【摘要】 对在役混凝土结构及其构件进行健康监测、损伤诊断及灾害预警具有重大的理论意义和实践价值。为反映声发射能量与混凝土材料破坏过程之间的关系,对在单轴多级循环加载条件下的混凝土试件进行了声发射试验,记录声发射能量的变化规律。试验对象为初始孔隙率为3.3%、6.7%及9.2%的混凝土圆柱试件,分析其加载过程中的声发射能量,得到混凝土试件在弹性压密阶段、损伤稳定积累阶段以及损伤快速积累阶段时声发射能量与荷载曲线的关系,引入活跃系数Act对声发射现象发生的活跃程度进行表述,提出基于声发射能量评价混凝土工作状态的方法。当出现能量峰值出现下降后再次激增,能量均值超过100mV×ms,且活跃系数Act出现在20~70范围内连续放缓的现象时,预示着混凝土材料的破坏。更多还原

【Abstract】 There are great theoretical significance and practice value to service the concrete structure and monitor its components to be monitored in health and diagnosed in damage,besides,its need badly to alert the disasters.To reflect the relationship between AE energy and failure process of the concrete materials,the test and research on concrete specimens were conducted to record the change rule of AE energy in the condition of uniaxial multilevel cyclic loading.The test objects are concrete cylinder specimens with 3.3%,6.7% and 9.2% original porosity.By analyzing the AE signals in the loading process,the relationship between the loading curve and the AE Energy was obtained in the 3 stages:the Elastic Compaction Phase,the Phase of stable accumulation for damage,the Phase of rapid accumulation for damage.The active factor was introduced to reflect the severity of AE and then a method based on AE Energy was proposed to evaluate the working state.The phenomena that the peak value of the AE Energy explode just follow itsbottom value,the average of energy is over 100,and the active factor continuously slows down in the range of 20~70 indicate the failure of concrete materials.更多还原