Price paid for access to a highway facility

The upper portion of a tunnel, often extending from springline to crown, pre-excavated in order to install arch support before opening the tunnel to full size.

A tunnelling method in which a complete top heading is excavated end-to-end before excavation of the lower bench is begun. Distinguished from heading-and-bench construction.

Underground construction system in which the ground slab is finished quickly and construction continues below this slab to finish the underground structure. This can allow a quick return of the surface to a needed use or a shorter overall building time.

Several phases of construction of immersed tunnels may involve towing. The main tow is to the location where outfitting for immersion is to be done, usually close to the immersion point. The final tow it to the immersion point.

The rail structure providing a single line of railway operation

Coming or going of persons or goods

Overloaded traffic conditions causing delays. Usually referring to vehicular trafic

Time lost in a journey from normal or potential conditions

The time to complete a journey or portion of a journey. The choice of start and end points for journey comparisons may affect analyses

Concrete directionally placed under water through a steel or plastic pipe.

The non-immersed structure abutting the first and last immersed tunnel elements.

Circular metal or pre-cast concrete piles to line tunnels or shafts

Roadway, track and service cells are each often referred to as tubes. Also used in the jargon expression immersed tube tunnel, meaning immersed tunnel (both circular and box shaped), perhaps originally intended to imply an immersed tunnel with a circular cross-section.

A tunnel, strictly speaking, is a subterranean passage open at both ends. Often used as a synonym for adit, drift or gallery

Layout approach of the geometrical transition between the surface road and the underpass

A machine that excavates a tunnel by drilling out the heading to full size in one operation and often called a mole. A full-face excavator

A machine that excavates a circular tunnel by cutting and/or abrading the heading to full size in one operation. Also referred to as a mole. The term has so commonly been associated with rock tunnelling that when a TBM is used in earth it is often prefaced by qualifier "soft-ground".

Welded circular steel plate sections placed inside the concrete lining to resist internal pressure and for watertightness.

Made using tunneling / boring techniques. This implies excavation with only limited access points from the surface