Investigation On The Substructure Of The Underground Powerhouse In A Large-scale Hydropower Station

With the rapid development of the hydro-electrical enterprise, the single-machine capacity record of the generator is continually broken, which causes the scale of the hydraulic structures more and more large. The safety of the hydraulic structures has been drawn more attention. The substructure of the powerhouse, especially the underground powerhouse of the large-scaled station, in the natural environment, is subjected to the continuously changing air temperature, solar radiation and water temperature. So the stress condition of the structure can be changed obviously and some cracks may appear in the structure. The integrity and endurance of the structure can also be affected. The increasing scale of the substructure of the powerhouse makes the vibration problem more significant, which is often extremely complex.In this study, taking the substructure of the Goupitan hydropower station as an example, a kind of the finite element software, ANSYS, is applied firstly to analyze the influences of the elastic modular and placement extent of the cushion layer on the stress condition and deformation of the concrete around the spiral case. Then, Willam-Warnke's five parameters broken criterion is used to carry on the nonlinear research on the three typical longitudinal sections of the substructure of the powerhouse. In addition, the temperature field and thermal stress of the substructure of the powerhouse are also analyzed in three conditions including the maximum temperature rising, the maximum temperature falling and the average temperature in many years. Based on this, the influence of the changing temperature on the reinforcing bars of the structure can be ascertained. Finally, the influences of all kinds of main factors on the natural vibration characteristics of the substructure of the powerhouse are analyzed, and the vibration of water turbine generator set induced by eighteen kinds of vibration source from the hydraulic, mechanic and electrical factors is given a detailed introduction and analysis. Based on the result of analysis, the resonance is calibrated. From the analysis above, the main conclusions are drawn as follows:(1) With the increase of the placement extent of the cushion layer above the...