Rheological Model And Permeability Coefficient Influence Research On Core Wall Rockfill Dam Deformation

Core wall rockfill dam has the advantages of making good use of local or nearby materials,adapting to the different deformation,flexible construction method,quick construction speed,easy to facilitate maintenance,which is preferred and widely used in the dam engineering field,core wall rockfill dams develop rapidly especially in our country over the past twenty years,with a large number of higher dams of two hundred meters(or more)already built,under construction and planning to be built.At the same time,there are many technical problems to be solved,the research of which on influential factors of high core wall rockfill dam deformation has become a critical issue.The application of nonlinear finite element method for rockfill dam deformation calculation provides an efficient solution,and the rheological model research,including all kinds of exponent model,logarithmic model,affects soil deformation calculation for a long time and has solved many key technical problems in engineering,contributing to the development of rockfill dam design theory in our country.But research on rheological model contrast application is still inadequate,leading to choosing rheological model seeming quite difficult in practical engineering,so conducting comprehensive comparison and application on rheological model will be of great significance.Meanwhile,core wall permeability space change influencing on the instantaneous deformation doesn't still cause enough attention.On the basis of extensive reading related literature from home and abroad,in the view of rheological model and the inversion analysis of long-term deformation parameters,the article selects two rheological models commonly used in current domestic long-term deformation of rockfill dam: Shen Zhujiang three parameters model and IWHR logarithmic model.First of all,theoretical contrast between the two models above has been carried out.Then,model parameter is worked out based on indoor test conducted by predecessors and similar engineering analogy rheology.Based on Xiao Langdi inclined core wall rockfill dam,finite element model has been built,discussing respective characteristics of the two rheological models in reflecting long-term deformation characteristics on rockfill,and logarithmic rheological model's practical advantages is to be reviewed on rockfill long-term deformation characteristics.But the deviation between measured value based on initial model parameters and calculated value is bigger.So it is necessary to inverse analysis deciding model parameters.Finally,the result calculated by inverting parameters and measured value coincides well,which can be used to predict long-term deformation.On core permeability study,the text starts with the factor of core wall permeabilityspace change which affecting the instantaneous deformation,combing with indoor compression test of core wall rockfill dam and permeability test,and examines the core wall permeability space change on the influence of deformation prediction.Through the thorough analysis above,conclusions can been drawn as follows:long-term deformation calculated by logarithmic rheological model,conforming to real measuring value,is more consistent in the displacement development trend.The long-term deformation calculation based on the inversion parameters can be used to predict core wall rockfill dam displacement and evaluate dam safety,and core wall permeability space change can also predict dam instantaneous deformation more accurately.