Current Status of Inspection and Repair of Difficult Drainage Pipelines in China

The detection and repair of pipeline defects are critical to the sustainable operation of drainage pipeline systems, and some technologies have been developed to cope with the challenges of difficult-type pipes, including pipes across canals and rivers, large-diameter and high-depth pipes, and high water-table pipes in their inspection and repair. However, there is a lack of systematic sorting of existing research results, which impedes implementation of these new technologies. This research systematically summarized the main application of inspection and repair technologies of these three difficult pipelines based on a nationwide investigation program. Notably, the boundary conditions and specific suggestions of the respective technologies as well as typical engineering instances were presented. Finally, this study discussed the future development perspectives of the detection and repair of drainage pipelines. The present work will hopefully assist in detecting and repairing difficult pipelines in the best way.