【摘要】 为探究初始缺陷对混凝土材料在单轴压缩下内部损伤破坏的影响规律,制作不同初始缺陷的立方体试块进行立方体抗压试验,并利用声发射采集系统及应变采集系统对试验的全过程进行监测,获得了可以描述立方体试块受载破坏过程的声发射事件率-时间柱状图、振铃计数率-时间柱状图、声发射事件率与应变-时间关联曲线图。结果表明:不同初始损伤下的立方体试块在受载破坏中均经历初始压密(I)、线性扩展(II)、稳定增长(III)以及失稳破坏(IV)四个阶段,并且随初始损伤的逐渐提高,压密阶段时间不断增长,"双峰"特征越趋于不明显,其立方体抗压强度显著降低。通过振铃计数计算得到的损伤变量绘制成损伤曲线可以较好反映出立方体受载破坏的各应力阶段。更多还原

【Abstract】 In order to explore the influence of initial imperfection on the damage and failure of concrete under uniaxial compression,cubic specimens with different initial damage were made to carry out the cubic compressive test.The whole process of the test was monitored by using acoustic emission(AE)acquisition system and strain acquisition system,and the cubic specimens with different initial damage were obtained,AE event rate-time histogram,ring counting rate-time histogram,AE event rate-strain-time correlation diagram for a bad process.The results show that the cubic specimens under different initial damage all undergo four stages of initial compaction(I),linear expansion(II),stable growth(III)and instability failure(IV).With the gradual increase of initial damage,the time of compaction phase increases continuously,and the"double peak"characteristics become less obvious,and the cube of the cube becomes unstable.The compressive strength decreased significantly.The damage variables calculated by ring counting can be plotted as damage curves,which can better reflect the stress stages of the failure of the cube under load.更多还原