Probing and convergence measurement
Abstract
The big investment in a sophisticated TBM and the expectation of mostly rapid advance rates can each be spoiled by the unexpected delays caused by ‘unexpected ground’. Only a few percent of the total length of a tunnel may be ‘unexpected’, yet these few percent could double the construction time in some cases. Although deep tunnels are notoriously difficult to predict, regular probe drilling during cutter change and maintenance shifts could largely remove the unexpected; especially if performed with two slightly diverging probe holes.
Fields of Study & Subjects
Tunneling and Rock Mechanics
Geotechnical Engineering and Analysis
Geotechnical Engineering and Underground Structures
Publication details
- Journal / source
- CRC Press eBooks
- Pages
- 123–128
- Publication date
- 19 January 2026
- Language
- EN
- Document type
- Book chapter