ABSTRACT
The E05 Korsvägen contract, part of the Västlänken project, includes two areas of rock cut, portal structures and rock tunnels through Almeda and Liseberg in Gothenburg, Sweden. A new, large span (circa 16 m) underground tunnel at low rock cover with mixed face conditions in an urban environment is proposed for this purpose. The objective of this paper is to present the temporary reinforcement and pre-support design requirements for these rock tunnels. The support typically consists of rock bolts sprayed concrete, steel ribs, forepoles and the creation of an artificial rock by soil replacement with concrete. Detailed empirical, analytical and numerical analysis calculations have been carried out for this purpose to provide a safe, robust and economical design. Convergence monitoring plots during construction are also presented demonstrating good correlation with design.
