| Term | Definition |
|---|---|
| Early strength |
Strength of shotcrete usually as developed at various times during the first few hours after shotcrete placement.
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| Earth tunnel |
A tunnel driven in relatively easily excavated earth or soil rather than in rock. Also commonly referred to as a soft-ground tunnel.
|
| Earth-balance shield |
A close-face shield designed for tunnelling in fine-grained soils by trapping excavated materials against the face and removing them at a rate slow enough to maintain pressures that counterbalance earth pressures, stabilize the face, and prevent ingress of water.
|
| Economic good |
Thing recognized as appropriate to the satisfaction of a human need and available dor this satisfaction but of which the quantity availble is less than that giving full satisfaction of the need.
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| Economic players |
Parties (groups) with an economic involvement in a project. May exclude those economically affected by a project but with no direct involvement.
|
| Ecosystem |
Community of alive beings that have a relationship.
|
| Element |
A length of tunnel that is floated and immersed as a single rigid unit.
|
| Elephant's feet |
Enlarged bearing areas at the bases of partially constructed linings, normally of the crown section
|
| Elevated |
Constructed aboveground -- typically on a raised structure
|
| Embodied energy |
The energy necessary to extract and process raw materials and then to construct a manufactured material or structure. Represents an initial energy investment in that material or structure
|
| Emissions |
Quantity of a substance that is thrown to the air.
|
| Employee |
A person paid to work for a company or government entity
|
| End of Tunnel Element |
(1) Primary or Inboard End: The end of the tunnel element that is to be connected first. This end will face either the previously immersed and adjoining element, or the terminal structure. This end is usually the end equipped with the immersion gasket. (2) Secondary or Outboard End: The other end of the tunnel element.
|
| Energy conservation |
The saving of energy by one project alternative in comparison with another. In complete analyses, this may include an analysis of the embodied energy involved in constructing and disposing of the facility at the beginning and end of its useful life
|
| Environment |
A general term used to describe the form and quality of the surroundings for a person or place. Usually has a strong connotation for the natural aspects of the surroundings
|
| Environmental accounting |
An analysis of the full environmental impact of a project or material from source of raw material through eventual disposal. Based on a global accounting rather than only local effects
|
| Environmental aspect |
Activity or action that could cause an impact on the environment.
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| Environmental burden |
The negative environmental impacts of a project or material used in a project
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| Environmental elements |
Parts or elements of the environment that could be modified by the construction activities.
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| Environmental impact |
Damage on the environment caused by an activity.
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