Project description

Subject

Analysis and prediction of penetration and cutter wear for TBM-tunnels in rock

Motivation and aims

The main reason to undertake this work is the fact, that the existing models were developed before 1990, when most tunnels excavated by TBM had diameters < 5,0 to 6,0 m. Modern highway and railway tunnels have substantially larger diameters, normally > 9,0 m. Also the rapid development of TBM-technique - diameter of cutters, materials of discs, cutterhead geometry, cutterhead bearings, variable rotation speed etc. - made it necessary to question the existing models and develop a new or improved version.

With the start of the ALPTRANSIT-projects in Switzerland in 1995 a new chapter of TBM-tunnelling with large diameter in hard rock began. Data from this and other projects like the Brenner Basetunnel and the Koralm Tunnel which will be excavated in the near future will be analysed and utilised for the development of the new model.

Project organisation

The core of the organisation is the research group, where the teams of six universities collaborate. The research work is performed in close cooperation with clients, engineers, contractors and TBM-experts. The researchers are supported by K. Gehring, who has developed one of the existing models. All participants have agreed to finance their work from their own resources. This solution provides an open access for new members and reduces the administrative and organisational work.

Project realisation

The research work for ABROCK is split into six work packages, each assigned to a university institute. The basic research work is performed by PhD-students. Criteria are developed and directions are given by a management committee, which is formed by the University professors. Progress of work, intermediate results and open questions are presented and discussed every 5 to 6 months in meetings or workshops.

Methodes used

Standard geotechnical laboratory tests, rock cutting tests in laboratories and penetration tests on site, analysis, processing and and evaluation of operational data, validation of proven and expected correlations between penetration, cutter wear and geotechnical parameters as well as numerical, operational and geotechnical modelling.

Data basis

A research of this type depends substantially on the type and number of projects from where data are available. The relevance of the new model depends very much on the quality of these data and the methods of analysis. Three types of data are required. The geological and geotechnical data are normally provided by the owners. Data on TBM-operation are provided either by contractors or owners. Data on cutter consumption are provided by the TBM-suppliers.

Time frame

Considering the complexity of the subject and the different starting dates and capacities of the research teams, an intermediate report will not be available before the end of 2012. The completion of the works is foreseen for 2015.