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Technical info


The New Austrian Tunneling Method (NATM), also referred to as Sequential Excavation Method (SEM) or Shotcrete Method, was developed in the 1950s when shotcrete was first used systematically to stabilize squeezing ground in a water diversion tunnel at the Runserau Hydroelectric Power Project in Austria.  

After a number of successful applications in mines, water, rail and some road tunnel projects this method was adopted for the first time in urban areas in soft ground for a section of the Frankfurt Underground Subway. The construction took place in Frankfurt Clay in 1968. Because of its flexibility, economic and safe performance more than two thirds of Germany's urban mass transit tunnelling in more than 10 major cities were carried out using this method in the 1970's. These tunnels were constructed mostly in clay, silty clay, silt and soft marl or similar soft ground conditions. 

In the intervening years many large cities around the world e.g. Athens, Brasilia, Dallas, Istanbul, Kyoto, Lisbon, Madrid, Paris, Rome, Sao Paulo, Seoul, Tokyo, Washington DC, amongst many others, have taken advantage of this innovative method.

NATM / SEM Construction Method, Dr. Sauer GroupJanuary 20, 2004

A brief introduction about the history and the principles of the New Austrian Tunneling Method.

Tunneling Under Dulles Airport, Moran P., Patel A., Hirsch DJune 1, 2003

The use of NATM to build a pedestrian tunnel under an operating airport.

Heathrow Express Rail Link NATM Trial Tunnel, Dean A. and Rulff J.June 1, 1992

A site trial to establish the feasibility of using NATM in London Clay.

Tunnel Design

Bond Street Station Upgrade Project (BSSU), London, UK, Cate Anthony, Dr. Sauer and Partners LtdApril 25, 2014

Works are now underway at Bond Street tube station, with the completion of both SCL shafts and over 60m of sprayed concrete tunnels to date.

Excavation and Support Systems, Dr. Sauer GroupJanuary 1, 1998

A short introduction about excavation, support sequences and interacting factors.

Tunnel Design Tools, Dr. Sauer GroupJanuary 1, 1998

A brief overview of computer aided analysis and calculation for design of underground strucutures.

Special Construction Methods

Doorframe Slab Method, Dr. Sauer GroupOctober 13, 2004

Description of the principles of this semi cut-and-cover method.

Ground Freezing, Dr. Sauer GroupOctober 13, 2004

The basics of ground freezing.

Caisson Method, Dr. Sauer GroupMay 20, 2004

An new and innovative underwater tunelling method.

Geotechnical Engineering

Referencing ground conditions, Mellors, T.October 31, 1995

The need for good ground investigations in combination with appropriately qualified and experienced engineers and geologists.

Monitoring & Documentation

In-Situ Measurements, Dr. Sauer GroupJanuary 1, 1998

A brief overview on in-situ measurements and their relevance.

Proceeding of the International Conference on North American Tunneling and the 22nd General Assembly of the International Tuneling Association, April 21-24, 1996


Tunnel Inspection

Transit Cooperative Research Program

Tunnel Widening & Rehabilitation

AUA Conference

North American Tunneling 2004 Conference and Exhibition

Atlanta, GA

Infrastructure Upgrade through Innovative Tunnel Rehabilitation, Urschitz, G., Maliszewski, C. A. and Galvin, J. M.June 1, 2003

Rapid Excavation and Tunneling Conference, New Orleans, LA, June 2003

Complete transformation for the Cameron culverts, Egger, K., Alhussaini, H. and Baker, E.May 1, 2001

Tunnels & Tunneling North America, May 2001

Waterproofing & Water Control

Achieving Dry Stations and Tunnels with Flexible Waterproofing Membranes, Egger, K.., Mergelsberg, W., Sauer, GMarch 2, 2004

1st Brazilian Tunnels and Underground Structures Conference, February 29  - March 3, 2004

North American Tunneling Conference, June 6-11, 2000. 

Waterproofing Systems, Dr. Sauer GroupJanuary 1, 1998

Cut-and-cover waterproofing at the Georgia Avenue Petworth Station Washington D.C. USA.

Flexible membrane based waterproofing systems in-use since the mid-sixties for tunnels recently have been incorporated into other subterranean applications, including cut-and-cover structures.

Project Management & Contracting Strategies

SEM/NATM Design and Contracting Strategies, Urschitz, G., Gildner, J.April 21, 2004

North American Tunneling Conference, April 17-21, 2004

Urban Tunnelling Consequences, Sauer, Dr. G.March 12, 1998

World Tunneling March 1998

Efficacy and equity of the management of large underground projects, Muir Wood, A. M. and Sauer, Dr. G.May 3, 1981

Rapid Excavation and Tunneling Conference, May 03-07 1981