Performance analysis of tunnels opened with TBM under difficult conditions: Silvan and Nurdagi tunnels

It has been seen from the literature that there are not enough studies on tunneling under difficult conditions with TBM and the studies are limited. Difficult excavation conditions affect the excavation performance of tunnels opened by TBM much more than conventional tunnels. Considering that it is not possible to redesign the TBM according to the excavation conditions later, it becomes necessary to carry out the geotechnical study in a comprehensive way. In the tunnels where comprehensive geotechnical studies are not done, irreparable problems are encountered. In this study, the problems experienced in Silvan and Nurdağı tunnels opened under difficult conditions with TBM and the effects of these problems on excavation performance are examined in detail and the solution methods applied are given widely. In addition, the effect of study parameters and formation characteristics on TBM performance was analyzed. In this context, firstly, thrust, torque, torque / thrust ratio, penetration, penetration index and rpm changes were examined along the opening parts of Silvan and Nurdağı tunnels for each formation. Then, the relations between thrust and penetration, torque and penetration, torque and rpm, penetration and specific energy were investigated. Finally, the double effects of these parameters on penetration and specific energy have been presented with MATLAB program. In the first chapter; types of tunnels, tunneling methods and problems that may be encountered in tunneling are given. In the second chapter; types of TBMs, parameters affecting TBM performance, performance estimation methods and previous studies are given in detail. In the third chapter; Diyarbakır Silvan irrigation tunnel and Gaziantep Nurdağı high speed train tunnel projects are discussed thoroughly and the problems encountered during the construction of these tunnels and the methods used to solve those problems are analyzed. In the fourth chapter, the effects of the problems experienced in two tunnels on the excavation performance (thrust force, torque, specific energy) and disc consumption are evaluated. In the fifth chapter, results and recommendations are given. Key Words: TBM, tunnelling, gassy ground, karstic, TBM performance.