Structure Behavior Of High Concrete Face Rockfill Dam On Complex Foundation

At the dam site of Jiudianxia project, river valley is narrow, overburden layer is thick, and the geologic engineering condition is complex. In this thesis, by use of the three-dimensional nonlinear finite element method, the static and dynamic structure behavior of Jiudianxia concrete face rockfill dam is studied in detail, and its rheological behavior and the simulation of sidewall extrusion method are analyzed too. The general law of stress and deformation of high concrete face rockfill dam on the complicated foundation is researched and summarized. It is demonstrated that the structure design of the dam is rational, which provides theoretical foundation for design and construction. The main contents are as follows:1. According to the real condition of Jiudianxia concrete face rockfill dam, the construction process and impoundment process are simulated in detail with the 3-D nonlinear FEM. The stress and displacement of the dam body, anti-seepage wall, concrete face, peripheral joint, facing joint and so on are obtained. It is shown that the stress and deformation of the dam are conformed to the general law, and the numerical value is in the acceptable range, though the river valley is slender, overburden layer is thick, and the geologic engineering condition is complex. It is proved that the design of the dam is rational and feasible.2. The FEM analysis model of sidewall extrusion method is established. And the calculation results show that the stress and displacement of the dam in both construction period and impoundment period is decreased, but the influence is little when the sidewall extrusion technology is adopted. And the deflection of concrete face is decreased, the stress is improved.3. By use of the Kelvin and Burgers rheological model, the construction process and impoundment process are simulated, and long-age deformation of dam and concrete face after running for ten years is forecasted. In addition, the deformation of dam and concrete face considering the rheological behavior of rock is compared with the one not considering the rheological behavior. And the influence of rheological behavior on arching effect is pointed out.4. The analysis model of seismic response and earthquake induced permanent deformation of dam is established with the 3-D nonlinear FEM. The seismic response characteristic and its general law of dam body and joint are analyzed in detail under the effect of design earthquake, including acceleration response, displacement response, stress response and so on. The results indicate that the seismic response characteristics of dam are conformed to the general law, and the dam is safe when subjected to the earthquake. Design code requirements are satisfied, and the design is rational and feasible.