TBM performance prediction based on rock properties

The knowledge of rock type and technology using for tunnel opening is essential for any mechanical excavation. In present, utilizing Tunnel Boring Machines (TBM) that is full-face tunnel machine is the most common way to excavate tunnels since this method offers numerous advantages over drill and blasting methods, for an example; TBM applies power to the rock in a relatively constant operation, automatically gathers up the cuttings and conveys them to a haulage unit. Having some prior knowledge of the potential performance of the selected TBM is very important in rock excavation projects for the scheduling and the cost estimation. Most of the TBM performance estimation analysis is based on TBM specifications, various intact or mass rock parameters. There have been numerous efforts in the last thirty years to develop methods to accurately predict TBM penetration rate in a given geology and rocks. These models/equations are mainly based on theoretical analysis combined with empirical data. Using the actual TBM field data, intact and mass rock properties, including rock strengths, brittleness and joint orientations, that was collected from a recently excavated hard rock TBM project in New York City, an empirical equation was developed for prediction of TBM performance.