Keller provides rapid design and mobilization to perform slope stabilization following a major landslide along Teton Pass.
The project
Highway 22 is a heavily traveled commuter road between Jackson, Wyoming, and Victor, Idaho. The permanent roadway on Teton Pass was first constructed in 1969 and was known as ‘The Big Fill’ due to the large amount of soil required to stabilize it.
A period of heavy rainstorms caused a slope failure at The Big Fill, resulting in a substantial landslide and closure of the roadway. A temporary re-route was constructed to reopen the roadway while the Wyoming Department of Transportation (WYDOT) initiated planning for the permanent repair.
Leveraging a previous relationship with the general contractor and WYDOT, Keller was contracted to complete the permanent repair. The permanent embankment was designed as a 1.5H:1.0V reinforced soil embankment, requiring a 100-ft excavation and a robust temporary support system that could also facilitate drainage under temporary and permanent conditions.
A soil nail wall was chosen as the temporary excavation support. Because conventional shotcrete facing would obstruct drainage, Keller developed a geotextile and wire mesh facing system that allowed continuous water movement through the slope.
The excavation was performed in 7-to 10-ft vertical lifts. To reach the upper portions of the slope, soil nails were drilled with remote operation drilling masts mounted to the arms of medium-sized excavators. Hollow thread bars were drilled with a sacrificial bit, allowing for the bars to be installed and grouted into place in one operation.
Following the installation of soil nails, Keller installed 9 5/8-inch micropiles using a rotary drilling method. The micropiles were installed into a 15-ft rock socket and were designed to provide shear reinforcement at the base of the new embankment.
Keller worked on a 24-hour, 7-day/week schedule to complete the work without delay.
