Herrenknecht AVN machines (AVN is short for the German for Automatic Tunnelling Machine Wet) are slurry pressure shields, also known as slurry machines. Equipped with a cone crusher, AVN machines really come into their own in non-accessible tunnel diameters and ensure safe tunnelling. The slurry support of the tunnel face enables AVN machines to be used in all types of ground: from silt and clay to non-cohesive soils and gravel through to rock, both in pipe jacking and segmental lining.