| 摘要 |
PURPOSE:To permit sand-covering operations to be performed and also the sludge layer to be improved by a method in which the sludge layer of the bottom under water is tilled by excavation and laminated with good-quality sand. CONSTITUTION:A sand covering device 8 is supported on the organic sludge layer 3 of the bottom under water by means of a guide pipe 7 hung down from a working ship and slowly moved. Good-quality sand is supplied through the pipe 7 to the device 8 and a tilling device 9 is turned. The sand is dropped through supply pipes 10 and 11 before and behind sides of the tilling device 9 to mix the sand and the layer 3 with stirring, where the sand dropped from the supply pipe 10 is laminated on the mixed sludge. The layer 3 can thus be improved and the sand-covering work can be attained.
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