Unpredicted and excessive tool wear is a major challenge in some tunnel projects. Due to more need for maintenance, abrasivity problems increese time and cost of excavation activity. A new laboratory test machine has been built in Engineering Geological Laboratory of Ferdowsi University of Mashhad, to obtain a proper view about relation between performance parameters of a TBM and the soil abrasion. In this paper the results of abrasion tests carried out on silica samples, as an abundant hard mineral, by the machin, are presented. Hence 36 tests have been performed on coarse silica sand samples, with various amount of deadweight and rotation speed at different times. The results prove direct relation between time, surcharge and rotation speed versus tool wear. For example a linear relation between tool wear and surcharge or rotation speed was observed. Besides a logarithmic relation was achieved for time effect

Keywords: Mechanized excavation, Tool wear, Soil abrasivity, Soil abrasion test

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