TDOT Rockfall Management System Saieb Haddad Geotechnical Engineer Geotechnical Engineering Section...
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Transcript of TDOT Rockfall Management System Saieb Haddad Geotechnical Engineer Geotechnical Engineering Section...
TDOT Rockfall ManagementSystem
Saieb Haddad
Geotechnical Engineer
Geotechnical Engineering Section
Tennessee Department of Transportation
Old Approach: Falling Rock signs
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…
New Approach:
• Develop a systematic method of identifying and repairing problem slopes.
Tennessee RMSDeveloped as a collaboration between TDOT, the
University of Tennessee, and Virginia Tech
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
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
Rockfall Hazard Management System Training Manual
Rockfall Hazard Rating System
Preliminary Ratings:
A – High Hazard
B – Moderate Hazard
C - Low Hazard
Failure Modes
• Planar Sliding• Wedge Sliding• Toppling• Differential Weathering• Raveling
Planar Sliding
Wedge Sliding
Toppling
Differential Weathering
Raveling
RMS WebMap Application
There are just under 2000 A and B SitesApproximately 49% are A Sites
Remedial MeasuresOften 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
RemovalBlasting
RestraintHigh Capacity Anchors
RestraintBolts/Dowels
Pile and Lagging WallRock Socket Drilling
RestraintPile & Lagging Wall
Pile and Lagging WallLagging in Place
ContainmentHigh Energy Fencing
ControlWire Mesh Drape
Catchment Area/Ditch Improvement
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
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.
Return to office or laptop
Data synchronization
Database & GIS interface
Field datacollection
QA/QC
Technical Response
Rock Fall/Rock Slide reported to the Geotechnical Staff
• 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.
Contractors Prequalification
Award Contract Start Construction
Skilled labor
Roadway closed due to traffic safety and work space.
The end