Field Experimental Study On Grain Sorting Behavior And Dewatering Technique Of Fine Particle Area In Dredged Slurries Reclaimed Land At Huaigan Xiangfu

For the river dredging engineering in Xiangfu reaches of Huai River,dredged slurries are disposed by the reclaimed land,which requires the requisition of large area of agricultural land along the Huai River.As a result of the method of hydraulic filling,the behavior of dredging slurries grain sorting will lead that fine particles,low permeability dredged slurries are aggregated around outfall area.Meanwhile the dredged slurried will keep a state of high water content for a long period of time,therefore it is difficult to satisfied the conditions of conversion of the reclaimed lands to agricultural fields.And The long-term high water content of dredging slurries around the outfall area is also extremely adverse for the seepage stability of cofferdam.So the determaining of the fine partical area,the rapid decreasing of the water content of the dredged slurries are crucial for agricultural fields and the seepage stability of cofferdam.Based on the above engineering problem,the analysis of the area of the fine partical area in the outfall area,the grain sorting rule and the dewatering technique effect in the reclaimed land are studies in this thesis.This main works in this thesis are as follows:(1)Field sampling at different locations of reclaimed land of dredged slurries are to determining the particle size distribution,water content,limit water content and specific gravity of dredged slurries.The spatial distribution of dredged clay particles,water content and limit water content in the reclaimed lands are discussed.The results show that the fine particle content and water content of dredged slurries increase gradually with the increase of distance of inlet reclaimed land,while little changes around the inlet reclaimed land.The liquid limt and plastic limit around the outlet increase gradually with the increase of distance of inlet reclaimed land.In addition,with the increase of depth,the clay content,water content,liquid limit and plastic limit water content of dredging sludge are gradually decrease;(2)The area of fine particle area in the reclaimed land is determined based on the clay content in dredged slurries.Though the analysis of the the water content and the limit water content in the fine particle area,the results show that it is feasible to determine the fine particles area by the distribution of clay content;(3)The high water content dredging slurries at the outlet reclaimed land is treated with the dewatering technique.The solid content of tail water,the height of slurries surface,the water content of treated area,the infiltration line and strength of dredged slurries are measured,and the effect of dewatering technique on high water content is analyzed.The results show that the dewatering technique discharged the tail water with a low solid content to meet the requirements of the surrounding environment.At the same time,the water content of dredged sludge is obviously decreased during the reclamation process,and the seepage stability of the cofferdam meets the stability requirements.In addition,the surface strength of dredged sludge is significantly improved to meet the tillage requirements.