Engineering geological appraisal of the rock masses and preliminary support design, Dorukhan Tunnel, Zonguldak, Turkey

This paper presents the results of engineering geological studies of the rock masses along a road tunnel. Rock mass qualities of the rock units along the tunnel were determined by means of Rock Mass Rating (RMR), Geomechanic Classification (Q) system, Geological Strength Index (GSI), Rock Mass Index (RMi) and New Australian Tunneling Method (NATM). In order to determine tunnel stability, necessary support types and categories RMR, Q, RMi and NATM systems were employed as empirical tunnel support design methods. However, these empirical design guidelines for tunnel support based on rock mass classification systems failed to analyze the support performance. The performances of the proposed support systems were analyzed by means of numerical analysis, described in this paper. A 2D finite element analysis program was used as numerical method. The necessary rock mass parameters were obtained by means of rock mass classification systems.