基于灰色理论的冻融混凝土本构方程研究

Research on Constitutive Relationship of Frozen-thawed Concrete Based on Grey Theory

我国北方处于寒冷地带,低温和冻融循环作用是造成混凝土性能劣化的重要原因。由于混凝土单轴受压应力—应变全曲线反映了混凝土最基本的力学性能,因此研究冻融循环作用下混凝土的应力—应变全曲线十分重要。本文通过已有的冻融混凝土单轴压缩试验所得的应力—应变关系参数,基于灰色理论建立预测方程,以小样本数据为基础,预测其他冻融次数下的混凝土本构方程参数。再根据过镇海建议的混凝土本构曲线进行拟合,得到一系列不同冻融次数下的混凝土应力—应变全曲线。结果表明,本文所拟合出的冻融混凝土应力—应变全曲线跟实验曲线吻合较好,可以用于试验范围内任意冻融次数的混凝土应力—应变全曲线的研究。

North of China is located in cold zone, therefore, action of low temperature and freeze thaw cycle become the main reason of deterioration of concrete performance. The stressstrain curve of concrete under freezethaw cyclic action is very important because the uniaxial compres sion stressstrain relationship of concrete reflects its basic mechanical performance. Based on grey theory and the existing stressstrain parametes of frozenthawed concrete tested by uniaxial com pression, predictive equations were established to predict the stressstrain parametes of concrete with other different freezethaw number. Then, according to the constitutive curve of concrete suggested by Guozhenhai, a series of stressstrain curves of concrete with different freezethaw numbers were fitted. The results show that the fitted stressstrain curves of freezethaw concrete by constitutive parameters predicted based on grey theory are in agreement with experimental ones. So this method can be used to study the stressstrain full curves of concrete with any freeze thaw number in the range of relevant experiments.