基于灰色理论的冻融混凝土本构方程研究

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。

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

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 stress-strain curve of concrete under freeze-thaw cyclic action is very important because the uniaxial compression stress-strain relationship of concrete reflects its basic mechanical performance.Based on grey theory and the existing stress-strain parametes of frozen-thawed concrete tested by uniaxial compression,predictive equations were established to predict the stress-strain parametes of concrete with other different freeze-thaw number.Then,according to the constitutive curve of concrete suggested by Guozhenhai,a series of stress-strain curves of concrete with different freeze-thaw numbers were fitted.The results show that the fitted stress-strain curves of freeze-thaw concrete by constitutive parameters predicted based on grey theory are in agreement with experimental ones.So this method can be used to study the stress-strain full curves of concrete with any freeze-thaw number in the range of relevant experiments.