当地震足够大时结构基础将会与下卧地基土发生分离,即所谓的基础提离现象。但该现象在常规的土-结构相互用(SSI)的地震响应分析中常常被忽视。核电站结构(NPP)由于特殊性,其设计地震强度一般较大,因而有可能发生基础提离现象。本文基于某简化核电站结构,利用大型通用软件ANSYS的接触面功能和弹簧单元,分别进行了四种工况的计算:(1)基础固定;(2)考虑基础提离,不考虑土-结构动力相互作用效应;(3)不考虑基础提离,但考虑土-结构动力相互作用效应;(4)同时考虑基础分离和土-结构动力相互作用效应。通过对比分析,确定合适的土-结构动力相互作用计算方法以及基础提离对核电站结构地震响应的影响。计算分析表明:(1)土-结构相互作用对核电站结构地震响应的影响不容忽视;(2)基础提离主要影响核电站结构竖向地震响应,而对结构水平向地震响应的影响较小。本文研究成果可为核电站结构的抗震分析提供参考。
Abstract
The structure foundation will separated from the supporting soil if the earthquake is big enough, which is the so called the phenomenal of foundation uplift. This phenomenal, unfortunately, is always neglected in seismic response analysis of soil-structure interaction (SSI) system. The designed seismic level for nuclear power plant (NPP) is usually very big because of its specificity, therefore, the foundation of nuclear power plant will probably separate from the supporting soil. Based on a simplified NPP calculation model and the by employing the contact function and spring element in the software ANSYS, four cases are considered, which are: (1) foundation fixed; (2) the foundation uplift is considered and the SSI effect is not considered; (3) the SSI effect is considered and foundation uplift is not considered; (4) both the foundation uplift and the SSI effect are considered. The influences of the SSI effect and foundation uplift on structure seismic response are analyzed by comparing the computation results. It is showed from the computation results that: (1) the influence of the SSI effect on structure seismic response can not be neglected; (2) foundation uplift influenced structure vertical response mainly, and has a very little influence on structure horizontal response. The research results in the paper can provide some references for seismic design of NPP.
关键词
基础提离 /
土-结构相互作用 /
地震响应 /
接触面 /
核电站
{{custom_keyword}} /
Key words
foundation uplift /
soil-structure interaction /
seismic response /
contact interface /
nuclear power plant
{{custom_keyword}} /
{{custom_sec.title}}
{{custom_sec.title}}
{{custom_sec.content}}
参考文献
[1] Chopra A. K. and Yim C. S. Simplified earthquake analysis of structures with foundation uplift [J]. Journal of Structural Engineering, 1985, 111(4): 906-930.
[2] Ioannis N. P. and Paul C. J. Rocking of slender rigid bodies allowed to uplift [J]. Earthquake Engineering and Structural Dynamic, 1983, 11(1): 57-76.
[3] Housner G. W. The behavior of inverted pendulum structures during earthquake [J]. Bulletin of the Seismological Society of America, 1963, 53(2): 403-447.
[4] Yim C. S. and Chopra A. K. Earthquake response of structures with partial uplift on Winkler foundation [J]. Earthquake Engineering and Structural Dynamic, 1984, 12(2): 263-281.
[5] Yim C. S. and Chopra A. K. Dynamics of structures on two-spring foundation allowed to uplift [J]. Journal of Engineering Mechanics, 1983, 110(7): 1124-1146.
[6] Song Y. H. and Lee D. G. Improved two-spring model for foundation uplift analysis [J]. Computers and Structures, 1993, 46(5):791-805.
[7] 俞载道,职洪涛,曹国敖. 基础提离、滑移对结构地震反应影响的探讨 [J]. 同济大学学报, 1997, 25(2): 141-146. (YU Zaidao, ZHI Hongtao and CAO Guoao. Study on the effect of base uplifting and sliding on earthquake response of structures [J]. Journal of Tongji University, 1997, 25(2): 141-146. (in Chinese))
[8] Naohiro N., Susumu I., Osamu K., et al. An Estimation Method for Basemat Uplift Behavior of NPP Buildings [C]. 18th International Conference on Structural Mechanics in Reactor Technology (SMiRT18), Beijing, 1995.
[9] Richart F. E, Hall J. R. and Woods R. D. Vibrations of soils and foundations [M]. Englewood cliffs, New Jersey, Prentice Hall Inc. 1970.
[10] Veletsos A. S. and Verbic B. Vibration of viscoelastic foundations [J]. International Journal of Earthquake Engineering and Structure Dynamics, 1973, 2: 87-102.
[11] Dobry R. and Gazetas G. Dynamic response of arbitrary shaped foundations [J]. Journal of Geotechnical Engineering, 1984, 112(2): 109-135.
[12] Gazetas G. Formulas and charts for impedances of surface and embedded foundations [J]. Journal of Geotechnical Engineering, 1991, 117(9): 1363-1381.
[13] ASCE Standard 4-98, Seismic Analysis of Safety-Related Nuclear Structures and Commentary [S]. ASCE, 1999.
[14] Sung G. C., Yong I.L., Jae S.K., et al. A Study on the Criterion of Fixed Base Condition in Soil-Structure Interaction Analysis of Nuclear Power Plant Structure [C]. 18th International Conference on Structural Mechanics in Reactor Technology (SMiRT19), Toronto, 2007.
{{custom_fnGroup.title_cn}}
脚注
{{custom_fn.content}}