Field investigation reveals that underground pipeline damage and poor compaction drive distinct subsurface road defects, highlighting targets for collapse prevention.
Key Points
To establish a multi-scale collaborative detection and risk assessment framework for identifying hidden subsurface defects beneath urban roads.
Evaluated N=153 endoscopically confirmed subsurface defect cases across urban roads in Hunan Province, China.
Endoscopic verification identified 115 loose zones, 28 voids, and 10 cavities among the 153 confirmed defect cases.
Inadequate backfill compaction accounted for approximately 70% of all detected defects (primarily early-stage loose zones), whereas damaged underground pipelines accounted for 30% of total defects but were associated with nearly 90% of severe cavity cases.
Risk assessment classified cavities and voids predominantly as high-risk defects requiring immediate intervention, while loose zones were primarily moderate- to low-risk.