City of Winnipeg SOUTHWESTERN RAPID TRANSIT CORRIDOR

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City of WinnipegSOUTHWESTERN RAPID TRANSIT
CORRIDOR

• Bidder Meeting
• October 16th, 2009

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Site Location
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Field Investigations

• - Klohn Krippen (2003) - Geotechnical
• 4 deep test holes, 1 shallow
• Groundwater monitoring
• Laboratory testing
• AECOM (2009) - Geotechnical
• 2 deep test holes ( rock coring)
• Groundwater monitoring
• Laboratory testing
• AECOM (2009) Hydrogeological
• Two test wells drilling
• Field pump tests

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Location of Test Holes
TW 1
TW 2
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Soil Stratigraphy
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Field and Lab Results
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Groundwater Conditions

• Clay 2 m below ground, Elv. 231 m
• Bedrock/Till Elv. 224 to 226 m
• Impact on
• Excavation stability
• Global stability
• Seepage

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Geotechnical Concerns

• Foundation type
• Rebound, heave and settlement
• Retaining walls
• Base heave
• Temporary shoring and excavation plan

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Bearing capacity and foundation type

• Raft foundation
• Design based on the concept of floating
  foundation
• Bearing capacity and settlement pressure are
  defined

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Rebound, Heave and Settlement
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Retaining walls

• Reinforced Concrete U-shaped section
• Reinforced Concrete Cantilever wall
• Coulomb Theory
• Design for surcharge from compaction during
  construction
• Design for live load surcharge from Cooper E90
  loading

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Base heave
Clay
h
Wclay
Till/Bedrock
FS Wclay /
?w h
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TYPICAL
EXTREME HISTORICAL
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Temporary shoring and Excavation plan

• Cut and cover construction
• Staged construction, Stage I and II
• Site constrains
• Limited space
• Utilities
• Private property
• Proximity to CN tracks
• Excavations plan include
• Open excavation
• Cantilever / Braced Shoring
• Combination of shoring and open excavation

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Temporary shoring and Excavation plan

• Excavation configurations
• Open Excavation, up to 6 m cut
• Other geometry lt 6m cut

1
4
3
3
1
3
3
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Temporary shoring and Excavation plan

• Excavation configurations
• Braced Shoring up to 9.5 m

4.6 Min
9.5
5
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Temporary shoring and Excavation plan

• Excavation configurations
• Combination of Braced Shoring and Open excavation

varies 5 m Min.
4.6
7m bench 5 m Crane pad
3
1
2-3
varies 7 Max.
3 - 5
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Temporary shoring and Excavation plan Lateral
Loads from Surcharge
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Temporary shoring and Excavation plan

• Base Instability analogous to bearing capacity

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Global Stability

• - Stress stability coupled finite element
  analysis
• Locally acceptable soil parameters
• Account for excavation unloading
• Model train loading
• Design objective FS 1.30

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Stability output
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Stability output
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Stability output
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Stress-Deformation Analysis
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Stress-Deformation Analysis
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Performance Monitoring Program

• Instrumentation will be installed to monitor
• Displacement of railway tracks
• Displacement of shoring system
• Horizontal subsoil displacement
• Excavation heave
• Groundwater levels

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• THANK YOU