某抽水蓄能电站下水库大坝抗震安全复核分析

Seismic Review Analysis of the Lower Reservoir Dam of a Pumped Storage Power Station

为依据GB 18306-2015《中国地震动参数区划图》、NB 35047—2015《水电工程水工建筑物抗震设计规范》等现行规范评价某已建抽水蓄能电站下水库大坝当前的抗震安全性,采用基于有限元振型叠加反应谱法的动力法进行了大坝抗震复核计算。计算成果表明,在地震工况下,坝踵垂直拉应力区小于坝底面宽度的7%,且未超过帷幕位置,坝基面抗滑稳定的抗力作用比大于1。此外,考虑到在设计阶段大坝抗震薄弱部位已针对性地采取了相关工程处理措施,经综合分析,大坝抗震安全性仍满足现行规范要求。

According to GB 18306—2015'Seismic ground motion parameters zonation map of China'and NB 35047-2015'Code for seismic design of hydraulic structures in hydropower projects',compared with the engineering design stage,the acceleration of design ground motion peak of RCC gravity dam under a pumped storage power station is increased from 0.065 g with a 50-year exceedance probability of 10%to 0.15 g with a 100-year exceedance probability of 2%,and the seismic design intensity is increased from VI to VII.In order to evaluate the seismic safety of the dam according to the current code,the dynamic method based on the finite element mode superposition response spectrum method is used to calculate the seismic resistance of the dam.The calculation results show that under the earthquake condition,the vertical tensile stress zone of the dam heel is less than 7%of the width of the dam bottom surface,and does not exceed the curtain position.The resistance ratio of the anti-sliding stability of the dam foundation surface is greater than 1.In addition,the weak parts of the dam have taken relevant measures in the design stage.In summary,the seismic safety of the dam still meets the requirements of the current code.