New testing method for the prediction of the dispersion of soil in slurry shield tunnelling

In this contribution, we present a new testing method for the prediction of the dispersion of soil in slurry shield tunnelling. It is based on the proven slake durability test equipment but differs substantially regarding the procedure for testing and evaluation. With the results, a substantial data analysis was conducted searching for correlations with typical characteristic soil parameters. For the first time in tunnelling practice, the test enables a qualitative assessment and therefore a prognosis of the expected dispersion based on quantitative values determined in a traceable and reproducible testing method. In addition the test allows for an estimation of the dispersion tendency based on figures for the plasticity and consistency, which are usually collected anyway in the preliminary stages of a tunnelling project. Contractual recommendations are also provided concerning the topic of dispersion. © 2018, Ernst und Sohn. All rights reserved.