Leaking Water Causing Sink Hole

Another project we were called in for several sinkholes in a backyard. After investigating there was an underground storm water culvert located 5 feet below that had several leaks. Directly under each sinkhole was a leak in the culvert. During rain events water would pull the soil surrounding the leak in the culvert in and wash it downstream, creating the sinkhole above. We strategically deep injected our grout through 1/2 pipe from the surface into the problem area at the culvert and sealed it off. As you can see in the video our polyurethane resins expanded thru the leaks sealing them up.