Nonlinear Dynamic Finite Element Analysis On Concrete Faced Rockfill Dam

The concrete faced rockfill dam(CFRD) has the advantages of safe, reliable, economical and practical, adaptable deformation, and good performance on anti-seismic, which has become one of the recommended type of dam. The subject combined with Fujian Xianyou Pumped Storage CFRD Project, develop the CFRD Three-dimensional nonlinear dynamic finite element analysis program independently. Then preliminary study on the regular pattern of stability of CFRD under the dynamic effect has been made, which can provide a reasonable theoretical basis and technical support for seismic design and actual construction for CFRD.The main contents are as follows:1) Extensive reading and study literature data on CFRD seismic analysis of domestic and international, take a summarized on the static and dynamic analysis of CFRD, then a detail introduction about the basic principles of static and dynamic finite element analysis of CFRD has been offered.2) Research a program named CFRDDYNA. F with FORRAN language which can calculation the three dimensional nonlinear finite element dynamic analysis of CFRD under seismic action. The dynamic constitutive model of rockfill use equivalent viscoelastic model, the mode of residual deformation use Shen Zhujiang model, dynamic water pressure use additional mass matrix method of Dam-water interaction. The method of solving nonlinear dynamic equation is using Wilson-θ method in small period and iteration combining large periods and small periods, until the two base frequencies between the iterations close to each other enough.3) Take some deep research on synthesize the simulated earthquake wave. The combination of theoretical and numerical solutions is applied to calculation that each frequency components contribute to the response spectrum in the amplitude spectrum correction. The correctness of the amplitude spectrum adjustment size has been to ensure, while the numerical stability and convergence of simulated earthquake wave iterative calculation are improved. The least square method is used to regulate earthquake wave generated in the iterative process, and then the corrected standard earthquake wave is normalized, which can eliminate the shift of velocity and displacement diagram of simulated earthquake wave.4) According to the particular case of upper dam of the Fujian Xianyou pumped storage CFRD, construct a three dimensional finite element model with the typical cross section, taking 3-d nonlinear static analysis for the dam. Stress and deformation distribution rules on the cases of during construction and waterrunning period have been obtained.5) The dynamic analysis of the project obtained:the largest acceleration distribution of dam, stress, deformation, deflection maximum distribution of the panel, distribution of the maximum displacement of the peripheral joints in the process of earthquake, seismic minimum factor of safety of time curve of panel, seismic stability safety factor of time curve of the downstream and upstream slope, and distribution of permanent deformation after the earthquake.6) According to the results of the above calculations, take a seismic safety evaluation for the upper dam, getting the conclusion of the dam meet seismic stability requirements.