Yellowstone National Park Emergency Slope Stabilization

Middle Creek and Mammoth Hot Springs, Wyo.

Best Project

Submitted by: GeoStabilization International

Owner: Wyoming Dept. of Transportation

Lead Design Firm: GeoStabilization International

General Contractor: HK Contractors

In June 2022, historic flooding caused extensive damage to Yellowstone National Park’s critical park infrastructure. To help with the reconstruction of roadways, GeoStabilization International completed two emergency design-build contracts totaling a combined $1.6 million.

Crews completed both contracts as fast as possible due to their emergency nature, but in both cases, no site-specific geotechnical information was available prior to construction, so assumptions were made during design. However, onsite engineering and testing allowed for continuous modifications to the design based on actual subsurface conditions. This approach showcased the importance of onsite engineering and testing in ensuring successful construction in emergency situations.

The first project, a subcontract from HK Contractors, involved stabilizing a large cut slope on the Old Gardiner Road Bypass at Mammoth Hot Springs, where 20,000 sq ft of both continuously grouted hollow bar soil nails and solid bar soil nails combined with high-tension Tecco Green mesh were used to stabilize large cut slopes to construct a new road corridor.

The Wyoming Dept. of Transportation awarded the second project, which involved the reconstruction of approximately 120 linear ft of roadway shoulder at the Yellowstone National Park East Entrance Gates. To address this, the team used hollow bar soil nails and shotcrete to rebuild lost shoulder width, with vertical micropiles and riprap for additional scour protection at the toe of the slope.

Yellowstone National Park Emergency Slope Stabilization

Photo courtesy GeoStabilization International

This section of Highway 14 had to remain open to tourism. Onsite engineering and testing again allowed the team to modify the design as needed, requiring close collaboration between the design and construction teams.

While the primary focus of the design was on functionality and structural stability, efforts were made to integrate the stabilization elements with the natural surroundings. The high-tension Tecco Green mesh and pinned mesh slope systems provide a green, vegetated appearance that blends with the park environment.

Crews completed the emergency repair on time and within budget in less than four months.