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调查、搜集和研究了汶川地震中被评定为高危以上险情的147座小型水库土坝的地震破坏情况,给出了高危以上险情土坝的地震破坏程度划分为中等破坏、严重破坏和极严重破坏三个等级的原则和标准,以及土坝的地震破坏程度与地震烈度、土坝的宽高比、上游坡比、坝高的经验关系表,可发现:土坝的几何形状对其破坏程度起着重要的作用;对于6～8度地震烈度区,土坝的宽高比越小,或上游坡比越小,或坝体越高,则土坝的破坏程度越严重;对于9度以上地震烈度区,土坝通常发生极严重破坏。依据高危以上险情土坝的地震反应分析结果,给出了土坝地震破坏程度与土坝宽高比、坝高、土坝上游坡比及坝顶加速度放大系数、坝体最大动剪应力的经验关系曲线,发现在相同的地震烈度水平下,土坝的宽高比越小,或上游坡比越小,或坝高越大,且坝顶加速度放大系数越大或坝体最大动剪应力越大,则其地震破坏程度越严重;坝体最大动剪应力超过30kPa的土坝,通常发生严重或极严重破坏,坝体最大动剪应力大于100kPa的土坝,通常发生极严重破坏;土坝离发震断层越远,则其坝顶加速度放大系数越大。本文给出的高危以上险情土坝的地震破坏程度与坝体几何形状的经验关系,可为今后土坝抗震设计提供参考依据。 相似文献
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汶川8.0级地震水坝震害调查 总被引：11，自引：1，他引：10
“5．12”汶川地震中水坝损毁严重,造成了巨大的经济损失。震后对69座溃坝险情和310座高危险情水库水坝进行了系统的调查,典型震害现象包括坝体裂缝、塌陷、滑坡、渗漏、启闭设施损坏和其他附属设施的损毁等。文中给出了不同烈度区的水坝震害分布,并对地震中水坝的震害现象做了初步总结和分析。 相似文献
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Small scale agricultural earth dams have been damaged by several past earthquakes. Damage to earth dams occurred at distances from the epicentre that increased in proportion to the scale of the earthquakes. On studying the damage a constant relation between the magnitude of the earthquake and maximum epicentral distance where the damage occurred was obtained. This relationship is similar to that obtained between the magnitude and the maximum epicentral distance at which liquefaction occurs. This, and the fact that earth dams which have been damaged several times due to liquefaction were near the critical epicentral distance, suggests that liquefaction of the foundation ground is the main cause of damage to earth dams. 相似文献
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2015年4月25日在尼泊尔廓尔喀县发生的8.1级地震及后续强烈余震,造成尼泊尔北部严重的人员伤亡和财产损失,灾区建筑物倒塌损失严重。本文利用现场震害调查资料和高分卫星遥感影像,开展建筑物震害遥感解译,得到各个遥感解译点的遥感震害指数,结合现场调查点评估的烈度拟合了遥感震害指数-实际震害指数转换关系,再根据遥感震害指数估计了全部解译点的震害指数及地震烈度。估计的烈度与现场调查结果对比显示出较好的一致性,研究结果为该地区今后发生地震提供了可借鉴的遥感评估震害指数转换模型。 相似文献
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汶川地震中极震区砌体结构教学楼典型震害分析 总被引：2，自引：3，他引：2
汶川8.0级大地震造成了巨大的损失,大量学校建筑遭受严重破坏,其中大部分是砌体结构教学楼。在此次地震中,极震区北川县擂鼓镇城区内的初中、小学和幼儿园等砌体结构教学楼的破坏极其严重,结构特征和震害现象十分典型。本文详细地介绍了擂鼓镇城区内5栋砌体结构教学楼的结构构造特点和震害现象特征,同时,总结归纳了砌体结构教学楼的典型震害并分析了震害原因;讨论并分析了建筑含墙率、开间大小、高宽比等因素对建筑的抗震能力的影响;通过结构易损性分析方法对教学楼在不同烈度下的破坏状态进行了计算,并与实际震害进行了对比分析;最后,为灾后教学楼的重建工作提出了建议。 相似文献
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土坝的地震易损性和震害速评 总被引：2，自引：0，他引：2
搜集了我国近年来几次大地震时处于５～１０度地震区内的１８０座水库土坝的震害资料,经分析后把影响震害的因素定为坝高、“水深比”、地基条件、地震烈度;震害等级取为“严重”、“较重”、“轻微”、“完好”。分别给出了适用于地震危害性评估时表示土坝地震易损性的震害概率矩阵,和适用于用确定性方法快速评估震害等级的表达式。最后给出了某土坝用两种方法进行震害评估的例子． 相似文献
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Konrad C. Hafen Joseph M. Wheaton Brett B. Roper Philip Bailey Nicolaas Bouwes 《地球表面变化过程与地形》2020,45(11):2664-2674
Stream ecosystems can be dramatically altered by dam-building activities of North American beaver (Castor canadensis). The extent to which beavers’ ecosystem engineering alters riverscapes is driven by the density, longevity, and size (i.e. height and length) of the dams constructed. In comparison to the relative ubiquity of beaver dams on the landscape, there is a scarcity of data describing dam heights. We collected data describing dam height and dam condition (i.e. damaged or intact) of 500 beaver dams via rapid field survey, differentiating between primary and secondary dams and associating each dam with a beaver dam complex. With these data, we examined the influence of beaver dam type (primary/secondary), drainage area, streamflow, stream power, valley bottom width, and HUC12 watershed on beaver dam height with linear regression and the probability that a beaver dam was damaged with logistic regression. On average, primary dams were 0.46 m taller than secondary dams; 15% of observed dams were primary and 85% secondary. Dam type accounted for 21% of dam height variation (p <0.0001). Slope (p = 0.0107), discharge (p = 0.0029), and drainage area (p = 0.0399) also affected dam height, but each accounted for less than 3% of dam height variation. The average number of dams in a dam complex was 6.1 (SD ± 4.5) and ranged from 1 to 21. The watershed a beaver dam was located in accounted for the most variability (17.8%) in the probability that a beaver dam was damaged, which was greater than the variability explained by any multiple logistic regression model. These results indicate that temporally dynamic variables are important influencers of dam longevity and that beaver dam ecology is a primary factor influencing beaver dam height. © 2020 John Wiley & Sons, Ltd. 相似文献
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地震引起的断层强烈错断是造成隧道等地下结构严重破坏的重要原因。以2022年青海门源6.9级地震中左旋走滑逆断层错动造成的隧道震害为调查基础,对左旋走滑逆断层错动下的震害特征及震害成因进行研究分析,主要得到如下结论：(1)左旋走滑逆断层造成大梁隧道线位严重错动,水平最大偏移约1.78 m,竖向最大抬升约0.68 m;(2)震害主要集中在断层影响范围内,其中隧道受破坏严重段约350 m,占隧道全长的5.33%,受破坏较严重段分别位于严重段大里程侧402 m和小里程侧646 m范围内,占隧道全长的15.96%,其余段落震害总体轻微;(3)施工缝、仰拱填充层等部位对强震较为敏感,震害表现突出。此次研究通过对震害特征分析得到的有益启示可为同类工程抗震设计提供参考与指导。 相似文献
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青海玛多7.4级地震发生后,本文作者随科考队开展了典型工程的震害调查。本文报道了黄河乡江旁村和昌马河工区这2个典型调查点的建筑震害情况。调查表明:邻近微观震中的黄河乡建筑震害程度相对较轻,主要表现为部分房屋落瓦,砖混结构少数承重墙及框架结构部分隔墙开裂,土木结构房屋部分严重破坏,部分围墙倒塌;而距微观震中以东85 km的昌马河工区建筑震害则相对较重:无抗震措施的砖木结构房屋全部严重破坏或倒塌,具备合理抗震措施的砖混结构基本完好或轻微破坏,在建轻钢厂房均钢柱倾斜、维护墙明显开裂并且围墙多数倒塌。调查分析表明:造成两地震害差异的主要原因为抗震措施差异以及地表破裂和砂土液化影响:黄河乡多数房屋具备合理抗震措施,昌马河工区多数民居缺少抗震措施;昌马河工区附近发现疑似地表破裂痕迹,而紧邻黄河乡的河岸发现砂土液化迹象。这表明昌马河工区的地震作用中类似近场的高频能量可能较多,而黄河乡地区则因砂土液化使得高频地震动作用有所降低,由此造成两地震害程度与震中距呈现反差关系。 相似文献
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通过对2022年1月8日青海门源6.9级地震的震源机制、发震构造、房屋和重大生命线工程震害、地震地表破裂带等震害调查资料的综合分析,系统介绍了此次地震震源机制、发震构造、地震烈度分布特点、房屋破坏特征及机理、生命线工程破坏特征及地表破裂带特征。研究结果表明：门源6.9级地震震中位置位于冷龙岭断裂带的西段,性质以左旋走滑为主,其与震源机制解得到的结果相一致,均为走滑型破裂类型;地震最大烈度Ⅸ度,烈度Ⅵ度(含)以上面积约23 417 km2,等震线长轴呈NWW走向,长轴200 km,短轴153 km;整体上房屋破坏较轻,甘肃境内主要属Ⅶ和Ⅵ度区影响范围,极少部分为Ⅷ度区影响范围;此次地震中滑坡灾害和生命线工程震害较少,主要在Ⅸ和Ⅷ度区造成部分路面裂缝,最为严重的则为兰新高铁浩门至军马场区间祁连山一号隧道群线路桥梁严重受损,隧道震害主要集中在断层影响范围内,其中隧道受破坏严重段约350m,占隧道全长的5.33%,受破坏较严重段分别位于严重段大里程侧402m和小里程侧646m范围内,占隧道全长的15.96%,其余段落震害总体轻微;地震造成地表破裂带约22 km,地震造成的... 相似文献
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利用前人所编的历代（共四代）地震烈度（地震动）区划图,组合叠加后得到一个综合烈度（地震动）。这种叠加是一个集成的专家系统综合认识结果,以此作为坝体可能遭受地震破坏危险的因素。初步研究建立了混凝土大坝震害评估模型,此模型是考虑了坝体的结构类型、建设年代、使用现状、场地条件、抗震设防水平等因素,用逐步线性拟合方法进行回归分析得到的。用此模型对汶川地震破坏的坝体进行了实例分析,分析结果比较符合实际。最后,用这个模型对黄河上游10座重点混凝土大坝做了震害评估分析。 相似文献
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汶川大地震曲线梁桥震害及破坏机理分析 总被引：4，自引：0，他引：4
以汶川大地震中严重破坏的回澜立交桥为例,基于数值模拟手段并结合现场震害调查,分析了回澜立交桥的地震破坏机理。数值分析表明,地震时设有支座的最矮的1号桥墩支座发生滑移破坏,以致刚度较大（次矮）的2号刚构桥墩承受很大的地震惯性力,2号墩首先发生弯曲屈服,此后随延性发展因抗剪能力不足最终发生剪切破坏直至倒塌损毁,呈现典型的弯剪破坏特征。现场震害调查发现,回澜立交桥震害集中于抗弯刚度较大的刚构墩上,而其余桥墩震害相对较轻,主要表现为混凝土保护层的脱落、混凝土开裂以及墩顶支座的滑移破坏等。数值分析结果与震害调查呈现出较好的一致性。 相似文献
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汶川地震中绵阳市梓潼县水库土坝震害调查与分析 总被引：2，自引：0，他引：2
5·12汶川特大地震对绵阳市梓潼县170座水库造成了不同程度的破坏和严重的经济损失.依据绵阳市梓潼县水库地震灾害的现场科学考察资料,对绵阳市梓潼县48座高危以上险情水库土坝的震损情况做了初步总结和分析.典型震害现象包括裂缝、渗漏以及泄水建筑物和附属设施的损毁等;以梓潼县3座典型震损水库土坝为例,总结了震损水库的特点和经验教训,给出了一些建设性结论. 相似文献
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Concrete dams suffering from alkali-aggregate reaction (AAR) exhibit swelling and deterioration of concrete or even cracking over a long period. The deterioration of concrete may significantly affect the dynamic behavior of the structures, and it is necessary to estimate seismic safety of the deteriorated dams subjected to strong earthquakes. A unified approach is presented in this paper for long-term behavior and seismic response analysis of AAR-affected concrete dams by combining AAR kinetics, effects of creep and plastic-damage model in the finite element method. The proposed method is applied to a gravity dam and an arch dam. The long-term behavior of the AAR-affected dams is first predicted in terms of anisotropic swelling, spatially non-uniform deterioration of concrete, and cracking initiation and propagation with the development of AAR. The seismic response of the deteriorated dams is subsequently analyzed based on the state of the structures at the end of the long-term analysis. The AAR-induced expansion displacements obtained from the proposed method are in good agreement with the measured ones in the long-term operation. The simulated cracking patterns in the dams caused by the continuing AAR are also similar to the field observation. The results from the seismic analysis show that AAR-induced deterioration of concrete and cracking may lead to more severe damage cracking in the dams during earthquake. The dynamic displacements are also increased compared with the dams that are not suffering from AAR. The seismic safety of the AAR-affected concrete dams is significantly reduced because of the AAR-induced deterioration of concrete and cracking. 相似文献
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In the paper a recently proposed method for damage localization and quantification of RC-structures from response measurements is tested on experimental data. The method investigated requires at least one response measurement along the structures and the ground surface acceleration. Further, the two lowest time-varying eigenfrequencies of the structure must be identified. The data considered are sampled from a series of three RC-frame model tests performed at the structural laboratory at Aalborg University, Denmark during the autumn of 1996. The frames in the test series were exposed to two or three series of ground motions of increasing magnitude. After each of these runs the damage state of the frame was examined and each storey of the frame were classified into one of the following six classifications: undamaged, cracked, lightly damaged, damaged, severely damaged or collapse. During each of the ground motion events the storey accelerations were measured by accelerometers. After application of the last earthquake sequence to the structure the frames were cut into pieces and each of the beams and columns was statically tested and damage assessment was performed using the obtained stiffnesses. The damage in the storeys determined by the suggested method was then compared to the damage classification from the visual inspection as well as the static tests. It was found that especially in the cases where the damage is concentrated in a certain area of the structure a very good damage assessment is obtained using the suggested method. © 1998 John Wiley & Sons, Ltd. 相似文献
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Yoshinobu Tsuji Fumihiko Imamura Hideo Matsutomi Costas E. Synolakis Puspito T. Nanang Jumadi Satoshi Harada Se Sub Han Ken'ichi Arai Benjamin Cook 《Pure and Applied Geophysics》1995,144(3-4):839-854
A field survey of the June 3, 1994 East Java earthquake tsunami was conducted within three weeks, and the distributions of the seismic intensities, tsunami heights, and human and house damages were surveyed. The seismic intensities on the south coasts of Java and Bali Islands were small for an earthquake with magnitudeM 7.6. The earthquake caused no land damage. About 40 minutes after the main shock, a huge tsunami attacked the coasts, several villages in East Java Province were damaged severely, and 223 persons perished. At Pancer Village about 70 percent of the houses were swept away and 121 persons were killed by the tsunami. The relationship between tsunami heights and distances from the source shows that the Hatori's tsunami magnitude wasm=3, which seems to be larger for the earthquake magnitude. But we should not consider this an extraordinary event because it was pointed out byHatori (1994) that the magnitudes of tsunamis in the Indonesia-Philippine region generally exceed 1–2 grade larger than those of other regions. 相似文献
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现役古建木结构普遍存在残损现象,这将影响结构的抗震性能。本文以北京故宫的咸福宫西配殿为研究对象,通过简化其屋顶、斗拱、榫卯和柱脚节点建立结构的理想模型,并在此基础上考虑材料老化和节点性能降低等因素建立其残损现状模型。通过地震易损性分析,得到古建木结构的地震易损性曲线并进行理想和残损结构的震害等级及其发生概率对比。研究结果表明:残损现象降低了咸福宫西配殿的刚度和自振频率;相比于理想结构,咸福宫西配殿残损结构在小震作用下发生轻微损坏的概率增大21.1%,在中震作用下发生中等破坏的概率增大3.7%,大震作用下发生严重破坏的概率增大10.6%;咸福宫西配殿在大震作用下发生倒塌的概率很小,体现了木结构具有良好的抗震性能。 相似文献
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This work presents a novel procedure for identifying the dynamic characteristics of a building and diagnosing whether the building has been damaged by earthquakes, using a back‐propagation neural network approach. The dynamic characteristics are directly evaluated from the weighting matrices of the neural network trained by observed acceleration responses and input base excitations. Whether the building is damaged under a large earthquake is assessed by comparing the modal parameters and responses for this large earthquake with those for a small earthquake that has not caused this building any damage. The feasibility of the approach is demonstrated through processing the dynamic responses of a five‐storey steel frame, subjected to different strengths of the Kobe earthquake, in shaking table tests. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
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主余震作用下,断层距（RJB）和余震次数的不同对结构造成的损伤也大不相同,进行主余震序列下桥梁损伤评估时需要考虑断层距、余震次数等影响因素。基于OpenSees平台,以一座连续梁桥为例,根据人工主余震构造时不同的影响因素,选用余震衰减和PGA调幅的人工主余震构造法构造主余震序列进行结构损伤分析,并与实际主余震事件的损伤结果作对比,研究人工构造主余震序列预测结构损伤的可行性。结果表明：基于PGA调幅构造主余震的方法,当考虑余震衰减时,能够较好模拟出结构在实际主余震地震作用下造成的最终损伤,能够较合理的预测结构在实际主余震序列中的损伤指标;对区域主余震作用下的桥梁进行损伤评估时,需要考虑断层距和余震次数影响因素,桥梁距断层距RJB越近时结构的损伤状态越严重,余震发生次数越多则结构的损伤增量就越大,并且结构在人工主余震作用下RJB越大的地方,结构损伤增量误差程度越小,预测的损伤状态就越接近实际的损伤状态。 相似文献