基于声发射的装配式灌浆套筒剪力墙疲劳损伤演化的量化评价试验研究

Experimental research on quantitative evaluation of fatigue damage evolution of prefabricated shear wall with grouting sleeve connection based on acoustic emission

为量化评价装配式灌浆套筒剪力墙疲劳破坏特性,本研究提出使用声发射技术实时监测装配式灌浆套筒剪力墙在受到往复荷载作用下的全破坏过程,识别出不同阶段的损伤特性,并提取了与之相对应的声发射信号特征,利用解析声发射源的特征量化描述了剪力墙的损伤破坏行为。对两组不同套筒布置形式和不同主筋直径的装配式灌浆套筒剪力墙试件进行往复荷载试验,并对剪力墙试件试验结果进行分析。首先,基于得到的声发射数据和试验结果分析可知:在循环加载过程中装配式灌浆套筒剪力墙损伤过程可以分为3个阶段:(1)剪力墙体弹性压密微裂纹开展阶段;(2)剪力墙裂纹开展阶段;(3)剪力墙体破坏阶段。且声发射指标相较于传统的力学指标对于损伤过程的识别和描述更加灵敏。当监测到声发射定位点大量集中在剪力墙底部受压区,则表示剪力墙试件最终破坏形式为剪压破坏;当监测到声发射定位点大量集中在剪力墙两侧及两端,则表示剪力墙试件最终破坏形式为弯剪破坏。其次,将两组试验结果进行对照分析可得,主筋双排布置且直径更大的装配式灌浆套筒剪力墙试件具有更好的性能。最后,使用聚类分析方法对损伤破坏过程中的损伤源进行分类。结果表明,声发射技术,可以量化剪力墙的损伤过程,并为损伤提出预测和预警。

In order toquantitatively evaluate the progress of the damage characteristics of prefabricated shear wall with the grouting sleeve connection,it proposes to use the acoustic emission(AE)method to evaluate the mechanical behavior during the failure process of prefabricated shear walls under reciprocating loads in a real time,and to identify the damage characteristics at different stages,and the typical acoustic emission signal features caused by the different damage modes are extracted,and the damage behavior of the shear wall is described,accordingly.Two types of the prefabricated shear walls with different sleeve arrangements and diameters of the main reinforcement are compared.Firstly,based on the analysis of the obtained acoustic emission data and mechanical results,the damage process of the prefabricated grouting sleeve shear wall can be divided into three stages during the cyclic loading process.(1)The elastic stage with micro-cracks in the shear wall.(2)The cracking progressing stage.(3)The failure stage.Moreover,the acoustic emission index is more sensitive to the identification and description of the damage process than the traditional mechanical index.When it is monitored that a large number of acoustic emission sources are concentrated in the compression zone at the bottom of the shear wall,it means that the final failure mode of the shear wall specimen is shear compression failure.When it is detected that a large number of acoustic emission sources are concentrated on both sides and ends of the shear wall,it indicates that the final failure mode of the shear wall specimen is bending shear failure.Secondly,the comparative analysis of the two groups of experimental results shows that the shear wall specimens with double-row arrangement and larger diameter of the main reinforcement show better mechanical performance.Finally,the cluster analysis method is used to classify AE signals due to different AE sources in the process of damage destruction.The results show that the AE can quantify the damage process of the shear wall,and provide prediction and early warning for the damage.