Master thesis is focused on the rationalization of production of the forming segment, which is manufactured by company OMNI-X CZ. Familiarization with the product „forming segment“, with issue of production with possibility improvment. The work is also focused on the preparation of the clamping fixture, which should improve the production conditions. The main point of the work include the calculation of cutting forces, clamping forces of the fixture, verification of safety process with economic evaluation. The aim of this master thesis is to indicate the possible direction of the rationalization of the manufacturing of the shaping segments for OMNI-X CZ.

Block stability is common and has to be studied in detail for designing tunnels. Stability of block depends upon the shape and size of the blocks, stresses around the block and factors such as clamping forces and the ratio between joint stiffness. These factors are studied in detail and are the main objective of this thesis. In this thesis influence of loading and unloading of blocks on joint stiffness and thus on ultimate pullout force are analyzed. Normal stress on the joint plane is linked with shear stiffness of the joint and relaxation of forces. Changes of forces were considered to estimate joint stiffness and ultimate pullout force using new methods in the present thesis. First method takes into account changing clamping forces considering stiffness ratio constant (Crawford and Bray). The second method was developed in which the ratio between normal and shear stiffness was taken as a function of normal stress (Bagheri and Stille). In third method, gradually pullout force is increased which changes the normal stress and joint stiffness. The lower limit of joint stiffness gives a very conservative design. So a stiffness value based on the average of lower and upper limit of normal force has also been considered. A comparison between the new methods and the previous method proposed by Crawford and Bray which considers a constant ratio of normal and shear stiffness and constant clamping forces shows that Crawford and Bray’s solution overestimates the pullout forces hence the design is unsafe. It was observed that stiffness ratio is an important factor for estimating required rock support and safety.