| The technology of underground space is the developmental trend of Geotechnical engineering field in this century. Many giant water conservancy and hydroelectric power project lied in the remote mountains and gorge. Overground space is very limited, making use of underground space solved the space problem of hinge disposal, at the same time, it could take full advantage of water level difference to advance the using efficiency of water power. With the wide application of computer, numerical ainalysis for the stability of underground cavern has played a more and more important role. With numerical method, complicated geologic conditions, such as material's anisotropy and non-continuity, non-uniformity as well as complicated boundary condition can be considered.The underground power house of Silin Hydropower Station is mainly composed of main workshop, bus holes and main transformer room. It is belonged to the long-span, high-sidewall underground caverns. So the research on the stability of the underground caverns is very important to the support structure design and the safety during operation. This paper has got the initial stress field and boundary conditions. On this basis, the overall planar elastic-plastic finite element model of the underground caverns was established by ADINA (a finite element program for automatic dynamic incremental nonlinear analysis). Using the mohr-coulomb yield criterion and reasonable mechanical parameters, this paper has analyzed the changes of stress and displacement during the process of excavation. In addition, this paper also has discussed the effects to the analysis result of rock stability because of spray anchor shoring, fault and different excavation methods.The results show that surrounding rock plastic failure occurred mainly in the top arch, up-downriver side walls of main workshop and main transformer room, the development of surrounding rock plastic failure has been effectively checked after support. |
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