The sealing of the hydroelectric power plant reservoirs

Magistrska naloga opisuje različne tipe visokovodnih pregrad, njihove prednosti in slabosti. Poudarek je na zemeljskih pregradah. Predstavljeni so osnovni elementi zemeljskih nasipov, njihove funkcije in različne tehnologije tesnjenja. Podana je pomembnost in zahtevnost zemeljskega visokovodnega nasipa kot objekta 3. geotehnične kategorije, ki potrebuje kvalitetne in strokovno korektne standarde ter smernice za projektiranje in izvajanje. Zaradi nedodelanosti nacionalnih standardov in pravil se udeleženci projekta zatekajo k tujim smernicam, ki morajo vsaj ustrezati merilom in osnovnim zahtevam po globalni stabilnosti po EVROKODU. Velika potencialna nevarnost ob porušitvi objekta zahteva avtomatizirano tehnično opazovanje, ki pošilja podatke v realnem času v bazo, kjer se jih s pomočjo programske opreme obdela in analizira. Monitoring parametrov, ki vplivajo na stabilnost in funkcionalnost (meritve deformacij in filtracije vode), predstavlja le majhen odstotek (do 3 %) vrednosti celotne investicije, kar na oceno tveganja ob primeru katastrofe predstavlja minimalni vložek. Izdelano je finančno ovrednotenje različnih karakterističnih prerezov nasipa na akumulacijskem jezeru na spodnji Savi, ki je pokazalo, da zmerno povečan obseg zemeljskih del bistveno ne spremeni vrednosti nasipa na tekoči meter, saj se izravnava masne bilance nasipa dogaja v prečni smeri s čim manj transporta materiala. Večji vpliv na vrednost ima izbira tehnologije tesnitve. Izvedena je bila analiza alternativnega predloga izvedbe tesnitve z betonsko oblogo (nasip po metodi \u27\u27CFRD\u27\u27) v programu PLAXIS 2D, ki je tehnično sprejemljiva, vendar neprimerna za izvedbo na območju bazena HE Brežice, saj je le ta predolg in preširok. Ugotvoljeno je bilo, da pri večjih dimenzijah kanala izvedba betonske obloge predstavlja ogromen poseg v okolje in ni več finančno ustrezna.Master thesis describes the different types of large dams and their pros and cons. The emphasis is on the embankment dams. The basic elements of embankment dams, their functions and different types of sealing are presented in the thesis. Because of their importance and complexity the embankment dams are ranked as objects of third geotechnical category. Such major object requires high quality and professionally correct standards and guidelines for design and construction. Due to the lack of national standards and rules civil engineers use foreign guidelines which must at least meet the criteria and basic requirements for global stability in EUROCODE. A high potential risk of collapsing earth dams requires automated technical observation in real-time connected with specific software. The monitoring of parameters that affect stability and functionality (deformations, water filtration and leakage) represents only small percentage (up to 3 %) of the value of the total investment. The financial evaluation of various characteristic cross sections of the embankment on the hydroelectric power plant reservoir on the lower Sava has shown that moderately increased amount of earthwork does not significantly change the value of the embankment per meter, since the equilibrating of the mass balance is done in transversal direction of the dyke. The choice of sealing technology has much greater impact on the value per meter. The geomechanical analysis of the alternative cross section sealed with reinforced concrete (CFRD) made with software PLAXIS 2D demonstrated that such dyke could be constructed in the basin Brežice. However, this type of dyke is not suitable for this particular reservoir because of its size. The construction of concrete lining is not appropriate for large riverbeds since it has huge environmental impact and it is also not financially adequate