基础条件对SSDI体系动力特性的影响

摘要

基于影响土-结构动力相互作用(SSDI)体系抗震性能和动力特性的因素除地基土特性与上部结构特性外,基础作为联系上部结构和土体的桥梁,其构造形式以及埋置深度对SSDI体系动力性能的影响不可忽视.通过采用有限元方法,对某工程高层建筑算例进行计算分析；利用ANSYS程序中重新启动法、APDL参数设计语言编制程序实现对地基土的非线性模拟,并通过土体边界、土体与结构间非线性接触的研究,对整个SSDI体系在实测地震波作用下的动力反应进行计算分析,研究桩筏基础、桩箱基础2种不同基础形式以及不同基础埋深条件对上部结构动力反应效应的影响.研究结果表明:桩箱基础条件时上部结构动力反应较小,基础埋深越大,上部结构动力反应越小.研究成果为工程抗震设计考虑基础条件对土-结构动力相互作用效应的影响提供了理论依据,对完善抗震设计规范具有参考价值.%Based on the fact that the influence factors of dynamic characteristics and aseismic capability for soil-structure-dynamic-interaction (SSDI) system include the soil characteristics and structural characteristics, and the foundation acted as a bridge associating structure with soil, its forms, as well as embedded depth cannot be ignored. Using the ANSYS program of finite element method, non-linear simulation of the soil and dynamic responses of SSDI system was achieved with restart method, APDL parameter design language program and simulating soil boundaries, soil and structure nonlinear contact under the action of seismic waves was measured. Many issues were studied such as the changes of the structural dynamic characteristics under pile-raft foundation and pile-box foundation conditions, as well as the dynamic response effects of upper structure in different foundation embedments. The results show that dynamic response of upper structure is small in pile-box foundation condition, and the foundation embedment is bigger, the upper structure dynamic response is smaller. Theoretical evidence is provided for the seismic design by considering foundation conditions of soil-structure-dynamic-interaction system, and the research results have reference value for the code of seismic design.