Analysis Of Stress And Deformation Of CFRD Based On Transverse Isotropic Model

Concrete faced rockfill dams(CFRD)has benefited from its many advantages and has been widely applied in recent years.There is a growing number of high and super high CFRD as design and construction technology progress.The finite element method can to some extend reveal the character of the stress and deformation of a dam.However,due to the complex characteristics of rockfill,the result is often different from the measured value,while the material parameters are usually from the indoor triaxial test,the effect of contractible dimension should be taken into consideration.Rolling compress construction is adopted in CFRD construction,therefore the rockfill can be regarded as transversely isotropic body,nevertheless,commonly used nonlinear elastic models consider the soil as an isotropic body.To improve a model to correctly simulate the transversely isotropic character and obtain model parameters through back-analysis with measured data can not only make the calculated value of the deformation more consistent with measured data,but also make the prediction of operation of dam more precise,which has great importance for engineering practice and design.Based on the basic theory of transversely isotropic,the paper analyzes the flexibility matrix of the transversely isotropic body in order to acquire its stiffness matrix.Based on the Duncan E-B model,the transversely isotropic model is developed through the UPFs tool of ANSYS secondary development,using displacement back-analysis based on differential evolution algorithm(DEA)to obtain appropriate parameters.The finite element analysis of Tankeng concrete faced rockfill dam is carried out by using the transversely isotropic model and the E-B model respectively.By comparing the results of these two models and the measured data,the reasonability and the effectiveness of transversely isotropic model are verified.The main contents of this paper are as follows:1.The stiffness matrix of transversely isotropic model is deduced from the flexibility matrix,and the UPFs tool developed by ANSYS is used to develop the transversely isotropic model subroutine.2.Combining the three-dimensional finite element method and the intelligent optimization method,gathering measured data for the anti-measuring point for back-analysis,constitutes the fitness function by least squares of deformation between in-situ observation data and finite element value,3.Introducing the method of displacement back-analysis based on DEA,parameters are got by back-analysis according in-situ observation data of Tankeng CFRD;4.With parameters acquired from back-analysis,three-dimensional calculation of the CFRD is carried out.By comparing the results of transversely isotropic model,Duncan E-B model,and the results of the transversely isotropic model are closer to the measured data.