Study On Creep Characteristics And Model Of Soft Soil In Ningbo

In recent decades,with the Chinese rapid economic development,the development of coastal areas is particularly rapid.The rapid development of economy with the rapid construction of high-rise buildings,highway,railway,subway,pit and other buildings,Chinese coastal areas are widely distributed in a large number of soft clay.Because of the characteristics of soft soil,the deformation of soft soil has significant characteristics.It often leads to a large number of Engineering settlement occurred.Based on the review of present research,one-dimensional consolidation creep,one-dimensional over consolidation,and triaxial shear creep of the soft soil in Ningbo coastal region are conducted.Through the analysis of the test data,the consolidation creep property characteristics are studied,changing before and after the creep test,the microscopic analysis of the soft soil is carried out.Base on the test result,empirical creep model and creep device model suitable for this region are established.The following conclusions are obtained:(1)By loading one-dimensional consolidation creep tests and one-dimensional over consolidated soil test,the strain rate method and Casagrande method to classify the primary and secondary consolidation,consolidation of Ningbo undisturbed soil and remolded soil and over consolidated soil and the completion time of the secondary consolidation coefficient.(2)The three axis shear creep test was carried out by using the method of respectively.The effect of OCR on the axial strain was studied,the relationship between the strain and time logarithmic curve was analyzed,and the "strain rate method" was used to classify the primary and secondary consolidation.(3)Soil samples were scanned by electron microscope(SEM)before and after the experiment,and the microstructure and the change of soil samples under different test conditions were quantitatively analyzed.Quantitative analysis of microstructure of soil samples by Image-Pro Pius technology.(4)The creep test results to establish empirical model is established for based on the three device model and five device model;and the rule of change of the model parameters,physical significance,advantages and disadvantages were analyzed.