Bemessung, Anwendung und Qualitätssicherung von Stahlfaserspritzbeton im Tunnelbau

Design, Execution and Quality Management of Steel Fibre Reinforced Shotcrete in Tunnels

The shotcrete method has been proven for tunnel structures since years. Shotcrete can be used unreinforced, in combination with reinforcement meshes and with fibre reinforcement.
At the moment most steel fibre shotcrete tunnel liners have non-structural fibre reinforcement. However, the addition of fibres increases the fracture energy of the material and changes the shotcrete behaviour from brittle to ductile with higher reliability.
Steel fibre shotcrete can also replace shotcrete with traditional mesh reinforcement. The verification of steel fibre shotcrete takes the post cracking tensile strength of the material into account. The tensile strength of the cracked fibre concrete can be derived from bending tests on beams cut out of a larger shotcrete sample.
This paper presents the different types of executed shotcrete applications in tunnels and the necessary test methods.