ABSTRACT
The most important issue to be considered during the tunnel construction is to be ensure the excavation stability. In EPB TBM method, the face support pressure is one of the effective way to provide excavation stability. The aim of this study is to calculate the face support pressure of TBM excavation carried out in soft ground conditions as part of a metro line passing through an urban area in Istanbul, Turkey, by using different empirical and numerical methods. The results obtained from these different approaches were compared and discussed. Results show that empirical methods may give different values based on the assumptions made. However, almost all empirical approaches are in good agreement with the numerical method. Moreover, it has been shown that when the face support pressure, whose purpose is to reduce the deformations caused by excavation, is applied less or excessively as a result of calculation error, it causes the deformations to increase.
