混凝土受压过程的声波特性试验研究

Experimental study on acoustic characteristics of concrete during the compression process

检测混凝土结构使用阶段的工作应力状态对评估既有工程结构的安全可靠性非常重要,实际工程中可以采用超声波无损检测技术进行检测.为探讨混凝土构件受压过程的声波特征,制作了多组混凝土试件,采用加载装置进行逐级加载至破坏,加载过程中利用超声波无损测试设备.对不同轴向应力条件下混凝土试件的声学特征进行了测试,分析讨论了时域、频域声学参数与试件承受压应力之间的关系.研究结果表明:超声波波速与混凝土试件压应力之间具有较好的相关性且稳定性好;声波信号的首波幅值及最大振幅绝对值与混凝土压应力之间的相关性较差;声波频域信号中的主频幅值与混凝土压应力之间存在相关性,但受试件内部裂缝的干扰较大;在混凝土结构压应力检测中,推荐采用波速作为评价混凝土应力状态的声学指标.

Detection of the working stress status for concrete structures is very important to evaluate the safe reliability of the as-built engineering structures.The ultrasonic nondestructive testing technology can be used in practical engineering.In order to explore the acoustic characteristics of concrete members subjected to compressive process,several groups of concrete specimens were made,and the loading device was used to load to damage step by step.Use the ultrasonic nondestructive testing equipment during the loading process.The acoustic characteristics of concrete specimens under different axial stress conditions are tested;the relationship between the acoustic parameters in time-domain,frequency-domain and the compressive stresses on the specimens was analyzed and discussed.The results show that the correlation between ultrasonic wave velocity and compressive stress of concrete specimens is great and stable;the correlation between the first wave amplitude,maximum amplitude of acoustic signals and compressive stress of concrete is poor;the correlation between the main frequency amplitude of acoustic signals in the frequency domain and compressive stress of concrete exists,but the interference from internal cracks of specimens is large;in the detection of compressive stress of concrete structures,it is recommended to use wave velocity as the acoustic index for evaluating the concrete stress state.