Authors: D. Young, A. Dean
Abstract
Over the next decade and beyond, numerous tunnels will be constructed in seismic areas to facilitate the movementof people, goods, and services. The purpose of this paper is to discuss the performance of precast concrete tunnel linings (PCTL) in seismic events. PCTL systems are comprised of a number of segments, which are assembled in the tail-shield of the tunnel boring machine, and are typically used in soft-ground tunnels. When PCTL are used, the final tunnel lining system can be either one-pass or two-pass. One-pass PCTL have become the most favoured lining type for closed-face soft ground transit tunnels, due to the overall value added to the project. However, the seismic behaviour of PCTL is not well understood, and the volume of published work on the subject is relatively thin.
As a result, tunnels that could be lined with a one-pass PCTL system are sometimes constructed with two-pass systems at significantly higher cost. This paper, which builds on the authors’ previous research, is intended to bridge the gap between the theory of PCTL design and the performance of the lining during earthquake shaking. Case histories of PCTL performance in the Northridge (1994), Kobe (1995), Athens (1999), and Hualien (2002) earthquakes are available. Lessons learned from these tunnels are presented. PCTL have inherent advantages over other tunnel linings when subjected to earthquake shaking.
These advantages are discussed and related to the case histories noted above. PCTL performance in these case histories is related to previous tunnel seismic performance studies and reports by others.
