Authors: D. Young, A. Dean
Abstract
Design of tunnel eyes for closed face tunnelling involves a multidisciplinary approach that includes consideration of geotechnical parameters, TBM specifications, temporary excavation and shoring design, ground improvement, tunneling induced settlement, scheduling, and constructability considerations. These issues are all inter-related at tunnel eyes and, as a result, coordination of these issues within the construction contract documents becomes a significant issue. Because of the multitude of inter-related design considerations at tunnel eyes, together with the lack of widely accepted design procedures, construction of tunnel eyes is often problematic, which can lead to construction delays, disputes and claims. This paper is intended to be used as a guide to assess data needs, design considerations, and methodologies for construction of tunnel eyes.
Selected tunnel eye design and construction case histories are reviewed so that tunnel contractors, designers and construction managers can relate more easily to tunnel eye design considerations. In sum, a framework for developing preliminary designs of tunnel eyes is presented, together with a discussion of steps required for successful tunnel eye design and construction.
