ABSTRACT
Large metropolitan cities require constant infrastructure investments to fulfill the needs of ever-growing population. With the advancements in mechanized tunneling, utilizing TBMs for infrastructure and utility tunnels has become a very efficient method. However, considering the high initial capital investments, TBM design and selection becomes important for the success of the project. European Potable Water Transmission Project utility tunnels were designed to travel more than 19 km under the densely populated areas of Istanbul. The project crosses complex geological conditions. Based on the complexity of geological conditions, time frame and the operational concerns, the tunnel excavated simultaneously by two identical EPB TBMs. In this study, it was aimed to investigate and compare the performance of both TBMs by analyzing excavation data obtained from the data logging system of the TBMs. In addition, TBMs’ reaction under risky or difficult conditions caused by fault lines, excessive hydrostatic pressures, and abrasive sand drives will be presented case by case.
