Design & Performance of Flexible Debris Flow Barriers in a Narrow Canyon

Implementation of engineered, flexible debris flow barriers to protect roadways and other infrastructure is increasing. Simultaneously, design methodology has advanced rapidly. An example of a state-of-the-art installation was constructed in Colorado Springs, Colorado. The Waldo Canyon Fire (July 2012) resulted in significant debris flow risk to watersheds affected by the burn area. These watersheds are characterized by rugged topography, historically intense precipitation events, and narrow outlets. Public and private entities supported the construction of debris flow barriers to protect infrastructure and lives within the floodplain of Camp Creek. The USGS estimated a probability of 45% for a debris flow volume greater than 100,000 m³ for the ten-year precipitation event. A design methodology based on field and laboratory testing and computer modeling was utilized. A thorough field assessment was performed to determine input parameters for barrier design using proprietary software. Two sites were selected based on channel morphology and storage capacity. Limited access required helicopter transport of construction materials. Alluvial material presented drilling challenges and high anchor design loads required significant installation depths. Load-testing sacrificial anchors to determine actual bond strengths allowed anchor depths to be reduced, and considerable time and money savings were realized. Daily construction oversight by the engineer allowed rapid adjustments to design based on field conditions, permitting the project to be finished within the allotted timeframe. The barriers were successfully completed and contained several debris flow events. Extreme precipitation in the fall of 2013 led to some design modifications to the installations.

Language

  • English

Media Info

  • Media Type: Digital/other
  • Features: Figures; Photos; References;
  • Pagination: pp 224-241
  • Monograph Title: Proceedings of the 65th Highway Geology Symposium (HGS 2014)

Subject/Index Terms

Filing Info

  • Accession Number: 01640004
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Jun 24 2017 11:29PM