【作者】 刘洁平；

【导师】 张令心；

【作者基本信息】 中国地震局工程力学研究所 ， 防灾减灾工程及防护工程， 2009， 博士

【摘要】 土-结构相互作用是一个具有重大理论意义和工程应用价值的课题。在过去四十年的研究中,在理论和实践方面已取得重大进展,但仍存在许多有待进一步研究的重要问题,发展一种有效和实用的土-结构相互作用分析方法以及了解土-结构相互作用对结构地震反应的影响就是其中的两个问题。本文在国内外土-结构相互作用研究发展现状的基础上,以钢筋混凝土高层建筑为研究对象,进行了高层建筑土-结构相互作用地震反应分析研究,为重要个体高层建筑和一般高层建筑的土-结构相互作用地震反应分析提供了多种实用的分析手段,为认识土-结构相互作用对高层建筑地震反应的影响和抗震设计方法提供了依据。本文将土与结构作为一个整体,采用能很好模拟上部结构和下部地基基础受力特性的平面土-结构相互作用模型,提出了一种实用的高层建筑土-结构相互作用地震反应整体分析方法。该方法的上部结构采用平面框架-剪力墙(筒体)协同工作模型;地基土体以在计算平面内高度为H、宽度为B、在出平面方向厚度为t的土体来模拟;土体在静力分析时采用Duncan-Chang模型,动力分析时采用等效线性化模型;基础根据其形式及刚度,分别以梁单元、刚块单元或受弯板单元来模拟。为了在一般单体机上实现所提出的方法,对有限元软件MSC.Marc进行了二次开发,添加了多层土的静力Duncan-Chang本构关系模型和动力等效线性化本构关系模型,并通过两个算例验证了其可靠性,使MSC.Marc软件成为该方法的理想分析工具。此方法可用于重要单体高层建筑详细的土-结构相互作用分析。选择了不同高度、不同结构类型和不同场地条件的位于厚和深厚地基土层上的10栋典型钢筋混凝土高层建筑,采用所提出的整体分析方法,对比分析了基岩波、地面波和地震动等效输入波,以及考虑与不考虑土-结构相互作用体系的自振特性和地震反应,详细研究了土-结构相互作用对位于厚和深厚地基土层上高层建筑地震反应的影响。通过对地震反应影响的综合分析,在地震动输入、自振特性、相互作用影响因数、体系地震反应等方面得到了一些具有实用价值的结论和关系式,在此基础上,给出了一种以结构与土层第一周期系数αT为指标的高层建筑土-结构相互作用地震反应分析简化评估方法。该方法无需进行复杂又费时的高层建筑土-结构相互作用分析,仅利用简单省时的结构和土层反应分析结果,就可估计出高层建筑土-结构相互作用体系的反应,可用于高层建筑考虑土-结构相互作用地震反应的初步估计。以采用所提出的整体分析方法计算得到的10栋典型高层建筑的计算结果为标准,上部结构仍采用整体分析方法给出的平面框架-剪力墙(筒体)协同工作模型,参考《动力机器基础设计规范》(GB50040-96),给出了地基基础的两层简化模型,通过与10栋典型高层建筑标准结果的对比,进行了地基质量、土体模型自由度、抗剪刚度和阻尼比的逐步改进。将地基土体质量由原模型的基础以下基岩以上的土体质量改为整体分析法给出的土体质量;将地基土体由原模型的两个自由度改为多个自由度,并给出了各层土体抗剪刚度的确定方法;建议土层的剪切模量G取0.5倍的Gmax、阻尼比取15%,提出了修正的层层简化模型,给出了一种高层建筑土-结构相互作用简化分析方法。通过该方法和整体分析方法的计算结果比较发现,较原两层简化模型的方法,土-结构体系的自振特性和结构顶点加速度峰值有明显改善,结构顶点加速度反应谱更为合理,尤其是长周期段峰值所对应的周期均与整体分析方法结果更为接近。由此表明,该方法可作为一种合理实用的高层建筑土-结构相互作用简化分析方法,用于一般高层建筑土-结构相互作用的分析和重要高层建筑土-结构相互作用的初步分析。另外,该方法给出的地基基础简化分析模型,也可推广应用于其它类型建筑物、结构工程的地基基础和土-结构相互作用分析中。更多还原

【Abstract】 Soil-structure interaction (SSI) is an important subject with great theoretical significance and application value of engineering. Though the significant progresses on the respects of theory and application for past forty years have been made, there are still important problems to be solved. Developing an effective and practical analysis method considering SSI,and knowing the effects on seismic response considering SSI of structures are two of these problems. In this paper, on the basis of the current development of SSI research at home and abroad, the reinforced concrete high-rise buildings as a research object, the study on seismic response analysis considering SSI of high-rise buildings is conducted. Some practical analysis measures are provided for seismic SSI response analysis of important individual high-rise buildings or general high-rise buildings considering SSI. The basis is provided for understanding the effects on seismic response of high-rise buildings considering SSI and seismic design method.In this paper, soils and structure as an integrated system using plan SSI model, which can simulate the mechanical characteristics of the upper structure and the lower foundation well, a practical method for seismic response analysis considering SSI of high-rise buildings is proposed. In this integral analysis method, the plan frame-shear wall (tube) cooperation model is used in the upper structure. A soil mass with height H and width B in-plane, and thickness t out-plane is used to simulate the foundation soils. Duncan-Chang model of soils is used in static analysis; equivalent linearization model of soils is used in dynamic analysis. According to the shape and stiffness of basements, the flexible, rigid and pile foundation are simulated by beam element, rigid block or plate element respectively. In order to realize this method in personal computer, the redevelopment of the finite element analysis software MSC.Marc is done, which Duncan-Chang model for static analysis and equivalent linearization model for dynamic analysis of multi-layer soils are added, and two examples are calculated to verify the reliability of the redevelopment. Thus software MSC.Marc becomes an ideal analysis tool for this integral analysis method. This method can be used for the seismic response analysis considering SSI of important individual high-rise buildings in details.Ten typical reinforced concrete high-rise buildings with different heights, IVdifferent structural types and different site conditions are selected, which are located in thick and deep foundations soils. Using the integral analysis method of seismic response analysis considering SSI, the bedrock wave, ground motion wave and equivalent seismic input wave are compared and analyzed, and the natural vibration characteristics and seismic response of soil-structure system considering SSI are compared and analyzed with those of structure system not considering SSI. The seismic SSI effects on the response of high-rise buildings located in thick and deep foundation soils are analyzed and studied in details. Through the comprehensive analysis of effects on the response considering SSI, some practical conclusions and relationships are obtained on some respects of ground motion input, natural vibration characteristic, SSI effect factor, and seismic response. On the base of these conclusions and relationships, a simplified assessment method of seismic response analysis considering SSI of high-rise buildings is obtained, regarding the first period coefficient of structure and soils -αT as an index. In this method, it is not necessary to conduct the complex and time-consuming SSI analysis of high-rise buildings. Using the results of simple and time-saving structure or soil response analysis, the response of SSI system can be assessed. This method can be used for the primary assessment of seismic response analysis considering SSI of high-rise buildings.Taking the calculation results of ten typical high-rise buildings using the integral analysis method as a standard. The plan frame-shear wall (tube) cooperation model is still used to simulate the upper structure in the integral analysis method. Refering to the“Code for design of dynamic machine foundation (GB50040-96)”, the two-layer simplified model of foundation is proposed. By comparing with the standard results of ten typical high-rise buildings, the two-layer model is gradually revised on respects of foundation mass, degree of freedom of foundation model, shear stiffness and damping ratio of soils. The mass of foundation is improved from the mass between basement and bedrock to the foundation mass of the integral analysis method, the freedom of foundation is improved from two-degree to multi-degree, the shear stiffness of each layer is given also, the shear module G of soils is suggested to take as 0.5 times Gmax and the damping ratio is taken as 15%. A corrected multi-layer model of foundation is proposed, and a simplified analysis method of high-rise buildings considering SSI is proposed. It can be seen by comparing the results of the multi-layer method and the integral analysis method that, the natural vibration period and the maximum acceleration peak value of roof are improved more obviously than those of the old two-layer simplified method, and the acceleration response spectra of roof are improved more reasonably, especially the periods corresponding to peak values in long period range the periods are similar to those of the integral analysis method. So it can be seen that this simplified method can be used for the seismic response analysis considering SSI of general high-rise buildings, or the primary seismic response analysis considering SSI of important high-rise buildings. In addition, the simplified model of foundation in this simplified method can be also extended to use on the foundation and soil-structure interaction of other types of buildings and structural engineering.更多还原