1. TDOT Rockfall Management System
Saieb Haddad
Geotechnical Engineer
Geotechnical Engineering Section
Tennessee Department of Transportation

2. Old Approach: Falling Rock signs

3. History/Background Most of the “Easy” routes have been developed.
Meanwhile, the previously lightly traveled, more challenging routes have seen increased traffic.
In addition, weathering of rock slopes along existing routes continues…

4. New Approach:
Develop a systematic method of identifying and repairing problem slopes.

5. Tennessee RMS Developed as a collaboration between TDOT, the University of Tennessee, and Virginia Tech

6. Research Project Goals
Identify Hazardous Sites
Develop a Rockfall Hazard Rating System
Statewide Coverage of TDOT Roadways
Ability to prioritize remediation
Inclusion of photos
Database and GIS System

7. Hazard Rating Components
Slope height
Ditch effectiveness
Average Vehicle Risk (AVR)
Roadway Width
Decision Site Distance (%DSD)
Geologic characteristics (Structural/weathering modes)
Block size/volume per event
Presence of water on slope
Rockfall history

8. Rockfall Hazard Management System Training Manual

9. Rockfall Hazard Rating System

10. Preliminary Ratings: A – High Hazard B – Moderate Hazard
C - Low Hazard

11. Failure Modes Planar Sliding Wedge Sliding Toppling
Differential Weathering
Raveling

12. Planar Sliding

13. Wedge Sliding

14. Toppling

15. Differential Weathering

16. Raveling

17. RMS WebMap Application

18. There are just under 2000 A and B Sites Approximately 49% are A Sites
Through 3 years of study and field work we identified just under 2000 A and B sites along state responsible roads.
There are just under 2000 A and B Sites Approximately 49% are A Sites

19. Remedial Measures Often used in combination
Removal – Blasting, scaling, trimming
Restraint – High capacity anchors, rock bolts, anchored wire mesh, retaining walls
Containment – High energy fencing
Control – Draped wire mesh
Widening of ditch/catchment area

20. Removal Blasting

21. Restraint High Capacity Anchors

22. Restraint Bolts/Dowels

23. Pile and Lagging Wall Rock Socket Drilling

24. Restraint Pile & Lagging Wall

25. Pile and Lagging Wall Lagging in Place

26. Containment High Energy Fencing

27. Control Wire Mesh Drape

28. Catchment Area/ Ditch Improvement

29. Challenges
Developing/selecting the most cost-effective remedial measures (maintaining traffic is a critical factor).
Producing construction plans/contract documents
Funding
Keeping database up-to-date

30. Civil Engineers, Infrastructure, Highways, and Public Safety
Highway Engineers traditionally have needed a working knowledge of route geometry/surveying, construction methods, structural design, hydraulics, hydrology, soils and materials.

31. Database & GIS interface
Field data collection
Data synchronization
Return to office or laptop
QA/QC
Database & GIS interface
So they system looks something like this, we gather data in the field using the PDA’s, synchronize with the computer and then our records are available as a GIS layer and in our database.

32. Technical Response

33. Rock Fall/Rock Slide reported to the Geotechnical Staff

35. Site inspection.
Stability assessment.
Highway closure or maintain partial traffic (important decision).
Geotechnical Investigation and Analyses.(could include drilling and testing).
Perform repair design and contract document/ emergency contract.

36. Contractors Prequalification

37. Award Contract Start Construction

38. Skilled labor

39. Roadway closed due to traffic safety and work space.

42. The end