Application of NATM (New Australian Tunneling Method) to Port Authority of Allegheny County's State 1, Light Rail Transit System Mt. Lebanon Tunnels

摘要

The purpose of the demonstration project was to implement into an existing tunnel design, an alternative design to allow construction of the tunnel system using the New Austrilian Tunneling Method (NATM) - the state-of-the-art in tunnel design and construction. NATM is both a design philosophy and a general, but practical approach to tunneling. It's goal is to achieve a technically sound, safe and economical design. It is a concept which considers the geological formation surrounding the tunnel excavation as both a load and a load carrying ring. NATM principles, design approach, bidder prequalification process and bid struction, results of tunnel instrumentation and summaries of geological conditions are also presented. The report provides evidence that NATM is a tunneling philosophy which produces technically sound, cost competitive designs capable of being bid and constructed within the framework of existing American contracting practices.