非线性场地放大效应及其在地震动衰减关系中的应用
发布时间：2018-07-16 23:45
【摘要】：地震动衰减关系在地震安全性评价、地震危险性分析及为抗震设计提供定量设防标准等工作中都发挥着重要作用。场地非线性放大模型是地震动衰减关系(GMPEs)的重要组成部分,它可以通过多种方法构造,最好的办法是直接通过强震数据回归得到。然而,即使是在强震记录丰富的日本,其含有有效土体强非线性效应记录的数量太少,以至于单纯依靠强震记录还不能够推断出可靠的非线性场地模型。因此本文用数值模拟方法来获得场地反应谱放大比。本文选取的基岩强震动记录是来自日本和PEER数据库中不同类型的地震。这些记录的矩震级、震源距和峰值地面加速度分布范围广泛。建立的一维模型是基于日本Kik-net强震台站实测剪切波速资料,台站的场地周期、场地土体厚度和阻抗比分布范围也较大。本文提出一个以运用场地分类、并以一维等效线性模型为基础的非线性场地放大模型。为了克服一维模型的局限性,本文提出了一个新的模型调整方法将非线性放大模型应用于地震动衰减关系中。本文主要工作如下：(1)收集了大量日本Kik-net、K-net和PEER强震数据,这些数据来自不同构造类型的地震,其震级、震源深度、震源距离范围很广。以此为基础来建立本文研究的数据库。(2)按Kik-net场地实测的剪切波速计算场地周期,并将场地按照计算的场地周期进行分类。依据土层深度、剪切波波速并在一个给定范围内随机选取土层非线性模型。用SHAKE程序等效线性分析计算出场地的放大比。(3)首先选取经验模型拟合计算的反应谱放大比,然后基于上一步的模型来逐步进行残差分析,确定模型参数。最终选取的模型考虑到了场地阻抗比、地震矩震级和震源距离的影响。(4)结合残差分析所有的参数,本文建立了一个随机效应模型,回归得到了模型参数。在回归分析过程中,用极大似然估计的改变量并结合各个系数中值和标准差的比值来检验各个参数。如果某一项参数回归系数的中值与标准差之比小于2,表明它在统计上可能不显著。从比值最小的一项参数开始检验,在模型中去掉这一项后,如果在统计上不显著,极大似然函数值的减小量小于1,就把这一项参数从模型中去掉。从而就得出了一组场地非线性放大模型。(5)考虑到对于世界上许多真实的强震台站和实际工程场地来说,一维模型是一个简单的假设,所以本文设计了一个方法来调整一维模型,使它能够适用于地震动衰减方程。
[Abstract]:The attenuation relationship of ground motion plays an important role in the evaluation of seismic safety, seismic risk analysis and the provision of quantitative fortification standards for seismic design. Site nonlinear amplification model is an important part of ground motion attenuation relation (GMPEs). It can be constructed by a variety of methods, and the best way is to get it directly from strong earthquake data regression. However, even in Japan, where strong earthquake records are abundant, there are so few records of strong nonlinear effects in soil that it is not possible to infer a reliable nonlinear site model by relying solely on strong earthquake records. Therefore, the amplification ratio of site response spectrum is obtained by numerical simulation. The bedrock strong motion records selected in this paper are from different types of earthquakes in Japan and per databases. The moment magnitude, focal distance and peak ground acceleration are widely distributed in these records. The one-dimensional model is based on the measured shear wave velocity data at the Kik-net strong earthquake station in Japan. The site period, the distribution range of soil thickness and impedance ratio are also large. This paper presents a nonlinear site amplification model based on site classification and one-dimensional equivalent linear model. In order to overcome the limitation of one-dimensional model, a new model adjustment method is proposed to apply the nonlinear amplification model to the attenuation relation of ground motion. The main work of this paper is as follows: (1) A large number of data of Kik-net-K-net and per strong earthquakes in Japan are collected. These data come from different tectonic types of earthquakes, whose magnitude, focal depth and focal distance range are very wide. Based on this, the database of this paper is established. (2) the site period is calculated according to the measured shear wave velocity of Kik-net site, and the site is classified according to the calculated site period. According to soil depth, shear wave velocity and a given range of random selection of nonlinear soil model. The amplification ratio of the site is calculated by equivalent linear analysis with Shake program. (3) the amplification ratio of the response spectrum is first selected from the empirical model fitting, and then the residual error analysis is carried out step by step based on the previous model to determine the parameters of the model. Finally, the influence of site impedance ratio, seismic moment magnitude and focal distance is taken into account. (4) combined with the residual analysis of all parameters, a random effect model is established and the model parameters are obtained by regression. In the process of regression analysis, the variables of the maximum likelihood estimation and the ratio of the median value of each coefficient to the standard deviation are used to test each parameter. If the ratio of median to standard deviation of a parameter regression coefficient is less than 2, it may not be statistically significant. When the minimum ratio parameter is removed from the model, if it is not statistically significant and the maximum likelihood function decreases less than 1, the parameter is removed from the model. Therefore, a set of nonlinear amplification models are obtained. (5) considering that the one-dimensional model is a simple hypothesis for many real strong earthquake stations and practical engineering sites in the world, this paper designs a method to adjust the one-dimensional model. So that it can be applied to the equation of ground motion attenuation.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU435
本文编号：2128090
[Abstract]:The attenuation relationship of ground motion plays an important role in the evaluation of seismic safety, seismic risk analysis and the provision of quantitative fortification standards for seismic design. Site nonlinear amplification model is an important part of ground motion attenuation relation (GMPEs). It can be constructed by a variety of methods, and the best way is to get it directly from strong earthquake data regression. However, even in Japan, where strong earthquake records are abundant, there are so few records of strong nonlinear effects in soil that it is not possible to infer a reliable nonlinear site model by relying solely on strong earthquake records. Therefore, the amplification ratio of site response spectrum is obtained by numerical simulation. The bedrock strong motion records selected in this paper are from different types of earthquakes in Japan and per databases. The moment magnitude, focal distance and peak ground acceleration are widely distributed in these records. The one-dimensional model is based on the measured shear wave velocity data at the Kik-net strong earthquake station in Japan. The site period, the distribution range of soil thickness and impedance ratio are also large. This paper presents a nonlinear site amplification model based on site classification and one-dimensional equivalent linear model. In order to overcome the limitation of one-dimensional model, a new model adjustment method is proposed to apply the nonlinear amplification model to the attenuation relation of ground motion. The main work of this paper is as follows: (1) A large number of data of Kik-net-K-net and per strong earthquakes in Japan are collected. These data come from different tectonic types of earthquakes, whose magnitude, focal depth and focal distance range are very wide. Based on this, the database of this paper is established. (2) the site period is calculated according to the measured shear wave velocity of Kik-net site, and the site is classified according to the calculated site period. According to soil depth, shear wave velocity and a given range of random selection of nonlinear soil model. The amplification ratio of the site is calculated by equivalent linear analysis with Shake program. (3) the amplification ratio of the response spectrum is first selected from the empirical model fitting, and then the residual error analysis is carried out step by step based on the previous model to determine the parameters of the model. Finally, the influence of site impedance ratio, seismic moment magnitude and focal distance is taken into account. (4) combined with the residual analysis of all parameters, a random effect model is established and the model parameters are obtained by regression. In the process of regression analysis, the variables of the maximum likelihood estimation and the ratio of the median value of each coefficient to the standard deviation are used to test each parameter. If the ratio of median to standard deviation of a parameter regression coefficient is less than 2, it may not be statistically significant. When the minimum ratio parameter is removed from the model, if it is not statistically significant and the maximum likelihood function decreases less than 1, the parameter is removed from the model. Therefore, a set of nonlinear amplification models are obtained. (5) considering that the one-dimensional model is a simple hypothesis for many real strong earthquake stations and practical engineering sites in the world, this paper designs a method to adjust the one-dimensional model. So that it can be applied to the equation of ground motion attenuation.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU435
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