【摘要】 以台湾集集地震的近断层地震动记录TCU051-EW、TCU052-EW、TCU054-EW、TCU068-EW、TCU068-NS、TCU082-EW作为输入,使用有限差分程序FLAC对北京市拱形断面结构形式的单层三跨典型地铁车站进行了水平向弹塑性动力时程分析,研究了近断层地震动破裂向前方向性与滑冲效应引起的两种不同形式地震动对典型地铁车站结构动力响应的影响。计算结果表明:虽然破裂向前方向性效应与滑冲效应的输入地震动峰值加速度设置相同,但由滑冲效应地震动引起的结构相对水平位移差、峰值加速度及地震应力明显大于由破裂向前方向性效应地震动引起的结构相对水平位移差、加速度及地震应力,滑冲效应地震动较向前方向性效应地震动对地下结构的破坏更具危害性;输入破裂向前方向性效应近断层地震动时,拱形中跨顶板中部、边跨拱形顶板中部及中柱上端的水平方向加速度峰值均大于结构底板及中柱下端、底板中心等部位水平方向加速度峰值,即破裂向前方向效应地震动对结构上端的加速度反应特性具有放大作用,而输入滑冲效应近断层地震动时,结构上端水平方向加速度峰值却均小于结构下端水平方向加速度峰值,即滑冲效应地震动对结构上端的加速度反应特性具有减小作用,意味破裂向前方向性效应地震动造成结构上端动力响应较大,而滑冲效应地震动会使得结构底部动力响应较大。更多还原

【Abstract】 Near-fault ground motion records of TCU051-EW,TCU052-EW,TCU054-EW,TCU068-EW,TCU068-NS,TCU082-EW from the Chi-Chi earthquake in Taiwan were selected as seismic inputs,and then time history analysis of elasto-plastic seismic responses of a single-layer three-span representative subway station with arched cross section in Beijing were carried out using finite difference procedure FLAC.The influence of two different kinds of near-fault ground motion caused by rupture forward directivity and fling step on the dynamic responses of the representative subway station structure was studied.It was shown that,although seismic peak ground accelerations of rupture forward directivity and fling step were set as the same,the relative horizontal displacement,the peak acceleration and the seismic stress of the structure caused by fling-step ground motion are significantly larger than those caused by rupture forward directivity ground motion,which implied that the fling-step ground motion caused more severe damage to underground structures than the forward directivity ground motion did;when the seismic input was rupture forward directivity ground motion,the middle positions of arched roofs of middle spans,the middle positions of arched roofs of side spans,and the top positions of columns had larger horizontal accelerations than the bottom of the structure did,which meant the horizontal acceleration of the top of the structure was amplified under rupture forward directivity ground motion;when the seismic input was fling-step ground motion,the top of the structure had smaller horizontal accelerations than the bottom of the structure did,which meant the horizontal acceleration of the top of the structure was reduced under the fling-step ground motion.The rupture forward directivity ground motion had more severe dynamic response on the top of the structure,while the fling-step ground motion had more severe dynamic response at the bottom of the structure.更多还原