Evaluation of Laboratory Scale Testing of Tunnels and Tunnel Intersections. Volume 1

Abstract : A major goal of this project is to advise DNA on the future role of small size (laboratory scale) testing in supporting design and target assessment of deep underground structures. The project team reviewed past laboratory size tests and small size structural models loaded in field tests. The testing was sponsored primarily by DNA and conducted by SRI International, Terra Tek, Inc. and the University of Illinois in the past 10-15 years. Data from the U.S. Army Engineer Waterways Experiment Station and foreign literature on the subject were also evaluated. The core issue addressed is: has laboratory scale testing, whether in the form of replica-scale testing or material-scale testing, established itself as a legitimate means to study prototype tunnel behavior? The answer based on our review is a qualified no. There are sufficient questions of geometry at SRI and boundary conditions at Terra Tek to cast doubts on the validity of their results as prototype behavior.