| Summary: | Thesis (M.Eng.)--Memorial University of Newfoundland, 1989. Engineering and Applied Science Bibliography: leaves 193-200. An experimental program was carried out to examine the influence of the presence of an offshore structure on the pore pressures in a soil bed under the influence of wave loading. A bed of silt 0.4 m deep was placed in a wave tank and subjected to waves ranging in frequency from 0.6 to 1.2 Hz. generated by a flap type wavemaker. Pore pressures in the soil bed and wave heights were measured and recorded. Then a model of a gravity based offshore oil exploration platform was placed on a sand berm over the soil bed and subjected to waves at the same frequencies as without the model. The bottom pressure wave data was compared to those predicted by linear wave theory and pore pressure in the soil bed for the case without the model in place were compared with those predicted by the Putnam-Liu solution. Also, pore pressures with and without the model in place were compared. It was found linear wave theory accurately predicts the magnitude of the bottom pressure wave, while measured pore pressures varied considerably from those predicted by the Putnam-Liu solution, depending on frequency. It was found that the pore pressures were lower in both sand and silt when the model was in the tank for similar wave heights and frequencies and that pore pressures built-up rapidly in the sand berm with wave loading.
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