Consolidation Deformation Characteristics And Calculation Methods Of Recently Dredger Fill

In recent years,the reclamation area are increasing sharply in the coastal areas of China.There are great difference between derdger fill and natural sedimentary soil in engineering characteristics.Generally,there are a long period of natural deposition for natural sedimentary soil,so it has a certain stress history and structural characteristics.However,the time of filling from the completion of the dredger fill to the project construction is short,and the deformation characteristics of derdger fill is different form natural soil for its large pore ratio,high water content,high permeability and compressibility.Therefore,the consolidation deformation and long-term deformation characteristics of dredger fill need to be studied.It's found that the settlement of the dredger fill reinforced using vacuum preloading has a large settlement after the vacuum preloading.In this thesis,the consolidation deformation characterstics are studied and the content is as follow :(1)The permeability and compression characteristics of dredger fill are studied using permeation and consolidation apparatus.The calculation model of the permeability and the compression are proposed.(2)Base on the theory of large deformation consolidation,an analytical solution of consolidation deformation considering consolidation of soil below dredger fill is proposed,and a program is compiled using finite difference method.(3)The factors affecting consolidation characteristics of dredger fill is analyzed in this thesis.Based on the theory of large deformation consolidation,some influence factor are analyzed to provide parameter basis for design and construction including the consolidation curves of sand drain(drainage plate)setting depth,sand well spacing,equivalent radius of drainage plate and consolidation stress.(4)The reasons for the settlement development after vacuum consolidation unloading are analyzed by the stress path test.The influence law of different principal stress ratio on the deformation characteristics after unloading was gaven and the deformation characteristics after unloading in different depth soil was analyzed.(5)The creep characteristics of dredger fill under different stress paths are studied using three axis stress path tester.The influence of stress path on the creep characteristics of foundation was analyzed,and the Singh-Mitchell creep empirical model of new dredger fill was established.