Landslide-Prone Corridors

THE PROBLEM

Corridors built across active or marginally stable slopes generate a long-running maintenance bill — annual paving repairs, recurring shoulder failures, periodic emergency closures. Standard fixes treat the symptom each cycle. Stabilizing the corridor takes corridor-scale drilling work: drainage to pull water pressure out of the failure mass, and anchor systems to hold what's left.

JDC'S APPROACH

JDC's work on Highway 20 in Eddyville, Oregon installed over 587,000 feet of horizontal drains — approximately 111 miles — across a 5.5-mile stretch of new highway, over ten years of construction. Multiple active landslides were addressed with aggressive horizontal drain placement. Weirs measured several million gallons of water in 48-hour periods during large rain events. We deployed multiple drill units and worked shifts around the clock to meet tight contract schedules.

On the anchor side, JDC installed 81 multi-strand tieback tendons averaging 140 feet in length on Interstate 94 near Theodore Roosevelt National Park as part of a grade beam retention wall — a pilot design for the North Dakota DOT to evaluate post-tensioning as an alternative to recurring paving repairs. Post-grouting was the link to bond strength in the low-strength formation. Dyna-force sensors and load cells were installed to quantify slide movement post-construction.