In this paper the recent sewerage and metro tunnel projects in Istanbul are summarized. A model improved as a part of NATO - TU Excavation project, that relates the cutting performance of mechanical excavators to rock mass cuttability index, is discussed with the recent data collected. The model may serve as a useful guide to contractors and machine manufacturers prior starting a tunnel project.
Dans cet expose on a resume les derniers travaux dans les tunnels d'lstanbul. On a realise ce model soutenu par Ie projet " NATO- TU Excavation" et on a defini I'index de rupture des roches en tenant compte la performance mecanique des tunneliers à I'etat de creusement. On a critique aussi ce model en prenant base les donnees obtenues durant les travaux dans les tunnels. Nous pouvons dire que ce modele sera guide aux autres participants aux creusement des tunnels.
Mit dieser Arbeit werden die jungsten Tunnelprojekte in Istanbul vorgestellt. lm Rahmen NATO-Excavation Project wurde ein Modell, das die Leistungen der mechanischen Vortriebsmaschinen mit Hilfe eines definierten Schneidindex fuer Gesteine feststellt, entwickelt. Das Modell wird mit den hier gesammelten Daten getestet. Es wird noch erklart, daß das hier vorgestellte Modell schon in der Planungpshase des Tunnels fuer den Zulieferer- und Tunnelbaufirmen ein Wegweiser sein wird.
Roadheaders have been widely used both in civil and mining industries since 1970. The main advantages are mainly; high advance rates, safety, less strata disturbances and less labor. The capital cost of these machines is very high, so if they are not selected considering rock mass properties the Consequences might be a nightmare for tunnel engineer. A contractor is always interested in predicting the machine performance prior to starting a tunnel project that will definitely define the tunnel drivage economy. The past few research works were focused on the prediction of the performance of roadheaders or TBM's from laboratory rock cutting tests. The work originated in Newcastle Upon Tyne University dealt with the correlation of in-situ data with the results of core cutting tests (Fowell and McFeat-Smith, 1976; McFeat-Smith and Fowell, 1977, 1979). In that study the specific energy obtained from small scale rock cutting test was the key factor in the machine performance prediction. A more realistic model was developed by using full scale rock cutting test results in Earth Mechanics Institute of Colorado School of Mines by Ozdemir and Rostami, et al. (1994); Ozdemir (1995). However, the work described in this paper differs from the two previously mentioned in the fact that it is based on the statistical interpretation of the field data that has been collected since 1988 from different sewerage tunnels in Istanbul (Bilgin, et al., 1988, 1990; Seyrek, et al., 1994).
Factors affecting the cutting performances of mechanical excavators can be summarized as below: -Job organization and skill of machine operator affect the machine utilization time that plays an important role in determining job duration time.
Paleozoic sedimentary formations from Lower Devonian to Middle Carboniferous are prevalent in the area. Many faults and geologic discontinuities developed due to Hercinian and Alpine Orogenies. The rock formation, locally named Trakya Formation is formed of fine grained, laminated, fractured and interbedded siltstone and mudstone. RQD values vary between 0 and 90%. Some diabase dykes have also been encountered while driving the tunnels and these affected progress rates as they are significantly harder than rock excavated along the major part of the tunnel routes.