CAJ | 학술논문

针对现行水工抗震规范中对近断层地震缺乏考虑这一实际问题，首先讨论了近断层、远场地震动的差别，对比了近断层、远场地震动对地下洞室地震响应的影响，继而提出一种新的人工合成近断层地震动时程的方法，并采用合成的近断层地震动时程对某水电站地下洞室群进行了近断层地震稳定性专门研究。结果表明：与常规地震分析中考虑的远场地震动相比，近断层脉冲型地震动的主要特征为Vmax/Amax和Dmax/Amax（Vmax、Dmax、Amax分别为速度峰值、位移峰值、加速度峰值）指标更大，且近断层脉冲型地震动的主要能量集中在1 Hz以下的频段；在相同峰值加速度幅值、相同反应谱的前提下，近断层地震动对高边墙、大跨度地下工程的破坏程度远比远场地震动大；较之前人的研究方法，文中提出的近断层脉冲型地震动合成方法考虑了[1/Tp,1] Hz这一频段内的地震波信息，更具合理性；在设定的计算条件下，地下厂房洞室群有在近断层地震动作用下发生失稳的危险性，需要进一步针对近断层地震动进行专项风险性评价，以讨论是否需要增设针对性的抗震支护措施。
침대현행수공항진규범중대근단층지진결핍고필저일실제문제，수선토론료근단층、원장지진동적차별，대비료근단층、원장지진동대지하동실지진향응적영향，계이제출일충신적인공합성근단층지진동시정적방법，병채용합성적근단층지진동시정대모수전참지하동실군진행료근단층지진은정성전문연구。결과표명：여상규지진분석중고필적원장지진동상비，근단층맥충형지진동적주요특정위Vmax/Amax화Dmax/Amax（Vmax、Dmax、Amax분별위속도봉치、위이봉치、가속도봉치）지표경대，차근단층맥충형지진동적주요능량집중재1 Hz이하적빈단；재상동봉치가속도폭치、상동반응보적전제하，근단층지진동대고변장、대과도지하공정적파배정도원비원장지진동대；교지전인적연구방법，문중제출적근단층맥충형지진동합성방법고필료[1/Tp,1] Hz저일빈단내적지진파신식，경구합이성；재설정적계산조건하，지하엄방동실군유재근단층지진동작용하발생실은적위험성，수요진일보침대근단층지진동진행전항풍험성평개，이토론시부수요증설침대성적항진지호조시。
The near-fault ground motion has long been ignored in the seismic design phase of the underground caverns. Hence this issue needs to be seriously addressed. The differences between near-fault and far-field ground motions are firstly discussed, along with the impact of the respective ground motion on underground caverns. Then a modified simulation method of near-fault pulse-type ground motion is proposed. And with the simulated ground motion, the seismic stability of underground caverns for a hydropower station is studied. The results indicate that compared with the conventional far-field ground motion, the near-fault ground motion is characterized by greater Vmax/Amax and Dmax/Amax values (where Vmax, Dmax, Amax are peak values of velocity, displacement and acceleration). And energy of near-fault ground motion is concentrated in 0~1 Hz band. The damage caused by near-fault is far more serious than that of by far-field ground motion, even with same amplitude and spectrum. The proposed simulation method is well logical for considering the information carried in the [1/Tp, 1] Hz. With current calculation conditions, the underground powerhouse is in a potential danger of failure under the near-fault ground motion. Thus further specific risk assessment for near-fault ground motions is expected to check if specialized seismic reinforcement measure is required.