In this master's thesis we developed a method for dimensioning the primary tunnel lining made of fiberreinforced shotcrete based on laboratory test results of the toughness of flat specimens. We examined specimens reinforced with 9 different types of fibers, varying length, surface area, aspect ratio, tensile strength and elastic modulus. For each specimen, we calculated the absorbed energy based on the measured force-displacement diagram. By considering the common properties of fibers within each set of specimens, we categorized them into 6 groups. Using the DIANA FEA software we performed a series of numerical backcalculations for each fiber group. We utilized a model for fiber-reinforced concrete as prescribed by the fib Model Code 2010 standard. During the iterative numerical analyses we adjusted 8 input parameters: fL, fR1, CMOD1, fR2, CMOD2, fR3, CMOD3 and CMODult. The objective was to accurately simulate the force-displacement curve obtained from laboratory tests. The results of the backcalculations were presented graphically, demonstrating the influence of all 8 input parameters on the shape of the force-displacement curve. An interaction diagram was created following Eurocode 2 and the Austrian Guideline for Fiber-Reinforced Concrete ÖVBB Richtlinie Faserbeton. The input data for constructing the interaction diagram included the thickness of the primary tunnel lining, the width of the analyzed section, the compressive strength of concrete (which can vary over time) and the fiber group. By accomplishing these tasks, we successfully achieved the foreseen objective of the master's thesis. During the process we also identified areas for improvement and obtaining more precise results during the research process.
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