State highway crews will build new barrier walls to prevent loose soil from falling onto Highway 87 near the site of a March landslide, the Arizona Department of Transportation said Wednesday.
Engineers noticed a new mound of soil between mileposts 222 and 224 on Dec. 17, and have been closely monitoring the site since, said ADOT public information officer Bill Pederson.
Recently, crews detected new movement at the site, and engineers decided to erect barrier walls to prevent loose soil from moving onto the highway.
One southbound lane will be closed temporarily Friday morning to allow crews to install 200-feet of new concrete barriers near milepost 224. Both lanes should be reopened by 5 p.m. Friday. ADOT says there is no immediate danger to drivers.
Heavy rainfall in December concerned ADOT officials because it coincided with new movement at the site.
A survey conducted by the Arizona Geological Survey after the March 21 landslide that closed Highway 87 for one week and may cost $18 million to repair concluded that heavy rain might have partly triggered the slide.
During phase one of the repair project, crews installed a 4-foot-wide drainage pipe, concrete pilings and monitoring devices. During phase two, expected to begin early spring, crews will construct a 20-foot-high retaining wall using the pilings on the west side of Highway 87.
Additional erosion-control measures are planned for both sides of the highway.