Controlling Large Rockfalls on Steep Slopes, the Kama Bluffs Experience

This paper will discuss how, over the last few decades, the Ministry of Transportation personnel had observed sporadic, large scale rockfall events originating from an igneous rock mass forming pronounced bluffs above the TransCanada Highway near Kama, Ontario, Canada. A preliminary design agreement was entered into to evaluate the potential rockfall hazard and to recommend a range of solutions. A subsequent agreement was let for the detailed design of site-specific remediation of the lower, highway cut incorporating machine scaling and trim blasting followed by ditch clean out, as well as for the design of a high energy rockfall catchment fence to be installed along the crest of the lower slope to protect the highway from blocks of rock originating hundreds of meters above the highway. A 200 meter long, 2000 kJ system was installed in 20 panels, each 10 meters long with 21 base plates, 22 upslope anchors connecting the cables to the fence posts and 16 lateral anchors dividing the overall fence into 4 independent sections. Construction for this project was deferred to allow nesting peregrine falcons the opportunity to raise their young without interruption and was completed within budget in the fall of 2008. The system was designed to restrain a 10,000 kg block of rock falling from the upper bluff, striking the talus pile below the rock face and then traveling downslope towards the highway. Block speeds of approximately 20 meters per second can be handled with the system as-designed. This paper reviews the rockfall hazard potential, the remediation design process and the construction details of the final mitigation measures installed at the site.

  • Corporate Authors:

    New York State Thruway Authority

    200 Southern Boulevard, P.O. Box 189
    Albany, NY  United States  12201-0189
  • Authors:
    • Wood, David
    • McKenna, Peter
    • Daneff, Derek
    • Senior, Stephen
  • Conference:
  • Publication Date: 2009

Language

  • English

Media Info

  • Media Type: CD-ROM
  • Features: Maps; Photos; Tables;
  • Pagination: pp 71-88
  • Monograph Title: Proceedings of the 60th Highway Geology Symposium

Subject/Index Terms

Filing Info

  • Accession Number: 01142314
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Oct 21 2009 8:29AM