1. Elm Street Rockslide Repairs Montpelier City Council Meeting February 22, 2006

2. Rockslides Happen

3. THE PROBLEM:  Toppling of steeply dipping rock strata  Sliding of toppled strata on lower slope

4. Historic Slide Area  Slide scarp (light gray) at right crest, debris at toe of slope.  Lower chevron toppled debris set in motion

5. Historic Slide Area

6. Slide Mechanisms  Flexural Toppling at Crest  Lower chevron toppled debris set in motion

7. Slide Mechanisms  Flexural Toppling at Crest  Lower chevron toppled debris set in motion

8. Proposed Repairs  Stabilize Flexural Toppling at Crest with Un-tensioned Rock Bolts called Rock Dowels;  Scale slide debris and chevron toppled debris on the lower slope that could provide a source of future slide debris;  Stabilize and repair Cliff Street slide scarp with a rock nail retaining wall;  Stabilize adjacent steep soil slopes with a Tecco® soil retention system; and  Reduce the potential for further toppling with spot rock dowels, scaling, tree removal, dental shotcrete.

9. Project Progress  Temporary Rockfall Protection Measures

10. Project Progress  Stabilization of Cliff Street Slide Scarp  Drainage Installation and Shotcrete Facing

11. Project Progress  Utilities Relocation  Shotcrete Application  Monitoring of Loose Rocks

12. Project Progress  Layout, Anchor installation and Setup of Rockfall Catch Fence

13. Project Progress  Rock Nail Installation

14. Project Progress  Water Main Relocated

15. Project Progress  A Large Boulder…..

16. Project Progress  Highwall Scaling and preparation of foundation area for new retaining wall.

17. Project Progress  Cliff Street Reopened February 14th.

18. Project Progress  First layer of shotcrete and rock nails installed,  Scaling progressing downslope

19. What’s Next?  Completion of the retaining wall  Rock Bolting of the Highwall  Drain hole drilling

20. What’s Next?  Stabilization of soil slope transitions - Tecco  Final Scaling  Installation of Concrete Barrier and paving on Cliff Street.

21. Acknowledgements  Tom McArdle – DPW  Police Chief Doug Hoyt, Department and Fire Department  Mayor Mary Hooper & City Manager William Fraser  VTrans – Tom Eliassen, Chris Benda, Bill McManus  Vermont Geological Survey – Larry Becker and Jon Kim  Vermont Survey and Engineering  Dubois Construction Special Thanks to Montpelier and State Folks