3D Finite Element Analysis Of CFRD Considering The Rheologic Character Of Rockfill

Rolled-concrete face rockfill dam which has developed since the late of 1960s under the efforts of the international dam workers is a kind of new dam. With the merits of the throwed-filled face rockfill dam and without the defects of it, the rolled-concrete face rockfill dam has been given great attention because of its strongpoint such as little input, short period, good security, easy finding materials, convenient construction, facility river diversion and wide adaptability.Methods such as linear elastic finite-element method, nonlinear finite-element method and elastic-plasticity finite-element method can be used in the structural analysis of concrete face rockfill dam. The structural characters of the face rockfill dam can be reflected by the results of nonlinear FEM and elastic-plastic FEM in a certain extent. However, the rockfill which is neither elastic body nor plastic body is in fact a synthesis which has qualities of elasticity, plasticity and viscidity. Except stress, time also has influence on the distortion of the rockfill, and this kind of material characteristic is often called rheologic character. The most important matter of the concrete face rockfill dam is to control the distortion of the dam body, and the dam distortion resulted by the rheologic character is greatly influenced by time, and many face rockfill dams also have sedimentation several years after its completion, so considering the influence of the rheologic character when solving the distortion of the face rockfill dam is very important to the development of the rockfill dam in China.First, the introduction of the basic elastic-plasticity theories of the nonlinear FME in the hydro-structure projects is given in this paper, then the basic equations, constitutive relations and yield rules of the materials under the elastic-plastic conditions are showed. The paper also has given the mechanics of the rheologic character and several kinds of rheological models, and the six-parameter rheological model is used in the paper. After reading lots of papers which are related in the numerical simulation in the hydraulic engineering, the author gives many numerical simulation methods which are common used in hydraulic-structure projects. The paper has used the FEM software ANSYS and given the secondary development of it, and the numerical simulation which fits the constitutive relations of rockfill is established by the use of AODL language. After the modification of the material quality subroutine in the ANSYSY software, the six-parameter rheological model is called in to do calculation as a subroutine. According to the XIALIUJIA concrete face rockfill dam, the sedimentation quantity in different work conditions and the influence on the dam face by the stress and strain are researched, and the sedimentation quantity, stress and strain when considering the influence of rheologic character are calculated, after these calculations the stress and strain of the face is studied. According to the comparison and analysis of the results of the two methods which consider or not consider the rheologic character, conclusion that the rheologic character has great influence on the stress and strain of the face can be achieved.