Instituto Superior de Engenharia de LisboaDepartamento de Engenharia Civil

Disciplina de Inglês

Tunneling ConstructionNew Austrian Tunneling

Method - NATM

Cristóvão Andrade Nº 38644

New Austrian Tunneling Method –NATM

Method Origin:• New Austrian Tunneling Method- Created betwen 1957

and 1965;• Austrian origin;• Developed by Muller, Rabcewicz and Pache.

Propertys:• Tunnel auto-sustention;• Aplication of a shotcrete layer;• Monotorization of the tunnel state.

New Austrian Tunneling Method - NATMConstructive Method:

- Creation of a first suport on the surface of the tunnel opening (loosenig zone) to avoid deterioration;- Opening of a tunnel traject not very long ;- Projection of concrete in all the circular perimetre of the excaved zone (25 at 50 mm);- Introduction of metalics suports (cambots);- Fixation of the sustention reinforcement (usualy 6mm);- First hand of shotcrete, in a layer with thickness not superior at 150 mm;- Perfuration of the formed layer for the inserection of the anchorages;- Introduction of the suport for the next excavation cicle.

New Austrian Tunneling Method - NATM

New Austrian Tunneling Method - NATM

Legend Objective of the control Instrument1 Deformation of the

excavation surface.Convergence tapeSurveying marks

2 Deformation of the pavement of the tunnel envelope.

Strainsters

3 Monitorization of the pavemente suport, of the anchorage element.

Anchorage force

4 Monitorization of the pavimente suport referent at concrete layer.

Embedments gaugePreasure Cells

New Austrian Tunneling Method – NATMCase of Study – Frankfurt Subway

• NATM method it was apllied at 55 - 70 % of the excavation process;

• Joining the utilization of a tunneling machine roadheader to execute the process, it was possible spent 20% of the time of execution in relation at the use of any other kind of it;

• This utilization alows get specifics operations of NATM method, like the terrains suport – in this case, it was not with shotcrete in the tunnel walls, but with the inserection of steel archs like temporarly suports.

New Austrian Tunneling Method - NATM

Bibliography/ Reference:

• Tatiya, Ratan. “Civil excavations and tunneling: a pratical guide.”, Bristol, 2005.