Study On The Work Behavior Of Concrete Face Rock-fill Dam During Construction And Impoundment Period

Being provided with small investment, short working period and many other advantages, the concrete face rock-fill dams (CRFD) have become one kind of the competitive dam types. Rockfill, as the main material of CRFD, its constitutive model selection and parameters determination are always difficult in the earth-rock dam numerical analysis. The domestic researches of the rockfill’s constitutive model are based on the hypothesis of generalized hook’s law and the traditional theory of plasticity, for example, Duncan E-B model, ShenZhuJiang double yield surface model and multi-potential surface model. However, the result of Duncan E-B model shows that the tensile stress is larger in the basement of concrete face, and the ones of ShenZhuJiang double yield surface model shows that the displacement is small. Therefore, a parameter-adapt and simple-mechanical constitutive model, which can reflect the actual stress-strain of the concrete face, is of great demand. The main contents are as follows:1.In this paper, Duncan E-B model, ShenZhuJiang double yield surface model and multi-potential surface of the constitutive model have been reviewed and analysised. Based on the previous study of the project group, which use the E-B model parameters in multi-potential surface model, and using the loading-unloading criterion of Duncan E-B model to judge the superiority of the loading-unloading of multi-potential surface model. Put forward using the E-B model parameters in ShenZhuJiang double yield surface’model, the stress and deformation analysis of Upper reservoir of Xianyou CFRD is carried out by using the 3-D FEM nonlinear program. Campare the results of calculation with the ones using Duncan E-B model, E-B model parameters in multi-potential surface model, ShenZhuJiang model parameters in multi-potential surface model, ShenZhuJiang model parameters in ShenZhuJiang double yield surface model, ShenZhuJiang model parameters in ShenZhuJiang model parameters in ShenZhuJiang double yield surface model and the the unloading poisson’s ratio is 0.3, ShenZhuJiang model parameters in ShenZhuJiang double yield surface model and the value of q is (?), the superiority of the model is prominent.2. The 3D nonlinear FEM calculation method adopts the mid-point increments to simulate the stage construction and impounding at the loading process. Using the linear elasticity model to simulate the concrete face, the non-thickness Goodman element is used to simulate the joint model of face to face, face to toe board and contact model of face to bedding cushion.3. Using E-B model parameters in the three models, compared the calculated settlement with the measured data. Compared the calculated stress and deformation of the concrete face, and compared the displacement of peripheral joints and vertical fracture with the project both domestic and foreign. The results show that when using ShenZhuJiang model parameters in Duncan E-B model, the maximum settlement are in good agreement with the measured data.The calculated displacement of peripheral joints and vertical fracture is smaller when campared with similar projects.The conclusion is that the results of using ShenZhuJiang model parameters in Duncan E-B model can avoid the larger tensile stress in the basement of concrete face, and overcome the small displacement in using ShenZhuJiang double yield surface model, which will have a greater applied prospect in engineering application.