27950632 Tunnel Construction

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TUNNEL CONSTRUCTIONTUNNEL CONSTRUCTION

Tunnel Construction

BY Dr. Ahmed Abdel-Atty Gab-Allah

(Zagazig University)

الرحيم الرحمن الله الرحيم بسم الرحمن الله بسم

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OUTLINEOUTLINE

1.1. INTRODUCTION.INTRODUCTION.

2.2. TUNNEL CONSTRUCTION SYSTEMS.TUNNEL CONSTRUCTION SYSTEMS.

3.3. TUNNEL CONSTRUCTION IN EGYPT.TUNNEL CONSTRUCTION IN EGYPT.

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1. INTRODUCTION1. INTRODUCTION

Importance of tunnels.Importance of tunnels.

Objective:Objective: Review latest tunnel construction systems.Review latest tunnel construction systems.

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2. TUNNEL CONSTRUCTION SYSTEMS2. TUNNEL CONSTRUCTION SYSTEMS

(a)(a) Cut and Cover System.Cut and Cover System.

(b)(b) Pipe Jacking System (Micro Tunneling).Pipe Jacking System (Micro Tunneling).

(c)(c) Shield Tunneling (TBM).Shield Tunneling (TBM).

(d)(d) New Austrian Tunneling Method (NATM).New Austrian Tunneling Method (NATM).

(e)(e) Immersed-Tube Tunneling System.Immersed-Tube Tunneling System.

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(a) Cut and Cover System(a) Cut and Cover System

Sequence of Construction (Stages 1 to 3)Sequence of Construction (Stages 1 to 3)

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(a) Cut and Cover System(a) Cut and Cover System

Sequence of Construction (Stages 4 to 6)Sequence of Construction (Stages 4 to 6)

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Cut and Cover SystemCut and Cover System

Advantages:Advantages:• Economy for shallow depths (4 - 10 m) and for Economy for shallow depths (4 - 10 m) and for

shorter applications.shorter applications.

• Un-sophisticated labor and equipment required.Un-sophisticated labor and equipment required.

• Adaptability to different conditions.Adaptability to different conditions.

• Simple structural & geotechnical analyses required.Simple structural & geotechnical analyses required.

• Safe environment (ventilation and fire hazard).Safe environment (ventilation and fire hazard).

Disadvantages:Disadvantages:• Possible disturbances to existing facilities.Possible disturbances to existing facilities.

• Practical limitations of depth.Practical limitations of depth.

• Unsuitability under buildings or water. Unsuitability under buildings or water.

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Soil Grouting TechniquesSoil Grouting Techniques

Jet Grouting: Soil Replacement ProcessJet Grouting: Soil Replacement Process

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Slurry Wall ConceptSlurry Wall Concept

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Ground Freezing ConceptGround Freezing Concept

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(b) Pipe Jacking System (Micro Tunneling)(b) Pipe Jacking System (Micro Tunneling)

Schematic RepresentationSchematic Representation

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Preparation ofPreparation ofDriving ShaftDriving Shaft

Jacking PipesJacking PipesUsing Hydraulic JacksUsing Hydraulic Jacks

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Guidance and Positioning UsingGuidance and Positioning UsingLaser-Guided Steering SystemLaser-Guided Steering System

Laser Guide &Laser Guide &Control Control MonitorMonitor

Screen CaptureScreen Capture

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MTBM Break Through MTBM Break Through

Extraction of MTBMExtraction of MTBM

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MTBM - Shields of Different Sizes MTBM - Shields of Different Sizes

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MTBM - Different Shapes of Cutting HeadsMTBM - Different Shapes of Cutting Heads

Dirt cutter headDirt cutter head(clay and silty sand)(clay and silty sand)

Sand shelves Sand shelves

Carbide cutter headCarbide cutter head(soft to medium hard rock) (soft to medium hard rock)

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Pipe Jacking System (Micro Tunneling)Pipe Jacking System (Micro Tunneling)Advantages:Advantages:

• Suitability for almost all types of soil.Suitability for almost all types of soil.

• Large depths with unlimited lengths of drive.Large depths with unlimited lengths of drive.

• High levels of accuracy and safety.High levels of accuracy and safety.

• Wide choice of pipe and joint materials.Wide choice of pipe and joint materials.

• High construction rates.High construction rates.

• Reduced manpower requirements.Reduced manpower requirements.

• Reduced environmental disturbance.Reduced environmental disturbance.

Disadvantages:Disadvantages:• Sophisticated equipment and highly skilled labor.Sophisticated equipment and highly skilled labor.

• Inability to make rapid changes in line or level.Inability to make rapid changes in line or level.

• Very expensive corrective actions, if required.Very expensive corrective actions, if required.

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(c) Shield Tunneling (TBM) (c) Shield Tunneling (TBM)

Cutter HeadCutter Head Tunnel TubeTunnel Tube

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Support Fluid Circulation SystemSupport Fluid Circulation System Tunnel Construction

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Construction SequenceConstruction Sequence Tunnel Construction

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Shield Tunneling (TBM)Shield Tunneling (TBM)Advantages:Advantages:

• Suitability for almost all types of soil.Suitability for almost all types of soil.

• Suitability for wide tunnels (highway, railway, etc.).Suitability for wide tunnels (highway, railway, etc.).

• Large depths ( > 10 m), with unlimited lengths of Large depths ( > 10 m), with unlimited lengths of drive.drive.

• Reducing environmental disturbance and utilities Reducing environmental disturbance and utilities diversions.diversions.

Disadvantages:Disadvantages:• Sophisticated equipment and highly skilled labor.Sophisticated equipment and highly skilled labor.

• Inability to make rapid changes in line or level.Inability to make rapid changes in line or level.

• Very expensive corrective actions, if required.Very expensive corrective actions, if required.

• Difficult structural and geotechnical analyses reqd.Difficult structural and geotechnical analyses reqd.

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ConstructionConstructionSequenceSequence

(d) NATM(d) NATMTunnel Construction

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NATMNATMAdvantages:Advantages:

• Best alternative for non-circular roadway tunnels.Best alternative for non-circular roadway tunnels.

• Suitability for almost all stable to strong ground Suitability for almost all stable to strong ground types, including rock.types, including rock.

• Suitability for a variety of soil conditions. Suitability for a variety of soil conditions.

• Small thickness of tunnel lining, reducing the Small thickness of tunnel lining, reducing the amount of excavation.amount of excavation.

• Economy and speed of construction.Economy and speed of construction.

Disadvantages:Disadvantages:• Highly skilled workers and expert engineers.Highly skilled workers and expert engineers.

• Safety measures for shotcrete application.Safety measures for shotcrete application.

• Ground water freezing and/or soil strengthening Ground water freezing and/or soil strengthening (in case of water-bearing cohesionless soil).(in case of water-bearing cohesionless soil).

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(e) Immersed-Tube Tunneling System(e) Immersed-Tube Tunneling SystemTunnel Construction

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(e) Immersed-Tube Tunneling System(e) Immersed-Tube Tunneling System

Construction Sequence:Construction Sequence:1.1. Dredging the trench in river or sea bottom.Dredging the trench in river or sea bottom.

2.2. Prefabrication of tunnel sections, and sealing ends Prefabrication of tunnel sections, and sealing ends with bulkheads.with bulkheads.

3.3. Floating the sections to the tunnel trench.Floating the sections to the tunnel trench.

4.4. Lowering the sections to seabed.Lowering the sections to seabed.

5.5. Joining the sections together underwater.Joining the sections together underwater.

6.6. Removing the temporary bulkheads.Removing the temporary bulkheads.

7.7. Backfilling the trench.Backfilling the trench.

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Immersed-Tube Tunneling SystemImmersed-Tube Tunneling System

Advantages:Advantages:• Economy (most economical alternative for any type Economy (most economical alternative for any type

of underwater tunnel crossing).of underwater tunnel crossing).

• High construction rates (particularly for steel tube High construction rates (particularly for steel tube tunnels).tunnels).

• Wide variety of different conditions.Wide variety of different conditions.

Disadvantages:Disadvantages:• Casting basin (for concrete box tunnels).Casting basin (for concrete box tunnels).

• Highly skilled and experienced workers.Highly skilled and experienced workers.

• Safety measures for underwater construction.Safety measures for underwater construction.

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DEVELOPMENTS & FUTURE TRENDSDEVELOPMENTS & FUTURE TRENDSIN TUNNEL CONSTRUCTIONIN TUNNEL CONSTRUCTION

Conventional Tunneling:Conventional Tunneling:

Areas Developments

Blast Tunneling

Drilling techniques. Blasting technology. Re-use of excavated material.

Tunneling in Loose

Sand

Injection. High-pressure injection. Soil freezing.

Shotcrete Safety Measures

Special shotcretes without accelerators that reduce concrete solidity.

General Equipment Developments

Advances in diesel motor technology (less pollutants in exhausted gases).

Handling of Groundwater

Two-layer plastic sealing tracks (double water-pressure resistance).

Final Lining in Concrete

Measures for protecting inner concrete linings (to prevent tears).

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Pipe Jacking (Micro Tunneling):Pipe Jacking (Micro Tunneling):• Computerized laser guidance to reduce pipeline Computerized laser guidance to reduce pipeline

misalignment.misalignment.

• Pipe jacking at great depths below the ground, and Pipe jacking at great depths below the ground, and in unstable ground conditions.in unstable ground conditions.

• Pipe jacking over a very long distance.Pipe jacking over a very long distance.

• Lubrication to reduce jacking forces, enabling Lubrication to reduce jacking forces, enabling larger diameter pipes and longer tunneling lengths.larger diameter pipes and longer tunneling lengths.

• Possibility of pushing pipes along a curved line.Possibility of pushing pipes along a curved line.

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Shield Tunneling (TBM):Shield Tunneling (TBM):• Design changes for TBMs to reduce damages to Design changes for TBMs to reduce damages to

lining segments (due to impact of rear shield jacks): lining segments (due to impact of rear shield jacks): Rollers attached to the segments that slide on Rollers attached to the segments that slide on

rails attached to the sidewalls (enabling ideal rails attached to the sidewalls (enabling ideal load distribution, and reducing the wheel loads load distribution, and reducing the wheel loads which impact on the newly placed ring).which impact on the newly placed ring).

• Convertible shield machine:Convertible shield machine: Working in soft rock as a shielded TBM, andWorking in soft rock as a shielded TBM, and Working in soft ground as a compressed air Working in soft ground as a compressed air

shield.shield.

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New Austrian Tunneling Method (NATM):New Austrian Tunneling Method (NATM):• Heavy-duty Roadheader for constructing traffic Heavy-duty Roadheader for constructing traffic

tunnels through the rock.tunnels through the rock.

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3. TUNNEL CONSTRUCTION IN EGYPT3. TUNNEL CONSTRUCTION IN EGYPTMajor Tunnel Projects in EgyptMajor Tunnel Projects in Egypt

Sys. Major Applications Length(m)

Width(or diam.)

(m)Cut and Cover

(Diaphragm Walls)Metro Line 1 (Running Tunnel).Metro Line 1 (Stations).Metro Line 2 (Stations).Al-Galaa Tunnel.Al-Thawra Tunnel.Al-Oroba Tunnel.

4,700*144**1740*600385760

9.0027.00

Variable15.8015.5011.00

Pipe Jacking (Micro Tunneling)

Greater Cairo Wastewater Tunnels.Pedestrian Tunnels.

VariableVariable

VariableVariable

Shield Tunneling(TBM)

Metro Line 2 (Running Tunnel).Ahmed Hamdi Tunnel.

9,3901,640

9.5011.80

NATM Has Not Been Applied

Immersed-Tube Tunneling

Has Not Been Applied

* Total length of cut and cover construction.* Total length of cut and cover construction.** Length of a typical station. ** Length of a typical station.

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Thank you for listeningThank you for listening

Tunnel Construction

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27950632 Tunnel Construction