考虑静水压力损伤和孔隙水效应的混凝土动态本构模型研究

Concrete is a kind of composite material and this composition influences its dynamic properties a lot. The commonly used concrete material models in hydrocodes neglect the damage induced by hydrostatic pressure although concrete is not a homogeneous material. Similarly, the influences of concrete saturation on the strength model and equation of state have not been considered enough. To address these problems, the project will be carried out to study the concrete damage induced by combined action of hydrostatic pressure and deviatoric stresses. Then the damage mechanism induced by hydrostatic pressure will be revealed and a new damage model considering hydrostatic pressure will be established. The project also aims to carry out the impact tests on the concrete specimens with different saturations to study the influence mechanism of pore-water on the material dynamic properties. According to the testing results, an equation of state considering the pore-water-pressure effect and a strength model considering the pore-water-viscosity effect will be established. At last, combining the study results and the current concrete constitutive theory, a new dynamic concrete model considering the hydrostatic damage and the pore-water effect will be built. This work will promote the development of concrete constitutive theory and increase the numerical accuracy of the responses of concrete structures subjected to high dynamic loadings and complex environments.

混凝土组成的多相性显著影响其材料动力学性质，现有混凝土动态本构模型大都忽略了由材料非均质性引起的静水压力损伤，也没充分考虑含水饱和度对状态方程和动态强度的影响。针对这些问题，本项目拟开展混凝土材料在静水压力和偏应力共同作用下的损伤研究，揭示静水压力劣化材料性能的机理，建立考虑静水压力作用的损伤模型；开展不同饱和度混凝土试件的单轴及多轴冲击实验，探究孔隙水影响材料动态性能的机制，建立考虑孔隙水压力效应的状态方程和考虑孔隙水粘性效应的强度模型；最后，结合现有混凝土本构理论，建立考虑静水压力损伤与孔隙水效应的混凝土动态本构模型。本项目的研究成果将推动混凝土类脆性材料本构理论的发展，提高混凝土结构在强动力荷载、复杂服役环境下数值模拟的精度。

作为多相复合材料，混凝土表现出复杂的动态力学性质，现有混凝土动态本构模型并没有合理考虑由材料非均质性引起的静水压力损伤与含水饱和度对动态强度的影响。针对这些问题，本项目开展了混凝土材料在静水压力往复加载以及静水压力偏应力共同作用下的损伤试验研究，揭示了材料非均质性引起的偏应力是静水压力劣化混凝土材料性能的本质原因，建立了考虑静水压力作用的损伤力学模型；本项目开展了不同饱和度混凝土试件的单轴静力试验、多轴静力试验和单轴冲击实验，探明了孔隙水影响材料动态性能的机制，研究表明自由水降低了混凝土材料的静力强度与动力抗压强度，但使动态抗拉强度有所提高，基于研究结果建立了考虑孔隙水压力效应强度模型；结合K&C混凝土本构理论，建立了考虑静水压力损伤与孔隙水效应的混凝土动态本构模型。本项目的研究成果将推动混凝土类脆性材料本构理论的发展，提高混凝土结构在强动力荷载、复杂服役环境下数值模拟的精度。