Phase two at the landslide site on Highway 87 that will cost at least $8 million to repair is under way, the Arizona Department of Transportation reports.
During the last month, construction crews began installing 26 drilled shafts on the slope that failed in March, said ADOT spokesperson Bill Williams. The shafts are 73 feet deep and 5 feet in diameter.
“A drilled shaft is sort of like a reinforced steel cage that has concrete poured into it,” Williams said.
“The series of drilled shafts are designed to hold back the slope and try to keep Mother Nature from moving that slope again.”
On the northbound side of the highway, crews are installing a 300-foot-long multi-plate extension after crews detected slope failure, Williams said.
“This will buttress the hillside on the opposite side of the landslide zone, a little further north near the bend in the road.”
Work on phase two is expected to continue for another four to five months.
The Slate Creek landslide broke nearly 45 feet of ground, leaving the southbound lane of Highway 87 near milepost 224, six miles north of Sunflower, broken and buckled. The highway was closed for six days and southbound lanes were reopened in late May.
Royden Construction crews of Phoenix have already installed a 4-foot-wide drainage pipe, concrete pilings and monitoring devices to measure any future movement in phase one and two of the project.
ADOT spent $5.5 million on phase one of the project and expects to spend $2.5 million on phase two.