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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.

Light at the End of the Tunnel, Sauer, Dr. G.January 1, 1990

Development and advantages of the NATM.

Rapid Excavation and Tunneling Conference, June 11-14, 1989

Further Insights Into the NATM, Sauer, Dr. G.January 1, 1988

When an invention is something new: from practice to theory in tunnelling.

Project Overview

The Beacon Hill Tunnels and Station are part of the 14 mile initial segment of the Sound Transit Central Link Light Rail Line that will establish a high capacity commuter connection from downtown Seattle to Sea Tac then on South to Tacoma. The 4,300 foot running tunnel under Beacon Hill will be mined by Earth Pressure Balance Machine (EPB), while the deep mined Station will be constructed using slurry walls and the New Austrian Tunneling Method (NATM), referred to as Sequential Excavation Method (SEM) for this project.

The rehabilitation of Marc Brunel's Thames Tunnel was undertaken over a 24 month period by WS Atkins and Dr. Sauer Company acting as a specialist tunnelling, shotcrete and waterproofing consultant, with the contract awarded to Taylor Woodrow Civil Engineering Ltd (TWCE).

The Corsica Street Ventilation Shaft comprise the permanent pressure relief and ventilation adit connecting the down line running tunnel to the shaft and the temporary access adit tunnel, which will be used to inspect the TBM cutter head and shield before being used to construct the permanent emergency access opening to the down line running tunnel.

Facilities Description

Facilities Description

Project Overview

The Silver Line will become a complete transit line of the Massachusetts Bay Transportation Authority (MBTA) in Boston, MA with the design and construction of Silver Line Phase III that will link two transit improvement projects:

Phase I - the Washington Street Replacement Service Project a dedicated busway lane with seven stops along a 3.2 km (2 mile) widened section of Washington Street from Dudley Station in the south to the New England Medical Center Station (NEMC)