The purpose of master's thesis is the analysis of a road section, which is partly constructed as cut and cover tunnel and partly in form of a caisson. The analysis covers the new road section from junction Velenje jug to junction Slovenj Gradec on the third development axis that will establish a road link from the Koroška region to the southeastern part of Slovenia (from Austrian to the Croatian border). The geotechnical analyses of the proposed structures are difficult due to the demanding geotechnical conditions governed by the high groundwater level and low bearing capacity of soils. The groundwater in some parts is even under artesian pressure. The analyses were made with geotechnical software Plaxis 2D. Four different cross sections along the road section were analysed. Two in the form of a cut and cover tunnels version and two in the form of caissons. All essential loads and geometric properties of structures were included in numerical analyses with Plaxis 2D. Even small shear keys were considered. Their purpose is to create a connection between the diaphragm (retaining) wall, which is required to carry out the pit excavation, and final structures. The structures are designed as sealed, using impermeable HDPE membrane as waterproofing, but allowing free flow of water along the contact between the diaphragm and structure walls. During the construction of the structures the drainage system made of round pipes with diameter of 200 mm is necessary to prevent hydraulic failure. The optimal level of drainage pipes and length of diaphragm wall was determined based on the analyses of the critical cross section HC-86 and then adopted for the analyses of other three cross sections. During the excavation process the diaphragm walls are supported with mechanical struts to reduce internal forces and maximum movement of diaphragm walls due to high lateral pressures. The numerical analyses included all construction phases from initial to final state, where the drainage system is terminated. The master's thesis also presents the basic control procedures for hydraulic failures according to Eurocodes. Various terms related to construction elements and analyses procedures are also explained. Various controls, analyses and dimensioning of structural elements are presented in the last part. The optimal drainage level was analysed in the order to prevent hydraulic failure and the essential elements of structure, drainage pipes and shear keys were dimensioned.
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