Primary tunnel lining with PP FRS and rigid bolts

Steel fibre reinforced shotcrete has been extensively used in tunnels for underground support for better rock quality, and in combination with bolts for poorer rock quality. In this paper are presented results of the laboratory research and field tests to investigate the possibility of using the polypropilene (PP) fibres instead of steel ones. The laboratory research includes testing the properties of different sorts and shapes of PP fibres from different concrete mixes and standard bending test of concrete prisms. With obtained data the computer analyses were conducted, for different stages of construction, by means of FLAC computer program, which included the interaction of primary layer and reinforced rock.