白鹤滩地下厂房结构动力特性及抗震分析
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摘要
白鹤滩水电站地下厂房结构刚度相对较小,且工程场址所在区域隶属于地震活动强烈的川、滇地震带,结构的振动特性及抗震计算是设计中的关键问题。利用有限元法建立三维数值模型,对厂房固有自由振动特性、共振复核,机墩、楼板等结构在机组振动荷载作用下的响应及地震作用下的结构响应进行了计算研究。结果表明:厂房结构基频与机组额定转频及飞逸转频的错开度均大于20%,在现有振源激励下不会发生显著共振;在机组振动荷载作用下,楼板的各向加速度均小于规范限值0. 315 m/s~2,人体感觉不到不舒适;楼板和风罩等是抗震设计的重点,正常运行情况的静力荷载对结构的受力起控制作用,地震作用对白鹤滩地下厂房结构不会带来严重危害。
Because the underground powerhouse of Baihetan Hydropower Station has relatively small structural stiffness and locates in seismic-active Sichuan and Yunnan seismic zones, the vibration characteristics and seismic calculation of powerhouse structure are key problems in the design of powerhouse. A three-dimensional numerical model is established by using finite element method to study the vibration characteristic and resonance of powerhouse, the response of piers and floors under unit vibration loads, and the structural response under earthquake action. The results indicate that,( a) the stagger degrees between the base frequency of structure and the rated frequency or runaway frequency of unit are all more than 20%, and no significant resonance will happen under current excitation source;( b) the accelerations of floor boards are less than the specification limit value( 0. 315 m/s~2) under the vibration load of unit, and staff will not feel uncomfortable; and( c) the floors and wind covers are the keys of anti-seismic design, the static loads under normal operating condition plays a controlling role on structure stress,and the earthquake action will not bring serious harm to powerhouse structure.
Because the underground powerhouse of Baihetan Hydropower Station has relatively small structural stiffness and locates in seismic-active Sichuan and Yunnan seismic zones, the vibration characteristics and seismic calculation of powerhouse structure are key problems in the design of powerhouse. A three-dimensional numerical model is established by using finite element method to study the vibration characteristic and resonance of powerhouse, the response of piers and floors under unit vibration loads, and the structural response under earthquake action. The results indicate that,( a) the stagger degrees between the base frequency of structure and the rated frequency or runaway frequency of unit are all more than 20%, and no significant resonance will happen under current excitation source;( b) the accelerations of floor boards are less than the specification limit value( 0. 315 m/s~2) under the vibration load of unit, and staff will not feel uncomfortable; and( c) the floors and wind covers are the keys of anti-seismic design, the static loads under normal operating condition plays a controlling role on structure stress,and the earthquake action will not bring serious harm to powerhouse structure.
引文
[1]樊启祥,汪志林,吴关叶.金沙江白鹤滩水电站工程建设的重大作用[J].水力发电,2018,44(6):5-10.
[2] NB/T 35011—2016水电站厂房设计规范[S].
[3]刘依松,陈灯红.基于无质量地基模型的重力坝地震响应分析[J].三峡大学学报:自然科学版,2014,36(4):6-10.
[4]李静,陈健云.动力相互作用分析中无质量地基的应用研究[J].世界地震工程,2007,23(2):58-62.
[5] GB/T 13441. 1—2007机械振动与冲击人体暴露于全身振动的评价第1部分:一般要求[S].
[6] NB 350471—2015水电工程水工建筑物抗震设计规范[S].
[2] NB/T 35011—2016水电站厂房设计规范[S].
[3]刘依松,陈灯红.基于无质量地基模型的重力坝地震响应分析[J].三峡大学学报:自然科学版,2014,36(4):6-10.
[4]李静,陈健云.动力相互作用分析中无质量地基的应用研究[J].世界地震工程,2007,23(2):58-62.
[5] GB/T 13441. 1—2007机械振动与冲击人体暴露于全身振动的评价第1部分:一般要求[S].
[6] NB 350471—2015水电工程水工建筑物抗震设计规范[S].