Creep Characteristics Of Soft Soil And Post-Construction Predicted Research On Road Foundation

The deformation under the constant stress growth with the time is the creep of soft soil.As the role of soft soil creep, it will inevitably produce excessive settlement when building Construction on soft soil, this paper combined with the Transportation Projects (2008CDB369) "microstructure effects in Consolidation process of soft clay and Monitoring of Freeway" and Key project of Ministry of Education Project (109110) "microstructure effects in Consolidation process and settlement analysis of soft clay" In Hubei Province, relied on treatment of soft clay foundation in Wuhan to Yingshan expressway.Soft soil creep Characteristic and Settlement Law in typical section systematic studied based on laboratory experiment and in-situ observation。Meanwhile, the settlement after the issue was explored, numerical simulation was used by ABAQUS in the actual project.And compared the simulation results and the measured results, the following main contents and conclusions as follow:First, Soft soil creep Characteristic Analysised based on laboratory experiment and in-situ observation, Soft soil creep constitutive model and calculation parameters was determined。The variation of surface settlement,lateral displacement,pore water pressure and layered settlement was analyzed and summarized.Second, the numerical simulation was used by ABAQUS in the actual project, the numerical simulation results showed that:(1) Vertical displacement and lateral displacement were calculated by extended D-P model approach to the measured data, the filling speed has great influence on the settlement process, the settlement speed will higher during filling time but smaller during the load time.The excess pore water pressure change as growth-dissipation-growth-dissipation and decreased in the whole process。But larger growth will be appear around 200 days.(2) Taking creep of Soft Clay into account, then to predict post settlement, it could be found that results predicted were larger than results calculated by traditonal method. Greater the height of overloading prepress on soft road foundation was, bigger the surface settlement during period of preloading would be. Within a certain range, Greater the height of overload prepress, shorter the time of preloading would be. But non-linear relationship existed between each other, because with the preloading height increased, the preloading time would upturn.Finally, comparing numerical simulation results with results of in-situ test, it could be concluded that considering creep was necessary during treatment of Soft Clay. In the actual project, various factors should be considered in determination of overloading heigt during preloading.