Improved Design for Tunnel Supports: Analysis Method and Ground Structure Behavior, A Review

摘要

The report presents the results of a study on ovservational methods and their potential for improving tunnel design and construction. Advantages and limitations of these methods in particular regarding their application in the United States are examined and initial steps to improve the methods are presented. Specifically, the report gives a detailed description of the New Austrian Tunneling Method (NATM), the most advanced observational method. Following a review of contractual and legal issues in tunneling, an assessment is given of the technical, contractual, operational and economic aspects of observational methods that need to be improved. The first research results providing such improvements are presented. They include a concept for less conservative empirical design methods, a comprehensive review and criique of presently available analysis methods, a simplified analysis method for preliminary design and an extensive discussion of ground structure behavior. These results which are not only applicable to observational methods and the detailed review of the NATM can be used in practice.