集集地震余震地震动衰减关系及其不确定性研究

发布时间：2019-05-14 11:17

【摘要】：强地震动是地震工程中引起土木工程结构破坏的主要原因,作为地震预测、工程抗震以及震后救灾的基础,地震动衰减关系及其不确定性对地震危险性分析有着重大的影响。近些年,研究主余震序列对结构的影响成为热点,现有结构的地震反应分析和抗震设计一般只考虑主震,但由于结构的累积损伤效应,余震对结构物的倒塌常常起关键性的作用。现有的成果主要集中在主震方面,对余震的研究较少,尤其是余震序列,为了全面考虑余震对结构的影响,合理地进行地震动参数的设计,有必要对余震进行地震动衰减关系的研究。地震序列指的是发生在狭小空间内的一系列地震,其震源机制可能存在联系或有相似的发震背景,于是,同一场地和同一震源区对地震动衰减关系的不确定性影响,是值得充分考虑的。台湾集集地震记录到了丰富的强震动记录,地震序列规模惊人,尤其是余震序列数量更是庞大,有利于推进余震地震动衰减特性及其不确定性的研究。本文以集集地震余震地震动记录为基础建立数据库,采用随机效应方法对所选用数据进行地震动衰减关系的统计回归,通过对衰减结果的分析和对误差的分解,获得台湾地区的地震动特性以及不同因素对地震动的影响特征,从而为更为合理地减小地震动衰减模型的不确定性提供些参考和依据。本文研究工作的主要内容和结果包括:(1)搜集震源信息和台站场地资料,建立集集地震余震地震动数据库,分析台湾地区地震动基本特性。针对NGA计划中的CB08模型,从传播路径、震源特性和反应谱三个方面进行适用性分析。发现CB08模型现有回归结果与集集地震余震地震动记录相比估值偏高,尚不能合理地反映台湾地区独特的地质构造与波传播路径效应。(2)利用台湾集集地震余震地震动数据,采用随机效应方法建立地震动衰减关系,对回归结果进行分析和比较。总体而言,本文结果对中小震有一定的参考价值,但对于大震结果偏小。(3)将余震地震动衰减关系应用于地震危险性分析中,并采取不确定性校正。发现地震动超越概率曲线在校正前后有相当大的变化,校正后的超越概率有了显著提高,尤其体现在低概率段。(4)利用集集地震余震序列单一场地和单一路径地震动数据进行衰减关系的不确定性研究,根据不同的地震动影响因素对模型误差进行系统性分解和定量分析,最后与其他研究成果进行比较。发现通过减少误差项,模型的不确定性可以明显减小。
[Abstract]:Strong ground motion is the main cause of civil engineering structural failure in seismic engineering. As the basis of earthquake prediction, engineering earthquake resistance and post-earthquake relief, the attenuation relationship and uncertainty of ground motion have a great impact on seismic risk analysis. In recent years, the study of the influence of the main aftershock sequence on the structure has become a hot spot. The seismic response analysis and seismic design of the existing structures generally only consider the main shock, but due to the cumulative damage effect of the structure, Aftershocks often play a key role in the collapse of structures. The existing results mainly focus on the main shock, and the research on aftershock is less, especially the aftershock sequence. In order to consider the influence of aftershock on the structure in an all-round way, the design of ground motion parameters is carried out reasonably. It is necessary to study the attenuation relationship of ground motion in aftershocks. Earthquake sequence refers to a series of earthquakes that occur in a narrow space. The focal mechanism may be related or has a similar seismic background. Therefore, the uncertain influence of the same site and the same source area on the attenuation relationship of ground motion. It is worthy of full consideration. The Taiwan Jiji earthquake records have a wealth of strong vibration records, and the scale of the seismic sequence is amazing, especially the large number of aftershock sequences, which is helpful to promote the study of the attenuation characteristics and uncertainty of aftershock ground motion. In this paper, a database is established based on the seismic aftershock ground motion records of Jiji earthquake. The random effect method is used to carry out the statistical regression of the attenuation relationship of the ground motion, and through the analysis of the attenuation results and the decomposition of the error, The ground motion characteristics in Taiwan and the influence characteristics of different factors on ground motion are obtained, which provides some reference and basis for reducing the uncertainty of ground motion attenuation model more reasonably. The main contents and results of this paper are as follows: (1) collect the source information and station site data, establish the earthquake aftershock ground motion database of Jiji earthquake, and analyze the basic characteristics of ground motion in Taiwan. Aiming at the CB08 model in NGA plan, the applicability of the model is analyzed from three aspects: propagation path, focal characteristics and response spectrum. It is found that the existing regression results of CB08 model are higher than those of aftershock ground motion records of Jiji earthquake, which can not reasonably reflect the unique geological structure and wave propagation path effect in Taiwan. (2) using the aftershock ground motion data of Jiji earthquake in Taiwan, The attenuation relationship of ground motion is established by random effect method, and the regression results are analyzed and compared. Generally speaking, the results in this paper have certain reference value for small and medium-sized earthquakes, but the results for large earthquakes are small. (3) the attenuation relationship of aftershock ground motion is applied to seismic risk analysis, and uncertainty correction is adopted. It is found that the transcendence probability curve of seismic motion has a considerable change before and after correction, and the transcendence probability after correction has been significantly improved. In particular, it is reflected in the low probability section. (4) the uncertainty of attenuation relationship between single site and single path ground motion data of Jiji earthquake aftershock sequence is studied. According to different influencing factors of ground motion, the model error is systematically decomposed and quantitatively analyzed, and finally compared with other research results. It is found that the uncertainty of the model can be obviously reduced by reducing the error term.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P315.9

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