ABSTRACT
According to the New Austrian Tunneling Method (NATM), subsequent to each excavation step shotcrete is directly applied onto the surrounding rock mass, forming a supporting structure which is usually loaded already several hours after application due to further advance of the tunnel. Only a few advanced material models for shotcrete for representing the highly nonlinear, time-dependent material behavior have been proposed in the literature so far. Recently, in (Neuner, Gamnitzer, & Hofstetter 2017) a new constitutive model for shotcrete, denoted as the SCDP model, based on a combination of the theory of plasticity, the theory of continuum damage mechanics, and a modified version of the solidification theory (Bažant & Prasannan 1989) was presented. The model represents time-dependent material behavior, as well as hardening and softening material behavior of shotcrete. In the present contribution, an extension of the SCDP model, and a comparison with two selected, frequently used shotcrete models, i.e., the models proposed by Meschke (1996), and by Schädlich and Schweiger (2014), are presented. The comparison is based on a benchmark example of a deep tunnel driven by the NATM, which is derived from a stretch of the Brenner Basetunnel.
