| Term | Definition |
|---|---|
| Submersion |
The part of the installation activity that takes an element from being afloat to sitting on the bed
|
| Subsurface |
Underground, beneath the surface
|
| Subsurface / Underground planning |
Planning activity aiming to divide subsurface for human activities according to the ecological, economical and technical point of view
|
| Subsurface mapping |
Mapping of subsurface spaces (results of underground human activities) from the various point of view (location, dimensions, geological conditions, environmental impact, actual technical state, reusing possibilities, etc.)
|
| Subway |
A underground pedestrian tunnel beneath a street. A metro system
|
| Sump |
Sumps (reservoirs) are provided at the portals and at low points (nadirs) to contain quantities of run-off and leakage water compatible with storage requirements of the pumps provided. Oil-water separators are usually required, and sumps within a tunnel most often discharge to portal sumps.
|
| Suspended Slab |
Slab provided to span across a cell above a space, such as ceiling and roadway slabs when ventilation ducts above or below the roadway are used.
|
| Sustainable development |
The type of overall development (economic, social, energetic, environmental, etc.) which makes it possible to meet the needs of the present generation without jeopardizing those of the future generations.
|
| Swell |
An increase in rock volume when it passes from the intact to the broken state
|
| Swelling |
Increase in volume upon exposure to water
|
| Swelling ground |
Material that expands in volume by absorbing or adsorbing water so that it tends to move into a tunnel opening or to exert great pressure upon the supports.
|
| Swing shift |
Shift that extends from 4:00 pm to midnight. See day shift.
|
