WMATA YELLOW LINE TUNNEL LINER AND PORTAL WALL REPAIR, 2022
Highlights
- Combined use of several NOH2O® injection techniques for positive-side, curtain grouting to remediate water leaks through liner sections, joints and bolts
- NOH2O® successfully formed a waterproofing membrane in the annular space between inner steel and outer concrete tunnel lining
Project Overview
Sovereign was tasked to demonstrate through a field trial that NOH2O® could provide cost- effective sealing of voids at the interface between the steel liner and outer concrete components of the tunnel structure to mitigate water infiltration.
Strategy
Sovereign designed a demonstration project employing curtain grouting, injection of NOH2O® through our specially designed bolts, sealing of joints between steel liner segments, and grout data management and reporting. Sovereign also included an emergency grouting plan if water ingress at any location exceeded a pre-determined threshold value.
Results
Sovereign performed curtain grouting of the steel tunnel liner and the concrete interface between Station Mk. 56+25 and 56+45 in the Inbound Track (L1) of the Yellow line. Our methods included careful drilling and documentation of grout holes, pre-grouting dye testing, injection of NOH2O® through grout holes, specially-designed bolts and ports created at steel liner joints. A record book containing detailed grouting data was made available to WMATA during and after the successful trial program.
