Beaver to Junction Project, Beaver, UT

FHWA Central Federal Lands Highway Division and CH2M HILL

The project consists of widening and realigning of portions of Utah PLH 29 between Beaver and Junction, Utah. The roadway improvements were for safety and mobility on the mountain road.

Yeh and Associates performed a geotechnical investigation along the roadway, including evaluation of geologic structures, geologic hazards, surface and subsurface conditions, pavement condition surveys and alternative alignments for the proposed roadway. As part of the realignment, three fill walls, three cut walls and numerous cut slopes were planned. The terrain throughout the site was mountainous with steep slopes on either side of the roadway requiring difficult access drilling.

Three active landslides were observed along the cut side of the existing alignment, along with minor raveling of the fill side slopes. Rockfall was frequent in these areas with the existing roadside ditches in constant need of maintenance. The size of the rockfall in the areas ranged up to 2-foot diameter boulders. Seeps were observed along one section of the roadway where during the spring the roadway reportedly became saturated.

Based Yeh and Associates field investigation, recommendations were provided for selection and design of soil nail, mechanically stabilized earth (MSE) and rockery retaining walls. Mitigation measures were provided for slope stabilization and rockfall. The designated waste disposal site was found to be situated within the mapped limits of the “Big Cove” landslide and further analysis was recommended to verify the suitability of the waste site. The work was coordinated with the US Forest Services, the State of Utah and the county.

Yeh’s key personnel that worked on the project included Shan-Tai Yeh who was the QA/QC reviewer, Rick Andrew was the project manager and Ben Arndt was the project engineer for the investigation and design.