The phase of construction covering the period between the element floating on the surface and installed on its foundation or temporary supports at bed level

Study of the influence on the environment of a construction

Away from the shaft or portal of a tunnel toward the heading.

A device for precisely measuring the inclination from vertical of a casing or structure to which the inclinometer is attached. Lateral displacements at specific locations along a common axis are obtained by multiplying the sines of the inclination angles by the distance separating the location at which the measurements are taken.

Ground that requires support when a tunnel is excavated through it. Essentially the opposite of competent ground or firm ground. See heavy ground for related definition.

A method of construction whereby a short section of an element is constructed, then jacked along to enable the adjacent section to be cast against the previous section.

The "indirect advantages" of underground structures are those that are observed in the following alternative options: (1) either do nothing at all, (2) or opt for another type of solution, which does not oblige to build underground, but which meets the expectations of the various concerned "parties" in a less effective way

Belonging to non living media.

The downward movement of water from the surface into the soil.

Defined as an "underlying foundation or basic framework". Has come to mean a diverse collection of constructed facilities and associated services that support industry, commerce and everyday living

The cost of establishing a facility and putting it into initial operation. See also construction cost

Relatively short-term tunnel or shaft support installed for stability and safety during construction operations, with elements generally left in place and incorporated into the final linig. Initial support is often referred to as primary support.

This phase of construction covers preparation for immersion, the immersion, foundation preparation, backfilling, and completion of the interior works

All items including men, equipment, and supplies required to perform a function.

The interior curve of an arch, as of a tunnel lining.

A value of an amenity or object that is independent of whether there is a financial market for the amenity or object. Such values depend on community or individual attitudes

The lowest section of a tunnel, i.e., the floor. On a circular configuration, it is approximately the bottom 90 degree of the arc of the tunnel. On a square-bottom configuration, it is the bottom of the tunnel.

Process in which the invert of a tunnel is poured separately. See arch pour.

When tunnel ribs tend to move inward at the tunnel invert, compression struts are installed across the invert to resist this movement. These are the invert struts.

Expenditure now, or in the near future, in order to obtain benefits spread over time. Also means the amount of the expenses.