不同初始损伤高强混凝土动态劈拉特性试验  

Dynamic Splitting and Tensile Properties Experiments of High-Strength Concrete with Different Initial Damage

作　　者：吴瑾 陈徐东[1] 孙阳阳 宁英杰 毕振帅 Wu Jin;Chen Xudong;Sun Yangyang;Ning Yingjie;Bi Zhenshuai(College of Civil and Transportation Engineering,Hohai University,Nanjing 210098,P.R.China;College of Defense Engineering,Army Engineering University,Nanjing 210014,P.R.China;Zhejiang Communications Construction Group Co.,Ltd.,Hangzhou 310051,P.R.China;Nanjing Longwoo Technology Co.,Ltd.,Nanjing 211899,P.R.China)

机构地区：[1]河海大学土木与交通学院,南京210024 [2]陆军工程大学国防工程学院,南京210014 [3]浙江交工集团股份有限公司,杭州310051 [4]南京隆沃科技有限公司,南京211899

出　　处：《地下空间与工程学报》2023年第6期1818-1827,共10页Chinese Journal of Underground Space and Engineering

基　　金：173计划技术领域基金(2019JCJQJJ009)。

摘　　要：为进一步探明既有损伤高强混凝土结构在冲击荷载下的动态劈拉特性,采用分离式霍普金森压杆装置研究了不同初始损伤的两种高强混凝土在冲击载荷下的动态劈拉性能。同时,基于数字图像处理技术对试件进行了裂缝演化监测。结果表明:初始损伤程度相同时,高应变率下C60混凝土的应变率敏感性显著高于C80混凝土;随着应变率的增加,损伤程度较低的试件的应变率敏感度较高,高损伤程度的C80混凝土的应变率敏感程度有所降低;初始损伤程度增大,混凝土内部产生的微裂纹增多,新裂纹形成所消耗的能量明显大于初始损伤造成的试件既有裂纹扩展所消耗的能量;基于DIC技术发现,随着初始损伤程度的增大,C80混凝土的微应变阈值及裂缝开口位移均呈现下降趋势。To further investigate the dynamic splitting and tensile properties of existing damaged high-strength concrete structures under impact loading,the dynamic splitting and tensile properties of two types of high-strength concrete with different initial damage under impact loading are investigated using a separated Hopkinson compression bar device.Meanwhile,the crack evolution of the specimens was monitored based on digital image processing techniques.The results show that:The strain rate sensitivity of C60 concrete at a high strain rate is significantly higher than that of C80 concrete at the same initial damage level.With the increase in strain rate,the strain rate sensitivity of the specimens with a lower damage level is higher,and the strain rate sensitivity of C80 concrete with high damage level decreases.With the increase of initial damage level,the microcracks generated inside the concrete increase,and the energy consumed by the formation of new cracks was significantly greater than that consumed by the expansion of cracks at initial damage.Based on the DIC technique,it was found that the microstrain threshold and crack opening displacement of C80 concrete showed a decreasing trend as the initial damage level increased.

关 键 词：初始损伤 高强混凝土 分离式霍普金森压杆 动态劈拉性能 数字图像相关 

分 类 号：TU528.31[建筑科学—建筑技术科学]