Study Of One-dimensional Consolidation And Creep Of Dredge Fill

Dredger fill is a special artificial soil, its consolidation time is longer, with a verydistinct rheological properties. The dredger fill foundation will appear as inadequatebearing capacity, have a great post-settlement, even worse， it would leadto engineering problems such as uneven foundation settlement, ground cracking, thebuilding tilting or even collapse. Academic and engineering circles has beenwidespread concern in the long-term deformation of soft soil, Characteristic ofconsolidation and creep characteristics of soft soil cause deformation has timeliness.So the study of long term deformation mechanism of dredger fill and explore its creepconsolidation characteristics, and further improve the settlement calculation model, isimportant to the engineering that build in the dredger fill foundation.At present in the laboratory study on consolidation creep deformation areassumed to produce no lateral deformation, but for the dredger fill, regions that satisfythis assumption is very limited, in the large load area, or in the edge position of thedam the lateral deformation is often not equal to0, even for the central region also cannot ignore the impact brought about by the instantaneous settlement. This thesis isaimed at dredger fill of Shantou Xinxi area, based on indoor consolidation test (rigidconsolidation and flexible consolidation), theoretical analysis and correspondingnumerical calculation to study the mechanism of consolidation creep deformation ofsoft soil and analysis the influence of lateral deformation conditions on soft soil creepcharacteristics of one dimensional consolidation.main content of research and conclusions are as follows:1. Study on the basic characteristic of dredger fill, the experiment reveals thatthe silt layer of dredger fill in Shantou Xinxi area contains a lot of sand and shellsand other impurities, different depth of dredger fill layers have similar physicalproperties and concentrated distribution, all of them are high water content, high voidratio, low permeability, shear strength is relatively low. The soft soil in ShantouXinxi area are unconsolidated soil, still has the very strong compression. 2. From rigid consolidation test results(lateral deformation is equal to0)can beseen that the boundary between primary and secondary consolidation is very evidentand the most suitable for the Casagrande method to determine when loading ratiogreater than or equal to1. The secondary consolidation coefficient Cawas increased atfirst, after reaching the Peak in the vicinity of the preconsolidation pressure graduallydecreased and finally tends to be stable. The water content, void ratio, test methodsuch as loading ratio, the preconsolidation pressure and other factors will impact onthe secondary consolidation coefficient. Secondary consolidation of soft soil isnonlinear, stress-strain curve can fit a logarithmic function relationship.3. Through the flexible consolidation test(lateral deformation is not equal to0), dredger fill appeared similar consolidation behavior with rigid consolidation test, itshow that those two consolidations have the same consolidation mechanism. Thedredger fill produces large instantaneous deformation, it leads to the completion ofmain consolidation ahead of time and decrease the secondary consolidationcoefficient.4. Based on the three elements model, studies One dimensional viscoelasticproblems for saturated soil of the flexible consolidation test, and deducedthe corresponding analytical solutions, based on the analysis solution analysis theone-dimensional viscoelastic consolidation character of flexible consolidation.