Development of Dredged Mud Stabilization Method By Pneumatic Bent Tube System

摘要

: Generally, dredged mud placed in a disposal pond needs to be improved to obtain sufficient bearing capacity for land use. For this soil improvement, draining methods such as a sand drain method are normally used. These improvement methods, however, require a long construction time and are of high cost. In order to convey low moisture content mud dredged by a grab dredger to a disposal pond, a pneumatic tube system is used normally. The dredged mud consolidation method developed here is able to reclaim sound foundation land by using a modified pneumatic tube system. Cement paste is injected (approximately 50 to 80kg per 1m~3 of mud) to mud flow in a pneumatic tube and it is mixed with the mud by pneumatic force particularly during flowing in a specially designed tube called SNAKE MIXER (patented). The Snake Mixer is composed of a series of bent tubes inserted in liner tube to stimulate the mixing of the mud with cement paste. This newly developed mud consolidation system is able to convey low moisture content dredged mud and mix in cement paste with in order to reclaim sound foundation land. The maximum treatment capacity of this system is approximately 1000 m~3 per hour currently. This system promotes efforts to recycle waste mud for efficient use by adopting a system cheaper and faster than conventional soil improvement methods. The paper reports on the characteristics of the Snake Mixer and gives examples of actual works conducted in various fields.