Investigation and engineering geological assessments of Zonguldak-Devrek Bartın motorway and tunnels

In Zonguldak-Devrek Bartın motorway project, it has been found out that there was a need for two tunnels of 0.9 km and 0.8 km. Tunnels are most essential components of a linear engineering structure across a highly dissected and rugged mountain range. However, when compared with other engineering structures, the number of unknowns is higher. Geology, hydrogeological, morphological and engineering geological models are basic constituends in engineering projects for a reliable geotechnical model. Üzülmez tunnel will be excavated in the Carboniferus aged formations. Sapça tunnels will be excavated Cretecaus aged formation. Field studies carried out along the tunnel alignments indicate that ground water level is below the tunnels. In relation to engineering geology, 1/2000 scaled engineering geological maps and cross-sections have been prepared tunnels alignments. Thus, detailed discontinuity survey, laboratory investigations and determination of rock mass properties have been carried out. Empirical approach has been employed in the design of the tunnels. Relationship Q and RMR empirical classifications, it has been identified that the tunnels would be generally be excavated in medium to poor quality rock masses. As to the analytical approaches, taking into consideration in-situ stress conditions and rock mass properties, stress-strain analysis and rock-support interactions have also been investigated using Phase2 (4.05) software. The relation of uniaxial strength and schmidt test values have been confirmed. Key words.-Engineering geology, tunnel design, rock mass classification, stress- strain, rock support interaction