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J. Macht, R. Lackner, Ch. Hellmich, H.A. Mang:
"Shotcrete Creep Properties - Review of Material Tests and Structural Analyses of Tunnels";
in: "Creep, shrinkage and durability mechanics of concrete and other quasi-brittle materials, Proceedings of the 6th international conference", F.-J Ulm, Z.P. Bazant, F. Wittmann (ed.); Elsevier Science, Amsterdam, 2001, 285 - 300.

The key to successful tunnel excavation is the compliance of the support system. If shotcrete shells are employed as tunnel support, this compliance stems to a large degree from the creep properties of the shotcrete material. The aim of this paper is to quantify these properties. The starting point are creep properties determined from Bazant's B3-model (Bazant and Baweja, 1996). This model was developed for ordinary concrete. These creep properties of ordinary concrete are then modified in order to match the intrinsic creep characteristics of shotcrete. Such modifications are derived from two independent tests, a stress-driven creep test and a strain-driven relaxation test. The influence of the modified creep parameters on the structural response is demonstrated by means of the analysis of two tunnels recently constructed in Austria.

Keywords: shotcrete, creep, tunneling, short-term creep, hybrid analysis