A study of the rheological consolidation test and rheological model parameters for the Ningbo soil layer

Consolidation and rheological properties of soft soil and their values are important parts of the researches of long-term settlement of structures on soft ground. A series of rheological consolidation tests for two typical soil samples in the Ningbo Rail Transit project are carried out based on the advance GDS consolidation test system. Parameters of the primary consolidation and secondary consolidation behaviour of soft soil are obtained based on the test. On the basis of the introduction of a three components rheological model (Gibson model), the model parameters for the three components rheological model are obtained by using the Matlab fitting method. The results indicate that the secondary consolidation behaviour of the Ningbo soft soils exhibit obvious nonlinear properties; the secondary consolidation coefficient is approximately in linear relation to the compression index and there is Ca/Cc=0.02±0.01; the one-dimensional rheological consolidation behavior for the Ningbo soft soil agrees with the Gibson’s three components rheological model; the modulus and viscosity coefficient of the rheological model increase with the increasing consolidation pressure.