Summery
In 2017 an old wooden bridge where Range Road 3191 crosses the Turtle River in northwest Sask. was removed and two 100 ft long x 15 ft diameter corrugated culverts were installed in its place. In 2018 an unusually quick thaw created very high water levels and large flow ice in the Turtle River which eroded the earth around one of the culverts enough that the grid road bed began to settle. The road maintenance staff excavated an area where the road was settling and found a large void and water flow along the exterior of the culvert. The crew then filled the void with gravel and bentenite as a temporary repair.
Problem
In October of 2018, Liftech was contracted by the engineering firm that had replaced the bridge. Coffer Dams were built and river flow was diverted through the other culvert. Four large pumps were installed to remove as much water as possible while we worked. Two rows of 5/8" holes 36 inches apart were drilled down both sides of the culvert below water level. Starting at the downstream end of the culvert we injected HMI's 201 polyurethane foam and using a thermal imager we were able to track the flow of the polyurethane around and under the culvert and ensure that we had completely filled the void caused by the wash out.
Solution
3,407 pounds of 201 polyurethane foam was injected around the exterior of the culvert, filling the voids and binding the soils to stop any further washout. The work was completed in 2 1⁄2 days and the road was put back in service, eliminating the need to dig up and reinstall the culvert.
