ABSTRACT
During tunnel drives with shield machines in clay formations strong clogging may occur, especially when using a fluid-supported tunnel face and a slurry circuit mucking system. The consequences include difficulties for the excavation process. At first, the clogging hinders the transport of the spoil in the cutting wheel, excavation and suction inlet area and then leading to further obstructions which can result in a complete interruption of the material flow. If clogging cannot successfully be mitigated, they can lead to a drastic performance reduction due to a reduced advance rate and to the time required for additional cleaning efforts.
1.2 Development from first clogging to standstill
