Quantitative Comparison and Effectiveness Evaluation of Striking and Sliding Excitation Methods in Acoustic Identification of Concrete Voids

The long-term safety and durability of concrete building structures depend largely on their internal quality. Wall voids, as typical hidden defects, directly affect the structural bearing capacity and service life. Such defects may not only lead to surface hollowing and peeling but also develop into serious safety accidents such as local collapse. At present, acoustic detection methods are widely used in engineering practice due to their convenience and efficiency. Among them, the strike method and the slide method, as two basic excitation methods, are commonly used on-site detection methods. However, existing studies still lack the systematic comparative analysis of these two methods, especially in terms of objective evaluation based on quantitative characteristics. To fill this research gap, this study designed a strict controlled experimental scheme. By collecting acoustic signals under these two excitation methods, the time-domain waveform characteristics, frequency-domain response characteristics, and time-frequency distribution patterns were systematically analyzed. The results show that, compared with the traditional strike excitation, the slide excitation method shows significant advantages in concrete wall void detection. It not only has higher detection accuracy but also exhibits better stability and repeatability. Further analysis found that the slide signal is superior to the strike signal in terms of feature distinguish ability and anti-interference ability. Its voltage distribution curve shows more obvious separation characteristics, which significantly reduces the risk of misjudgment. Through systematic quantitative comparison, this study provides a reliable experimental basis for the acoustic detection of concrete wall voids and has important reference value for promoting the standardization and intelligent development of non-destructive testing technology.