Comparison between Soil Abrasion Test (SAT) and Soil Abrasion Index (SAI)

The performance of soft-ground tunnel boring machines can be significantly impacted by soil abrasivity. During the last decade, several soil abrasion testing systems have been developed to characterize abrasivity of various soil mixes in different conditions. This article discusses the comparison between the results of a Soil Abrasion Test (SAT) developed by Stiftelsen for Industriell og Teknisk Forskning (SINTEF)/Norwegian University of Science and Technology (NTNU) and the Soil Abrasion Index (SAI) testing system developed by the authors. The reason for this comparison is the availability of SAT results for a few tunneling projects that were constructed in recent years. Obtaining any relationship or correlation between the SAI and SAT will allow the use of some of the machine field performance data to evaluate the ability of SAI in predicting the wear on these machines. The study of SAT has been conducted on the testing device designed and fabricated based on the original specifications of NTNU. The study was designed to evaluate the sensitivity of the SAT testing system to some of the controlling parameters and testing procedures as compared to the SAI test. This article summarizes the result of a series of specially designed tests to evaluate the impact of various testing parameters on SAT results as well as a comparison of the results between the two tests.