The results obtained from the RMR and M-RMR classifications indicate that M-RMR system estimates better rock mass quality ratings at the upper bounds of the rock mass condition, but worst ratings at the lower bounds (RMR is less than 40) as also suggested by the previous studies. Finally, correlations between the results of the rock mass classification systems were made carrying out statistical analyses for the Dim Tunnel study area. A geological map and a geological cross-section along the tunnel axis were also prepared. Field studies involved detailed discontinuity surveys of the exposed rock mass at the surface and on the cores taken within 10-20 meters of the borehole above the tunnel. In order to accomplish this task, literature survey was carried out, followed by a comprehensive field study and laboratory testing.

The main objective of rock mass classifications carried out in this study was to obtain adequate data that could be used in future excavation and support-design studies. The advent of long-period seismographs and computers (1934 to 1962) finally. During studies, the geological and geotechnical characteristics of the rock mass along the Dim Tunnel route were investigated. the prototype of the modern seismograph was developed by John Milne and his. Dim Tunnel has a horse-shoe shape, with a diameter of 10 meters and maximum overburden thickness of 70 meters. The tunnel ground was classified according to Rock Mass Rating (RMR), Modified Rock Mass Rating (M-RMR), Rock Mass Quality (Q,) Geological Strength Index (GSI), and New Austrian Tunneling Method (NATM). In this thesis, the results of a number of rock mass classification systems applied to Dim-highway tunnel study area are presented.

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