Study On Stress And Deformation Of Concrete Face Rock-fill Dam By Finite Element Calculation

Concrete Face Rock-Fill Dam is one of the main dam types of earth and rockfill dam. It is primarily made of rockfill and gravel, which is of bearing function, and atthe upper side of darn,the concrete face is located, which is of antiseepage function. The concrete face dam has the advantage of low requirement for foundation, easy diversion, low cost, convenient and fast construction, etc, and it is one of the three new dam types that are popularized in current water resources and hydropower engineering.Rockfill as the main material of embankment dams, its constitutive model selection and parameters determination was a difficult problem all the time in the numerical analysis of earth-rock dam. At present the building of commonly used constitutive model of rockfill was mainly according to assumptions and concepts of generalized Hooke’s law or traditional plastic constitutive theory in domestic stress-strain analysis of CFRD. Such as Duncan E-B model, ShenZhuJiang double yield surface model, etc. Yang Guanghua, with other people, has put forward the multi-potential surface of the constitutive theory basing on the generalized plastic mechanics theory, starting directly from the mathematical principles and avoiding the traditional theory of elastic-plastic yield surface which relates to the inherent difficulty in the concept.the main contents and results of this paper are as following:1.In this paper, two kinds of commonly used rockfill constitutive models and multi-potential surface model have been reviewed and analysised. On the foundation of predecessors Studies, multiple potential surface model parameter selection ShenZhuJiang model parameters, ShenZhuJiang model and multiple potential surface model are fully considered the unloading cases constitutive model. Unloading poisson’s ratio of the traditional model was taken for 0.3, This paper reference for the practice of predecessors, the initial poisson’s ratio of Duncan E-B model will instead of unloading poisson’s ratio, the calculation results improved. Of course, due to the lack of test test practice, its rationality needs further research2.The stress-deformation analysis of Upper reservoir of Xianyou CFRD with the model is carried out by using the developed 3-D FEM program, and results are compared to show the superiority of the improved model. The FEM calculation method take advantage of the mid-point increments to simulate stage construction and impounding at the loading process. In this proceduce,linear elastic constitutive model is celection to simulate concrete panels, and Goodman thickness of cell-free is used to simulate the interface between the panel and cushion besides the water sealing connection between the vertical joints and the peripheral joints.3.At last, settlement calculated by the three model are compared with the measured maximum value. The results show that ShenZhuJiang model fully considered the unloading cases constitutive model is in a good agreement with the measured maximum value.This overcome the problem of smaller vertical displacement calculated with Shen Zhujiang’s double-yield surface model before. Multiple potential surface model stresses along slope direction occurring at the bottom of face slabs calculated by multiple potential surface model is more close to ShenZhuJiang model results.But the displacement value is smaller.