A municipal maintenance hole was experiencing active groundwater infiltration and ingression through joints, pipe penetrations, and hairline cracks in the concrete structure. During peak groundwater conditions, steady inflow was entering the system, increasing treatment volumes and placing additional strain on downstream infrastructure.
The challenges were significant:
Geotechnical polyurethane was selected to permanently seal the active groundwater leaks from the interior of the maintenance hole.
Using specialized injection equipment, hydrophobic polyurethane resin was strategically injected through small ports at identified infiltration points. Upon contact with water, the material reacted and expanded, forming a watertight seal within cracks, joints, and surrounding soil interfaces.
The expanding resin traveled beyond the visible leak path, filling hidden fissures and sealing water migration channels in the surrounding soil. This created a compression seal from the outside in—without excavation.
Key advantages of the approach included:
All work was completed safely within the confined space environment and with minimal impact to municipal operations or surrounding traffic.
The groundwater infiltration was successfully stopped at its source. Active leaks were sealed, and the surrounding soil interface was stabilized, preventing further water migration into the maintenance hole.
For the municipality, this resulted in:
No service interruption to residents
By using geotechnical polyurethane, the municipality achieved a permanent, cost-effective repair without the disruption typically associated with traditional waterproofing or structural rehabilitation methods.
