43 / 2021-10-07 20:47:53

基于TTS本构模型的真三轴条件下热蠕变研究

平面应变,温度循环,应力历史,TTS本构

真三轴条件下单调和循环温度荷载显著影响土体轴向、径向变形和侧压力系数，对能源地下结构抗裂、沉降控制及承载力设计提出了新的挑战。基于清华热力学岩土（TTS）本构模型，开展了一维压缩和平面应变状态下饱和黏土和粉土的排水热蠕变模拟。结果表明：真三轴条件下，各主应力方向的热蠕变不同，产生温度剪应变；热体积应变收缩时，某些应变分量可能出现膨胀，TTS可以合理描述这一性质。Monotonic and cyclic thermal loading significantly affect the axial and radial deformation, and lateral pressure coefficient of soil under true triaxial condition, which poses new challenges to the crack resistance, settlement control and bearing capacity design of underground energy structures. Thermal creep simulation was carried out for saturated clay and silt under 1D compression and plane strain in drained situation based on Tsinghua thermodynamic soil (TTS) constitutive model. The results showed that: the creep caused by thermal loading is different in each principal stress direction under true triaxial states, resulting in thermal shear strain; when thermal volume strain shrinks, some strain components may expand, which can be reasonably described by TTS.