James Thomson C. Eng

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A New Approach to Constructing Underground
Stations

• James Thomson C. Eng
• Jacked Structures SA
• www.jackedstructures.com

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Jacked Installations for Large Structures

• Some Early Projects
• Modular installation of foundations, abutments
  and piers
• Box Jacking

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Modular Concept
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Wandsworth- 1969
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The Box Jacking Concept
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Brent Cross -1974
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New Concepts

• The Jacked Arch
• The Jacked Deck

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The Jacked Arch Concept
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The Jacked Deck Concept
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Cliffsend Underpass

• A 20m wide 126m long road underpass below rail
  tracks
• Client East Kent CC
• Contractor Volker Fitzpatrick Hochtief JV

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Cliffsend Underpass
Tender Scheme
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Volker Fitzpatrick Hochtief JV
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Cliffsend Underpass
Final Scheme
Volker Fitzpatrick Hochtief JV
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Cliffsend Road Underpass Aerial View
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Cliffsend Road Underpass Jacked Deck Face
Excvation
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Cliffsend Road UnderpassDeck Jacking Installation
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Underground Metro Stations

• Installation by Jacked Arch and Jacked Deck
  Methods

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Metro Stations-Arch Configurations
Top Box with Piles
Modular foundations and Walls
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Metro StationsArch Configurations
Foundation Box
Foundation Tunnel
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Four Platform Arrangement
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Alternative Four Platform Arrangement
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Jacked Deck Concepts
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An underground station piled abutments from a
high level box and a jacked arch
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Application of Jacked Deck to Launch Boxes

• Typically
• 22m -24 m span
• Around 200m long
• Depth varying from 6m-10m

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 Advantages of the Jacked Arch and Deck Approach

• By breaking down the process into elements
  reduces the exposed soil face
• Minimises jacking forces and reaction
  arrangements.
• Continuous support of the excavation with a full
  structural lining
• Surface settlement is minimal
• Use of precast units allows higher quality
  construction

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 Advantages of the Jacked Arch and Deck Approach

• A wide range of geometry and configurations
• Installation to very close line and level
  tolerances
• Methods are applicable to both shallow
• and deep structures
• Provides greater clear spans over much
• longer drive lengths.
• Small launch platform area

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