引用本文:程卓群,彭刚,孙尚鹏,王普,刘苗苗.基于Najar能量法的混凝土动态双轴受压损伤特性分析[J].水利水运工程学报,2019,(4):100-106
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基于Najar能量法的混凝土动态双轴受压损伤特性分析
程卓群, 彭刚, 孙尚鹏, 王普, 刘苗苗
三峡大学土木与建筑学院,湖北宜昌
摘要:
利用动静力三轴试验机进行不同加载速率、不同侧向压力下混凝土的抗压试验,基于改进的Najar能量法,提出一种新的损伤变量计算方法,以此分析侧向压力和加载速率对混凝土双轴受压状态下损伤演化的影响。研究结果表明:① 峰值应力随加载速率的增大而增大;相同加载速率下,峰值应力随侧压力增大而增大,混凝土达到峰值应力后承载力下降趋势不受侧压影响;② 混凝土双轴受压状态下损伤演化可分为线弹性阶段、损伤加速变化阶段和损伤收敛阶段;③ 加载速率越大,损伤加速发展阶段损伤变量的增长越迅速且该阶段对应的应变范围越小;④ 侧向压力对混凝土损伤演化有明显影响,混凝土损伤的发展随着侧应力的增大而出现滞后现象。
关键词:  混凝土  Najar能量法  应变速率  双轴抗压  损伤
DOI:
分类号:TU502
基金项目:国家自然科学基金资助项目(51579139);三峡大学学位论文培优基金资助项目(2019SSPY033)
Analysis of dynamic biaxial compression damage characteristics of concrete based on Najar energy method
CHENG Zhuoqun, PENG Gang, SUN Shangpeng, WANG Pu, LIU Miaomiao
College of Civil Engineering & Architecture, China Three Gorges University, Yichan
Abstract:
The compression tests of concrete under different lateral pressures and different loading rates are carried out by using a dynamic and static triaxial testing machine. Based on the improved Najar energy method, a new calculation method for damage variables is proposed to analyze the influences of the lateral pressures and loading rates on the damage evolution of concrete under biaxial compression stress. The analysis results show that:(1) The peak stress increases with the increase of the loading rates. Under the same loading rates, the peak stress increases with the increase of the lateral pressures. When the concrete reaches the peak stress, the decreasing trend of the bearing capacity is not affected by lateral pressures. (2) The damage evolution of concrete under biaxial compressive stress state can be divided into three stages: the elastic stage, the damage acceleration stage and the damage convergence stage. (3) The higher the loading rate is, the faster the damage variable increases in the accelerated development stage and the smaller the strain range in this stage. (4) The lateral pressure has a significant influence on the damage evolution of concrete. The development of concrete damage lags with the increase of the lateral stresses.
Key words:  concrete  Najar energy method  strain rate  biaxial compression  damage
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