Umbrella Arch
The umbrella arch is a temporary support system forming a structural umbrella from the insertion of an assortment of longitudinal support members installed from within the tunnel, above and around … Continue reading
Drill and Blast Method
Drill and blast method is mostly used method for the excavation throughout the world. The method can be used in all types of rocks and the initial cost is lower … Continue reading
Ground Anchor
A prestressed grouted ground anchor is a structural element installed in soil or rock that is used to transmit an applied tensile load into the ground. Grouted ground anchors, referenced simply … Continue reading
Jet Grouting
Jet Grouting is a versatile erosion based system used to create in situ engineered geometries of soil-cement generally with limited required access. Jet Grouting creates in-situ columns of grouted soil … Continue reading
Submerged Floating Tunnel
Tunnels in water are by no means new in civil engineering. Since about 1900, more than 100 immersed tunnels have been constructed. Bridges are the most common structures used for … Continue reading
Immersed Tube Tunnel
Immersed tube, also called Sunken Tube, technique of underwater tunneling used principally for underwater crossings. The method was pioneered by the American engineer W.J. Wilgus in the Detroit River in … Continue reading
Sheet Pile Wall Construction
Sheet pile walls are retaining walls constructed to retain earth, water or any other filling materials. These walls are thinner in section compared to masonry walls. Sheet pile walls are … Continue reading
Secant Pile Wall Construction
Secant pile walls are formed by constructing intersecting reinforced concrete piles. The secant piles are reinforced with either steel rebar or with steel beams and are constructed by either drilling … Continue reading
Diaphragm Wall Construction
Diaphragm wall is a continuous wall constructed in ground in to facilitate certain construction activities, such as: As a retaining wall As a cut-off provision to support deep excavation As … Continue reading
New Austrian Tunneling Method (NATM)
The New Austrian Tunneling method (NATM) was developed between 1957 and 1965 in Austria. It was given its name in Salzburg in 1962 to distinguish it from old Austrian tunnelling … Continue reading
Tunnel Boring Machine (TBM)
A tunnel boring machine (TBM) also known as a “mole“, is a machine used to excavate tunnels with a circular cross section through a variety of soil and rock strata. … Continue reading
Tunnelling Terms
Accelerator A substance added to concrete/shotcrete to accelerate setting. Adit A tunnel driven from ground surface to provide access to or drainage from underground workings; a length of tunnel driven … Continue reading
Cut and Cover
Construction Methodology In a cut and cover tunnel, the structure is built inside an excavation and covered over with backfill material when construction of the structure is complete. Cut and … Continue reading