One of a number of tunnels driven sequentially and in parallel. They are progressively connected one with another to form a single tunnel of larger cross-section. May also be called drifts

Drill jumbo which has an open space in the center large enough for muckers, cars, and locomotives to pass through the jumbo; supported by separate rails, tracks, or tires.

A device that acts as a seal between two contacting surfaces.

(5) Temporary Immersion Gasket: This is usually an extruded rubber section that acts as a seal when it is compressed. After completion of the permanent joint, the seal is no longer needed. This type of gasket is commonly used in the United States.

(4) Soft-nosed Gasket: See Gina Gasket, above.

(3) Omega Gasket or Seal: This seal, shaped like the Greek letter Omega (W) is installed across flexible immersion joints from within a tunnel after immersion and joining. It may form a secondary permanent seal or it may become the primary seal. It is bolted to the internal faces each side of the joint. It may be replaced in a similar manner on an as-needed basis. Because of its shape, it can sustain fairly large longitudinal and transverse movements at the joint.

(2) Gina Gasket: A proprietary form of gasket used to seal immersion joints, particularly on concrete tunnels. It consists of a full-bodied rubber section able to transfer large compression forces, and a soft nose able to provide an initial seal under low compression. For binocular sections, each circular tunnel usually has its own gasket around the perimeter, whereas most other forms of tunnel use a single gasket around the external perimeter. The gasket provides a temporary seal and compression contact face during immersion installation, remains in place, and may provide a permanent seal at flexible joints.

(1) A device that acts as a seal between two contacting surfaces.

Usually either hinged to a wall or floating, this structure is used to close off the fabrication facility from the adjacent water to allow dewatering of the facility.

Methods to acquire information about properties of bedrock, soil and groundwater

Increase of the temperature of the earth from the surface downwards, averaging about 1 degree Farenheit for each 60 feet

A steel (lattice) arch normally erected at regular centres as the tunnel advances. It is sequentially erected from component parts as the lining is progressively formed and encapsulated within the shotcrete. It is normally provided in the crown section to provide temporary protection to miners from the risk of collapse. The girders can be fully circumferential.

An analysis that attempts to treat issues on a global rather than local, regional or national basis.

Finely abraded or pulverized rock particles and claylike altered rock found between the walls or within the fractures of a fault or shear zone; the result of grinding movements that crushe the affected rock.

Mechanical device for taking up and holding excavated soil / rock to be lifted or moved.

The overall vertical alignment of an underground opening.

Locally, the same as "gradient", i.e., the rate of incline or decline in terms of degrees from the horizontal, percent of rise to the horizontal distance, or in feet of vertical projection per mile of horizontal projection.

The crossing of two transportation elements one above the other rather than at a surface intersection

The level of the ground surface

See Screeded Foundation.