Workers are repairing a 13-foot sinkhole under the Oak Ridge High School soccer field.
It started as an 18-inch hole two weeks ago, said Allen Thacker, Oak Ridge Schools maintenance and operations supervisor. A section of the field “fell out,” and water was observed at the bottom.
Workers dug down about eight feet and found water running in, Thacker said.
He said there were concerns about the 198 geothermal wells buried up to 300 feet deep under the soccer field, which was built in 2005. Water that circulates through plastic pipes in the wells helps heat and cool the high school.
While the sinkhole is next to a geothermal well, it is not caused by a problem with any of the wells, Thacker said.
Geoservices of Knoxville drilled 10-foot and 12-foot holes on either side of the sinkhole and recommended a reverse rock filter. That uses a pile of rocks that start with large 12″ rocks on the bottom, tapering off to fine “crusher run” on top, covered by three to four feet of clay and one foot of topsoil.
Thacker said the work should be finished by the end of the week. He is scheduled to give an update on the sinkhole during an Oak Ridge Board of Education meeting at 7 p.m. today.
To make the repairs, Blount Excavating has dug a hole in the middle of the soccer field about 15 to 20 feet wide and 13 feet deep, down to the lowest water point.
Thacker said the work could cost between $42,000 and $45,000. Sod could be replaced on the field between Monday and Wednesday next week. The field can be used 10-14 days after that.
The Oak Ridge Wildcats boys soccer team has away games this week. Two home games next week will be played at Blankenship Field, Thacker said.