Terminology and Its Implications for Quality in Underground Construction

Abstract

Quality has all too often remained an elusive and abstract concept in our industry, despite being of vital interest to everyone involved in tunneling and underground construction in general. Nontunneling engineers, managers, and owners are often confused by terminology and acronyms, which are often biased by individual perceptions of some inherent level of quality. Acronyms are not always understood in the same way. Prime examples are the acronyms NATM (New Austrian Tunneling Method), SCL (sprayed concrete lining), SEM (sequential excavation method), TBM (tunnel boring machine), and EPBM (earth pressure balance machine). This may lead to an incorrect presumption that a level of quality is always associated with a particular method, approach, or material. The intent of this paper is to persuade the underground construction industry to move beyond the acronyms and ambiguous terminology toward identifying and communicating fundamental considerations of quality design and construction. Examples are given where change is needed.