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1.
汶川地震高速远程滑坡速度研究 总被引：2，自引：0，他引：2
汶川地震诱发了大量的高速远程滑坡。在超强的地震动作用下,坡体结构被撕裂并抛射后,受到坡体前缘地形及自身势能的影响,很容易转化为碎屑流作远程运动,这种高位滑坡以其很快的运动速度和超常的运动距离造成了巨大的灾害与损失。本文在对汶川地震大型典型高速远程滑坡大量现场调查的基础上,分析了坡体临空飞行运动初始速度、滑程运动最大速度以及碎屑流运动速度,并且以东河口滑坡为例,对比了不同计算方法下的运动速度和运动性,得到东河口滑坡的运动特征值μ=0.2292,最大运动速度Vm ax=63.40 m/s,平均运动速度超过25 m/s,属于超高速滑坡运动以及强碎屑流性质。 相似文献
2.
不同地区地震活动的强度和频率是不同的.基于地震危险性分析的地震滑坡危险研究在综合了地震烈度、位置、复发时间等因素的基础上,考虑了地震动峰值加速度时空分布的特点,可以有效地应用于潜在地震滑坡危险区区划.以汶川地震灾区为研究对象,根据研究区的地质构造、地震活动特点等划分出灾区的潜在震源区,对该区进行地震危险性分析,并在此基础上采用综合指标法做出基于地震危险性分析的地震滑坡危险性区划.所得地震滑坡危险性区划按照滑坡危险程度分为高危险、较高危险、较低危险和低危险四级,表示未来一段时间内研究区在遭受一定超越概率水平的地震动作用下,不同地区地震滑坡发生的可能程度. 本文给出的地震滑坡危险性区划结果中,汶川地震滑坡崩塌较发育的汶川、北川、茂县等部分区域均处于高危险或较高危险区域;在对具有较高DEM精度的北川擂鼓镇地区所作的地震滑坡危险性区划中,汶川地震中实际发生的地震滑坡灾害与地震滑坡危险区划结果表现出较好的一致性.对区域范围而言,基于地震危险性分析的地震滑坡区划,可为初期阶段的土地规划使用及重大工程选址提供参考. 相似文献
3.
Analysis of landslide damage caused by the 2008 Wenchuan earthquake using strong motion data: A case study in the Beichuan county town 
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下载免费PDF全文 The county town of Beichuan county, China, experienced catastrophic destruction due to landslides induce by the 2008 Wenchuan earthquake. In consideration of the special location of the county town, this paper selected the landslides induced in the town as representative of large-scale near-rupture landslides, and quantitatively analyzed why the landslide damage was so destructive in the town by using strong motion data obtained from the Wenchuan earthquake in the Longmenshan area. Three methods were employed to estimate the landslide damage using strong motion data. (1) Peak ground accelerations (PGAs) on the hanging wall were used to evaluate the PGAs on the landslide sites in the town. The evaluated average PGAs were all greater than 1 g, indicating that the ground motion intensity was very strong during the earthquake. (2) Acceleration time histories, from another station with similar geological conditions to the town, were used to evaluate the critical acceleration changing range, and the estimated values showed the geological conditions were very susceptible to earthquakes. (3) Acceleration time histories, from two stations on the hanging and foot walls of the rupture, and near the town, were used to calculate the Newmark displacements, and all the evaluated displacements indicated that landslides were very likely. The results show that the slopes, susceptible to earthquakes in the Beichuan county town, were easily triggered under such strong ground-motion intensity and developed into large-scale catastrophic events. 相似文献
4.
汶川大地震触发了多处高速远程滑坡,导致了大量的人员伤亡及财产损失。其中,东河口滑坡是这次地震触发的最为典型的高速远程滑坡之一,同时也是目前备受关注、争论颇多的滑坡之一。野外调研结果表明,该滑坡的成因和动力特征主要包括震裂溃屈、水平抛射、碎屑流化和振动液化等4个方面。为了对该滑坡滑动过程中的振动液化这一动力特征进行模拟再现,在东河口滑坡体上采集了具有代表性的滑带土作为试验样品,并以该地震时的实测地震波作为动力输入,利用目前国际上最先进的DPRI环剪试验机,对滑坡滑动过程中的振动液化现象进行了一系列环剪试验研究。结果表明,地震作用过程中,发生在滑坡潜在滑面上的振动液化现象是导致高速远程滑坡产生的一个重要因素;伴随着振动液化过程,滑体的剪切强度迅速降低并产生逐渐增大的剪切位移,为高速远程滑坡的形成提供了条件 相似文献
5.
Xiaowu Pu Lanming Wang Ping Wang Xiufeng Tian Shiyang Xu Shaofeng Chai Haitao Guo 《地震研究进展（英文）》2022,2(3):100114
A series of housing collapses and other serious damage was caused by the 2008 Wenchuan MS 8.0 earthquake in the seismic intensity Ⅵ areas of the Loess Plateau, which is hundreds of kilometers away from the epicenter, and which showed a remarkable seismic intensity anomaly. The seismic disasters are closely related to the seismic response characteristics of the site, therefore, the systematic study of the far-field seismic response law of the Wenchuan earthquake in the Loess Plateau is of great significance to prevent the far-field disaster of great earthquake. In this paper, the seismic acceleration records of several bedrock stations and loess stations from the seismogenic fault of the Wenchuan earthquake to the Loess Plateau were collected, and the attenuation law of ground motion along the propagation path and the characteristics of seismic response on the loess site are studied, and the mechanism of amplification effect of ground motion is analyzed based on the dynamic feature parameters of the loess site obtained through the HVSR method. Taking a typical loess site of thick deposit as the prototype, a series of shaking table tests of dynamic response of loess site models with different thicknesses were carried out. Amplification effect, spectral characteristics of acceleration in model sites were analyzed under the action of a far-field seismic wave of the Wenchuan earthquake. The results show that seismic attenuation on the propagation path along the NE strike of the seismogenic fault to the Loess Plateau is slower than that in other directions, and the predominant period range of ground motion on bedrock site of the Loess Plateau presents broadband characteristics. Because the natural periods of loess sites with thick deposits are within the predominant period range of bedrock input wave, loess sites appear significant amplification effect of ground motion, the horizontal acceleration of ground motion exceeds 0.1 ?g, the seismic intensity reaches 7°. The thicker the loess deposit is, the more significant the change of spectral characteristics of ground motion on loess sites, and the narrower the predominant period range of ground motion becomes, and the closer it is to the natural period of loess sites. Therefore, for some old houses on thick loess sites, the poor seismic performance and strong seismic response eventually led to their collapses and damages because their natural periods are very close to the predominant period of ground motion of the Wenchuan earthquake on thick loess sites; For these damaged high-rise buildings, the resonance effect might be the main reason for their damages because their natural periods are included in the predominant period range of ground motion of the Wenchuan earthquake on thick loess sites.These research results would provide a basis for seismic disasters prediction and evaluation and seismic design of construction engineering in the Loess Plateau. 相似文献
6.
汶川MS8.0大地震在远离震中近200 km的汉源县县城产生了高烈度异常, 其原因比较复杂．为了分析土层结构对汶川大地震中汉源县老县城高烈度异常的影响, 在汉源县城震害科学考察基础上, 依据地震烈度异常的分布情况, 在背后山滑坡前缘地带布设5个工程地质勘察钻孔, 获得了汉源县老县城场地土层结构资料．在现场测试和室内试验的基础上, 给出了汉源县老县城场地各层土体动力学参数．本文利用汶川地震九襄强震台的强震记录, 结合其台站的场地资料反演给出了汉源县老县城的基岩地震动时程, 作为地震反应分析的基岩输入地震动．在此基础上利用土层地震反应一维等效线性方法对汉源县老县城场地进行了地震反应分析, 并将计算所得结果与Ⅵ度区其它强震台站获得的强震记录进行比较．研究结果表明, 汉源县老县城土层结构对地震动的放大作用导致地表地震动异常, 是汉源县老县城高烈度异常的主要原因之一． 相似文献
7.
Wenying Li Yong Zhang Yueyi Xu Xujun Zheng Rongjiang Wang Jinrong Su Guixi Yi Qinghua Huang 《地震科学（英文版）》2021,34(1):3-14
Two large landslides successively blocked the Jinsha River at the same location in Jiangda Village on October 10 and November 3,2018,respectively.The dynamic processes and possible interactions of the two landslides need to be studied to better understand the physical processes involved,and to provide information on future disaster mitigation.We investigated their force histories and sliding directions by inverting regional broadband seismograms.The scale of the October landslide was approximately three times that of the November event.The October event revealed a particularly strong deceleration force,which may have been caused by a collision between the sliding mass and ground surface.In contrast,the November event had a relatively weaker deceleration force,indicating that it may have been gradually stopped by the landslide dam formed during the October landslide.The sliding directions of the two landslides differed significantly in terms of both horizontal and vertical directions,indicating a change in their sliding surfaces.We conclude that unconsolidated materials at the top of the October landslide continued sliding along a curved slope during the November event.From our seismic models of dynamic processes,both the October landslide and local background may have affected and even changed a subsequent landslide's mechanism. 相似文献
8.
APPLICATION OF TWO SIMPLIFIED NEWMARK MODELS TO THE ASSESSMENT OF LANDSLIDES TRIGGERED BY THE 2008 WENCHUAN EARTHQUAKE 下载免费PDF全文
下载免费PDF全文 At present, with the wide application of the Newmark method, various Newmark empirical formulas with different ground motion parameters have been fitted by many researchers based on global strong-motion records. However, the existing study about the Wenchuan earthquake does not quantitatively evaluate the applicability of different Newmark models based on the actual landslides distribution. The aim of this paper is to present a comparison between observed landslides from the 2008 Wenchuan earthquake and predicted landslides using Newmark displacement method based on different ground motion parameters. The factor-of-safety map and critical acceleration(ac)map in the study area are obtained by using the terrain data and geological data. The distribution of Arias intensity(Ia)and PGA in the study area is obtained by using the attenuation formulas of Arias intensity(Ia)and PGA, which is regressed by Wenchuan ground motion records. Based on the distribution of Arias intensity(Ia)and PGA parameters, we obtained the predicted locations of landslide using Newmark regression equations which are generated using global strong-motion records. The results shows that the assessment results can better reflect the macroscopic distribution characteristics of co-seismic landslides, most predicted landslide cells are distributed on the two sides of the Beichuan-Yingxiu Fault, especially the Pengguan complex rock mass in the hanging wall. The abilities to predict landslide occurrence of the two Newmark simplified models are different. On the whole, the evaluated result of simplified model based on parameter Ia is better than that based on PGA parameter. The GFC values obtained by the Newmark model of Ia and PGA parameters are 65.7% and 34.9%respectively. The evaluated result based on Ia can better reflect the macro distribution of coseismic landslides. The Ls_Pred value based on the Newmark model of parameter Ia is 26.5%, and the Ls_Pred value based on the Newmark model of PGA parameter is 10.3%. However the total area of predicted landslides accounts for 2.4% of the study area, which indicates that the predicted landslide cells are greater than the observed landslide cells. This reminds us that depending on the current input of shear strength and ground-motion parameters, we can only conduct landslide hazard assessment in macro areas, the ability to predict landslide can be improved using more accurate topographic data and input parameters. 相似文献
9.
地震和降雨是滑坡产生的两大诱因。一般认为二者的耦合作用概率小,在现实中也较少发现有此种实例。岷县漳县6.6级地震中黄土地震滑坡广泛发生,本文通过现场调查,在相关降雨量数据、航空影像空间分析的基础上研究了两个地点(永光村滑坡和堡子村滑坡)的典型地震黄土滑坡的空间展布特征和发生、发展过程,分析了诱发机制。结果发现:(1)地震滑坡呈带状分布与地震发震构造走向一致;(2)位于极震区范围的永光村黄土滑坡具有泥流特征,土体含水量可达塑限以上,是由于过量降水和强地震动耦合作用下发生;(3)堡子村黄土地震滑坡则主要为强地震动所诱发,滑距较短,并具滞后发生特性。本结果对未来地震中滑坡的预防与防治具有借鉴意义。 相似文献
10.
汶川Ms8.0级地震驱动的构造抬升作用和滑坡、泥石流剥蚀作用如何影响龙门山的地貌生长是目前争论的焦点。本文运用GIS技术,定量计算了湔江流域的坡度、地形起伏度、面积—高程积分等地貌参数,根据这些参数的计算结果,对湔江流域的构造地貌特征进行了量化分析;以汶川Ms8.0级地震重灾区湔江海子河右岸流域的滑坡、泥石流为例,并且利用野外实测资料、卫星照片及数字高程资料等,对于汶川地震驱动的构造抬升与滑坡、泥石流的表面侵蚀过程进行研究,获得以下初步认识:(1)湔江流域的映秀—北川断层以北地区地貌处于"壮年期",坡度、地形起伏度大;(2)汶川Ms8.0级地震后该地区发生了严重的同震滑坡及震后滑坡、泥石流灾害,海子河右岸流域的同震抬升量为5 339×104m3,同震滑坡量为3 852×104m3,同震抬升量大于同震滑坡量,地貌出现生长现象;(3)地震产生的泥石流量应略大于1 000×104m3,同震滑坡物质的30%转化为了泥石流量,因其海子沟右岸陡峻的坡度,绝大部分的泥石流冲入海子河,成为河道沉积物;(4)以目前湔江海子河流水搬运能力,在能够完全搬运出同震滑坡物质的前提下,同震滑坡物质搬运出龙门山至少需要283.2 a,表明在一个地震周期内,龙门山的同震滑坡物质可以搬运出龙门山;(5)准周期性相当震级地震引起的构造抬升及其均衡反弹作用也是龙门山的形成有重要作用的因素之一。 相似文献
11.
12.
汶川特大地震汉源烈度异常原因的初步分析 总被引：7，自引：1，他引：6
远离震中的汉源县老县城在汶川大地震中遭到了严重震害,是Ⅵ度区内的唯一的Ⅷ度烈度异常区.汉源的地震烈度异常现象引起学术界的广泛关注.在汉源科学考察基础上,介绍了汉源震害情况,收集和整理了汉源县城及附近有关工程场地的强震和土体力学参数资料.通过背后山滑坡体有限元分析结果与汉源附近强震台记录的比较,从传递函数角度分析了背后山滑坡复活对烈度异常的影响,研究了汉源特殊土层结构对地震动的影响.结果表明,背后山滑坡的复活和特殊土层结构的放大作用等场地条件的影响是引起烈度异常的主要原因.所得结论对进一步分析汉源烈度异常的原因具有一定的参考价值. 相似文献
13.
Rigid sliding block analysis is a common analytical procedure used to predict the potential for earthquake-induced landslides
for natural slopes. Currently, predictive models provide the expected level of displacement as a function of the characteristics
of the slope (e.g., geometry, strength, yield acceleration) and the characteristics of earthquake shaking (e.g., peak ground
acceleration, peak ground velocity). These predictive models are used for developing seismic landslide hazard maps which identify
zones with risk of earthquake-induced landslides. Alternatively, these models can be combined with Shakemaps to generate “near-real-time”
Slidemaps which could be used, among others, as a tool in disaster management. Shakemaps (a publicly available free service
of the United States Geological Survey, USGS) provide near-real-time ground motion conditions during the time of an earthquake
event. The ground motion parameters provided by a Shakemap are very useful for the development of Slidemaps. By providing
ground motion parameters from an actual earthquake event, Shakemaps also serve as a tool to decouple the uncertainty of the
ground motion in sliding displacements prediction. Campania region in Italy is studied for assessing the applicability of
using Shakemaps for regional landslide-risk assessment. This region is selected based on the availability of soil shear strength
parameters and the proximity to the 1980 Irpina (M
w
= 6.9) Earthquake. 相似文献
14.
汶川地震远场地震动特征及其对长周期结构影响的分析 总被引：5，自引：0，他引：5
汶川8．0级大地震中,中国数字强震动台网获得了大量的数字强震动记录,这些记录特别是远场记录具有丰富的长周期地震动分量。本文根据东南强震动中心获取的区域数字强震动记录,分析汶川8．0级地震的远场地震动特征,研究了基岩场地及深厚软弱场地的长周期地震动及其差异;根据长周期结构的特点,选取建于深厚软弱场地上的江苏A050强震台的超长地震记录进行结构地震反应分析,研究汶川8．0级地震对远场长周期结构的影响,并结合实际震害特点,提出了长周期结构抗震及地震安全对策中一些值得注意和思考的问题。 相似文献
15.
本文以滑波理论为依据，总结了山西地震带的两种不同特点的滑坡。即：振荡式滑坡及触发式滑坡。虽然两种滑坡都可分为变形、解体、滑动、毁灭等四个阶段，但其动力不同。振荡式滑波的滑动面倾角小，因而滑力来源于强震振动，而触发式滑坡的滑动面倾角大，因而滑力来自滑体本身静荷载。对两种滑坡的研究对预防及减轻强震带来的次生灾害有重要的意义。 相似文献
16.
地震滑坡资料与实际强震动记录是开展地震滑坡成灾机理研究的重要基础数据,如何科学管理这些数据资料,并最大限度地发挥其科学价值仍然是一个值得探索的问题。文章以黄土高原地区7次典型历史地震诱发黄土滑坡和125次地震(2001—2018年)的强震动记录为基础数据,依托开源GIS平台+MySQL数据库,构建黄土高原地震滑坡与强震动记录数据库管理系统。该系统界面规范、友好,参数获取方便,图表展示清晰、流畅,不仅为地震滑坡和强震动记录数据资料的管理与应用提供一个科学便捷的平台,也为黄土地震滑坡成灾机理研究提供坚实的数据基础,亦对黄土高原地区防灾减灾工作的开展具有一定的参考价值。 相似文献
17.
A comparative study of bridge damage due to the Wenchuan, Northridge, Loma Prieta and San Fernando earthquakes 总被引：2，自引：1，他引：1
George C.Lee 《地震工程与工程振动(英文版)》2009,8(2):251-261
A comparative study of selected bridge damage due to the Wenchuan, Northridge, Loma Prieta and San Fernando earthquakes is described in this paper. Typical ground motion effects considered include large ground fault displacement, liquefaction, landslide, and strong ground shaking. Issues related to falling spans, inadequate detailing for structural ductility and complex bridge configurations are discussed within the context of the recent seismic design codes of China and the US. A significant lesson learned from the Great Wenchuan earthquake, far beyond the opportunities to improve the seismic design provisions for bridges, is articulated. 相似文献
18.
越来越多的地震滑坡相对于地震断层的不对称分布震例让人们意识到断层上盘效应的存在。 然而,目前有关断裂运动方式与滑坡空间分布关系的研究还不够充分和深入。在收集大量地震滑坡震例资料并获得其分布规律的基础上,建立了一个简化的断层模型,以地震波在地表与断层面之间反射传播特性为基础,探讨断层倾角改变对地表地震动强度的影响。进而,以汶川地震触发的大型滑坡为例,研究了断层的几何特征和运动方式对诱发滑坡空间分布的影响。结果表明,断层的倾角对滑坡空间分布范围具有控制作用,随着倾角的增加,垂直断层走向的滑坡分布范围逐渐减小;并且,大型滑坡的初始坡面受到断裂运动方向的影响,与断裂运动方向一致的坡面更容易发生滑坡。所获结果不仅有助于提高区域性地震滑坡危险区域的预测精度,而且对认识大型滑坡的滑动机制、主控因素以及可能的滑动规模、滑距等也起到促进作用。通过对滑坡崩塌的认识来辅助提高对地质构造、地震断层等的认识,应是地震诱发滑坡崩塌研究的新的意义所在。 相似文献
19.
兰州观象台存放台阵在汶川特大地震中获取了10组三分量数字强震动加速度记录.本文依据这些实际观测资料研究了黄土场地在地震发生后的自由场地面运动加速度过程及其特征.结果表明在震源、场地和震中距相同情况下,场地上不同测点记录的加速度峰值存在一定程度的差异,较明显地反映了场地地形对EW分向地面自由场加速度的影响.10个测点的峰值加速度(PGA)均显示EW向大于NS向,而垂直向最小;各测点的傅里叶谱值,尤其是在小于1 Hz频段范围内,差异极小. 相似文献
20.
土层场地对地震动的影响较大,建(构)筑物的选址及其抗震设防必须考虑土层场地的放大作用,以避免或减轻其震害.汶川地震中,布设在渭河盆地中的数字强震动台网共有27个台站(包括2个基岩台站和25个土层台站)获得良好的主震加速度时程.利用这些加速度时程,选择汤峪台做为参考场地,基于考虑几何衰减的传统谱比法分析研究了25个土层场... 相似文献