Review and assessment of the NTNU/SINTEF Soil Abrasion Test (SAT™) for determination of abrasiveness of soil and soft ground

• Soil abrasivity measurements can be an indicator of TBM excavation tool life.
• Cost estimations of worn out excavation tools.
• Classifications based on statistical analysis of recorded test results.
• Comparisons between laboratory measurements and tool life.

Measuring soil abrasivity for excavation tool life estimation, is becoming more necessary as tunnels are longer and with limited access to execute interventions and tool changes from shafts. The tool life is a major contributor to the tunnel excavation costs and tunnelling progress. The aim of this paper is to explain the consequences of tunnelling in abrasive soil and soft ground conditions, and explain the NTNU/SINTEF Soil Abrasion Test™ (SAT) which is one approach to measure soil abrasivity. In this paper a total of 254 different soil samples (clay, silt, sand and gravel are represented) originating from 8 different countries have been tested and included in the discussion of the SAT™ procedure’s applicability. Further, the paper relates the SAT™ test values to commonly known tribological theories regarding abrasion as well as presenting trends and correlations between the measured SAT™ value and measured scraper, ripper and disc cutter life from a total of nine completed TBM/pipe jacking projects, excavated with slurry shield face support.