Study On Engineering Characteristics Of Dredged Sludge Based On Calcium Flocculant

In recent years,with the rise of sea reclamation,more and more dredged silt is produced during construction.Because of its high content of fine particles and extremely low bearing capacity,dredged silt cannot be reused directly.Yard in order to shorten the time and speed up the construction site,to carry on the vacuum preloading treatment,although the vacuum preloading technology has already widely used in engineering,but it still exists the drain siltation,attenuation problem such as vacuum degree,so in order to make dredged silt foundation bearing capacity,vacuum preloading technology still needs further improvement.In this paper,a series of laboratory tests and studies have been conducted on dredged silt with high moisture content in Bengbu.The research contents is as follows:First,two kinds of calcium flocculants(Ca(OH)2 and Ca Cl2)were selected to conduct flocculation deposition test through the flocculation gauge test to explore the influence of different kinds and different dosage on the self-weight deposition characteristics of dredged silt.The results show that the effect of Ca Cl2 on the self-weight deposition characteristics of dredged mud with high water content is better than that of Ca(OH)2,and the settlement rate is also faster.The optimal content of Ca Cl2 is only 0.25% of the dry soil mass,while the final moisture content of Ca(OH)2 increases with the increase of the content,and the flocculation effect is not obvious.Second,conduct indoor flocculation-vacuum preloading simulation test,analyze its vacuum degree,settlement amount and water output during the test process,and test the moisture content and compressive strength of soil after vacuum pumping.Finally,the content of calcium flocculant most suitable for dredged silt in Bengbu was obtained as follows: Ca(OH)2 with dry soil mass of 0.5% and Ca Cl2 with dry soil mass of 2%.Finally,through unconfined compression test,the influence rule of initial moisture content,flocculant content and age of dredged silt on unconfined compression strength and stress-strain curve of dredged silt solidified soil is analyzed,and it is concluded that Ca(OH)2 has more significant influence on early strength of solidified soil,while age has greater influence on solidified soil E50.