【作者】 张波；

【导师】 陶连金；

【作者基本信息】 北京工业大学 ， 土木工程， 2012， 博士

【摘要】 随着轨道交通的发展和地铁施工技术的日臻成熟，车站和区间隧道断面形式逐渐演化，换乘车站逐渐增多，车站的空间交叉现象愈来愈普遍。地铁结构形式的多样化及空间结构组合的普遍性是未来地铁发展的必然趋势。对于地铁换乘站或交通枢纽，车站-车站、车站-区间隧道相互空间交叉，再加上其间的连接通道，构成了错综复杂、相互影响的地下空间结构体。地震作用下，由于在交叉、连接等部位的地基位移分布不同，较一般地下结构更易产生较大变形和附加内力；此外，地震波在结构上引起的横向剪切变形，会导致连带结构处于纵向拉压或弯曲的复杂应力状态，即整个地下立体式交叉结构在地震作用下的变形受力状态更加复杂，且相互作用更加显著。本文依托国家973课题―城市地下基础设施的地震破坏与抗震理论（2007CB714203）‖和北京市自然科学基金重点项目―地铁车站立体交叉结构地震响应及抗震设计方法研究（8111001）‖，根据北京地区地质条件、地铁车站结构形式、车站-隧道典型组合形式等特点，主要从地震作用下地铁车站典型结构的破坏机理、破坏模式和车站-隧道不同组合条件下的地震响应等两个方面进行了相关的分析与研究，具体的研究内容和研究成果如下：以土体电镜扫描为研究对象，把数字图像处理技术引入土体的细观结构观察和定量分析中，求解土颗粒孔隙度、颗粒粒径及颗粒形状等细观颗粒组成参数，为建立颗粒流离散元细观模型提供物理参数。在基础上，对土样的三轴试验进行模拟，并研究细观力学参数（包括：摩擦系数、平行连接强度及刚度比）对宏观性质的影响。建立基于典型地铁车站结构大型振动台试验的有限差分-颗粒流离散元耦合模型，对车站结构模型在地震中的地震响应和破坏现象进行模拟分析。在耦合计算模型中，土体采用连续模型、结构采用颗粒流离散元模型模拟，在FLAC边界节点处建立接触面，将FLAC在大应变模式计算的位移通过接触面传输给颗粒流离散元；并将颗粒与接触面计算的相互作用力传输给FLAC，作为施加在各节点上的力，从而实现耦合运算。结果表明，数值模型的计算结果与试验结果能够较好的拟合；地震加载过程中，柱板、墙板节点为地铁车站模型结构的薄弱部位；模型的整个破坏过程和能量转化过程可分为3个阶段；结构的破坏过程可以通过颗粒孔隙率、配位数和接触力的变化以及能量的转化规律反映出来。设计并开展地铁车站-隧道不同密贴组合结构的振动台试验，建立以覆土厚度为主要控制因素的相似关系处理方法，对不同的组合结构形式输入不同的地震作用，主要研究：自由场振动特性和模型振动前后的动力性质变化以及物性演变过程；单层连拱形地铁结构的地震受力和变形特征以及土-结构相互作用的土压力和位移变化规律；并行隧道结构的地震受力和相互影响规律；地铁车站及隧道结构在不同空间组合形式下的地震响应影响规律。基于试验结果和建立在振动台试验基础上的FLAC模型模拟分析得到以下规律：模型在振动激励下，土体的自振频率不断降低，阻尼比增加。模型箱的顶部反应位移大于底部，反应加速度则底部大于顶部。模型箱的边界吸波效果良好，且土体具有明显的滤波性质；结构的存在对上部土体的反应加速度具有减弱作用；结构与土的相互作用较为明显，且与埋深，结构尺寸等呈现不同的分布规律；结构墙柱应变大于梁板，节点处应力集中；车站倾斜放置时，结构-土相互作用力受竖向土压力控制；相对于单体车站，结构的应变幅值由墙柱向顶板转移，且分布趋于平均分布；并行隧道结构的存在加剧了对土体剪切波的反射和集中，对单体隧道的反应加速度、动土压力、动应变幅值等均具有放大效应；底部隧道结构的存在对传来的地震波具有吸收作用，使得上部车站的地震响应减弱，且减弱幅度随夹层土体厚度的增加而减小。更多还原

【Abstract】 With the development of subway and maturation of construction technology, thecross-section form of station and tunnel has been changed. The transfer station hasbeen gradually increased, the phenomenon of space cross-station been increasingcommon. The diversification of subway station structure form and universality ofspace cross-station is the development trend of the future subway. The space-cross ofstation-station and station-tunnel and the connecting channel between them of Metrotransfer station or transport hub constitute a complex interaction of underground spacestructure. A greater deformation and additional internal forces will be generated in theconnection point under earthquake. In addition, the transverse shear deformationcaused by seismic waves in the structure will make another structure in a complexstress state of longitudinal tension or bending. In short, the deformation and stressstate of underground three-dimensional structure under earthquake is more complexand more significant interaction.This work was financially supported by a grant from the Major State BasicResearch Development Program of China (973Program),‖the earthquake damageand seismic theory of unban underground infrastructure‖. No.2007CB714203, andsupported by Beijing Municipal Natural Science Foundation.‖Study on seismicresponse and design method of three-dimensional intersected underground subwaystructures‖. No.8111001. According to the geological conditions in Beijing, thesubway station structure, and the typical combination of characteristics of station andtunnel, this article focuses on two aspects of analysis and research related to failuremechanism and mode of typical subway station structure and seismic response ofthree-dimensional intersected underground subway structures. The specific researchcontents and results are as follows:Taking silt soil image photographed by scanning electron microscope as theresearch object, use image treatment technology for microstructure observation andquantitative analysis of soil, solve the parameter of particle composition of soil, suchas porosity, grain diameter and granular shape. These works provide physicalparameters for granular flow model developing. And then simulate the tri-axial test ofthe soil and study the variation rules of property of silt soil with micro-parameters,such as friction coefficient, parallel-bond and stiffness ratio.A continuum-discrete element coupled model is built based on a large-scaleshaking table test of typical subway station in Beijing, to simulate the seismicresponses and the damage process of subway station structure model. In the couplingmodel, the soil is simulated by finite-difference method, and the structure is simulatedby particle flow code. Interfaces are built between the adjacent nodes on the boundaryof FLAC model and used as walls in PFC. Displacement calculated by FLAC inlarge-strain model transfer to PFC through interfaces, and the interaction force between particle and walls transfer to FLAC, so as to approach the couplingcalculation. The result shows that the experimental results can be well fitted. Theinterior column and nodes of column and plates are weak parts of subway stationstructure model during inputting earthquake waves. The whole damage process andenergy conversion process of structure model can be divided into three phases. Thechange of porosity, average number of contacts and contact force and the energyconversion law can response the damage process of structure model.Design and carry out shaking table test of different combinations of subwaystation and tunnel. Establish the treatment method of similar ratio with mainlycontrolling factors of over burden quality. Enter the different types of seismic waves.The main contents are as follows: the vibration characteristic of free field and itsdynamic nature of change and evolution of physical properties during the vibration,seismic force and deformation characteristics of arch station and the variation of earthpressure and deformation of soil-structure interaction, seismic force and interactionlaw of parallel tunnels, interaction law of seismic response of different combinationsof subway station and tunnel.The following laws are obtained by the analysis of shaking table test results andnumerical simulation by FLAC based on the shaking table test. The natural frequencyof soil decreases and damping ratio increases in the process of vibration. The topdisplacement of model box is larger than the bottom, and the distribution law of theacceleration is contrary. The effect of absorbing seismic waves of model boxboundary is good. The filtering nature of soil is obvious. The acceleration response ofshallow soil is weakened with the structure buried. The interaction force between soiland structure is comparatively large, and the distribution law is obviously differentaccording to different depths and structure sizes. The strains of columns and walls arelarger than which of beams and plates. The structure stress concentration is located onnodes. The interaction force is controlled by vertical earth pressure. The distributionof maximum strain value is transfer from columns and walls to beams and plates andtends to uniform. The existence of parallel tunnel structure intensifies the reflectionand exacerbates of shear waves in the soil, which amplify the response of acceleration,earth pressure, and strain of single tunnel. About the combinations of subway stationand tunnels, the bottom tunnels structure can absorb the earthquake waves comingfrom shaking table test, and reduce the seismic response of the upper station structure.The week effect reduces with soil thickness increasing.更多还原