The Three-dimensional Finite Element Analysis Of Group Tunnels Of The Underground Penstocks

With the continuous construction of large hydropower stations in China, more and more large HD value penstock widely applied.In the hydropower stations of high dams and large reservoirs, due to ground conditions, the group tunnels of a giant underground penstock layout is optimal for water conveyance system in the hydropower station.On the basis of reading from design, construction, operation and other aspects about underground penstock.Select the small spacing, large span of the group tunnels of giant underground penstock as the research object,application of elastic theory method,time history analysis method of the structure dynamic and Block Lanczos method of ANSYS analysis,with the construction of Xiluodu hydropower station is composed of group tunnels of giant underground penstock as an example, the establishment of ANSYS three-dimensional finite element model.Consider the gap between the steel pipe with an external concrete and surrounding rock influence and three co-carrying role, to consider the different external water conditions and the period seismic waves impact, steel pipe run of six kinds of conditions within the pressure static analysis, natural vibration characteristics and earthquake response analysis.Through the analysis of the mode get a small spacing, large span of group-hole pipe use of the most unfavorable conditions and the most unfavorable position.The variation of stress and displacement of underground penstock,which in different size of the gap between steel and concrete and surrounding rock or the variation of the outside water pressure.The venue of the surrounding rock around underground penstock, the difference of damping about steel in horizontal or vertical suffered by the surrounding rock. As well as in the underground penstock cross-section, horizontal and Y direction to the different laws the seismic response on the earthquake response.The reveals show that it is reasonable to small spacing and large span of of the group tunnels of giant underground penstock, the spacing of underground penstock is2times of the hole diameter The proposed method and the results can provide a valuable reference for the group-hole of giant underground penstock engineering practice.