制与宏观的物理力学行为建立联系。基于该理论模型,研究了非饱和土的热水力耦合问题,通过模拟结果与试验数据的对比,证实了模型的有效性。模拟结果表明,模型具有描述非饱和土在不同温度和吸力下的固结和剪切特性以及非等温条件下的热体应变特性的能力。

Based on the thermodynamic theory of granular matter and the theory of mixtures, combined with the modified soil water characteristic curve (SWCC) model, considering the granular level energy dissipation caused by changes of temperature and saturation, a new thermo-hydro-mechanical coupled model for unsaturated soils is proposed. The model introduces the concepts of granular entropy and granular temperature. The constitutive relationship of non-elastic deformation can be obtained through the thermodynamic identity. The relationship between the dissipation mechanism of unsaturated soils and the macro-physical and mechanical behavior is established by using the migration coefficients and energy function model. Based on the theoretical model, the thermo-hydro-mechanical (THM) coupling behavior of unsaturated soils is studied. The validity of the model is verified by comparing the simulated results with the experimental data. The results show that the proposed model has the capability to describe the consolidation and shear behavior of unsaturated soils at different temperatures and suctions and the thermal volumetric strain changes under non-isothermal conditions.