Tunnelling in Fault Zones – State of the Art

摘要

Alpine fault zones are complex structures, exhibiting highly heterogeneous rock mass conditions. Inrnaddition the permeability can vary in a wide range. High displacements, stability problems, andrnground water inflows are common phenomena observed during tunnelling through fault zones.rnBesides the choice of an appropriate construction method for such conditions, the safety and long-termrnstability of the underground structure are major issues. The paper addresses investigation methods andrntargets to obtain the key parameters determining the rock mass behaviour, as well as rock massrncharacterization methods, criteria for the selection of appropriate construction methods, depending onrnthe expected conditions. Even with the most advanced investigation and design methods uncertaintiesrnwith respect to geological structure, rock mass parameters, and hydrological conditions remain.rnA continuous updating of the ground model thus is essential for safe and economical tunnelling.rnAdvanced methods of short-term prediction and investigation ahead of the face during construction arernpresented. State of the art excavation and support methods are shown and future developmentsrndiscussed