Swelling rock behaviour in a tunnel: NATM-support vs. Q-support – A comparison

The Q-system is one of the most applied classification tool in modern tunnelling. After an exact evaluation of the parameters the rock support can be determined via the “Q-support chart”. In an already finished tunnel, mainly driven through limestone, the Q-system was tested under difficult geological conditions (shale–marl). Scope of the appraisal was a comparison of the support suggested by the “Q-support chart” with the real performed support after the NATM, regarding partly massive damages. This article is a contribution referring to the last publication on the topic “fitness of various engineering design tools” from [Palmstrom, A., Stille, H., 2007. Ground behaviour and rock engineering tools for underground excavations. Tunnelling and Underground Space Technology 22, 363–376].