MONTGOMERY CO., Va. -

Interstate 81 South in Montgomery County has re-opened.

The road had been closed since Tuesday because of an unstable slope at mile marker 124. Virginia Department of Transportation crews are building a truck climbing lane between mile markers 120 and 125.

According to VDOT, the contractor removed enough of the unstable material off the slope to allow I-81 South to re-open. Crews will continue working to remove more debris in the coming days.

The size of the unstable slope grew Monday from 50 feet to 120 feet in length after a round of blasting. VDOT made the decision to close the road after geotechnical experts reviewed it.

Work on the truck climbing project is scheduled to be finished in November.

Here is the news release from VDOT:

Both lanes of southbound Interstate 81 between mile markers 120 and 125 in Montgomery County near Blacksburg, Va., are open to traffic. The lanes reopened before 5 p.m.
 
The contractor has removed enough of the unstable material to get the slope to the condition where it is safe to reopen southbound I-81. Crews will continue to work to remove additional material in the days ahead.
 
On Tuesday, Aug. 27, southbound I-81 traffic was detoured off the interstate and onto Route 11/460 due to the unstable slope. During a scheduled blast on Monday, Aug. 26, an existing crack the slope increased from approximately 50 feet to 120 feet in length.  Geotechnical specialists reviewed the slope, and VDOT in the interest of public safety decided to close southbound Interstate 81.
 
Work on the truck climbing lane project is expected to be completed in November 2013.  For traffic information and updates, visit www.511Virginia.org.

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VDOT says there is no timetable as to when Interstate 81 South in Montgomery County will reopen.

The road has been closed since Tuesday.

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As of 2:45 p.m. Thursday, there was a 10-mile backup.

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Both lanes of Interstate 81 South in Montgomery County remain closed Wednesday.

It's not clear when the interstate will re-open. Virginia Department of Transportation crews are fixing an unstable slope at mile marker 124 where a truck climbing lane is being built. VDOT decided to close I-81 South on Tuesday.

Crews have been blasting as part of a project to construct a truck climbing lane between mile markers 120 and 125. During a blast Monday, a 50-foot existing crack in a slope increased to approximately 120 feet in length.

VDOT spokesperson Jamie Smith said rain did not impede blasting Wednesday morning. She said VDOT is working as quickly as possible to remove debris from the area.

Geotechnical experts reviewed the slope, and a decision was made to close the southbound lanes.

Officials warn drivers to prepare for delays in the area.

DETOUR

Traffic is being detoured on I-81 South at Exit 132 (Dixie Caverns), onto Route 11/460, and back onto I-81 South at Exit 118 (Christiansburg).

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According to the Virginia Department of Transportation, both southbound lanes of Interstate 81 in Montgomery County near Blacksburg will close starting Tuesday at 4:30 p.m. The lanes will remain closed for at least one day, with the possibility of closures extending to as long as ten days.

The southbound lanes will close starting at mile marker 132, and a detour will be in place.

Traffic will be detoured at exit 132 (Dixie Caverns) onto Route 11/460 and back onto Interstate 81 at exit 118 (Christiansburg).