Simple Spreadsheets to Estimate the TBM Penetration Rate Based on NTNU, RMi and QTBM Methods

There are several traditional, widely used empirical methods for estimating TBM performance, all developed from data recorded in real tunnelling projects. As with any empirical approach, these methods must be applied with care—particularly when geological, geotechnical, or machine conditions differ from those on which the models were originally based. Nevertheless, they can still offer a useful indication of the expected performance range for a selected TBM.

In our 2012 paper, we examined the influence of various rock mass and machine parameters on TBM penetration rate (https://link.springer.com/article/10.1007/s10706-012-9594-2). The study showed that applied thrust per disc is the dominant factor controlling penetration in the NTNU and RMi models, whereas the Q-value (from the Q classification system) is the most influential parameter in the QTBM model. Uniaxial compressive strength of intact rock has relatively minor impact in both NTNU and QTBM. Joint spacing plays a significant role in NTNU and RMi, while in QTBM, low induced biaxial stress (<1.7 MPa) and low quartz content (<5%) greatly increase their influence on penetration rate.

I also developed three spreadsheets implementing the NTNU, RMi, and QTBM methods to help estimate penetration rate.

Empirical Based TBM Performance Prediction Methods.pdf

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NTNU.xlsx

Download XLSX • 17KB

RMi.xlsx

Download XLSX • 16KB

Qtbm.xlsx

Download XLSX • 19KB