Crews are driving soil nails into an East Tennessee hillside to stabilize land around a section of Interstate 75 after a
massive slide took out southbound lanes, which could be closed all summer.
Elmo Greer & Sons LLC, East Bernstadt, Ky., already had crews on-site when the slide occurred on May 8. The contractor was
repairing damage to the highway after a section of embankment collapsed on March 8.
Greer’s $9.3-million contract, awarded in April, calls for removing a section of highway, going to bedrock, and stabilizing
and rebuilding the slope.
The latest slide, on a 180-ft embankment, has added to the work, but neither the contract nor the Sept. 28 deadline has
changed, Mark Nagi, Tennessee Dept. of Transportation (TDOT) spokesman, said.
Before the highway can be rebuilt, “there will have to be temporary excavation that will leave that side of the interstate
unprotected and almost vertical,” Saieb Haddad, TDOT geotechnical engineer, said.
“We are assessing the situation day by day,” he said.
Current plans call for using specialized launch nails—20-ft pieces of rebar shot straight into the hillside—for
stabilization, in addition to the rebar-and-grout combination of soil nails, he said.
Depending on subsurface investigation, crews may also use 10-ft to 15-ft post-tension nails to strengthen and stabilize the
area.
Further, subcontractor Soil Nail Launcher Inc., Grand Junction, Colo., is putting 20-ft and 50-ft nails under the northbound
lanes, Nagi said.
After placing more than 200 soil nails, crews will cover the area with fencing and grout for additional stabilization before
bringing in more than 200,000 tons of rock to build the new embankment, Haddad said.
TDOT currently has single north- and southbound lanes open on I-75, which has an average traffic load of 28,340 vehicles
daily. The agency has posted alternate routes for both traffic in both directions, routing it through Caryville, LaFollette
and Jellico. Wide loads must take other highways.
lanslide-in-east-tennessee.asp