【作者】 张季；

【导师】 梁建文；

【作者基本信息】 天津大学 ， 防灾减灾工程及防护工程， 2013， 博士

【摘要】 地铁作为当今城市轨道交通系统的重要组成部分，对于缓解大城市日益严峻的交通拥堵状况具有重要作用。地铁隧道通常由单个或多个洞室组成，根据工程波动理论，洞室对地震波的散射作用必将对隧道沿线地震动产生影响，并可能造成沿线既有地面建筑物抗震设防水平不足。我国是一个地震频发国家，有一半以上大中城市位于7度及以上的抗震设防区，因此研究隧道对其沿线地震动所造成的影响具有重要意义。将频域内间接边界元法与傅里叶时频变换法相结合，在时域内研究了天津地区典型线性场地中单洞室、双洞室对地表地震动的影响，典型场地包括干土场地和饱和场地，地震动运动方式包括平面内运动和平面外运动。研究表明，洞室的存在可显著改变洞室附近场地的地表地震动大小和频谱。对于所输入的Taft波和El Centro波，就双洞室来讲，地表PGA（加速度峰值）最高可被放大45.2%；此外，反应谱频谱特性也会发生变化。建立了一种新的有限元与间接边界元耦合算法，并将耦合方法与等效线性化方法结合，实现了对土层非线性的模拟，在此基础上进一步研究了天津地区典型非线性场地中单洞室、双洞室对平面内地震动的影响。研究表明，洞室对地表地震动具有显著的非线性放大作用。对于所输入的加速度峰值分别为0.1g和0.2g的Taft波和El Centro波，就双洞室来讲，地表PGA最高可被放大30.7%。研究表明，层状场地中地铁隧道对地震动具有显著的放大作用，建议在地铁隧道设计过程中考虑这一影响。更多还原

【Abstract】 As an important ingredient of today’s urban railway transit system, subway playsa significant part in easing serious traffic congestion in large cities. Subway tunnelsare usually composed of one or more parallel cavities, according to engineering wavepropagation theory, the effect of scattering by cavities on seismic waves shallundoubtedly exert influence on seismic motion in the vicinity of tunnels, and makeaseismic capacity of the existing buildings nearby inadequate. China is an earthquakefrequent country, over half of its large cities are located at regions of seismic intensity7or higher degree, and consequently, study about the influence of tunnels on seismicmotion nearby will be of great significance.By combing indirect boundary element method (IBEM) in frequency domain andFourier time-frequency transform, and taking typical linear sites in Tianjin district asexamples, effects of single cavity and twin cavities in layered half space on surfaceground motion are studied, the sites include dry site and saturated poroelastic site, andthe vibration modes include anti-plane vibration and in-plane vibration. It is shownthat, existence of cavity remarkablely changes magnitude and spectrum of groundseismic moiton nearby. Under the excitation of Taft wave and El Centro wave, as fortwin cavities, the amplification of PGA can be up to45.2%. Besides, spectralcharacteristic of response spectrum will also be changed.A new algorithm coupling FEM and IBEM is established, and by introducingequivalent linear method into such algorithm, nonlinear characteristic of soil layer canbe taken into consideration, on this basis, by taking typical nonlinear site in Tianjindistrict as an example, effects of single cavity and twin cavities in layered half spaceon surface ground motion are further studied. It is shown that unlinear amplificationof surface ground motion by cavity is also obvious. Under the excitation of Taft waveand El Centro wave with PGAs of0.1g and0.2g, while as for twin cavities, theamplification of PGAcan be up to30.7%.Significant amplification of seismic motion by underground metro tuunels isrevealed in present study, such amplification should be better taken into account whendesigning subway tunnels.更多还原