某河床式水电站厂房抗震复核及结构优化

Research on Seismic Review and Structural Optimization of the Powerhouse of a Riverbed Hydropower Station

采用反应谱法与时程分析法对某河床式水电站厂房7号、8号坝段进行抗震复核分析,得到坝体在地震工况下的结构动位移与动应力分布;通过对两种方法计算得出的结果进行分析对比,论证了7号、8号机组坝段在地震工况下的稳定安全性。研究表明,进水口拦污栅墩高46 m、宽1.6 m,属于薄板结构,在地震工况下其响应极为不利,其腹部产生横河向动位移最大达38.22~45.47 mm,其上部与坝顶相接处产生超过10 MPa的动应力响应,需要对该处进行结构优化。在拦污栅中部296 m和308 m高程设置2个厚度1 m的支撑板结构,在不影响过水性能的同时显著增加了结构的稳定性和整体性。改进后,拦污栅墩腹部横河向位移降低为8.5 mm,上部与坝顶相接处最大拉应力降低为2.493 MPa,抗震性能得到了明显的提高。

The response spectrum method and the time history analysis method are used to conduct seismic review analysis on the No.7 and No.8 dam sections of the powerhouse of a riverbed hydropower station,and the dynamic displacement and dynamic stress distribution of the dam body under seismic conditions are obtained.Through the analysis and comparison of the results calculated by the two methods,the stability and safety of the dam sections under seismic conditions are demonstrated.The studies show that,because the trash rack pier of water inlet is 46 m high,but only 1.6 m wide,which is a thin-plate structure,its response is extremely harmful under seismic conditions.The maximum horizontal lateral displacement is 38.22-45.47 mm in the abdomen,and the joint with the dam crest produces a dynamic stress response exceeding 10 MPa,which requires structural optimization.Two support plate structures with a thickness of 1 m are installed at the elevations of 296 m and 308 m of the trash rack,which significantly increases the stability and integrity of the structure without affecting its water-passing performance.After the improvement,the lateral displacement of the abdomen of the trash rack pier is reduced to 8.5 mm,and the maximum tensile stress at the junction of the upper part and the dam crest is reduced to 2.493 MPa,shows the seismic performance has been significantly improved.