. Concepts for drilling and excavating in and below the ocean bottom. Underwater drilling; Ocean bottom. ^3 FLANSE OP. TWENTY 2V-BN-2« 23' a TWO '/"z'tPT. REO'O FOR INSTRUMENTATION w. Figure 72. Experimental GRAYLOC flanged test fixture, showing details of gasket shape (Mikesell and Brown, 1968). Dewatering of a cavity sealed as discussed above and diagrammed in Figure 57, does not appear to present any insurmountable problems but will require very careful planning. One approach might be to drop a partially insulated container of liquified air in the excavated space before closing the hat
. Concepts for drilling and excavating in and below the ocean bottom. Underwater drilling; Ocean bottom. ^3 FLANSE OP. TWENTY 2V-BN-2« 23' a TWO '/"z'tPT. REO'O FOR INSTRUMENTATION w. Figure 72. Experimental GRAYLOC flanged test fixture, showing details of gasket shape (Mikesell and Brown, 1968). Dewatering of a cavity sealed as discussed above and diagrammed in Figure 57, does not appear to present any insurmountable problems but will require very careful planning. One approach might be to drop a partially insulated container of liquified air in the excavated space before closing the hatch and providing a siphon (Figure 73) so that as the liquid air boiled and displaced the water, the air would remain as a large bubble. The system would still be at ocean pressure, and a previously installed pump would be energized by power from the surface to reduce the high-pressure air to the desired one atmosphere. There would always be the danger that combustible gases from a subbottom source would provide an explosive atmosphere. Since these gases might not easily be detected or might not be released at full ocean pressure, one method might be to charge the space with liquid nitrogen initially and later provide oxygen just before the entry of personnel. Summary Methods for sealing and dewatering a subbottom cavity in rock appear to be within the state-of-the-art. Further trade-off studies and investigation of potentially superior systems are needed. 94. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Naval Civil Engineering Laboratory (Port Hueneme, Calif. ). Port Hueneme, Calif. : Naval Civil Engineering Laboratory
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Keywords: ., bookcentury1900, bookcollectionbiodivers, booksubjectoceanbottom
