Hydrodynamic Stability of Offshore Pipelines

U ovom diplomskom radu je obrađena tematika polaganja podvodnih cjevovoda, kao i ispitivanja stabilnosti istih. Svi podvodni cjevovodi moraju biti projektirani i izvedeni na način da zadrže stabilnost uslijed djelovanja hidrostatičkih i hidrodinamičkih opterećenja. Dakle, potrebno je dokazati stabilnosti konstrukcije pod utjecajem valova i struja. Svakako jedan od češćih zahtjeva je ograničenje horizontalnih/vertikalnih pomaka ili pak, dopuštenje limitiranih pomaka, pod uvjetom da isti ne dovedu do bilo kakve materijalne štete ili opasnosti. Proračun stabilnosti je proveden u posebno izrađenom obrascu (MS Excel), pri čemu su usvojene DNV RP E305 norme. Posebno je izrađena parametarska analiza, u kojoj se, pokazalo na koji način su ovisne pojedine veličine. Konkretno se tražila veza između minimalne potopljene težine cjevovoda i utjecajnih faktora poput visine valova, perioda valova, dubine vode, promjera cjevovoda i dr. Cilj prethodnih istraživanja je upravo utvrđivanje na koji način i u kojoj mjeri različiti čimbenici utječu na stabilnost cjevovoda.This master thesis deals with a submarine pipe laying, as well as determining stability. All submarine pipelines have to be designed and built so they can obtain the stability in spite of hydrostatic and hydrodynamic loads. Thus, it is necessary to prove the stability while the construction is exposed to waves and currents. One of the requirements is especially to completely limit horizontal/vertical movements or, to let some happen but not at the cost of any kind of material damage. Calculation of stability is carried out in MS Excel spreadsheet. DNV RP E305 code is used for this. An parametric analysis is specially carried out, which has shown relationships between some parameters. In this case, it is demonstrated, in which way the minimum submerged pipeline weight depends on some factors such as wave height, wave period, water mean depth, pipeline diameter etc. The point of this study was to determine in which way and at what intensity do different factors affect pipeline on-bottom stability