Theoretical And Experimental Analysis Of Liquid Rheology Coupling With Consolidation On Soft Clay

Soft clay distributes widely in coastal areas and has significant rheological properties.Rheology has a significant impact on the long-term strength and deformation of soft clay.Experimental research for the influence of material composition on soft clay rheological properties verified that the rheology of soft clay is mainly caused by the shear viscous flow of highly viscous substances(called rheological substance)in clay,such as organic matter,oxide,absorbed water film,and the micro-clay particles enveloped by the absorbed water.Therefore,the rheology caused by rheological substances is called " liquid rheology".In this paper,the deformation characteristics of liquid rheology coupling with consolidation and its internal mechanism on soft clay have been studied with a combination of experiment and theoretical analysis.A series of soft clay samples with different types and contents of rheological substances were prepared for direct shear liquid rheology test and liquid rheology-consolidation coupling test,and the main factors affecting the liquid rheological properties of soil clay and their mechanism have been analyzed.Through the introduction of multi-element rheological models,the analysis equations of direct shear liquid rheology and consolidation coupling liquid rheology are established,in which the liquid deformation and rheological properties of soils with different types and contents of rheological substances under different loads can be determined uniformly from a set of model parameters.Besides,based on the effect mechanism of shearing force on the water adsorption potential barrier against the mineral surface,the long-term rheological drainage of soil has been explained with the "shear migration drainage" creep mechanism;based on the molecular dynamics simulation results of the adsorption potential of water molecules on the mineral particle surface,the "shear migration drainage" creep equation for soil has been derived from Rate Process Theory.Based on the above research work,the obtained results are as following:(1)The analysis of direct liquid rheological properties of soft clay with different rheological substance contents shows that the rheological substances in soil will first deform and flow,and then "drive" soil particles to move until rheological failure under a shear load;the more content of rheological substances in the soil,the easier it is to "drive" soil particles,which is manifested as a smaller creep stress threshold and viscoplastic viscosity in the macroscopic view.(2)Based on the influence of rheological substance content and load grade on the direct liquid rheological properties of soft clay,a liquid rheological model for soft clay was established by connecting the Binham body and the improved Murayama Shola model in series,in which the Murayama Shola model was improved by introducing a nonlinear spring in the form of a power function;the model contains of parameters that can reflect the effect of the amount of rheological substances,while the direct shear liquid rheological properties of soft clay with different rheological substance contents under different stress levels can be uniformly described with one set of model parameters by it.(3)Based on the deformation characteristics analysis of consolidation coupling liquid rheology of soft clay,a variable-parameter consolidation coupling liquid rheology model for soft clay was established;in which the expression of model parameters changing with effective stress was given according to the evolution law of absorbed water film and pore characteristics during the rheological-consolidation deformation of soil;the model can describe the nonlinear change process of the consolidation coupling liquid rheology characteristics of soft clay,while the model calculation results are consistent with the test results and the model calculation parameters are highly correlated with the content of rheological substances in soil.(4)The calculation results of the "shear migration and drainage" creep equation of soil are in good agreement with the test results,which makes a self-consistent proof for the "shear migration drainage" creep mechanism of soil.