Assessment of the interaction of TBM and rock mass in rock tunnelling based on geomechanical calculations / Bewertung der Interaktion von TBM und Gebirge im Felstunnelbau auf der Basis von geomechanischen Berechnungen

Continuous tunnelling in rock under deep overburden necessitates - particularly when a tunnel boring machine (TBM) with shield is used - extensive consideration of the processes of stress transfer resulting from the advance of the tunnel. In order to design the constructional layout of the TBM, it must be possible to estimate the actions to be expected on the cutterhead, shield skin and shield tail.
Proven analytical calculation methods like the convergence confinement method are still in common use because of their simple application and deliver reliable results for the loading on the tunnel lining, but the variable equilibrium in the advance area is not sufficiently taken into account, although of decisive significance for the determination of the possible loading on the TBM - and thus for the assessment of the feasibility of the tunnelling method - and so a method is required, which can take this into account.
This paper starts with analytical and empirical modelling methods and describes ways of extending them and their scope of application. Rotationally symmetrical modelling methods, which are manageable in practice, are presented and their possible applications are explained. A particular feature is the possibility of simulating rapidly changing rock conditions, such as are encountered when tunnelling through fault zones.