ABSTRACT

Tunnel drives with EPB-Shields in fine grained soils could lead to clogging e.g. in the excavation chamber. In these soils water is usually being used to change the consistency index of the support media in the excavation chamber. In addition, additives are often used in the suspension to reduce the risk of further clogging. Systematically investigations to reduce the clogging potential of fine grained soils using additives for EPB-Shields are unusual. Laboratory tests were carried out to investigate the adhesion tension in order to describe the clogging potential for EPB-Shields using water. In the laboratory tests an additive was also used to change the consistency index and to simulate the soil conditioning of EPB-Shields. Comparable investigations carried out to determine the influence of the additive. It can be shown that a reduction of the adhesion tension is possible and the correct use of additives could have a significant influence.