【作者】 郭靖；

【导师】 陈健云；

【作者基本信息】 大连理工大学 ， 水工结构工程， 2013， 博士

【摘要】 随着经济的飞速增长,我国城市化进程日益加快,人口和物质财富逐渐向城市高度集中,开发地下空间,建立以地铁为主体的城市地下交通系统作为缓解城市交通最快捷、最有效的途径越来越引起重视。城市地下空间的飞速开发,其抗震安全性必然会成为建筑工程抗震和城市防灾减灾研究的重要内容。大型地下结构内部人口比较集中,空间受限,疏散缓慢,一旦遭受地震破坏,直接造成的生命和财产损失与地上结构相比将更为严重,而且地下结构的修复工作相对困难,间接经济损失同样巨大。地铁交通工程大都贯穿于城市内部,其地表附近一般都已经存在建成的建筑物,或者为了交通方便而在地铁工程附近新建商业区、居民小区等,地下空间结构的存在将改变临近建筑物的地基条件,并改变地震波的传播路径,进而影响地表建筑的地震响应。本文针对上述问题,重点分析了地下结构的动力变形特性,以及地下结构的存在对地表临近建筑结构地震响应的影响,主要研究内容如下：(1)根据土-地下结构拟静力相互作用法,分析排水和不排水条件土体中,地下结构剪切变形与输入激励波波长的关系。研究了土-地下结构拟静力相互作用法的计算原理和适用条件；建立有限元模型,输入由地下结构横截面尺寸所确定的不同频率的正弦波作为激励,分析在排水和不排水条件下,不同高宽比地下结构的剪切变形与激励波波长的关系,给出了不排水条件时采用静力代替动力荷载进行计算的适用条件；同时分析了柔度系数以及土体与地下结构的相对刚度两因素的影响规律。(2)研究了单自由度体系在含有速度脉冲的近断层地震动作用下的响应,对比分析了矩形地下结构在脉冲型近断层地震动和无脉冲远场地震动作用下的剪切变形。首先运用小波分析的方法将含有速度脉冲的近断层地震动分解为高频波和脉冲波两部分,分别分析其对单自由度体系动力响应的影响,论述了仅用脉冲模型模拟近断层地震动的局限性；其次,建立不同截面形状的地下结构模型,计算不同柔度系数时,地下结构在远场地震动和脉冲型近断层地震动作用下的剪切变形系数,研究脉冲型近断层地震动对地下结构地震响应的影响,以及随柔度系数变化的规律。(3)分析了地表建筑结构常用的简化模型,研究了高阶振型对地表结构层间位移谱、以及对层间位移沿结构无量纲高度分布的影响；以地铁车站为研究算例,重点分析当地铁车站埋置于不同类型场地中时,地下结构的存在对地表临近建筑能够产生影响的地表区域范围。根据现行规范对场地类型的规定,选取软土、中软土和硬土三种类型的均质场地做为研究基准,以纯弯曲、纯剪切和弯剪组合三种类型的结构作为研究对象,给出了有、无地铁车站时,三种场地中所选结构层间位移角的变化趋势；将地铁车站水平宽度作为地下结构与地表建筑相对距离的衡量基准,分析地下结构的尺寸与其所能影响到的地表建筑所处位置的关系,总结地下结构的影响范围随场地条件变化的规律,并分析对不同类型地表结构的影响程度；研究不同场地条件下,地下结构的存在对场地设计地震动的影响。(4)地铁车站属于大型地下空间结构,以两层双柱三跨式地铁车站为例,着重从场地土体刚度、加速度峰值以及地表建筑变形类型三个方面进行分析,研究地下结构对地表临近建筑地震响应的影响。首先在有限元软件中分别建立无车站的自由场模型和土体-地铁车站相互作用模型,基于广义层间位移谱分析地铁车站的存在对地表临近建筑结构地震响应的影响；其次,研究了地表结构自震特性和距车站水平距离两个因素对地表结构层间位移角、及其沿结构无量纲高度分布的影响规律,同时分析了场地土体与地下结构相对刚度,以及输入地震动峰值加速度的变化对所得结果的影响；最后,分析了不同自振周期的地表结构所受地下结构影响的变形类型。(5)以成层土体中浅埋地铁区间隧道为研究对象,分析隧道对不同类型地表建筑地震响应的影响以及所能影响到的地表区域范围。首先根据有、无隧道存在的情况下地表结构层间位移的计算结果,分析隧道的影响随地表建筑与隧道之间的相对位置发生变化的规律；其次,针对隧道可能贯穿建筑下方的情况,重点分析了隧道对位于其上方的地表结构层间位移角的影响,给出了不同自振周期地表结构的层间位移角在有、无隧道影响下沿结构高度的分布,并分析地表建筑的变形类型。更多还原

【Abstract】 With the development of modern society, the increasing cost and decreasing availability of surface land often results in the development of new space and transportation infrastructure placed underground.As a prevalent part of the infrastructure of modern cities,underground structures, such as subway transportation system and underground plaza, are used for a wide range of application and becoming an important part of urban lifeline in China. If underground structures were destroyed during the earthquake, they might result in more serious damage than the surface buildings for their characteristics:population concentration in the structures, space limitation, exit blockage and so on; in addition, it will be confronted with complex difficulties for the repairing. The failures of a number of underground structures in recent earthquake suggest that the seismic performance of underground structures is not safety as being expected; therefore, the seismic analysis of underground structures becomes an important research content and attracts much attention of civil engineering and urban disaster prevention and reduction. Generally, Underground transportation system will be throughout the modern cities, and subway stations may be built in commercial or residential areas where surface buildings already exist, or the presence of an underground transportation facility may attract new construction in its vicinity. As a result, the underground station may not only change the original site conditions, but also may have an effect on local ground motions. Clearly, it is necessary to investigate the interaction between underground structures and adjacent ground buildings since seismic design of surface buildings is commonly based on the assumption that there is no cavity in the foundation.Based on the above issues, the research emphasis in this dissertation are the dynamic deformaction of the underground structures and the influence of underground structures on adjacent surface buildings, and the major contents are concluded as follows:(1) The relationship between racking deformation of structure and wave length of input motion is investigated by pseudo-static interaction analysis when underground station is buried in drained and un-drained conditions separately. The principle and the adaptive conditions are described; The FEM models and a number of harmonious sinusoidal waves whose frequencies are calculated by the dimension of the underground structure are used to determine the variation of the racking coefficient with the excited wave length in both drained and un-drained condition; the adaptive issue which assumes that the static method can be used in dynamic analysis is discussed when the condition is changed from drained to un-drained; finally, the effect of two factors which means flexibility ratio and relative stiffness between ground and structure is also analyzed.(2) Seismic analysis of SDOF systems under near-fault ground motion with velocity pulse is investigated, and racking deformations of the underground structure with rectangle section subjected to far-field and near-fault ground motions are contrastively analyzed. Firstly, the near-fault ground motion with velocity pulse are decomposed into pulse-type component and high-frequency component by wavelet analysis method, and the effect of each component on the SDOF system is studied; Then, the racking coefficients of underground structure with different flexibility ratios and section dimensions are extensively calculated when the structures subjected to excitations with and without pulse, and the effect of near-fault ground motion on the underground structure is discussed and concluded; Finally, the influence of the flexibility ratios on the issue is also studied.(3) The simplified model and the principle of the generalized inter-story drift spectrum are introduced briefly, and the influence of high modes on the inter-story drifts and their distribution along the height of structures is analyzed. The range of areas in where the surface structures will be influenced by the subway station is extensively investgated when the station is buried in different types of homogeneous foundations. According to the Code for seismic design of buildings, the foundations where station is buried are assumed to be three types:soft site, medium soft site and stiff site. Simultaneously, the adjacent structures are equivalently simplified as flexural, shear and combined shear-flexural models. The variation tendency of the inter-story drift ratios of structures is investigated in the three foundations with and without subway station; the relationship between the dimension of the station and the position where the surface buildings exist is emphatically analyzed; the range of area in where the dynamic response of surface buildings will be effected by the subway station is studied and concluded; Finally, the influence of the underground structures on the seismic design patameters of ground motions for different site conditions is investigated and concluded statistically.(4) A subway station with two-story-three-span-island is considered to investigate the influence of the underground structure on the adjacent surface buildings, which is focused on relative stiffness, peak acceleration and deformation types of the structures. Firstly, generalized inter-story drift spectrum combined with two FEM models with and without subway station are used to analyze the change of the inter-story drift of the surface buildings because of the existence of a underground station; Then, the influence of two key factors, the fundamental period of the building and the distance between the building and the station, on the IDR distribution along the height of the structures is investigated; Following, the effect of two factors, the relative stiffness and the PGA of the input motion, on the seismic response of adjacent building is summarized and concluded; Finally, the deformation types for the structures with different foundational periods caused by the existence of a station are extensively analyzed.(5) A typical subway tunnel which is buried in the layered soil is selected to analyze the influence on the dynamic response of the surface adjacent structures. Firstly, based on the generalized inter-story drift spectrum, the variation of the response of the surface structures with the distance from the tunnel is investigated when there is a tunnel in the foundation and not; Secondly, as a characteristic of subway tunnel, it is possible that the surface structures exist on the top of the tunnel, therefore, the influence of subway tunnel on the buildings which stand on the top of the tunnel is investigated; Finally, the difference of IDR distribution along the height between when the tunnel exists and not is summarized, and the deformation types of the structures are analyzed.更多还原