摘要
循环扰动荷载对地下工程稳定安全具有重要的影响。利用GCTS动态岩石三轴试验系统,对混凝土试样开展常规三轴及三轴循环加卸载试验,研究了循环荷载作用下混凝土的力学特征、变形机理及能量演化规律。研究结果表明:三轴循环加卸载条件下混凝土峰值强度低于常规三轴峰值强度;随着循环次数增加,滞回环面积及塑性应变逐渐增大,试样损伤逐步加剧;混凝土试样破坏时弹性模量逐步降低,相同加载次数时弹性模量随围压增大而不断增大,试样刚度增大;随着循环次数增大,每个循环内总能量密度及耗散能密度都呈现出缓慢增大-急剧增大-减小的趋势,单个循环内总能量及耗散能密度的急剧增大可作为判断混凝土试样损伤破坏的前兆信息。
Cyclic disturbance load has an important effect on the stability and safety of underground engineering.In this research,GCTS dynamic rock triaxial testing system was used to carry out conventional triaxial and triaxial cyclic loading-unloading tests,the mechanical characteristics,deformation mechanism and energy evolution law of concrete under cyclic loading were investigated.The results show that the peak strength of concrete under triaxial cyclic loading-unloading is lower than that under conventional triaxial loading-unloading.The hysteresis area and plastic strain gradually increase with the increase of cycle number,and the damage of concrete sample is gradually intensified.The elastic modulus decreases in the sample destruction,and the elastic modulus increases with the increase of confining pressure in the same cyclic number,and the stiffness of the sample is increased.As the cyclic number increases,the total energy density and dissipation energy density in each cycle show a trend of slow increase-sharp increase-decrease.The total energy and dissipation energy density increase sharply in a single cycle,which can be used to determine the occurrence of the damage failure of concrete sample.
作者
张利军
ZHANG Lijun(The Fourth Engineering Co.,Ltd.of China Railway 20th Bureau Group,Qingdao Shandong 266061,China)
出处
《铁道建筑技术》
2022年第11期20-24,47,共6页
Railway Construction Technology
基金
中铁二十局集团第四工程有限公司技术开发项目(2021320084)。
关键词
混凝土
循环加卸载
围压效应
变形破坏特征
能量特征
concrete
cyclic loading-unloading
confining pressure effect
deformation and failure characteristics
energy characteristics
