tunnel construction method
TRANSCRIPT
-
7/29/2019 tunnel construction method
1/36
2nd Seminario Internacional de Tuneles y aplicaciones ITS26 de Marzo de 2010 Buenos Aires
Tunnel Construction Methods:Conventional vs Mechanized
March 26, 2010
Prof. Andre P. Assis, PhD(ITACET / UnB)
Harvey W. Parker, PhD(ITA / Consultant)
-
7/29/2019 tunnel construction method
2/36
2nd Seminario Internacional de Tuneles y aplicaciones ITS26 de Marzo de 2010 Buenos Aires
Huge Diverse Demand for Tunnels Worldwide Motorways & Ring Roads to reduce traffic congestion
Long and/or Deep Road Tunnels to connect populations
By-Pass Historic, Cultural, Scenic, & Congested Locations
Underground Parking
Mass Transit Systems
Public Utilities & Flood Control
City Center Revitalization
Construction Method is Affected by the Purpose
and Numerous other Factors, Especially the
Geology
-
7/29/2019 tunnel construction method
3/36
2nd Seminario Internacional de Tuneles y aplicaciones ITS26 de Marzo de 2010 Buenos Aires
Factors to Consider inSelection of Construction
Method
Geology
Rock or Soil
Mountain or River Crossing
Urban or Rural
Number of Lanes ~ Tunnel Size
Length
Safety & EnvironmentalConstraints
Schedule & Cost
Risk Tolerance
Two Basic Categories
Technical Feasibility
Cost & Schedule
-
7/29/2019 tunnel construction method
4/36
2nd Seminario Internacional de Tuneles y aplicaciones ITS26 de Marzo de 2010 Buenos Aires
Better Exploration & Understanding of Ground Behaviour
Ground/Groundwater Pressures
Evaluation & Control of Induced Movement
Minimize Potential for Damage
Modern Technology Results in Tunnels
Better, Faster, Cheaper, Safer
Quality Mechanization of the construction process
New Generation of Pressurized TBMs TBMs now routinely used in ground conditions considered inappropriate a few years ago
Innovations Provide our Industry with More Choices than just the traditionalChoice Between Conventional vs Mechanized. In Continuous State of Change
Recent Tunnel Engineering Advances ImproveSelection of Construction Method
-
7/29/2019 tunnel construction method
5/36
2nd Seminario Internacional de Tuneles y aplicaciones ITS26 de Marzo de 2010 Buenos Aires
Geology & GeoHydrology
Priority of surface space
Long term (type of infrastructure)
Short term (during construction)
Type, cross-section size and length of the tunnel Location andsurrounding environment of the tunnel. Potential for Public Disruption
Local tradition and experience, schedule, type of contract and
contractual stability
Cost & Schedule
Must PredictProductivity
Labor & Material Costs
Construction Methods and Technology
-
7/29/2019 tunnel construction method
6/36
2nd Seminario Internacional de Tuneles y aplicaciones ITS26 de Marzo de 2010 Buenos Aires
Evaluate on RiskManagement Principles
Select Con
-
7/29/2019 tunnel construction method
7/36
2nd Seminario Internacional de Tuneles y aplicaciones ITS26 de Marzo de 2010 Buenos Aires
Road Tunnel Types
Varies 80' - 103'53'
20'
22
Var
93'+/-
NBSB
53'
Different configurations,technologies, standards
-
7/29/2019 tunnel construction method
8/36
2nd Seminario Internacional de Tuneles y aplicaciones ITS26 de Marzo de 2010 Buenos Aires
Tunnel Size
Alaskan Way, Seattle
~17m OD for Four (4) Lanes
-
7/29/2019 tunnel construction method
9/36
2nd Seminario Internacional de Tuneles y aplicaciones ITS26 de Marzo de 2010 Buenos Aires
Now, Several 3 LaneRoads in ~14m Tunnels
-
7/29/2019 tunnel construction method
10/36
2nd Seminario Internacional de Tuneles y aplicaciones ITS26 de Marzo de 2010 Buenos Aires
A86 in Paris
11.6 m diameter for 4, possibly u ltimately, more lanes!!- small vehicles only, 3m clearance
-
7/29/2019 tunnel construction method
11/36
2nd Seminario Internacional de Tuneles y aplicaciones ITS26 de Marzo de 2010 Buenos Aires
Tunnelling in Soft Ground (Soils)
Cut-and-Cover
TunnellingMethods
Conventional Tunnelling
Special Methods
Mechanized Tunnelling
Conventional CC
Immersed & Other
-
7/29/2019 tunnel construction method
12/36
2nd Seminario Internacional de Tuneles y aplicaciones ITS26 de Marzo de 2010 Buenos Aires
Cut-and-Cover vs Tunnel
-
7/29/2019 tunnel construction method
13/36
2nd Seminario Internacional de Tuneles y aplicaciones ITS26 de Marzo de 2010 Buenos Aires
Difficult to build from surface
Urban constraints (alignmentsdefined by demand andinterferences)
Cost of relocation
Construction costs
Cost of Public Disruption
Cut-and-Cover
-
7/29/2019 tunnel construction method
14/36
2nd Seminario Internacional de Tuneles y aplicaciones ITS26 de Marzo de 2010 Buenos Aires
Door Frame Tunnel in Metro Brasilia
-
7/29/2019 tunnel construction method
15/36
2nd Seminario Internacional de Tuneles y aplicaciones ITS26 de Marzo de 2010 Buenos Aires
"Submerged" Cut-and-Cover:Immersed Tunnels
Mo nt Baker Ridge
-
7/29/2019 tunnel construction method
16/36
2nd Seminario Internacional de Tuneles y aplicaciones ITS26 de Marzo de 2010 Buenos Aires
Mount Baker RidgeSeattle
Stacked-Drift
InnovativeIncrementalconstruction - small
parallel drifts (likebarrel staves)
Inside diameter 19m
Five through lanes
plus pedestrian, bike
Ventilation and lifesafety systems
-
7/29/2019 tunnel construction method
17/36
2nd Seminario Internacional de Tuneles y aplicaciones ITS26 de Marzo de 2010 Buenos Aires
Conve
ntionalT
unnellin
g
-
7/29/2019 tunnel construction method
18/36
2nd Seminario Internacional de Tuneles y aplicaciones ITS26 de Marzo de 2010 Buenos Aires
Tunnelling in Soil
Conventional Tunnelling Sequential Excavation Methods (SEM)
Mechanized Tunnelling Full-Face Excavation
Open-face
Pressured-face TBM
Door Frame or Special Construction
Challenge: Stability & Settlement
Sequential Excavation
-
7/29/2019 tunnel construction method
19/36
2nd Seminario Internacional de Tuneles y aplicaciones ITS26 de Marzo de 2010 Buenos Aires
Sequential ExcavationMethod (SEM)
Low Mobilization time & cost
Rate of Advance slower than TBMbut sometimes competitive in totalproject time
Various, flexible shapes possible
Quality & Workmanship is Crucial
Practice now accepted as safebut image is not universally good
Transitions / off-ramps easier
-
7/29/2019 tunnel construction method
20/36
2nd Seminario Internacional de Tuneles y aplicaciones ITS26 de Marzo de 2010 Buenos Aires
TcnicasAlternativas:
CongelamentoGround
Improvement
and Reinforcement
-
7/29/2019 tunnel construction method
21/36
2nd Seminario Internacional de Tuneles y aplicaciones ITS26 de Marzo de 2010 Buenos Aires
MechanizedTunnelling
General Mechanized
-
7/29/2019 tunnel construction method
22/36
2nd Seminario Internacional de Tuneles y aplicaciones ITS26 de Marzo de 2010 Buenos Aires
General MechanizedSelection Flow Chart
Source: ITA Working Group 14, Mechanized Tunnelling, 2000
-
7/29/2019 tunnel construction method
23/36
2nd Seminario Internacional de Tuneles y aplicaciones ITS26 de Marzo de 2010 Buenos Aires
Pressurized-Face TBMs:
EPB, Slurry and Mix Shield
Sl
-
7/29/2019 tunnel construction method
24/36
2nd
Seminario Internacional de Tuneles y aplicaciones ITS26 de Marzo de 2010 Buenos Aires
EPB vs Slurry
Selection Between
-
7/29/2019 tunnel construction method
25/36
2nd
Seminario Internacional de Tuneles y aplicaciones ITS26 de Marzo de 2010 Buenos Aires
Selection BetweenEPB and Slurry
Not an Easy Question
Past Years: Slurry for Sands; EPB for Silts & Clays
Must know geology and conduct soil tests
Now newer Conditioning Agents injected at the face extend the range of bothmethods of construction
Disk Cutters extend use of both for Boulders & Variable Rock
Slurry TBMs commonly used for higher water pressures
Careful not to create a blow to surface
Face stability is generally more robust with EPB
Other Issues Prediction of Rate of Advance
Abrasion and/or Clogging=maintenance or repair in Interventions
Plant Size & Muck disposal issues
-
7/29/2019 tunnel construction method
26/36
2nd
Seminario Internacional de Tuneles y aplicaciones ITS26 de Marzo de 2010 Buenos Aires
Tunnelling in Rock
Tunnelling
Methods
Drill and Blast
Full-Face TBM
- Gripper
- Double Shield
Partial-Face TBM
-
7/29/2019 tunnel construction method
27/36
2nd
Seminario Internacional de Tuneles y aplicaciones ITS26 de Marzo de 2010 Buenos Aires
Drill and Blast Technology Has Improved Extending
Range of Drill & Blast Projects
Almost no mobilization time. Often Still Used forShorter Projects with variable ground & changing cross
section in remote areas without power
-
7/29/2019 tunnel construction method
28/36
2nd
Seminario Internacional de Tuneles y aplicaciones ITS26 de Marzo de 2010 Buenos Aires
Mechanized Tunnelling in Rock
Challenge:
-
7/29/2019 tunnel construction method
29/36
2nd
Seminario Internacional de Tuneles y aplicaciones ITS26 de Marzo de 2010 Buenos Aires
gCutting Tools and Power
-
7/29/2019 tunnel construction method
30/36
2nd
Seminario Internacional de Tuneles y aplicaciones ITS26 de Marzo de 2010 Buenos Aires
Combined Methods:Conventional and
Mechanized
Tunnelling
-
7/29/2019 tunnel construction method
31/36
2nd
Seminario Internacional de Tuneles y aplicaciones ITS26 de Marzo de 2010 Buenos Aires
Conventional vs. Mechanized Tunnelling Good for Geometric flexibility
Adaptable to broad range ofground conditions
Temporary exposure tounsupported ground
Contractual flexibility
Lower mobilization & plant costs
Suitable for political risk or lack
of contractual stability Lower costs for short tunnels &
where labor is inexpensive
Often slow but not expensive
New Technology is adaptable tomore ground conditions
Less disturbance to theremaining ground
Better and more regular quality(industrial process)
Mechanization better for workers
Safer because generally under
protective shield Faster rate of advance
Significant mobilization & Plantincreasing Cost & Schedule
Costs and schedule more
favorable for longer tunnels
-
7/29/2019 tunnel construction method
32/36
2nd
Seminario Internacional de Tuneles y aplicaciones ITS26 de Marzo de 2010 Buenos Aires
Final Remarks
-
7/29/2019 tunnel construction method
33/36
2nd
Seminario Internacional de Tuneles y aplicaciones ITS26 de Marzo de 2010 Buenos Aires
Final Remarks
Significant increase of the demand of underground structureseverywhere
Two Basic Issues are
Technical Feasibility
Cost & Schedule
Underground structure feasibi lity depends on global costanalyses (construction costs + indirect benefits)
Road Tunnels demand a large cross section
Trend is toward larger diameters
Conclusions
-
7/29/2019 tunnel construction method
34/36
2nd
Seminario Internacional de Tuneles y aplicaciones ITS26 de Marzo de 2010 Buenos Aires
Conclusions
Construction methods and technology depend ongeology, tunnel location, size, local tradit ion etc.
A large number of factors must be considered
Not just a decision between conventional & mechanized
Combination of mechanized and sequential excavationmethods or Special Methods may be beneficial
Conclusions
-
7/29/2019 tunnel construction method
35/36
2
nd
Seminario Internacional de Tuneles y aplicaciones ITS26 de Marzo de 2010 Buenos Aires
Conclusions
Mechanized tunnelling for long tunnels andurban areas (industrial process, quality andcontrol of costs and schedule)
Trend is for greater innovation giving greater applicability anduse of mechanized in the future.
Conventional tunnelling for short tunnels andvariable conditions (geometry, geology and
political flexibility, and inexpensive labour)
-
7/29/2019 tunnel construction method
36/36
2nd Seminario Internacional de Tuneles y aplicaciones ITS26 de Marzo de 2010 Buenos Aires
Mucho Gracias