tunnelling scope, construction techniques and necessity
1. TUNNELING IN ROCK MASS:
(NECESSITY, SYSTEMATIC APPROACH,
PLANNING AND CONSTRUCTION)
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APPLIED MECHANICS DEPARTMENT
SVNIT,SURAT
GUIDED BY : SUBMITTED BY:
PROF S.KUMAR JOSHI AKSHAY
p16SM006
2. UNDERGROUND OR UNDERWATER
PASSAGE WAY, DUG THROUGH THE
SURROUNDING SOIL/EARTH/ROCK AND
ENCLOSED EXCEPT FOR ENTRANCE
AND EXIT,
TYPE BASED ON APPLICATION
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VEHICULAR
TUNNEL
RAIL
TUNNEL
CANAL
TUNNEL
3. NECESSITY
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To minimize land acquisition costsTo minimize land acquisition costs
To avoid steep grades and longerTo avoid steep grades and longer
routes.routes.
To avoid impact on
environmentally sensitive areas.
To avoid impact on cultural
heritage
4. SYSTEMATIC APPROACH & PLANNING
STAGES OF PLANNING
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PRE-PLANNING
DETAIL PLANNING
MONITARING AND
CONTROL
5. PRE-PLANNING
Justification for taking up the project
Objectives of the project
Alignment Selection
Investigation
Examining alternatives
Cost benefit analysis
Financial planning
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6. ALIGNMENTALIGNMENT SELECTIONSELECTION
The Alignment of the Tunnel must be consistent with
the alignment of the roadway leading to it.
The Alignment must consider factors like the sight
distances, minimum turning radius and design
speeds in its design.
Except for maintenance reasons, two way roads
should be discouraged in a single tube of tunnel, for
safety reasons.
Pedestrian and Cyclist use of tunnels should be
discouraged except a special passage is designed for
them.
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7. INVESTIGATIONSINVESTIGATIONS
Several investigations are required at the preliminary,
design and construction phases of a tunnel project. The
processes are highlighted below:
Collection and Review of Available Information for a
general knowledge of the area (Existing Topographical,
hydrological, Geological, Geotechnical, Seismic,
Environmental, Zoning etc)
Topographic and Aerial Photographs
Preliminary Surveys
Water Well Logs
Hydrographic Surveys
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8. Identification of Underground Structures and
Obstacles
Geologic Mapping
Subsurface Investigations
Test Borings and Sampling
Soil and Rock Identification and Classification
In - situ Tests •Geophysical Tests •Seismic Wave
Propagation •Laboratory Tests •Groundwater
Investigation •Pumping Tests
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10. 10
11.. TUNNEL CONSTRUCTION SYSTEMSTUNNEL 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 MethodNew Austrian Tunneling Method
(NATM).(NATM).
(e)(e) Immersed-Tube Tunneling System.Immersed-Tube Tunneling System.
Tunnel Construction
11. 11
(a) Cut and Cover System(a) Cut and Cover System
Sequence of Construction (Stages 1 to 3Sequence of Construction (Stages 1 to 3 ))
Tunnel Construction
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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)
Tunnel Construction
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Cut and Cover SystemCut and Cover System
AdvantagesAdvantages::
• Economy for shallow depths (4 - 10 m) and for
shorter applications.
• Un-sophisticated labor and equipment required.
• Adaptability to different conditions.
• Simple structural & geotechnical analyses
required.
• Safe environment (ventilation and fire hazard)
• DisadvantagesDisadvantages::
• Possible disturbances to existing facilities.
• Practical limitations of depth.
• Unsuitability under buildings or water.
Tunnel Construction
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Soil Grouting TechniquesSoil Grouting Techniques
Jet Grouting: Soil Replacement ProcessJet Grouting: Soil Replacement Process
Tunnel Construction
18. GUIDANCE AND POSITIONING USING
LASER-GUIDED STEERING SYSTEM
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Laser Guide &Laser Guide &
ControlControl
MonitorMonitor
Screen CaptureScreen Capture
Tunnel Construction
19. MTBM - SHIELDS OF DIFFERENT
SIZES
DIA. RANGES FROM 0.5M TO 3M
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Tunnel Construction
20. MTBM - DIFFERENT SHAPES OF
CUTTING HEADS
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Dirt cutter headDirt cutter head
(clay and silty(clay and silty
sand)sand)
Sand shelvesSand shelves
Carbide cutter headCarbide cutter head
(soft to medium hard(soft to medium hard
rockrock))
Tunnel Construction
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Pipe Jacking System (Micro TunnelingPipe Jacking System (Micro Tunneling
AdvantagesAdvantages::
• Suitability for almost all types of soil.
• Large depths with unlimited lengths of drive.
• High levels of accuracy and safety.
• Wide choice of pipe and joint materials.
• High construction rates.
• Reduced manpower requirements.
• Reduced environmental disturbance.
• DisadvantagesDisadvantages::
• Sophisticated equipment and highly skilled
labor.
• Inability to make rapid changes in line or level.
• Very expensive corrective actions, if required
Tunnel Construction
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(c) Shield Tunneling (TBM)(c) Shield Tunneling (TBM)
Cutter Head Tunnel Tube
Tunnel Construction
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Shield Tunneling (TBM)Shield Tunneling (TBM)
AdvantagesAdvantages::
• Suitability for almost all types of soil.
• Suitability for wide tunnels (highway, railway,
etc.).
• Large depths ( > 10 m), with unlimited lengths
of drive.
• Reducing environmental disturbance and
utilities diversions.
Tunnel Construction
25. DisadvantagesDisadvantages::
• Sophisticated equipment and highly
skilled labor.
• Inability to make rapid changes in line or
level.
• Very expensive corrective actions, if
required.
• Difficult structural and geotechnical
analyses reqd..
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26. 26
(d)(d) New Austrian Tunneling Method (New Austrian Tunneling Method (NATM)NATM)
Tunnel Construction
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NATMNATM
AdvantagesAdvantages::
• Best alternative for non-circular roadway
tunnels.
• Suitability for almost all stable to strong
ground types, including rock.
• Suitability for a variety of soil conditions.
• Small thickness of tunnel lining, reducing the
amount of excavation.
• Economy and speed of construction.
Tunnel Construction
28. DisadvantagesDisadvantages::
• Highly skilled workers and expert
engineers.
• Safety measures for shotcrete
application.
• Ground water freezing and/or soil
strengthening (in case of water-bearing
cohesionless soil).
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30. 30
(E) Immersed-Tube Tunneling System(E) Immersed-Tube Tunneling System
Construction SequenceConstruction Sequence::
1. Dredging the trench in river or sea bottom.
2. Prefabrication of tunnel sections, and sealing
ends with bulkheads.
3. Floating the sections to the tunnel trench.
4. Lowering the sections to seabed.
5. Joining the sections together underwater.
6. Removing the temporary bulkheads.
7. Backfilling the trench.
Tunnel Construction
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Immersed-Tube Tunneling SystemImmersed-Tube Tunneling System
AdvantagesAdvantages::
• Economy (most economical alternative for any
type of underwater tunnel crossing).
• High construction rates (particularly for steel
tube tunnels).
• Wide variety of different conditions.
DisadvantagesDisadvantages::
• Highly skilled and experienced workers.
• Safety measures for underwater construction..
Tunnel Construction
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DEVELOPMENTS & FUTURE TRENDSDEVELOPMENTS & FUTURE TRENDS
IN TUNNEL CONSTRUCTIONIN TUNNEL CONSTRUCTION
Conventional TunnelingConventional 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).
Tunnel Construction
