【作者】 郭晓云；

【导师】 薄景山；

【作者基本信息】 中国地震局工程力学研究所 ， 岩土工程， 2011， 博士

【摘要】 20世纪30年代M. A. Biot提出反应谱理论,至20世纪50年代G. W. Housner给出第一条抗震设计反应谱。从此,反应谱方法在世界范围内被广泛接受,这也标志着地震工程学的发展进入了反应谱理论阶段,工程界对反应谱的研究也一直持续到今天。目前,世界上多数国家均采用抗震设计反应谱作为抗震设计中确定地震动输入的主要依据。通常,归一化的抗震设计反应谱其形状由几个特征参数确定,其中最重要的是反应谱平台值和特征周期,反应谱的研究中大量的工作是如何科学地确定这两个特征参数。场地条件是影响反应谱特征参数的重要因素,但我国抗震设计规范只考虑了场地条件对反应谱特征周期的影响而没有考虑场地条件对反应谱平台值的影响,其重要原因之一是缺少有场地条件的强震记录。2008年5月12日14时28分,我国四川省汶川县附近发生了里氏8.0级特大地震,此次地震是新中国成立以来破坏性最强、波及范围最广、救灾难度最大的一次地震灾害,给我国人民带来了巨大的灾难。“十五”期间,中国地震局在南北地震带上布设了大量的强震台,这些强震台网在汶川特大地震中获得了丰富的高质量强震记录,并且很多强震记录具有详细的场地条件资料,这为我们研究反应谱和场地条件对反应谱特征参数的影响提供了重要的基础资料。本文全面系统地归纳、总结和评述了当前本领域的前沿成果和相关文献,在系统整理汶川地震强震资料的基础上,对汶川特大地震的加速度反应谱及其特征参数进行统计分析,深入研究了抗震设计反应谱的标定方法,探索反应谱特征参数与场地条件等因素之间的关系,开展了如下研究工作:(1)全面收集和整理了汶川特大地震的强震记录,收集了川、陕、甘三省的158个非基岩台站和16个基岩台站的强震记录、台址场地条件和地理位置等详细资料。对强震记录进行了整理,计算了每条强震记录的峰值加速度和修正后的峰值速度。(2)研究并提出了反应谱新的标定方法。反应谱的标定方法直接关系到反应谱特征参数的确定,本文在综述各种反应谱标定方法的基础上,提出了基于坐标变换的最小二乘法分段拟合方法,并通过对比不同反应谱标定方法,指出最小二乘法分段拟合方法是简便且合理的反应谱标定方法,采用此方法对汶川特大地震强震记录的反应谱进行了标定并获取了每条反应谱的特征参数。(3)研究了场地条件和断层距对反应谱特征参数的影响。加速度反应谱平台值表征了地震动的强度特性,该参数与多种影响因素有关。本文统计分析了不同场地条件和断层距区间内的加速度反应谱平台值,指出场地条件对加速度反应谱平台值有较大影响,随着场地变软,加速度反应谱平台值增大,并采用不同的分组方法计算了加速度反应谱平台值的场地影响系数。(4)研究了汶川地震强地震动的频谱特征。反应谱特征周期表征了地震动的频谱特性,本文通过对反应谱特征周期、加速度反应谱卓越周期和平滑化加速度反应谱卓越周期与场地类别、断层距离之间关系的统计分析,得到这三种频谱周期均随场地变软而增大,随着断层距离增加而增大。本文还拟合了加速度反应谱卓越周期和平滑化卓越周期与加速度反应谱特征周期之间的经验关系。(5)研究了汶川地震竖向地震动反应谱。计算近场和远场的竖向与水平(V/H)加速度反应谱比,对其表现出的不同特点和影响因素进行分析,指出近场V/H加速度反应谱比值明显受到上盘效应的影响,短周期上盘V/H反应谱比值大于下盘V/H反应谱比值,长周期下盘V/H反应谱比值大于上盘V/H谱比值。远场短周期段和长周期段的V/H反应谱比值均随着场地变软而减小,也随着断层距离增加而减小。(6)研究了场地条件和断层距离对竖向加速度反应谱平台值和特征周期的影响。研究得出,相同条件的竖向加速度反应谱平台值小于水平加速度反应谱平台值。计算了竖向加速度反应谱平台值的场地影响系数。研究结果表明,近场竖向加速度反应谱特征周期略小于水平加速度反应谱特征周期,远场竖向加速度反应谱特征周期略大于水平加速度反应谱特征周期。世界上的任何灾难无不以人类社会的进步为补偿,汶川特大地震给我们带来了巨大的灾难,灾区人民蒙受了巨大的经济损失。但是汶川特大地震也为我们提供了极为丰富的地震资料,为我们研究地震灾害提供了平台。总结和研究汶川特大地震的震害,深入研究强地震动的特征,对提高抗震能力具有重要的意义。本文的结论只来源于对汶川特大地震强震资料的详细研究,有些结果可能与我们通常的认知不一致。科学是一种探索,探索就会有失误,不足之处请批评指正。更多还原

【Abstract】 M. A. Biot presented response spectrum theory at the third decade of 20th century, and until the fifth decade of 20th century, G. W. Housner developed the first seismic design response spectrum. From then on, response spectrum method is widly accepted internationally, which indicate that the development of earthquake engineering come into response spectrum theory phases, and research on response spectra continues to today. At present, most countries of the world use seismic design response spectra calculating earthquake action on building structures. Usually, the form of smooth seismic design response spectrum is calibrated by several characteristic parameters, among which the most important are the peak platform value and characteristic period of response spectrum. In the study of response spectra, a lot of work is how to scientifically determine the two characteristic parameters. Site condition is an important factor effecting response spectrum characteristic parameters, but the code for seismic design of our country just consider site condition effects to the response spectrum characteristic period but not the peak platform value of response spectrum. One of the most important reasons is short of ground motion records with site condition.On May 12, 2008, at 14:28 PM local time, a great earthquake of Richter magnitude 8.0 occered near Wenchuan town in Sichuan province, and this earthquake was the most devastating, the most widely spread and the most difficult relief earthquake disaster, since the founding of New China, and it resulted in great tragedy for Chinese. In the“Tenth Five”plan of China, China Earthquake Administration set a great deal of strong motion instruments on the North-South earquake zone. These strong motion instruments net got abundant high quality digital ground motion records. Many of these ground motion records had detailed site condition, and this provides us abundant basic information for our research on spectra and site condition effect on parameters of resonse spectra. This dissertation comprehensively and systemically summarized the results of the current forefront of the field and related literature. Based on collatting strong motion records information of Wenchuan earthquake, it analyzed response spectrum of Wenchuan earthquake and its characteristic parameters statistically, did in-depth reseatch on methods of calibrating seismic design response spectrum, explored the relationship between the response spectrum parameters and site conditions and other factors. The investigation of this work includes:(1) Comprehensively collected and collated strong motion records of Wenchuan earthquake. Collected strong motion records, site condition of stations and station coordinates of 158 soil stations and 16 bedrock stations in Sichuan, Shanxi and Gansu province. Caculated peak ground acceleration and peak ground velocity of each strong motion record.(2) Researched and advanced a new method of calibrating seismic design response spectrum. Methods of calibrating seismic design response spectrum correlate with determination of redponse spectrum characteristic parameters. Based on summarizing many methods of calibrating seismic design response spectrum, this dissertation advanced least square fitting method based on coordinate transformation, and by comparing different calibrating methods, pointed out that least square fitting method is simple and logical calibrating method. Using this method, this dissertation caculated the characteristic parameters of Wenchuan earthquake strong motion records.(3) Researched the effects of site condition and distance from the fault to response spectrum characteristic parameters. Peak platform value of response spectrum denotes the strength characteristic of ground motion, and this parameter relates with a variety of factors. This paper statistically analyzed the peak platform value of response spectrum in different site condition and different distance from the fault subarea. It pointed out that site conditions have a great impact on the peak platform value of acceleration response spectrum. With the soft site, the peak platform value of acceleration response spectrum increases. It caculated the coefficients of site effects of the peak platform value of acceleration response spectrum on different site conditions with different grouping method.(4) Researched the spectrum characteristic of Wenchuan earthquake strong motion. Characteristic period of response spectrum reflects strong motion’s characteristic. By statistically analyzing the relationship between the characteristic period and the predominant spectral period and the smoothed spectral predominant period with site conditions and distance from the fault, this paper pointed out that these three kinds of period increase with the soft site, and increase with the incease of the distance from the fault. It also fit the empirical relationship between the characteristic period and the predominant spectral period and the smoothed spectral predominant period.(5) Reasearched the vertical response spectrum of Wenchuan earthquake strong motion. Caculated the ratio of vertical response spectrum to horizontal response spectrum near fault and far fault, and analyzed its different characteristices and factors. Point out that near fault the ratio of vertical response spectrum to horizontal response spectrum obviously affected by“hanging wall”effect. On short periods the ratio of vertical response spectrum to horizontal response spectrum on the hanging wall are bigger than the foot wall, and on the long periods the ratio of vertical response spectrum to horizontal response spectrum on the hanging are smaller than the foot wall. Far fault, on short periods and long periods the ratio of vertical response spectrum to horizontal response spectrum minish with the soft site, and minish with the far distance from the fault.(6) Researched the effects of site condition and distance from the fault to the peak platform value of vertical response spectrum and vertical response spectrum characteristic period. Research found that the peak platform value of vertical response spectrum is smaller than the peak platform value of horizental response spectrum with the same conditions. Caculated the coefficients of site effects of the peak platform value of vertical acceleration response spectrum on different site conditions. The results show that vertical response spectrum characteristic period is smaller than horizental response spectrum near fault, and vertical response spectrum characteristic period is larger than horizental response spectrum far fault.Any disaster of the world compensate to the prograss of the human socity. Wenchuan earthquake brought us great disaster, and people in disaster area suffered huge economic losses, but it provided us with abundant seismic information, and gave us a great chance to research earthquake disaster. Sum-up and study of the damage in Wenchuan great earthquake, depth researth of strong motion’s characteristics, have great significance to improve the seismic capacity. The conclutions of this paper are only come from research on Wenchuan earthquake strong motion data, and some results may be inconsistent with our usual understanding. Science is an exploration, and exploration will make mistake, please point out the inadequacies.更多还原