Scientific paper ID 2621 : 2024/3

The results of laboratory tests on nine 50/40/30 cm fiber reinforced concrete test bodies for primary tunnel lining are reported. The test bodies were aged until they reached their full strength in the authentic environment of a newly constructed tunnel. The optimum content of different amounts of fiber in the concrete mortar was sought. An overview of the application of fibers in sprayed concrete for the performance of tunnel linings is given, and their advantages are indicated. Emphasis is placed on the Norwegian tunnel method, which mainly uses fiber-reinforced sprayed concrete. The flexural strengths of the specimens were investigated experimentally under laboratory conditions to failure by compression presses. As a result of the testing, the flexural deflections of the test bodies were obtained. Corresponding graphs have been developed representing the specified loads and the resulting deformations. The bending capacity of a 40/30 cm concrete section with a length of 50 cm and a support distance of 40 cm reinforced with single reinforcement was determined. It has been proven that fiber concrete sections are equivalent to reinforced concrete.. Useful conclusions have been drawn about the technology for laying the primary lining of tunnels and its direct relationship to safety and performance.