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混凝土内部随机分布的微裂纹和孔洞等细观缺陷影响其破坏机理及宏观力学性能,且孔隙率随着外荷载的变化而不断变化。该文中将含缺陷(微裂纹、各种空隙等)混凝土复合材料简化为空心球力学模型,基于弹性力学理论推导并获得了混凝土当前孔隙率与材料初始孔隙率及体应变之间的定量关系;推导并得到了含孔隙混凝土的有效弹性模量、有效泊松比及峰值应变等与孔隙率的定量关系,进而得到了单轴加载条件下含孔隙混凝土细观单元的等效多折线本构关系模型。最后,采用细观单元等效化力学模型,研究了单轴加载(拉伸和压缩)情况下不同孔隙率混凝土材料的破坏过程及宏观力学性能,探讨了孔隙率变化规律及其对混凝土变形过程的影响。
Microcracks and holes, which are randomly distributed in the concrete, affect the failure mechanism and macroscopic mechanical properties, and the porosity changes continuously with the change of the external load. In this paper, the hollow-spherical mechanical model with defects (microcracks, various voids, etc.) is simplified and the quantitative relationship between the current porosity of concrete and the initial porosity and bulk strain of the concrete is derived and obtained based on the elastic mechanics theory. The quantitative relationship between the effective elastic modulus, the effective Poisson’s ratio, the peak strain and porosity and porosity was deduced and obtained, and then the equivalent multi-fold constitutive relation of mesoporous concrete with pore concrete under uniaxial loading was obtained model. Finally, using the equivalent mechanics model of meso-element, the failure process and macroscopic mechanical properties of concrete with different porosity under uniaxial loading (tension and compression) were studied. The variation law of porosity and its effect on deformation process of concrete Impact.