ABSTRACT
Prediction of penetration rate of tunnel boring machine (TBM) is important in tunneling design; however, the effect of machine specifications of the TBM on penetration rate remains poorly identified. This study defined a representative machine factor (MF) composed of thrust force, number of cutters, and TBM diameter, and its correlations with penetration rates, using the previously reported field data. In addition, the correlations between the machine factors and the unconfined compressive strength (UCS) of rocks were examined. The stronger relationship between penetration depth and MF than between penetration rate and MF was found. Finally, the generalized prediction-model to penetration depth per revolution was suggested. The presented findings provide insights into the roles of machine factors in TBM performance.
