基于KIK-net强震记录场地影响的估计

发布时间：2018-01-14 10:48

本文关键词：基于KIK-net强震记录场地影响的估计　出处：《苏州科技大学》2017年硕士论文　论文类型：学位论文

【摘要】：场地放大系数对建筑结构抗震设计有着重要影响,在第五代《中国地震动区划图(GB 18306-2015)》中,增加了考虑场地影响的场地地震动峰值加速度调整系数aF,《建筑抗震设计规范》GB 50011-2010进行局部修订,编制成的《建筑抗震设计规范》GB 50011-2010(2016年版)也反映这一结果。一般地,研究场地放大系数最常用的方法标准谱比法(SSR),即利用土层场地和附近参考基岩场地的强震记录的谱比获得。这一方法存在的问题和困难在于:真正的基岩场地很难找到,因为基岩表面的风化层普遍存在,而非常靠近土层场地的参考基岩场地(都有强震记录)很少。由于强震动记录受场地条件影响很大,以及收集资料的代表性和广泛性受到限制,这就使得传统的SSR不能直接应用于在KiK台阵覆盖的区域而获得放大因子。同时,对于每个台站还要考虑震源、传播途径和各个站点场地等因素,每个钻孔基岩的深度和各层土介质的波速等参数也存在差异,而且也没有考虑地震波在土介质之间的反射影响,都会对传统的SSR的结果产生影响。本文对上述问题进行研究,主要研究内容如下:1、本文根据日本KiK-net强震动观测台网2000年1月到2015年12月,震级高于4.5级,震源深度小于50km,震中距小于100km;并对每个数据的信噪比进行限制,满足信噪比的数据可不做滤波处理;接着对场地资料的合理性做出判定。最后挑选出102个台站1233组地震记录为本文的研究工作提供了坚实的基础。2、采用日本KiK-net台站的实际的地震记录(GIFH09)和一简单的场地资料,采用线性化的方法进行土层地震响应模拟,计算不同深度的地震动,并求取不同场地的加速度反应谱,从而得出深度校正因子的一般规律;其次利用8对KiK-net台站的加速度反应谱比和Nakamura法(单台谱比法)定性的分析出井下基岩谱比BSR_F(地表和井下的傅里叶谱比)大于标准谱比SSR;然后,考虑所有的KiK-net场地地表传递函数TF和基岩的传递函数BTF,并将它们与地表和井下的傅里叶谱比BSR_F进行比较。接着,基于上述结果,计算并建议一个简单而有力的深度校正因子。最后,将8组台站的标准谱比SSR、井下基岩BSR_F以及井下基岩谱比深度校正的结果进行比较,发现深度校正的井下基岩谱比BSRc_F与标准谱比SSR很接近,并可以代替标准谱比SSR来计算场地的放大系数。3、根据国内外场地调整系数的研究现状和发展趋势的总结,利用日本KiK-net实际地震动观测数据统计规律,并由上述得出的深度校正因子,采用我国场地分类的标准和国外的研究方法,进行我国场地分类标准的场地调整系数的研究,并给出场地调整系数建议值。
[Abstract]:Site magnification factor plays an important role in seismic design of building structure, in the fifth generation of "China ground motion zoning map GB 18306-2015". The adjustment coefficient of peak acceleration of ground motion considering the influence of site is increased, and the Code for Seismic Design of buildings (GB50011-2010) is locally revised. The Code for aseismic Design of buildings, GB 50011-2010 (2016 Edition), also reflects this result. The most commonly used method for studying site magnification is the standard spectral ratio method (SSRs). The problem and difficulty of this method is that the real bedrock site is difficult to find because the weathering layer on the bedrock surface is ubiquitous. The reference bedrock sites which are very close to the soil site (all have strong earthquake records) are very few. The strong motion records are greatly affected by the site conditions, and the representativeness and universality of the collected data are limited. This makes the traditional SSR can not be directly used in the area covered by KiK array to obtain the amplification factor. At the same time, for each station, we should consider the source, the transmission path and the site of each station and other factors. The depth of each borehole bedrock and the wave velocity of each layer of soil medium are different, and the reflection effect of seismic wave between soil media is not considered. In this paper, the above problems are studied, the main research contents are as follows: 1. According to the KiK-net strong motion observation network of Japan from January 2000 to December 2015, the magnitude of the earthquake is more than 4.5, the focal depth is less than 50km, and the epicenter distance is less than 100km. The signal-to-noise ratio of each data is restricted, and the data satisfying the signal-to-noise ratio can not be filtered. Finally, 102 stations 1233 sets of seismic records are selected to provide a solid foundation for the research work in this paper. Using the actual seismic records of KiK-net station in Japan and a simple site data, the earthquake response of soil layer is simulated by linearization method, and the ground motion at different depths is calculated. The acceleration response spectrum of different sites is obtained, and the general law of depth correction factor is obtained. Secondly, by using the acceleration response spectrum ratio of 8 pairs of KiK-net stations and the Nakamura method (single-station spectral ratio method), the underground bedrock spectrum ratio BSR-F (Fourier spectrum ratio of surface and downhole) is analyzed qualitatively. Greater than the standard spectral ratio (SSRs); Then, the transfer function TF of all KiK-net sites and the transfer function of bedrock are considered and compared with the Fourier spectrum ratio (BSR_F) of surface and underground. Based on the above results, a simple and effective depth correction factor is calculated and recommended. Finally, the standard spectral ratio of eight stations is compared to SSR. By comparing the results of downhole bedrock BSR_F and downhole bedrock spectral ratio correction, it is found that the downhole bedrock spectral ratio (BSRc_F) of depth correction is very close to that of standard spectral ratio (SSR). And can replace the standard spectral ratio SSR to calculate the site magnification factor. 3, according to the domestic and foreign site adjustment factor research status and development trend summary. Based on the statistical law of the actual ground motion observation data of KiK-net in Japan and the depth correction factor obtained above, the standard of site classification in China and the research methods abroad are adopted. The site adjustment coefficient of our country's site classification standard is studied, and the suggested value of site adjustment coefficient is given.
【学位授予单位】：苏州科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU352.11

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