冻融劣化混凝土冰冻状态动态轴压本构特征研究  

Study on dynamic axial compression constitutive characteristics of freezing-thawing deteriorated concrete in frozen state

作　　者：候春平 陈灯红[1] 彭刚[1] 刘昌勇 吴聪 HOU Chunping;CHEN Denghong;PENG Gang;LIU Changyong;WU Cong(College of Civil Engineering and Architecture,China Three Gorges University,Yichang 443002,Hubei,China)

机构地区：[1]三峡大学土木与建筑学院,湖北宜昌443002

出　　处：《实验力学》2020年第6期1101-1112,共12页Journal of Experimental Mechanics

基　　金：国家自然科学基金项目(51579139,51279092,52079072);湖北省自然科学基金(2018CFB652)资助。

摘　　要：为研究冰冻状态下混凝土的受力特征,以混凝土加载时的应变速率和冻融劣化程度为主要控制因素,采用Weibull-Lognomal理论,对多工况下的应力-应变曲线进行拟合分析,依据峰值应变、峰值应力、弹性模量等力学指标构建冰冻状态下混凝土动态轴压本构模型,分析了不同工况下冰冻状态下混凝土单轴抗压加载过程中,峰值点前刚度退化以及峰值点后应力跌落的特征。研究表明,模型的上升段控制参数m受应变速率和冻融裂化程度的双重影响,下降段控制参数t也具双重影响且与m呈现出相反的规律。冰冻状态下混凝土峰值点后的应力跌落指数和刚度退化阈值对应的应变发展水平具有率效应,与其他学者的试验进行对比发现,本文模型具有良好的适用性。In order to study the stress characteristics of the concrete under frozen conditions,the strain rate and degree of freeze-thaw degradation of the concrete are taken as the main control factors.The Weibull-Lognomal theory is employed to fit the stress-strain curve under different conditions.Based on the mechanical properties,such as peak strain,peak stress and modulus of elasticity,the dynamic axial compression constitutive model of concrete under frozen state is constructed.It has the characteristics that the stiffness will degenerate before the peak point and the stress will drop after the peak point under the uniaxial compression loading process.The results show that the control parameter m of the rising section of the model is affected by the strain rate and the degree of freeze-thaw degradation.The control parameter t of the falling section has a dual influence and exhibits the opposite law with the parameter m.The index of stress drop and the threshold of stiffness degradation after the peak point of the concrete in the frozen state have the rate effect.The model has good applicability when it is compared with other scholars′experiments.

关 键 词：Weibull-Lognomal理论 控制参数 本构模型 刚度退化 应力跌落 

分 类 号：TU528[建筑科学—建筑技术科学]