tunnels and underground excavations

Introduction
History
- Ancient tunnels
- From the Middle Ages to the present
  - Canal and railroad tunnels
  - Subaqueous tunnels
  - Machine-mined tunnels
Tunneling techniques
- Basic tunneling system
  - Geologic investigation
  - Excavation and materials handling
  - Ground support
  - Environmental control
- Modern soft-ground tunneling
  - Settlement damage and lost ground
  - Hand-mined tunnels
  - Shield tunnels
  - Water control
  - Soft-ground moles
  - Pipe jacking
- Modern rock tunneling
  - Nature of the rock mass
  - Conventional blasting
  - Rock support
  - Concrete lining
  - Rock bolts
  - Shotcrete
  - Preserving rock strength
  - Water inflows
  - Heavy ground
  - Unlined tunnels
Underground excavations and structures
- Rock chambers
  - Rock-mechanics investigation
  - Chamber excavation and support
  - Sound-wall blasting
- Shafts
  - Shaft sinking and drilling
  - Shaft raising
- Immersed-tube tunnels
  - Development of method
  - Modern practice
Future trends in underground construction
- Environmental and economic factors
  - Improvement of surface environment
  - Scope of the tunneling market
- Potential applications
- Improved technology

References & Edit History Related Topics

Images & Videos

A small yellow and red rail car sits on narrow tracks inside a curved, wood-lined tunnel of a coal mine in Zabrze, Poland.

Cars driving through the Lincoln Tunnel, with red and yellow lights reflecting off the tiled walls and ceiling.

Gotthard Base Tunnel

A Swiss Federal Railways high-speed train emerges from the concrete portal of the Gotthard Base Tunnel, surrounded by grassy slopes and forested mountains.

Tunnel terminology.

Building a tunnel under the Bosporus strait

At a Glance

default image

A small yellow and red rail car sits on narrow tracks inside a curved, wood-lined tunnel of a coal mine in Zabrze, Poland. — Railroad tunnel Small railroad in a tunnel of a coal mine in Zabrze, Poland.

tunnels and underground excavations

engineering

Written by

Kenneth S. Lane

Fact-checked by

Britannica Editors

tunnels and underground excavations, horizontal underground passageway produced by excavation or occasionally by nature’s action in dissolving a soluble rock, such as limestone. A vertical opening is usually called a shaft. Tunnels have many uses: for mining ores, for transportation—including road vehicles, trains, subways, and canals—and for conducting water and sewage. Underground chambers, often associated with a complex of connecting tunnels and shafts, increasingly are being used for such things as underground hydroelectric-power plants, ore-processing...

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