Evaluation and Stabilization of the Bret Landslide, Big Horn County, Wyoming

The Bret Landslide is located at approximate mile post 29.1 on United States Highway 14 in Big Horn County, Wyoming. The Landslide is an active portion of a much larger landslide which extends for over one thousand feet along the highway. This large landslide has been marginally stable since movement initiated in the spring of 1965 during construction to widen the highway along the route of an old wagon road. The Bret Landslide is approximately 600 feet wide and extends approximately 250 vertical feet from the highway down to Shell Creek at an average slope angle of 40 degrees. Several tension cracks have been mapped on the slope between the highway and the creek. The wet winter and spring of 2011 contributed to high runoff in Shell Creek which eroded the toe of the landslide resulting in an approximately 30-foot high over-steepened slope. After continued highway damage from landslide movement and several emergency attempts to stabilize the landslide, the Wyoming Department of Transportation (WYDOT) decided to explore options for permanent landslide mitigation. Numerous mitigation options were considered for geotechnical feasibility and constructability. Six options were further evaluated and presented to WYDOT for selection of the most feasible option. The preferred mitigation option was chosen and consists of micropiles and ground anchor tiebacks with highway reconstruction using a geogrid reinforced subgrade. The mitigation was designed to stabilize the highway considering the difficult site conditions. Construction of the mitigation began in April of 2014.

Language

  • English

Media Info

  • Media Type: Digital/other
  • Features: Figures; Photos; References; Tables;
  • Pagination: pp 374-387
  • Monograph Title: Proceedings of the 65th Highway Geology Symposium (HGS 2014)

Subject/Index Terms

Filing Info

  • Accession Number: 01640002
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Jun 28 2017 7:58PM