A model to predict daily advance rates of EPB-TBMs in a complex geology in Istanbul

This paper summarizes the results of a research study carried out to create a model to predict daily advance rates of EPB-TBMs in a complex geology in Istanbul. The model is based on the analysis of the accumulated data obtained from several projects. The model is first tested for Uskudar-Umraniye-Cekmekoy-Sancaktepe metro lines. The geology is complex consisting of sandstone, arcosic sandstone mudstone, siltstone, shale, limestone, andesite, and quartzitic conglomerate. The geologic units are frequently cut by andesite dykes having significantly fractured contact zones. Two EPB-TBMs having diameters of 6.57 m are being used for the lines where the prediction model was tested. Daily advance rates are predicted before starting the project and the results are tested first between shafts 8 and 7 and thereafter the completion of the excavation of the total length of 6250 m between the shafts 8 to 2. The results are also validated for a very recent Mecdiyekoy-Mahmutbey Metro Project for hard rock, sity clay and sand. It is believed that the concept behind the proposed methodology will serve a sound basis for decision making for similar projects having complex geology.