近断层地震动速度脉冲的识别方法及对隔震结构的影响研究

发布时间：2018-02-09 02:43

本文关键词： 速度脉冲识别速度脉冲特性标定谱地震动输入隔震结构　出处：《中国地震局工程力学研究所》2015年硕士论文　论文类型：学位论文

【摘要】：近三十年发生的几次大地震给人类造成了巨大的人员伤亡和经济损失,引起了科学家对近断层地震动的关注。其中,地震动速度脉冲作为近断层地震动特征之一,因其具有幅值大、周期长、包含长周期高能量及对结构影响大等特点备受各国学者关注。在研究近断层地震动速度脉冲时,首先需要识别出含速度脉冲的地震动,其次是对速度脉冲型地震动的工程特性进行研究,最后研究其对隔震结构的影响。本文针对上述三个问题展开研究,主要内容和结论如下:1.通过对前人定性和定量识别速度脉冲方法的总结,简要介绍了Baker(2007)、ShahiBaker(2014)定量识别速度脉冲方法,提出改进的经验模态分解(EMD)方法识别速度脉冲,并从理论上和实例上进行了对比。研究发现,EMD方法较其它两种方法,没有严苛的应用范围,本身自适应性强的特点扩大了它的应用范围,可以作为识别速度脉冲的一种参考和补充方法。2.通过对台湾集集地震含速度脉冲和不含速度脉冲两种地震动的三要素研究发现,速度峰值PGV、速度反应谱峰值所对应的周期Tpsv、能量持时Tp最能反映两种地震动之间的区别。含与不含速度脉冲PGV的比值平均值为2.21;含与不含速度脉冲的Tpsv的比值大多分布在1-2.66之间,其平均值为1.68。含脉冲地震动的能量持时要比不含脉冲的短,大约是不含脉冲地震动能量持时的0.69倍,含脉冲的地震动在很短的时间内能量累计要比不含脉冲的大。3.采用双参数标定法和最小二乘法分段拟合方法对台湾集集地震中的8组数据进行反应谱标定。通过研究其标定谱特征参数特征周期Tg、平台段高度βmax、衰减指数γ发现,在平均周期1.16 s之后,含脉冲的标定谱幅值大于不含脉冲的,并且平均是其1.98倍。因此规范中的设计谱需要考虑含速度脉冲的地震动对其影响。4.归纳总结了前人研究地震动速度脉冲对结构影响时选取地震动输入的原则:(1)满足同源性:即地震动时程来自于同一次地震、具有相同的震中距、相同的场地条件;(2)反应谱相似性;(3)每类时程数量不得少于8组;(4)尽量保持震中距范围基本一致。5.采用基于小波分析Baker提取速度脉冲方法,将选取的1999年台湾集集地震中30条FN方向含脉冲的地震动分解为Orig分量(没有进行小波分析的原始地震动)、Pulse分量(提取出来的脉冲)和Resid分量(原始地震动提取脉冲后剩余的不含脉冲分量);将Orig作为含脉冲的地震动、Resid作为不含脉冲的地震动输入6层框架隔震结构中,采用有限元分析软件ETABS对其进行非线性时程分析,研究含与不含速度脉冲的地震动对隔震结构的影响。通过研究结果,为保证隔震结构设计的可靠性,提出如下建议:(1)在距离震中比较近的区域内应考虑含速度脉冲的地震动对隔震结构的影响;这个“比较近的区域”建议为距震中80 km内;(2)当与拟建场地条件相似的含速度脉冲地震动记录数量比较少时,脉冲影响系数取1.34-1.60之间的放大系数。
[Abstract]:Several large earthquakes occurred in recent thirty years has caused huge casualties and economic losses to human, causing scientists to near fault ground motions. The pulse for near fault ground motion characteristics of ground velocity, because of its large amplitude, long cycle, long cycle and high energy including the characteristics of structure influence by many scholars in different countries. In the study of velocity pulse of near fault ground motions, first need to identify with velocity pulse ground motions, followed by the research on engineering characteristics of pulse type ground motion for speed, finally to study its effect on isolated structure. Based on the above three issues, the main content and the conclusions are as follows: 1. based on the previous qualitative and quantitative method of pulse recognition speed up, briefly introduced the Baker (2007), ShahiBaker (2014) quantitative recognition speed pulse method, the improved empirical mode State decomposition (EMD) method to identify the velocity pulse, and from the theoretical and practical examples are compared. It is found that the EMD method is compared with the other two methods, the scope of application not harsh, self adaptability features to expand its scope of application, can be used as a reference and supplement method.2. recognition speed pulse the set containing velocity pulse and without seismic velocity pulse study three two seismic elements found on the Taiwan set, PGV peak velocity, velocity response spectrum corresponding to the peak period of Tpsv, the Tp can reflect the difference between the two seismic energy duration. The ratio with and without the velocity pulse of the average PGV 2.21 with and without Tpsv; the ratio of velocity pulse is mostly distributed in between 1-2.66, the average value of 1.68. with pulse duration of ground motion energy than does not contain short pulses, is about 0.69 times without seismic energy pulse duration, Impulsive ground motions in a very short period of time than the accumulative energy without pulse high.3. using two parameter calibration method and least squares fitting method set 8 sets of data in the earthquake response spectrum calibration of Taiwan. Through the research on the calibration of spectral characteristic parameters of characteristic period Tg, platform height beta Max gamma attenuation index found that after an average period of 1.16 s, with amplitude greater than the free spectrum calibration pulse, and the average is 1.98 times. So the design specifications of the spectrum to consider containing velocity pulse ground motions on the impact of.4. summarizes the velocity pulse on the structural effects of selected ground motion input principle previous studies of ground motion: (1) meet homology: ground motions from the same earthquake, with the same epicentral distance, the same site conditions; (2) the response spectrum similarity; (3) the number of each class is not less than 8; (4) as Keep the epicentral distance scope consistent.5. using wavelet analysis Baker extraction method based on velocity pulse, will be selected in 1999 Taiwan set 30 FN in the direction of seismic ground motion is decomposed into impulsive Orig components (no original seismic wavelet analysis), Pulse (pulse component extracted) and Resid (component extraction after the pulse remaining free pulse component of the original ground motion); Orig as impulsive ground motions, Resid as free pulse ground motion input 6 layer frame isolated structure, using finite element analysis software ETABS, the nonlinear time history analysis, research with and without vibration effects on the velocity pulse. Isolated structure. Through the research results, in order to ensure the reliability of isolation structure design, put forward the following suggestions: (1) considering the velocity pulse ground motions on isolated structures in the shadow region should be relatively close to the epicenter The near area is recommended to be within 80 km away from the epicenter. (2) when the number of records with velocity pulse ground motion similar to the site conditions is relatively small, the amplification coefficient of 1.34-1.60 is between the impulse influence coefficient.

【学位授予单位】：中国地震局工程力学研究所
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P315.9;TU352.11

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