A project called “Recycling of Tunnel Excavation Material” has been running since November 2008, supported by the Austrian Research Promotion Agency (FFG) and eminent Austrian client organisations and companies engaged in tunnelling and hydropower station construction, to investigate the possible recycling of tunnel excavation material at eleven selected Austrian tunnel and hydropower projects. This is intended to demonstrate economical and environmentally positive recycling. Test strategies are also to be developed for the evaluation of the reusability of tunnel excavation material from the point of view of construction management and economics, both for the individual projects and also relevant to the main lithologies likely to be encountered in Austrian tunnels. Seit November 2008 wird in einem von der Forschungsförderungsgesellschaft (FFG) und namhaften Auftraggebern und Baufirmen des österreichischen Kraftwerks‐ und Tunnelbaus unterstützten Forschungsprojekt “Recycling von Tunnelausbruchmaterial” die mögliche Wiederverwertung von Ausbruchmaterial an elf ausgewählten österreichischen Tunnel‐ und Kraftwerksprojekten der Zukunft untersucht. Eine wirtschaftliche und umweltschonende Wiederverwertung soll nachgewiesen werden. Weiters werden für die einzelnen Projekte und die in Österreich bei Tunnelausbrüchen zu erwartenden Hauptlithologien Versuchsstrategien zur Beurteilung der Wiederverwendbarkeit von Tunnelausbruchmaterial aus baubetrieblicher und bauwirtschaftlicher Sicht ermittelt.

The Cerchar abrasiveness test is a common testing procedure for the prediction of tool wear but consistent and detailed recommendations of the testing procedure are inexistent until now. One point of disagreement is the required number of scratch tests per sample to obtain reliable results depending on the grain size of the samples. The focus of this work was to verify the influence of grain size on the number of required single examinations per sample. Grain size analyses were performed to get sum-curves of each tested rock sample. From the grain size data the median and the interquartile range of the grain sizes were calculated. CAI values after 5 and after 10 scratch tests were compared with the median and the interquartile-range of the grain size. No grain size dependency of the CAI deviation between 5 and 10 tests in the analysed range was observed. Einfluss der Korngröße auf den Cerchar Abrasivitätstest IntroductionThe abrasiveness of intact rock or rock mass affects the wear behaviour of drilling, cutting and milling tools. Conducted research programmes by various scientists show that abrasiveness of rocks depends on different parameters (e.g. structure and texture, equivalent quartz content, Young's modulus). Index-tests directly prove the wear behaviour of intact rock and therefore allow rating the abrasiveness. In Western and Central Europe the Cerchar abrasiveness test is a common testing procedure for the prediction of tool wear due to the fast measurement process and the low costs. The only formal description of this test is the French Standard AFNOR, NF P94-430-1 [1]. The working committee AK 3.3 "Versuchstechnik Fels" of the German Association for Geotechnics presently is discussing more detailed recommendations for the Cerchar abrasiveness test. ObjectiveThe influence of geological parameters (e.g. equivalent quartz content, Young's modulus, structure, texture and mineral content) on the Cerchar abrasiveness index are well investigated The number of tests that should be performed on one rock sample is not yet defined in a standard. In previous studies different numbers of tests are requested. For homogeneous, fine-grained rock samples two or three scratch tests were originally suggested. Only at rock specimen with a grain size > 1 mm, five or more scratch tests per sample should be conducted [8]. Practical experience in testing has shown that 5 scratch tests on each sample should be accomplished to obtain a better defined and comparable mean value [5]. Recently published results propose 20 to 25 tests for granites and sandstones for a reduction of the standard deviation to 10 % [4], [9].Due to these different testing instructions a study on the influence of the grain size on the Cerchar abrasiveness index was performed. As the Cerchar abrasiveness testing length is amounting to 10 mm, the grain size of the samples could have an impact on the CAI value. For example, larger quartz grains with grain diameters up to or more than 10 mm must affect the CAI to a higher value. If grain sizes in a rock sa...

Full scale linear cutting tests with variable cutter spacing and penetration were conducted on different Alpine lithologies. The analysis focusses on different aspects: First, the investigation of excavated material regarding grain‐size distribution curves and aspect ratios. Second, the investigation of cutting forces to better understand rock breakage and the directional dependence of cutting forces in an anisotropic rock mass. A critical view of TBM performance prediction models is also presented. Results show that the percentage of coarse grain is positively correlated with increased cutter spacing, and changing penetration did not result in significant changes of grain‐size distribution. Analysis of cutting forces shows that knowledge of cutting forces enables a deeper understanding of rock breakage. Furthermore, it is shown that common performance prediction models are not able to cover certain types of rock satisfactorily.Im Rahmen dieser Arbeit werden Linearschneidversuche mit variablem Schneidspurabstand und Penetration an repräsentativen alpinen Lithologien präsentiert. Das Schwergewicht der Auswertung liegt in der Analyse des Ausbruchmaterials hinsichtlich Sieblinien und Kornform sowie in der Betrachtung der gemessenen Schneidkräfte zum besseren Verständnis des Gesteinsbruchvorgangs, der richtungsabhängigen Kräfte bei anisotropen Gesteinen sowie der kritischen Betrachtung von TBM‐Leistungsprognosemodellen. Die Ergebnisse zeigen, dass der Grobkornanteil bei steigendem Schneidspurabstand zunimmt. Die Änderung der Penetration zeigt keinen gravierenden Einfluss auf die Kornsummenkurve. Die Analyse der Schneidkräfte zeigt, dass die Kenntnis von Schneidkräften wertvolle Einblicke in den Gesteinsbruchmechanismus bietet. Als weiteres Ergebnis wird deutlich, dass gängige TBM‐Leistungsprognosemodelle die Schneidbarkeit bestimmter Gesteinsarten nicht adäquat vorhersagen können.

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