基于裂纹扩展机理的损伤混凝土强度预测方法研究

Research of Damage Concrete Intensity Forecast Method Based on Concrete Crack Evolvement Mechanics

为解决含裂纹混凝土强度的预测问题,以断裂力学与细观力学相结合的方法,在混凝土双K断裂准则的基础上,提出了混凝土裂纹演化方程,给出混凝土裂纹特征尺寸随应力变化的表达式,由此得到了含裂纹混凝土材料的损伤本构关系。在此基础上,对含有裂纹的损伤混凝土强度进行了预测,与已有细观试验结果进行对比,表明该方法具有足够的精确度,此后重点讨论了裂纹角度对混凝土强度的影响。此方法可为混凝土结构中损伤混凝土的性能评估奠定一定的基础。

Based on fracture mechanics and microscopic damage mechanics,the effects of crack damage and crack evolvement on concrete intensity are studied. According to the double K fracture criteria of concrete,a equation for concrete crack evolvement is put forward,and explicit expressions on the dimension of concrete cracks are given,then a constitutive relation of damaged concrete is established. The damage concrete intensity is forecasted on the basis of the method. Compared with the existing experimental results,it shows that the method has enough accuracy. Moreover,cracks angle effects on damage concrete intensity are discussed. The method can lay the certain foundation for performance assessment of damage concrete in a concrete structure.