砂土流变行为的热力学本构模型研究

发布时间：2018-05-07 07:56

本文选题：热力学 + 颗粒温度　；参考：《岩土工程学报》2015年S1期

【摘要】：采用非平衡态热力学方法,通过引入颗粒熵sg和颗粒温度Tg描述砂土颗粒间碰撞、滑动、滚动等相互作用,用颗粒温度引起的弹性弛豫反映砂土内部的不可逆变形,构建了描述砂土宏观力学行为的热力学方程组。通过合理简化该热力学方程组分析了侧限压缩试验和各向同性压缩试验的流变规律,分析表明:简化的热力学模型能够较好地反映和预测砂土蠕变和松弛行为;砂土在外力加载过程中,颗粒熵(颗粒温度)被激发不断增大直至稳定值,在停止加载后的流变过程中,颗粒熵(颗粒温度)逐渐衰减,理论上最终衰减为零(排除外界扰动);颗粒熵衰减过程中,颗粒温度引发的弹性弛豫宏观表现为流变行为,随着颗粒熵衰减为零,理论上流变最终停止在一个稳定值。
[Abstract]:By using the non equilibrium thermodynamic method, by introducing particle entropy SG and particle temperature Tg to describe the interaction between sand particles, such as collision, sliding, rolling and other interactions, the elastic relaxation caused by the particle temperature reflects the irreversible deformation in the sand, and a thermodynamic equation is set up to describe the macroscopic mechanical behavior of the sand. The process group analyses the rheological behavior of the lateral compression test and isotropic compression test. The analysis shows that the simplified thermodynamic model can better reflect and predict the creep and relaxation behavior of the sand. In the process of loading, the particle entropy (particle temperature) increases continuously until the stability value, and in the rheological process after the loading is stopped. The particle entropy (particle temperature) attenuates gradually and eventually attenuates to zero (excluding the external disturbance). In the process of particle entropy attenuation, the elastic relaxation induced by the particle temperature is the rheological behavior. As the particle entropy attenuates to zero, the rheological behavior eventually stops at a stable value.

【作者单位】：清华大学岩土工程研究所;清华大学水沙科学与水利水电工程国家重点实验室;
【基金】：国家自然科学基金青年科学基金项目(51408333);国家自然科学基金重点项目(51038007)
【分类号】：TU441

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