Mitigating Landslides in Wyoming Using Multiple Innovative Designs and Technologies

The Wyoming Department of Transportation (WYDOT) recently completed two successful large-scale landslide mitigation projects. Yeh and Associates (YA) was the consultant selected to provide the professional design services and design support. The first landslide was located in the Snake River Canyon south of Jackson, Wyoming along Highway 89. The landslide area affected the end of a 20 foot high MSE wall which transitioned into an embankment fill that extended for more than 750 feet in length along the roadway. The failing wall and embankment were located approximately 500 feet above the Snake River. During the spring of 2011, the slide area became extremely active necessitating an emergency response. Two mitigation options were selected which included supporting the MSE wall on 5-inch diameter micropiles and using lightweight expanded polystyrene fill (EPS) in the failing embankment area. Construction was completed in the Fall 2011. The second slide known as the Narrows Landslide, located along State Highway 220 south of Casper, Wyoming, had been active since 1965. The slide extended for more than 500 feet in length along the roadway above the North Platte River. WYDOT and YA collaborated on an innovative drilled shaft mitigation design that became known as the Coupled Shear Pile (CSP) system. This system uses the frame action of two drilled shafts that are connected at the top by a rigid pile cap. The coupled system transfers the maximum moments generated by the moving slide mass through the rigid pile cap rather than having the maximum moment at the slide plane as occurs with a single row of drilled shafts. Using this coupled system, the size of the drilled shafts was reduced to 48 inches in diameter which is significantly smaller than single row drilled shaft stabilization systems assuming both moment and shear are considered in the design. Additionally the project specified an oscillating drilled shaft construction method that was successfully completed ahead of schedule in the summer of 2013.


  • English

Media Info

  • Media Type: Digital/other
  • Features: Figures; Photos; References;
  • Pagination: pp 81-100
  • Monograph Title: Proceedings of the 65th Highway Geology Symposium (HGS 2014)

Subject/Index Terms

Filing Info

  • Accession Number: 01640003
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Jun 29 2017 1:49PM