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841.
Field-observed phenomena of seismic liquefaction and subsidence during the 2008 Wenchuan earthquake in China 总被引:10,自引:8,他引:2
In the 2008 Wenchuan earthquake in Sichuan Province, a large number of buildings, water conservancy facilities, and transportation
facilities were severely damaged. The damage caused by liquefaction and earthquake-induced soil subsidence was widely distributed,
diverse, and extensive. Typical liquefaction and earthquake-induced subsidence damage for this region has been described by
investigations of soils and foundations in the earthquake-stricken area. Factors that influenced the liquefaction of soils
in Dujiangyan County were analyzed, accounting for regional geological conditions. The results identify several factors that
may affect the process of liquefaction and general damage to buildings, roads, levees, and dams. Such factors could serve
as the basis for further research into mitigating the damage caused by earthquake-induced liquefaction and subsidence. The
importance of detailed ground reconnaissance and the implementation of reasonable and effective measures to improve soft soil
are proposed for earthquake hazard reduction in similar areas. 相似文献
842.
赣南地区石雷石英闪长岩的成因:岩石化学、副矿物微量元素、锆石U-Pb年代学与Sr-Nd-Hf同位素制约 总被引:5,自引:2,他引:3
石雷石英闪长岩是赣南崇-余-犹地区比较特殊的闪长质侵入体。锆石的原位U-Pb定年表明,该岩体侵位于433.5±3.4Ma。全岩主量元素特征上显示出中偏酸性(SiO2=56.92%~64.70%),富Al(Al2O3=14.10%~14.83%),富碱(Alk=6.41%~7.40%)特别是富钾(K2O=3.86%~4.85%),镁、铁含量较高,MgO:3.47%~5.95%,FeOT:5.23%~8.14%以及低磷(P2O5=0.27%~0.4%)的特点;微量元素上主要富集K、Rb、Cs等大离子亲石元素和轻稀土元素,亏损Nb、Ta、Ti、P等高场强元素。磷灰石微量元素特征上显示高度富集稀土元素特别是轻稀土元素的特征;具有Eu的负异常(δEu=0.37~0.45)。ISr位于0.7073~0.7132之间,εNd(t)变化于-8.41~-4.97之间,两阶段钕模式年龄介于1.58~1.86Ga之间,Hf同位素组成相对均一,εHf(t)主要集中变化于-8~-2之间,两阶段Hf模式年龄加权平均为1.77±0.09Ga,这些特征都暗示了该石英闪长质岩体的形成是强烈壳幔相互作用的产物,区内加里东晚期可能发生了局部的岩石圈的减薄。 相似文献
843.
844.
Within the engineering profession and natural sciences, vulnerability is widely accepted to be defined as the degree of loss
(or damage) to a given element or set of elements within the area affected by a threat. The value of vulnerability is expressed
nondimensionally between 0 and 1. It is a fundamental component in the evaluation of landslide risk, and its accurate estimation
is essential in making a reasonable prediction of the landslide consequences. Obviously, vulnerability to landslides depends
not only on the characteristics of the element(s) at risk but also on the landslide intensity. This paper summarizes previous
research on vulnerability to landslides and proposes a new quantitative model for vulnerability of structures and persons
based on landslide intensity and resistance of exposed elements. In addition, an approximate function is suggested for estimating
the vulnerability of persons in structures. Different methods for estimating the vulnerability of various elements to slow
or rapid landslides are discussed. Finally, the application of the new model is illustrated through an example. 相似文献
845.
Huang Bolin Chen Lide Peng Xuanming Liu Guanning Chen Xiaoting Dong Haogang Lei Tianci 《Landslides》2010,7(1):1-11
In 2007 and 2008, six big damaging rockfalls occurred at four sites in Wu Gorge, the second gorge of the Three Gorges, China.
Detailed surveys and aerial-photographic interpretation identified 104 potentially dangerous rock masses. This paper reviews
previous rock-mass risk ratings, examines dangerous rock-mass structure and presents a new assessment system for rockfall
risk (ASRFR) in the Wu Gorge area. The ASRFR considers 15 factors: seven factors for hazard and eight factors for consequence.
Relative importance weights for these factors are ascertained using an analytic hierarchy process. Using an equation to calculate
the risk, the 104 dangerous rock masses were divided into three risk groups: high risk (33 sites), medium risk (33 sites)
and low risk (38 sites). The ASRFR analysis can be used to divide the shipping route through the Wu Gorge into seven courses
each of one of three classes: safe-route regions, yellow-alarm regions and red-alarm regions. The system provides geological
information and a rockfall-risk management tool for local government and the shipment-route department. 相似文献
846.
Hong Zhang Hung-Lung Huang Agnes Lim Robert Holz Steve Dutcher Fred Nagle Liam Gumley Jinnian Wang Runhe Shi Wei Gao 《Frontiers of Earth Science》2010,4(3):363-373
The Atmospheric Infrared Sounder (AIRS) and MODerate-Resolution Imaging Spectroradiometer (MODIS) on board NASA Earth Observing
System (EOS) Aqua spacecraft measure the upwelling infrared radiance used for numerous remote-sensing- and climate-related
applications. AIRS provides high spectral resolution infrared radiances, while MODIS provides collocated high spatial resolution
radiances at 16 broad infrared bands. An optimal algorithm for cloud-clearing has been developed for AIRS cloudy soundings
at the University of Wisconsin-Madison, where the spatially and spectrally collocated AIRS and MODIS data has been used to
analyze the characteristic of this algorithm. An analysis and characterization of the global AIRS cloud-cleared radiances
using the bias and the standard deviation between the cloud-cleared and the nearby clear measurements are studied. Scene inhomogeneity
for both land- and water-surface types has been estimated to account for the assessed error. Both monthly and seasonal changes
of global AIRS/MODIS cloud-clearing performance also have been analyzed. 相似文献
847.
淮南板集煤矿F512断层导水性分析及地面注浆加固 总被引:1,自引:0,他引:1
板集煤矿F512断层落差70m,存在着导通上覆新生界松散层水与下伏太原组岩溶水的威胁,同时,断层带的破碎岩体也将对巷道掘进和支护带来困难。该矿先后施工了3个水文地质钻孔进行抽水和压水试验,根据岩心鉴定成果和岩石RQD值,认为断层带的岩心较为破碎;依据抽水过程中的流量变化、水位降深值和水位恢复值等指标及压水试验中透水率分析,发现该断层的导水性较差,具有弱渗透性。参考相邻矿区的经验,决定对断层破碎岩体采用地面注浆方法进行加固。整个工种注入水泥浆1 600m3,破碎岩体得到了有效加固,巷道掘进顺利通过了F512断层。 相似文献
848.
Ling-zhi Huang Guang-ming Zeng Dan-lian Huang Li-feng Li Chun-yan Du Ling Zhang 《Environmental Earth Sciences》2010,60(8):1683-1691
Biosorption is an effective method to remove heavy metals from wastewater. In this work, the biosorption of Cd(II) onto Hydrilla verticillata was examined in aqueous solution with parameters of initial pH, adsorbent dosage, contact time, initial Cd(II) concentration,
temperature, and co-existing ion. Linear Langmuir and Freundlich models were applied to describe the equilibrium isotherms,
and both of the two models were fitted well. The monolayer adsorption capacity of Cd(II) was found to be 50 mg/g at pH 6 and
20°C. Dubinin–Radushkevich isotherm model was also applied to the equilibrium data. The mean free energy of adsorption (11.18 kJ/mol)
indicated that the adsorption of Cd(II) onto H. verticillata might be carried out via chemical ion-exchange mechanism. Thermodynamic parameters, including free energy (∆G
0), enthalpy (∆H
0), and entropy (∆S
0) of adsorption, were also calculated. These results showed that the biosorption of Cd(II) onto H. verticillata was a feasible, spontaneous, and exothermic process in nature. Desorption experiments indicated that 0.01 mol/L EDTA and
HNO3 were efficient desorbents for the recovery of Cd(II) from biomass. IR spectrum analysis suggested that amido, hydroxyl, C=O
and C–O could combine strongly with Cd(II). EDX spectrum analysis suggested that an ion exchange mechanism might be involved. 相似文献
849.
空心块体具有良好的阻水和促淤功能,近年来被广泛用于生态修复工程。本文结合水槽试验及Flow-3D数值模拟,分析了开敞型和半封闭型空心块体的阻水效应和泥沙淤积特性。结果表明:空心块体的开孔率对内部水流流速、紊动强度起主导作用,开孔率较小的半开敞型空心块体减速、制紊效果更强;开敞型和半封闭型空心块体近底层悬沙浓度分别增大56%和75%,两者均有利于促进泥沙在块体内部淤积,近底层水流紊动越强,泥沙淤积形态差异越大;空心块体所营造的低流速、泥沙微淤、内外连通的水沙环境是大型底栖生物的生境需求,半封闭型空心块体内部的低紊动水流结构更有利于大型底栖生物的栖息、繁衍。 相似文献
850.
海洋一号C/D(HY-1C/D)卫星中国海洋水色水温扫描仪(Chinese Ocean Color and Temperature Scanner,COCTS)主要用于探测海洋水色、水温等要素,这些要素需要经过卫星资料处理才能获取,而几何定位是预处理的核心,直接影响这些要素的质量。COCTS具有114°视场角和四元逐点摆扫的特征,据此研究出一套完整的几何定位方法。从0级数据中提取卫星星历,利用插值法从中获取采样时间对应的卫星位置和速度,进而得到轨道(ORB)坐标系到地心旋转(ECR)坐标系的转换矩阵。基于四元逐点摆扫的特征,中心视矢量分别绕X轴、Y轴旋转相应角度,获得扫描行各采样点ORB视矢量,建立视矢量与地球交叉点关系模型,从而对根据波段数据绘制的遥感图像进行地理定位。本文使用插值法替代了传统需要6个轨道根数来计算卫星位置的复杂方法,同时直接计算ORB到ECR的转换矩阵,而不采用传统的两步转换方法。经过多组数据计算及定性定量验证,HY-1C/D COCTS几何定位结果一致;采样像元尺度效应导致从星下点到两侧边缘、从赤道到两极,误差逐渐增大,约在两个像元内。该方法满足一定的定位精度要求,可以用于COCTS的几何定位。 相似文献