Design of Segmental Lining for Waterview Project, Auckland ... · PDF fileDesign of Segmental...
Transcript of Design of Segmental Lining for Waterview Project, Auckland ... · PDF fileDesign of Segmental...
Design of Segmental Lining for Waterview
Project, Auckland (NZ)
R. Mahajan, A. Kuras, S. Pradhan Parsons Brinckerhoff, Australia
Well-Connected Alliance – Waterview Connection
Content • Project overview • Geotechnical conditions • Key features of lining • Overview of design approach • Cam-pocket system design • Cross passage opening design • Performance • Conclusions
Well-Connected Alliance – Waterview Connection
Project Overview Overview
• Location - Auckland (NZ)
• Project Cost - NZ$1.4b
• Project Objective - Complete western ring route
• Project Model - Alliance (NZTA client)
• Delivery by - Well-Connected Alliance
• Tunnel Construction - Commenced 2013
• Commissioning - April, 2017
Tunnel (key elements)
• TBM - 10th largest EPBM machine
• Diameter - 14m (largest tunnel in Australia-Pacific)
• Reinforcement - World’s largest SFRC lining
Well-Connected Alliance – Waterview Connection
Geological Long-Section
Soil
Rock
Typical Su =50-250 kPa
Typical UCS EU1= <1 MPa EU2= 1- 5 MPa EU3= >5 MPa Vb=50-150 MPa
South Portal North Portal
Note- gradient exaggerated for illustration purpose
2
1
3
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Key Lining Features • Segmentation
9+1 key segment
450mm thick lining and 2m wide rings
3 types of ring (L, R and S) with 30mm taper
• Circumferential connection
3 spear bolt connections per segment
28 nos. of shear cams at spear bolts locations
• Longitudinal connection
2 spear bolt connections per joint
Total of 20 spear bolts per ring
• Reinforcement
3 types of reinforcement
Combination of SFRC and RCC segments
• Waterproofing
EPDM gaskets
Well-Connected Alliance – Waterview Connection
Layout
38.570
39.420
28 Shear cams & Spear bolts
Standard Segment
2 spear bolts
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Design Approach Optioneering
• Ring configuration - ‘8+1’ vs ‘9+1’
• Concept of cam pocket system ?
• Number of thrust rams
• Method of reinforcement
• Connectors- spear bolts vs dowels
Stage Lining design steps
1 Lining configuration and geometry assessment
2 Construction phase assessment
3 Structural capacity assessment
4 Waterproofing assessment
5 Stability assessment
6 Earthquake assessment
7 Fire assessment
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Analytical Assessment • Traditional closed form solution approach • 2D coupled bedded beam approach • 3D coupled plate element approach
2D beam spring model 3D plate element model
birdmouthing
Rigid Link
Well-Connected Alliance – Waterview Connection
SFRC Design Strengths • Minimum characteristic flexural strength (peak) target = 4.8 MPa
• Minimum characteristic residual flexural strength target = 3.0 MPa
• Minimum characteristic indirect tensile strength target = 3.8 MPa
Beam test (bending) Cylinder test (splitting)
Well-Connected Alliance – Waterview Connection
Segment Reinforcement
Well-Connected Alliance – Waterview Connection
Cam-Pocket System
Cams Pockets
Well-Connected Alliance – Waterview Connection
Why Proposed? Introduced to restrict differential ring deformation along section under
GNR (~8m cover) by creating structural interlock
Aids with minimising lipping and stepping during construction
providing greater surety of watertightness
Well-Connected Alliance – Waterview Connection
Cam Configuration
350
150
30
Profile
Clearance
5mm vertical clearance on inclined face & 2mm horizontal clearance
Takes account of lipping, birdmouthing of longitudinal joint & packing of
circumferential joint
Well-Connected Alliance – Waterview Connection
Analytical Assessment Capacity
2D/3D FEM results compared with past testing
2D FEM calculated failure load of 282kN
3D FEM calculated failure load of 400kN
Testing results suggest failure load of ~500kN 2D FEM
Testing
Well-Connected Alliance – Waterview Connection
XP Opening
Lintel Beam
Jambs
Vertical Wedges
Sill Beam
Connection
Vertical Stiffeners
Horizontal Stiffeners
Horizontal Wedges
Skin Plate
Rigid connection
Temporary Panels
Well-Connected Alliance – Waterview Connection
XP Optioneering • Configuration
• Circumferential connections
• Durability / Fire protection
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Steel Opening Canopy tubes
grouting tubes
Vertical wedge
Horizontal wedges
Temporary panels
1
2
3
4
5
6
Well-Connected Alliance – Waterview Connection
Lining Performance • Minimal stepping/ lipping between segments
• Tunnel generally dry • High tensile capacity of SFRC results in few cracks
observed for Type 1 segments
• 95% SB tunnel completed
Well-Connected Alliance – Waterview Connection
Conclusions • Success of lining design hinges on communication
between design and construction teams • Leverage off the experiences of Obayashi technical
department has proven to be invaluable • Optimisation of design relies on applying a range of
analytical methods • SFRC proven for large diameter tunnels • Cam pocket system introduces benefits
Well-Connected Alliance – Waterview Connection
Thank You