A peer-reviewed engineering case study followed combined drainage and waterproofing repairs in China’s Dashiling Tunnel. Over two years, leakage defects declined by more than 70 per cent, while the pavement leakage area shrank sharply. The work concerns one tunnel, and closely spaced repair stages prevent a separate estimate of each measure’s contribution.
A peer-reviewed field study examined repair work in Dashiling Tunnel, a mountain highway tunnel in China. Inspections spanning two years found a drop exceeding 70 per cent in leakage defects. The pavement area affected by leakage was approximately 3.9 per cent of its earlier extent. Across the assessed sections, defect density stayed below 0.3 points per linear metre. These findings came from engineering inspections.[1]
The investigation considered rainfall recharge, fractured rock, obstructed drainage and weakened waterproofing together. Engineers mapped visible damage and examined drainage performance and possible groundwater pathways. Repairs restored drainage first, addressed groundwater and pressure next, and then treated waterproofing and lining defects. Cleaning and localized pressure relief were combined with surface drainage arrangements. The approach extended beyond closing individual visible leaks to the broader water pathway.[1]
Rainfall showed no substantial year-to-year change during follow-up, reducing the plausibility of a simple drier-weather explanation. However, several measures were introduced close together, and the contribution of each cannot be isolated. Continuous groundwater inflow and behind-lining pressure measurements were unavailable. One tunnel cannot establish general performance across karst, major faults or unusually high water pressures; those conditions may require different investigations and targeted repair measures.[1]
