Industrial Curtain Grouting ProjectFebruary 14, 2021
Service Type: Polyurethane Curtain Grouting and Leak Sealing
Client: Industrial Customer
Location: St. Louis, MO
Structure Type: Below grade testing facility
Problem: The below grade 31′ x 29′ structure was holding water as high as 6′ behind the 12″ thick 9′ tall walls surrounding a large sensitive piece of testing equipment. Hydrostatic pressure was causing the cold joints to leak at the wall/ floor interface and floor slab control joints for the equipment footing which were 4′ thick. Also the pit is directly in the middle of the facility with no outer walls exposed.
Solution: Wall drains with shut offs were installed on all four walls to drain the water into a sump pit and relieve the hydrostatic pressure. A single component hydrophobic polyurethane resin was then used to inject through the wall to curtain grout all the vertical walls. A hydrophilic low viscosity single component was used to seal the cold joints between the floor and equipment footings.
Challenges: The customer was in a hurry to get the work completed and wanted it done asap. The earliest the project could be scheduled was mid January but snow and low temperatures were potential problems. The ambient and surface temperature were constantly monitored by the customer and relay back to make sure the ambient was above freezing and soil surface temps were at least 40+ degrees. At the time of work it had just snowed but the ambient temps were 36 degrees and soil surface temps were 41 degrees. The material and 5% catalyst was heated in the trailer on the way and on site in a tent to 80+ degrees to account for heat loss when injecting into the colder soil. The reaction times were exactly as expected. The other challenge was to inject below the splash bed but not clog the water mitigation pipe buried below the rocks in the splash bed, for that the injection probe was marked and flow timed per the expansion rated we were seeing and held 18″ below the surface as to not flow material into the pipe openings. Pipe was also periodically inspected with a bore camera during injection and upon completion.
Results: Project was completed in 5 days time with over 200+ mechanical injection ports installed, Some residual leaking occurred in the following weeks that were reinjected to a final result of no leaking. Periodically the wall drains do collect moisture but not enough to build hydrostatic pressure like it once was. Project was successful and a lifetime warranty on the work was given. Over 125 gallons of raw material plus catalyst was injected into the walls and floor.