Shift superintendent.

Continuous horizontal members along the sides of the tunnel at or near the spring line, when a top heading or multiple headings is driven to support arch sets. Often two I beam are used for wall plates. After excavating the bottom heading, supports are installed to support the wall plate from the mud sill.

Cables used to move elements. Warping is the act of moving elements using warps, usually out of a narrow channel or dock.

Polluted water that has to be eliminated through the drainage system.

Contamination of a liquid effluent which needs treatment before disposal

Criteria and specifications of chemical, physical and bacterial constituents of water supply, depending on its use for domestic, industrial or agricultural purposes; determination of organic and inorganic constituents, acidity, specific electrical conductance, temperature, colour, turbidity, odour, taste, coliform organisms.

A skin provided external to the immersed tunnel to improve the watertightness of concrete. The membrane may be of steel or other more flexible materials.

Special component embedded in concrete construction joints to reduce the permeability of the joints.

A measure of the capability of a tunnel to resist the penetration of water (leakage)

Shotcrete (sprayed concrete) in which all of the ingredients, including water and fibers, are mixed then conveyed through the delivery lhose, either pneumatically or by positive displacement, then projected at high velocity to the surface being shot.

A steeply inclined passageway between two underground workings.