新旧抗震规范下重力坝抗震安全性能分析

Analysis on anti-seismic safety capability of gravity dam under old and new seismic design specification

结合新修订的《水电工程水工建筑物抗震设计规范》(NB35047-2015)与原来的《水工建筑物抗震设计规范》(DL5073-2000),采用振型分解反应谱法分析了新旧规范下重力坝地震动应力、动位移与动加速度的分布规律。研究结果表明:与采用原规范计算得到的结果相比,采用修订规范后,各坝型基频对应的反应谱放大系数增大,计算出的坝顶动位移有所增大,而坝顶动加速度反应却呈现降低趋势;建基面部位地震动应力反应有所增大;坝头部位的地震动应力反应有所降低;坝头部位以下的上、下游坝面地震动应力有所增大。结论为工程设计人员利用新抗震规范对重力坝进行抗震安全性评价提供了参考。

Combined with the newly revised Code for seismic design of hydraulic structures of hydropower project （ NB35047 - 2015） and the old Specifications for seismic design of hydraulic structures （ DL5073 - 2000）, we used the model response spectrum method to analyze the distribution law of dynamic stress, dynamic displacement and dynamic acceleration of gravity dam under the new norm and old norm. The results show that compared with the calculated results by the old specifications, the response spectra amplification coefficients of various dams＇ fundamental frequency under the revised specification increase and the dynamic displacement of the dam crest increases, however, the dynamic acceleration of the dam crest decreases. The seismic dynamic stress at foundation surface increases and the seismic dynamic stress at dam head decreases. The seismic dynamic stresses of upstream and downstream dam surfaces below the dam head show a rising trend. These conclusions can provide references for project planner to evaluate the gravity dam anti - seismic safety under the new seismic code.