A New Concept of Additive Manufacturing for the Regeneration of Existing Tunnels

Among the new technologies driving the fourth industrial revolution in the construction industry, 3D Concrete Printing (3DCP) is playing a key role. The typical process is made through robotic arms or gantries equipped with nozzles, similarly to contour crafting in other industries. Despite 3DCP is appealing when applied to complex architectural shapes, the structural behaviour and geometrical size are limitations difficult to overcome. Upscaling the extrusion process to full sections, introducing a new concept of ultrafast adaptable slip-forming, is the access key to different sectors of the construction industry, as infrastructures. This paper will present the Extruded Tunnel Lining Regeneration (ETLR) technology developed by HINFRA with the scope to automatically regenerate the lining of existing damaged tunnels. “Tailored” features and issues of the aforesaid technology will be discussed in this paper, together with a design validation related to a Fibre Reinforced Concrete (FRC) tunnel lining.