The Creep Property Research Of Dong Ting Lake’s Soft Soil

With the soft soil of Dongting Lake area to the research object, a large number of indoor soil tests are carried out, and the statistical analysis for the physical and mechanical parameters of the soft soil to be done. And based on the conventional triaxial creep test, the creep characteristics of the soft soil of Dongting Lake are studied. The following research results are achieved:(1)By doing a large number of indoor soil tests, physical and mechanical data of soft soil of Dongting Lake are obtained. And using the principle of least squares, the relationship between the various indicators are analyzed, to obtain the regression equation between indicators, and to provide technical parameters for the engineering construction on soft soil foundation of the Dongting Lake area.(2)The indoor conventional triaxial creep tests are carried out, under the different loading ways, and the creep curves are obtained. The comparative analysis are showed that:when the confining pressure is greater, the soft soil creep deformation is smaller; when the confining pressure is smaller, the soft soil creep deformation is greater. Under the same confining pressure, the creep deformation with arithmetic loading way is evidently smaller than with geometric loading way.(3)Under the arithmetic loading way when the confining pressure is 100kPa, the soft soil creep curve are analyzed, using the Merchant model for fitting analysis, we found that the model is not suitable for describing the creep properties of soft soil in Dongting Lake. The fitting analysis with traditional Nishihara model has the same problem, when the stress level is less than the critical stress value. Therefore, this article proposed to modify the Nishihara model, which is to increase the Bingham body in the traditional Nishihara model for describing the stable creep stage, and the modified Nishihara model is suitable to describe the creep characteristics of soft soil in Dongting Lake.(4)By analyzing engineering instance, the modified Nishihara model can better predict the settlement of the soft soil foundation in Dongting Lake area, verifing the correction of the model, and can accurately describe the creep properties of soft soil in Dongting Lake.