ABSTRACT
In tunnel drives with a slurry-supported face, the excavated soil is necessarily subjected to mechanical and hydraulic actions, both in the excavation chamber and during hydraulic conveyance. Slurry shield tunnel excavation in semi-solid to solid clay and claystone environments can lead to the dispersion (slaking) of the soil aggregates. These become detached as gravel to stone size chips, but in extreme cases, they may separate further into fine particle aggregates. This raises the question of how much effort is required to remove the fines from the slurry. Large chips can be relatively easily removed, for example by sieving, but fine aggregates are much more difficult and costly to eliminate, requiring the use of, for instance, filter chamber presses and centrifuges. To date, few studies have focussed on the dispersion potential of fine-grained soils or rocks during slurry shield excavation, despite the economic urgency of this issue. Our experimental study aims to address this topic and fill the gap.
