Experimental Study on Grouting Quality Detection in Prestressed Pipeline Based on Scattered Wave Method

The grouting quality of prestressed pipelines directly affects the safety and durability of prestressed reinforced concrete bridge structures, attracting wide attention from the engineering community. Based on the principles of the scattering wave method, this paper designs and manufactures a large-scale model to simulate the actual construction testing environment. Several sets of design defects with significantly distributed spans in the prestressing ducts were pre-set, and the Engineering Geophysical Instrument System–Pipeline Grouting Profile (EGS-PGP) equipment developed was used to detect the grouting quality of the prestressed pipelines under different conditions, obtaining the frequency attenuation values at defect locations. The study shows that stability of the peak frequency throughout the test can indicate compact grouting, while a large fluctuation in the peak frequency range with no regular changes can indicate non-compact grouting; a sudden increase or decrease in peak frequency can effectively indicate the location of grouting defects along the pipeline. The number of sudden changes in frequency can indicate the number of gaps inside the pipeline. The chirp signal, compared to the hammer impact signal, shows greater stability and engineering application value in detecting defects using the scatter wave method. This study provides technical support for the detection of grouting quality in prestressed pipelines based on chirp signals.