This paper established a coupled thermo-hydro-mechanical mechanism in view of the soil particle rearrangement for saturated/unsaturated soils under the framework of granular thermodynamics. This model avoids concepts such as the flow rule, yield function, dissipation potential function, and hardening criterion. The effects of the loading path and the soil structure are reflected by constructing a density function of elastic potential energy considering the structural strength of a solid skeleton with a degradation factor. That is, the changes in the stress states are closely related to soil particle rearrangement and the transitions between different matter phases. A generalized effective stress principle is derived and is suitable for the coupled thermo-hydro- mechanical process. The deduced generalized phase stresses differ from the classical effective principle based on linear elastic porous media and can automatically consider the impact of the stress path, temperature path and soil structure. The established model spans the complete process from unsaturated to saturated soils and is verified by the typical test results.

本文在颗粒热力学框架下，针对饱和/非饱和土壤的土壤颗粒重排，建立了热-水-力耦合机理。该模型避免了流动规则、屈服函数、耗散势函数和硬化准则等概念。加载路径和土体结构的影响通过构造弹性势能的密度函数来反映，该函数考虑了具有退化因子的实体骨架的结构强度。即应力状态的变化与土壤颗粒重排和不同物质相间的转变密切相关。推导出了广义的有效应力原理，适用于热-水-机械耦合过程。推导出的广义相应力不同于基于线弹性多孔介质的经典有效原理，可以自动考虑应力路径、温度路径和土壤结构的影响。建立的模型涵盖了从非饱和土到饱和土的整个过程，并通过典型试验结果进行了验证。