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Erroneous Concepts behind NATM


The New Austrian Tunnelling Method (NATM) represents in the words of one of its main authors, L. Müller, a "structure of thought". It will be shown in the following paper that this structure rests not on an established theoretical foundation, but rather on two fun-damental misconceptions. The first concerns the definition of the NATM itself, according to whose concept the rock mass (ground) becomes part of the support structure. Upon closer examination this concept is revealed to be unfounded because the ground inevitably becomes part of the support structure in any tunnel independently of the selected method of construction. The second fundamental error lies in the claim that the NATM theory can optimize the design of the tunnel lining following the so-called Fenner-Pacher ground reaction curve. Since both theoretical and empirical justification is lacking for the existence of the latter, the central claim concern-ing the optimization of the lining design is groundless. In the final part of the paper, the question is discussed of why such misconceptions were able to gain such credence in the engineering community and why the NATM-theory was able to survive for so long without being refuted. The reason is that the NATM operates with ambiguous or unde-fined terms making it difficult to prove its incorrectness with logical argumentations


Kovári, Kalman

Index Terms:

rock; NATM; TunnelingGroup; Kovari, Kalman

Further Information:

Date published: 1993