【作者】 熊辉；

【导师】 邹银生；

【作者基本信息】 湖南大学 ， 结构工程， 2003， 博士

【摘要】 广大研究者和工程技术人员在实践中已经意识到将上部结构和基础考虑作为一相互作用的整体来进行设计的必要性和优越性，无论是对于静力还是动力特性研究，群桩-土-结构作为一个共同体计算出来的结果不仅与通常的固定基础(不考虑相互作用)假设所得有较大出入，而且不同土层土质、群桩属性条件下的相互作用体系所表现出的受力与变形特点也不尽相同。在遭受水平地震作用时的上、下部相互作用的抗震设计中，结构工程与岩土工程对这一领域各自有所偏重，前者较为关注其上部结构的惯性反馈相互作用，而后者则更加关注的是其桩土基础子结构的刚体相互作用，但场地土在抗震工程中的双重作用均是不可忽视的。本论文工作将围绕地基-基础-上部结构共同作用这一课题作进一步探讨，侧重于水平地震作用下层状地基土中的桩基-建筑物的动力相互作用的研究，为实践应用提供了适合于工程目的的、比较简捷的实用计算方法，亦拟为没有明确规范指导的桩(土)基础-结构抗震设计提供一定的理论依据和设计建议。本文共分为六章： 1．通过对大量相关文献的概述总结，分析了国内外开展土-结构物共同作用研究的现状及其发展水平，评述了已有研究工作成果的局限性及优缺点；提出了本文针对桩基上下部结构体系所采用的理论分析途径和基本框架思路。 2．建立了以适应工程需要的基于二维平面动力分析的简化整体有限元模型；提出了能有效考虑桩尺寸效应的桩-土无单元划分技术，在考虑了模型的边界效应、桩基的水平动力特性和桩土界面的滑移、接触非线性行为的基础上，从时域内较为全面的研究了层状土域中桩基上下部结构的惯性相互作用和运动相互作用两种基本效应。 3．建立了时域内的桩-分层土-框架结构的三维全域内的动力非线性分析模型，对不同工况地震作用下(诸如不同地震波输入、土的弹性与弹塑性以及桩土接触等条件)的地基土-桩基-上部结构共同作用进行了较全面的场动模拟。该方法的最大特点是结合近、远场域的有限单元网格渐分技术，通过边界三维弹阻单元的设置，可以突出再现上、下部共同作用体系在地震作用下的全时程线性、非线性反应特性，从而为精确开展各类结构动力相互作用的设计与试验测试奠定了一定的理论基础。 4．针对在处理多桩数以及不同型式群桩时，数值解析方法存在的复杂性、适用性等问题，本文以动力文克尔梁模型为基本理论，利用基于Haskell-Thomson理论的传递矩阵法，给出了分层地基中单桩在轴、横多向受力条件下的力与位移动力相互关系的显示表达。在改进了Gazetas均质土中的桩一土一桩相互作用三步法计算模式的基础上，考虑了轴向力系影响，分别提出了桩顶谐振条件下以及水平地震作用下计算层状介质中动力相互作用因子的新方法，进一步地扩展了群桩-土相互作用简化方法的应用范围。现有文献中尚未见这方面研究成果的报道。 5.利用层状介质中桩一桩动力相互作用因子分析，获得了任意构型、桩数、土层属性下的群桩系统阻抗反应;基于共同作用理论，本文导出了时域中上、下部相互作用动力平衡方程式。基于该方程式，考查了场地土层、桩距径比特别是群桩布置等诸多因素对于桩一土一结构体系的影响，对水平地震作用下群桩一土一上部结构的混合时域、频域内反应特性进行了较全面的分析;基于复形调优法，利用群桩动力阻抗的频域相关性，以体系周期为基本目标函数，提出了群桩多维极值条件控制下的抽桩动力优化设计方法;并编制了群桩一分层土一上部结构的动力相互作用分析及优化设计程序。通过实例分析表明，在带桩结构工程中应用该程序进行抗震作用下的动力计算是简单可行的，同时也为桩基承载结构设计提供了一种新的思路。 6.给出了一系列有关上、下部结构共同作用的对比算例和工程实例数值分析，总结出各参与要素对动力相互作用体系地震响应的作用规律，并探讨了桩-土一上部结构共同作用程度的简单判别方法;此外还得出了一些结论，为在抗震设计中较精确地考虑上、下部结构共同作用提出了一些建议，亦为抗震规范的进一步修订提供了一定的理论依据。更多还原

【Abstract】 As for static or dynamic investigation, the results figured out based on interactive SPS are deviate from that based on fixed-base hypothesis structure and the loading and deforming features exhibited in interactive system under the condition of various soil-layer, soil properties and pile-groups properties etc are also discrepant, so the interactive design of whole foundation and superstructure parts are necessarily and primely emphasized by numerous researchers in engineering practice. Despite the different keystones which structural engineering and geotechnical engineering emphasize respectively in aseismatic interaction analysis of upper-lower parts under horizontal earthquake, that is inertial feedback interactions of the structure subsystem to the former or kinematic interactions of the pile-soil foundation subsystem to the latter, but the dual effects of soil fields mustn’t be ignored. So the topic for farther discussion will be developed on the ground of soil-foundation-structure interactions, and emphasizes particularly on the investigation for dynamic effects on interaction of pile-supported structures subjected to lateral seismic load at layered-soil media. It will provide engineering application with practical and concise computational method, but also provides the aseismatic design for pile-supported structures with proper theory foundations and schemes to some extent on condition that definite codes are absent at present. The full article is divided into six chapters, as follows:1. With the summarization of lots of interrelated references, the studying actuality and developing level which about soil-structure interaction are presented. The limitations advantages and disadvantages existing in present researches are discussed too. Then the basic theory way and analyzing frame route related to upper-lower structural parts with pile-groups in this paper is introduced.2. The whole dynamic finite-element analysis simplified based on 2D plane is performed to adapt engineering requires. The effect of both kinematic interaction and inertial interaction on pile-soil-structure systems within layered soil field is relatively comprehensively investigated. At the same time, the boundary effect of model , the horizontal dynamic features of piles and the nonlinear characteristic of slide and contact on the interfaces of pile-soil are considered too on the ground of no-elementmeshing technique applied for dimensional effect of piles in stratum-soils.3. Following natural layered characteristic of soils, a simplified 3D nonlinear dynamic model of pile-supported superstructure system in time domain is presented. So the various time response histories of structures are realistically described and the seismic field-movements of the system are simulated under different working conditions such as various earthquake waves elasticity or elastoplasticity of soil and pile-soil contact etc. The linear or nonlinear characteristics of histories response of upper-lower structural parts under seismic are prominently re-shown by means of gradual meshing finite-elements for near-far fields with the 3D spring-dashpot boundary elements. Based on the above analysis, many designs and tests about interactive structures may be developed accurately.4. Instead of the applicability problem of some intricate numerical technique in dealing with large number piles and alterable type of pile-groups, based on the dynamic winkler-foundation beam model and Haskell-Thomson transfer matrix scheme, the explicit expressions indicating force-displacement relationship of pile are derived under simultaneous axial and lateral loads in layered-soil in order to obtain the displacements and internal forces of pile-foundation in frequency-domain. In terms of the Gazetas’s three-step procedure for pile-soil-pile interaction in homogenous media a new method for calculating dynamic interaction factors of layered-soil considering the influence by axial load is suggested under harmonic exc更多还原