(中国建筑科学研究院地基基础研究所，北京 100013)

［摘要］考虑土-结构动力相互作用，建立了双塔楼大底盘高层建筑动力响应分析的三维有限元模型，研究了筏板厚度变化对结构振动特性和地震响应的影响。不同筏板厚度结构动力响应的对比分析结果表明，随着筏板厚度增加, 结构主振周期呈减小趋势，地震侧移呈增加趋势，地震剪力在塔楼部分呈增加趋势但在地下室部分呈减小趋势。筏板的动挠度除在两塔楼外侧的边跨范围内，一般随板厚增加而减小，动弯矩除靠近地下室外墙局部范围内，一般则随板厚增加而增加。可见，筏板厚度并非越大越安全, 应在满足承载力和冲切等基本要求的前提下经过优选后确定

［关键词］双塔楼大底盘高层建筑；土-结构动力相互作用；厚筏基础；振动特性；地震响应

Influence of raft thickness on earthquake response of twin\|towers highrise structure

 Li Zhan

 (China Academy of Building Research, Beijing 100013, China)

Abstract:The three dimensional FEM models are constructed to analyze the effects of raft thickness on the vibration characteristics and seismic responses of the twin-towers high-rise building structures with enlarged base, and the dynamic soil-structure interaction is incorporated in the analysis as well. The dynamic responses are obtained and compared for different raft thickness with a dual-axial symmetric twin-towers structure. It is shown that the predominant periods of the structure decrease, the seismic lateral displacements increase, and the seismic forces increase in the upper towers and decrease in the basements with increasing of the raft thickness. While in the raft, with increasing of raft thickness, the displacements decrease except in the outside frame of the towers  and the moments increase  except in the loxal adjacent to retailing wall of basement.It can be concluded that larger raft thickness cannot guarantee much more safety for the structures. So the raft should be designed with an optimized analysis on the precondition matching the bearing capacity and punching shear resistance.

Keywords:twin-towers high-rise structures with enlarged base; soil-structure dynamic interaction; thick raft foundation; vibration characteristics; seismic responses

*“十一五”国家科技支撑计划重点项目(2006BAJ27B02)，中国建筑科学研究院科研项目(20071602330730008)。