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1.
合理描述土体动力本构关系对场地设计地震动参数取值的准确性有显著影响。以苏州城区200 m深的钻孔剖面为研究对象,对比分析了一维等效线性波传分析法（ELA法）和基于修正Matasovic本构模型的多自由度集中质量非线性分析法（NLA法）给出的深厚场地地震反应,研究了基岩输入地震动特性和地震基岩面的选取对深厚场地地震反应的影响。结果表明：（1）随基岩地震动强度（PGA）的增大,ELA法给出的地表PGA呈单调递增的特征,而NLA法给出的地表PGA呈先快速增大后缓慢减小或几乎不变的趋势;（2）ELA法和NLA法给出的地表加速度反应谱（Sa谱）在短周期范围内存在明显差异,ELA法对基岩高频地震动具有显著的滤波效应,而NLA法对基岩高频地震动的影响表现为随基岩PGA的增大先放大后减小的特征;（3）随地震基岩面深度的增大,地表Sa谱的谱值呈现出稍许增大的趋势,但对周期T<0.1 s部分,NLA法给出的地表Sa谱的谱值则呈现出稍许减小的现象;（4）中、大震作用下,地表地震动持时不仅与基岩地震动特性有关,还与地震反应分析方法和地震基岩面的选取密切相关,NLA法能更合理地反映基岩地震动强度和上覆土层厚度对地表地震动持时的影响。 相似文献
2.
通过实时地震观测数据获取能力和计算机性能的巨大提高 ,快速生成仪器观测的地面运动和地震动强度空间分布成为可能 ,利用这一成果结合地震灾害易损性研究成果和地震灾害评估模型 ,可以对破坏性地震造成的损失进行快速评估 ,为地震应急响应和决策指挥提供更可靠的信息支持。本文概述了利用强地面运动加速度观测资料进行地震灾害快速评估方法在国内外最新进展 ,提出了利用我省强震台网观测资料进行地震灾害快速评估的基本思路。 相似文献
3.
Airports are one of the critical infrastructures that play an essential role in managing natural disasters through receiving or sending aid and supplies. Air traffic control (ATC) towers are an inseparable part of each airport as the performance of airports depends on the functionality of their ATC towers. Many ATC towers have been designed and constructed based on older versions of modern seismic codes in which seismic design has followed a force-based design approach. This study addresses the seismic vulnerability of three in-service ATC towers which have been designed and constructed according to a force-based design concept. The height of the towers ranges from 24 to 52 m. Fragility curves have been used for the seismic vulnerability study of these towers. For the derivation of seismic fragility curves, 45 earthquake records were selected and classified into low, medium and high classes based on their ratio of peak ground acceleration (PGA) to peak ground velocity (PGV). It was observed that records with a low PGA/PGV ratio imposed the highest level of damage to the towers. However, when towers were subjected to the records with a high PGA/PGV ratio, the damage intensity was not significant. Results indicated that the intensity of seismic-induced damage to the tallest tower was significantly more than that of the shortest tower. It was concluded that only the shortest tower could satisfy the expected seismic performance objectives. 相似文献
4.
Lenin Ávila-Barrientos Carlos Valdés-González David A. Novelo-Casanova 《Natural Hazards》2011,59(2):655-664
Acceleration and velocity data of large earthquakes recorded by the Mexican National Broadband Seismological Network were
used to generate isoseismal maps for Mexico. The seismic data consist of 99 events recorded at 27 seismic stations located
in the southern and northern regions of Mexico from 2004 to 2009. The magnitude (Mw) of these events ranged from 4.1 to 7.1.
Peak ground velocity values (PGV) and peak ground accelerations (PGA) were estimated, and velocity-derived peak ground accelerations
(PGAv) were calculated. No important differences between PGAv and PGA values were found; thus, both parameters were used in
the isoseismal determination. The generated synthetic isoseismal maps were compared with those from an existing catalog for
large earthquakes in Mexico. Using empiric relations between PGA and MMI (modified Mercalli intensity) and PGV and MMI, the
obtained simulated intensity maps showed similar behavior to those reported in the catalog. The results indicate that the
PGAv values can be used to determine intensities when acceleration records (PGA) are unavailable. 相似文献
5.
In this study, seismological aspects and field observation of the 2010 Kuh-Zar earthquake has been investigated. The Kuh-Zar earthquake, of magnitude 5.7 (Mw), occurred in northeastern Iran on August 27, 2010. The area is surrounded by branches of the active faults which are coated by the quaternary alluvium. During the past several decades, this area has been struck by a number of earthquakes. This earthquake with a moderate magnitude caused a higher rate of damage contrasted with previous earthquakes of the same magnitude range in Iran. Fortunately, the source of the Kuh-Zar earthquake was in a sparsely populated area, and therefore, it caused a few loss of life with the highest observed intensity of shaking VII (modified Mercalli intensity) in the Kuh-Zar village. The shock killed 4 people, injured 40, and destroyed more than 12 villages. According to the field observation, the mechanism of this shock is defined as a left-lateral strike slip. We also checked out the properties of strong ground motions in this earthquake using the records availed by Iranian strong motion network. At KUZ station, about 7 km east of the epicenter, the recorded PGA and PGV in both horizontal and vertical components were remarkably large for an event of this size, and visual inspection of the velocity time history reveals a pulse-like shape. Unfortunately no other recording stations were located close enough to the fault to capture a directivity pulse. Finally, according to the strong-motion properties and observed information, ShakeMaps of the earthquake have been generated by the native intensity observations and the recorded strong motions. 相似文献
6.
以玉树7.1级地震诱发的玉树机场路堆积层滑坡为对象,该滑坡坡度约为10o,长×宽×厚为317 m×482 m×19.8 m,由以碎石土为主的上覆层、卵石土为主的滑动带及基岩3层组成,开展大型振动台模型试验,探究震后边坡再次承受振动荷载的能力以及地震垂直分量对坡体稳定性的贡献,分析其动力响应特征和失稳破坏机制。结果表明,强震作用下堆积层滑坡的永久变形是造成地震地质灾害的重要因素;随着输入地震荷载增大,坡脚率先破碎沉降,坡体中部产生弧形裂隙并产生沉降,坡顶出现贯穿张裂隙和剪切裂隙并向坡腰推进,表现出典型的牵引性滑坡特征;峰值加速度(PGA)、动土压力以及加速度频谱与输入地震波的强度、滑坡高程呈正相关;PGA放大系数呈现出明显的非线性特征,其变化趋势随地震荷载强度增大而减小,地震波垂直分量对滑坡PGA放大系数影响略大于水平分量。 相似文献
7.
叠交隧道是涉及隧道之间、隧道与土体相互作用的复杂体系,其安全性将严重影响城市轨道交通建设。目前,对于叠交隧道振动台试验的研究集中在水平平行和交叉叠交隧道、单向和双向地震动输入。鉴于此,利用自行设计的层状三向剪切模型箱,对竖直平行叠交隧道开展三向地震作用下的振动台模型试验,研究地基土−叠交隧道模型体系动力特性、地基土加速度、叠交隧道加速度、地表沉降、地基土孔压、叠交隧道动土压力及叠交隧道应变等地震响应。结果表明：随着震波峰值加速度（peak ground acceleration,简称PGA）依次增加,地基土−叠交隧道模型体系的自振频率随之减小,而阻尼比随之增大;叠交隧道周围地基土加速度和孔压的梯度差随着地震波PGA的增大而增大,且上隧道周围梯度差比下隧道更大;地基土对加速度的放大效应随着地震波PGA的增大而减弱;相同地震波作用下,相同位置处的叠交隧道加速度傅里叶谱形状相似,但幅值随着地震波PGA的增大而增大。此外,与顶部和底部位置相比,腰部位置加速度傅里叶谱频段范围变宽,幅值峰值有所降低;地表沉降峰值随着地震波PGA的增大而减小,相比地基土两侧位置,中心位置的沉降峰值明显较小;地震波的类型对叠交隧道动土压力峰值和应变峰值影响较小;对于动土压力峰值,两隧道的最大值均为腰部,而上、下隧道的最小值分别为底部、顶部;对于应变峰值,上隧道在腰部明显大于顶部和底部,而下隧道在4个位置相差不大。 相似文献
8.
本文采用有限差分和随机振动合成结合的复合方法,模拟了当礼县—罗家堡断裂发生矩震级Mw7.7级大地震时,在天水盆地产生的宽频带地震动场,分析了在设定地震条件下盆地内的地震动分布特征,为该区黄土地震滑坡分析提供了地震动参数结果。结果显示:(1)有限差分法和随机振动合成法可以很好地互补,得到盆地内地表宽频带地震动;(2)地震在盆地区域产生了强烈地震动,PGA(峰值加速度)介于150~900 gal,离断层较近的区域东南角的PGA最大,随着断层距的增加,PGA逐渐减小。河谷南侧的PGA值相比北侧较大,具备诱发滑坡的强大动力条件;(3)盆地区域PGV(峰值速度)最大为120 cm/s。受第四系覆盖层放大效应和地形放大效应共同影响,水平向地震动在盆地区域东侧和中部具有较大PGV,而西侧PGV相对较小。竖向地震动在盆地区域东侧较弱,而在中部和西侧较强,特别是最西侧陡峭的山坡上,PGV达到了最大值。此外,竖向地震动明显受到覆盖层厚度的影响,譬如在盆地区域南侧的中间部位,也具有较大的PGV。 相似文献
9.
Ali Kafaei Mohammadnejad Seyyed Mohammad Mousavi Mohammad Torabi Mehdi Mousavi Amir Hossein Alavi 《Environmental Earth Sciences》2012,67(1):53-70
This study presents new attenuation models for the estimation of peak ground acceleration (PGA), peak ground velocity (PGV), and peak ground displacement (PGD) using a hybrid method coupling genetic programming and simulated annealing, called GP/SA. The PGA, PGV, and PGD were formulated in terms of earthquake magnitude, earthquake source to site distance, average shear-wave velocity, and faulting mechanisms. A worldwide database of strong ground motions released by Pacific Earthquake Engineering Research Center (PEER) was employed to establish the models. A traditional genetic programming analysis was performed to benchmark the proposed models. For more validity verification, the GP/SA models were employed to predict the ground-motion parameters of the Iranian plateau earthquakes. Sensitivity and parametric analyses were carried out and discussed. The results show that the GP/SA attenuation models can offer precise and efficient solutions for the prediction of estimates of the peak time-domain characteristics of strong ground motions. The performance of the proposed models is better than or comparable with the attenuation relationships found in the literature. 相似文献
10.
桩板式抗滑挡墙地震响应的振动台试验研究 总被引：2，自引：0，他引：2
汶川地震路基震害调查表明,在顺层或堆积体边坡中的桩板式抗滑挡墙具有良好的抗震性能。为了更好地了解该结构的抗震性能和优化抗震设计方法,以大型振动台模型试验为手段对其进行研究。为明确地震作用下桩板式抗滑挡墙的地震响应特性,试验采用缩尺的卧龙台站实测地震波对模型激励。试验结果揭示了土压力沿桩身分布规律、桩体位移和边坡岩土体加速度的地震响应特征。研究表明,地震土压力沿桩身呈非线性分布,竖向地震荷载对水平加速度有放大效果。所以,双向加载时的地震土压力比水平单向加载时大,但二者差距在地震基本烈度VII、VIII度区域不显著。滑坡推力、滑床对桩的土体抗力和桩身位移均与输入地震动峰值加速度成正比,即随着地震动峰值加速度的增加,加速度放大比增大;滑动面材料剪切强度折减,滑坡推力、土体抗力和抗身位移均增大,且增大速率加快。此外,结合试验成果,建议了桩板式抗滑挡墙设计时地震综合影响系数Cz的合理取值,对应地震基本烈度VII、VIII、IX度区分别为0.2、0.35、0.4。试验结果有助于揭示该结构抗震机制,也为其抗震设计提供了可靠依据。 相似文献
11.
2008年汶川Ms8.0级强烈地震对远离震中的黄土塬地区造成了较为严重的破坏,局部场地的震害和地震动放大效应显著。以典型黄土塬场地为对象,应用地形台阵流动观测和有限元计算方法,系统开展强震动作用下黄土塬边坡场地动力响应特征研究;应用大型振动台模拟试验和数值计算方法,重点探讨黄土塬平台场地在汶川地震作用下地表加速度响应随覆盖层厚度、地震动强度的变化规律以及对建筑结构的潜在影响。结果表明：黄土塬边坡顶部存在低频但较高放大系数的现象,可能与斜坡高差与入射波波长之比密切相关;大角度（60°～70°）黄土塬边坡对地震动的放大效应十分显著,坡顶加速度峰值（PGA）放大可达2倍,反应谱卓越周期放大可达5倍;较厚黄土塬平台场地加速度放大可达2倍以上,地震烈度增加1度,对于场地上固有周期0.7～2.0 s和周期大于3.0 s的建筑物地震反应将显著增加。 相似文献
12.
Mahmoud Y. Al-Qaryouti 《Arabian Journal of Geosciences》2008,1(2):111-117
Using the recorded earthquake strong ground motion, the attenuation of peak ground acceleration (PGA) and peak ground velocity
(PGV) are derived in the southern Dead Sea Transform region. The expected values of strong motion parameters from future earthquakes
are estimated from attenuation equations, which are determined by regression analysis on real accelerograms. In this study,
the method of Joyner and Boor [Bull Seismol Soc Am 71(6):2011–2038, 1981] was selected to produce the attenuation model for the southern Dead Sea Transform region. The dataset for PGA consists of
57 recordings from 30 earthquakes and for PGV 26 recordings from 19 earthquakes. The attenuation relations developed in this
study are proposed as replacement for former probabilistic relations that have been used for a variety of earthquake engineering
applications. The comparison between the derived PGA relations from this study with the former relations clearly shows significant
lower values than the other relations. 相似文献
13.
This paper deals with the probabilistic seismic hazard analysis carried out in the Oran region, situated in the Northwest of Algeria. This part of Algeriawas historically struck by strong earthquakes. It was particularly affected during theOctober 9, 1790 Oran earthquake of intensity X. The main purpose of this work is to assessseismic hazard on rocks in order to provide engineers and planners with a basic tool for seismicrisk mitigation. The probabilistic approach is used in order to take into account uncertaintiesin seismic hazard assessment. Seismic sources are defined in the light of the most recentresults obtained from seismotectonics analyses carried out in North Algeria.Source parameters such as b-values, slip rate and maximum magnitude are assessed for eachseismic source. The attenuation of ground shaking motion with distance is estimated byusing attenuation relationships developed elsewhere throughout the world (Sadigh et al., 1993; Ambraseys and Bommer, 1991). The two relationships agree well with the local data. Differentchoices of source parameter values and attenuation relationships are assigned weights in alogic tree model. Results are presented as relationships between values of peak groundacceleration (PGA) and annual frequency of exceedance, and maps of hazard for returnperiods of 200 years and 500 years. A maximum peak ground acceleration of 0.42 g is obtainedfor the Oran site for a return period of 500 years. 相似文献
14.
Probabilistic seismic hazard analysis for Bangalore 总被引：5，自引：3，他引：2
This article presents the results of probabilistic seismic hazard analysis (PSHA) for Bangalore, South India. Analyses have
been carried out considering the seismotectonic parameters of the region covering a radius of 350 km keeping Bangalore as
the center. Seismic hazard parameter ‘b’ has been evaluated considering the available earthquake data using (1) Gutenberg–Richter (G–R) relationship and (2) Kijko
and Sellevoll (1989, 1992) method utilizing extreme and complete catalogs. The ‘b’ parameter was estimated to be 0.62 to 0.98 from G–R relation and 0.87 ± 0.03 from Kijko and Sellevoll method. The results
obtained are a little higher than the ‘b’ values published earlier for southern India. Further, probabilistic seismic hazard analysis for Bangalore region has been
carried out considering six seismogenic sources. From the analysis, mean annual rate of exceedance and cumulative probability
hazard curve for peak ground acceleration (PGA) and spectral acceleration (Sa) have been generated. The quantified hazard
values in terms of the rock level peak ground acceleration (PGA) are mapped for 10% probability of exceedance in 50 years
on a grid size of 0.5 km × 0.5 km. In addition, Uniform Hazard Response Spectrum (UHRS) at rock level is also developed for
the 5% damping corresponding to 10% probability of exceedance in 50 years. The peak ground acceleration (PGA) value of 0.121 g
obtained from the present investigation is slightly lower (but comparable) than the PGA values obtained from the deterministic
seismic hazard analysis (DSHA) for the same area. However, the PGA value obtained in the current investigation is higher than
PGA values reported in the global seismic hazard assessment program (GSHAP) maps of Bhatia et al. (1999) for the shield area. 相似文献
15.
Assessment of seismic hazard and liquefaction potential of Gujarat based on probabilistic approaches
Gujarat is one of the fastest-growing states of India with high industrial activities coming up in major cities of the state. It is indispensable to analyse seismic hazard as the region is considered to be most seismically active in stable continental region of India. The Bhuj earthquake of 2001 has caused extensive damage in terms of causality and economic loss. In the present study, the seismic hazard of Gujarat evaluated using a probabilistic approach with the use of logic tree framework that minimizes the uncertainties in hazard assessment. The peak horizontal acceleration (PHA) and spectral acceleration (Sa) values were evaluated for 10 and 2?% probability of exceedance in 50?years. Two important geotechnical effects of earthquakes, site amplification and liquefaction, are also evaluated, considering site characterization based on site classes. The liquefaction return period for the entire state of Gujarat is evaluated using a performance-based approach. The maps of PHA and PGA values prepared in this study are very useful for seismic hazard mitigation of the region in future. 相似文献
16.
The analyses of retaining walls in California showed many backfills are coarse material with some cohesion. In this investigation, seismic response of cantilever retaining walls, backfilled with dirty sandy materials with up to 30 kPa cohesion, is evaluated using fully dynamic analysis. The numerical simulation procedure is first validated using reported centrifuge test results. The validated methodology is then used to investigate the effects of three earthquake ground motions including Kobe, Loma Prieta, and Chi-Chi on seismic response of retaining walls. In addition, the input peak ground acceleration values are varied to consider a wide range of earthquake acceleration intensity. 相似文献
17.
One of the most critical lessons of the recent earthquakes is the need for seismic planning for lifelines, with appropriate
supplies and back up systems for emergency repair and restoration. Seismic planning, however requires physical loss estimations
before the earthquakes occur. Buried pipeline damage correlations are critical part of loss estimation procedures applied
to lifelines for future earthquakes. We review the existing pipeline damage relationships only for ground shaking (transient
ground deformations) in the light of recent developments and evaluate them with Denizli City, Turkey water supply system.
Eight scenario earthquakes with four different earthquake magnitudes between M6 and M7 caused by two different fault ruptures (Pamukkale and Karakova-Akhan Faults) were used. Analyses were performed by using
Geographical Information Systems (GIS). This high number of different scenario earthquakes made it possible to compare the
pipeline damage relationships at different ground shaking levels. Pipeline damage estimations for Denizli City were calculated
for each damage relationship and earthquake scenario. Relative effects of damage relationships and scenario earthquakes on
the results were compared and discussed. The results were presented separately for brittle, ductile, and all pipelines. It
was shown that the variation in ductile pipeline damage estimations by various relationships was higher than the variation
in brittle pipeline damage estimations for a particular scenario earthquake. 相似文献
18.
针对一种含贯通性顺倾结构面的岩质边坡,开展地震波场传播特性、动力演化规律和破坏机制研究。基于华丽高速公路金沙江大桥桥址边坡,实施了数值分析及振动台模型试验。通过地震波场数值模拟,明确了地震波场受贯通性结构面影响,在贯通性结构面和坡面之间反复叠加,加速度放大效应较均质边坡增大约1.8倍。振动台模型试验中不断增大地震输入烈度,加速度响应在烈度为Ⅷ度时发生突变,边坡由弹性响应阶段进入塑性阶段。在裂度为Ⅸ度时坡脚附近裂缝进一步扩展、贯通,直至发生整体滑动失稳,滑动面沿后缘陡倾结构面剪出、贯通性顺倾结构面滑动、下部坡脚附近剪出。强震后受扰动边坡若处在塑性阶段/不稳定阶段,在其他外力触发下有可能发生滑坡灾害。 相似文献
19.
Sokolov Vladimir Ovcharenko Arkady Loh Chin-Hsiung Wen Kuo-Liang 《Natural Hazards》2004,33(3):319-363
The paper describes an integrated approach to seismic hazard assessment, which was applied for the Taiwan region. First, empirical modelsfor ground motion estimation in the region were obtained on the basisof records from recent (1993-1999) earthquakes. The databaseincludes strong-motion data collected during the recent Chi-Chiearthquake (M=7.6, 21 September 1999) and large (M=6.8)aftershocks. The ground-motion database was also used for evaluationof generalised site amplification functions for typical soil classes(B, C and D). Second, the theoretical seismic catalogue (2001–2050)for the Taiwan region had been calculated using the 4D-model(location, depth, time) for dynamic deformation of the Earth' crustand 5D-model (location, depth, time, magnitude) for seismic process.The models were developed on the basis of available geophysical andgeodynamic data that include regional seismic catalogue. Third, theregion & site & time-dependent seismic analysis, which is basedon schemes of probable earthquake zones evaluated from the theoreticalcatalogue, regional ground motion models, and local site responsecharacteristics, has been performed. The seismic hazard maps arecompiled in terms of Peak Ground Acceleration (PGA) and ResponseSpectra (RS) amplitudes. The maps show distribution of amplitudesthat will not be exceeded with certain probability in condition oftypical soil classes during all possible earthquakes that may occur inthe region during time period of 2003–2025. The approach allowsintroducing new parameter that describes dependency of seismichazard on time, so-called 'period of maximum hazard'. Theparameter shows the period, during which every considered sitewill be subjected by the maximum value of ground motioncharacteristic (PGA or RS). 相似文献