The master's thesis examines the use of deformation elements in tunnel construction in squeezing rock masses, with particular emphasis on their application within the primary support of the eastern tube of the Karavanke motorway tunnel. On the Slovenian side of the tunnel, the excavation trough the Permo-Carboniferous section, particularly within the Hrušenska Fault Zone, was accompanied by large and largely anisotropic rock mass deformations that caused damage or failure of the primary support along longer sections of the tunnel. The thesis first presents the behaviour of highly deformable rock masses and the principles of flexible support systems and deformation elements. In the analytical part, the actual behaviour of the installed LSC-N deformation elements is evaluated based on geodetic measurements, photographic documentation and a visual assessment of the observed deformation mechanisms. The results indicate that the deformation capacity of elements was poorly utilized along most of the analyzed section and that the elements frequently did not deform as designed. Instead of predominantly axial compression, shear deformation and rotation of the elements were commonly observed. In the final part, numerical modelling in Plaxis 2D was used to analyse the influence of different deformation element positions on the deformation response of the tunnel and on loading of the primary support under both isotropic and anisotropic rock mass conditions.
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