DAUB recommendations for selection of tunnel-boring machines revised
By: Martin Schäfer
The "Recommendations for selection of tunnel-boring machines" drafted by the German Tunnelling Committee (DAUB) in 1997 have been revised. The new edition of this working aid redefines the fields of application of tunnel-boring machines and aligns the recommendations with current developments in the TBM sector.
The aim of the new recommendations is that of outlining bases for decision-making in the selection of tunnel-boring machines for use in rock and non-cohesive ground on process-engineering and geotechnical criteria. The correlations existing between the geotechnical, local and environmental boundary conditions and process- and mechanical engineering are also taken into account. The recommendations should be regarded as an aid to decision-making for engineers, and are not intended as a replacement for a project-specific analysis, which will, of course, continue to be the main basis for selection of a tunnel-boring machine. The new recommendations augment, in particular, DIN 18 312, "Underground Works"; VOB (German Construction Contracting Procedures) Part C.
The essential geotechnical characteristics variables are compiled for each specific process and for each machine type, and can be used as a guideline for selection of a TBM. Provided the key geotechnical parameters are known, an evaluation matrix in tabular form permits an extremely easy approximate assessment of the suitability of each type of machine. The qualitative suitability of a tunnel-boring machine is then depicted at three levels, with differentiation into principal applications, applications in which use of the machine is possible, and applications in which its use is at best borderline. Final selection of the most suitable type of machine is then performed on both environmental and economic factors.
The recommendations were first published in the "Tunnelbau 2011" (Tunnel Engineering 2011) pocket manual, and are available for free-of-charge download from the DAUB homepage: www.daub-ita.de. They have also been incorporated into the second edition of "Mechanised Shield Tunnelling" (Maschineller Tunnelbau im Schildvortrieb, Maidl et al.), to be published in January, 2011.