Riverside County - Orange County

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Riverside County - Orange County
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Riverside County - Orange County Major
Investment Study Tunneling Considerations in the
Santa Ana Mountains MIS Policy Committee April
29, 2005
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Riverside County - Orange County
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• Design and Construction Challenges
• Groundwater
• Landfill sites
• Active and non-active faults
• Ventilation

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Riverside County - Orange County
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• Groundwater Issues
• Groundwater levels affect surface ecology
• Tunneling should not affect groundwater levels
• Watertight linings required
• Linings designed for water pressure plus ground
  loads

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• Watertight Lining Options
• Cast in place, waterproof permanent lining
• Segmented pre-cast concrete lining

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Drill Blast Tunnel with Waterproof Permanent
Lining

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TBM with Segmented, Pre-cast Concrete Lining
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Watertight Segmental Concrete Tunnel
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How a Segment Gasket Works

• No Gasket Compression
• Start of Gasket Compression
• 75 Gasket Compression

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• Groundwater Design Challenges
• Groundwater pressures impact approach to
  construction
• Tunnel diameter of 46 feet limits allowable
  groundwater pressure to a tunnel depth of 700
  feet below groundwater surface
• Practical limit of 32 inches for segmental liner
  thickness

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Influence of Tunnel Diameter Depth of
Groundwater
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Riverside County - Orange County
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• Challenges of Tunneling
• Near Landfill Sites
• Face stability problems in tunnel excavation
• Potential of encountering contamination
• Potential damage to landfill lining
• Long term durability and contamination risks

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Riverside County - Orange County
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• Active and Non-active Faults
• Non-active faults characterized by stability or
  water ingress problems
• Active faults characterized by potential for
  large movements
• Elsinore fault active, last movement in 1910

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Riverside County - Orange County
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• Ventilation Design Considerations
• Smoke control in case of fire
• Air quality within the tunnel
• Quality of air discharged

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Riverside County - Orange County
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• Ventilation Options
• Longitudinal (Nozzles, Central or Jet Fans)
• Fully Transverse (supply and exhaust)
• Semi-Transverse (supply or exhaust)

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Riverside County - Orange County
Longitudinal Ventilation Longitudinal
Ventilation with Central Fans Saccardo
Nozzle Longitudinal Ventilation with Jet
Fans Longitudinal Ventilation with
Saccardo Nozzle Shaft
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Riverside County - Orange County
Fully Transverse Ventilation Fully
Transverse Ventilation with Supply and Exhaust
Systems
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Riverside County - Orange County
Semi - Transverse Ventilation Semi-Transverse
Supply Ventilation System Semi-Transverse
Exhaust Ventilation System
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Possible Ventilation System for Deep Tunnel
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Riverside County - Orange County
Possible Ventilation System for Deep
Tunnel Possible Ventilation Shaft
Layout
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