The use of 3D modeling for the prediction of the seismic demands on the gravity dams          下载免费PDF全文

M. Bybordiani  Y. Arıcı 《地震工程与结构动力学》2017,46(11):1769-1789

Seismic behavior of gravity dams has long been evaluated using a representative two‐dimensional (2D) system. Formulated for the gravity dams built in wide canyons, the assumption is nevertheless utilized extensively for almost all concrete dams due to the established procedures as well as the expected computational costs of a three‐dimensional model. However, a significant number of roller‐compacted concrete dams, characterized as such systems, do not conform to the basic assumptions of these methods by violating the conditions on canyon dimensions and joint‐spacing/details. Based on the premise that the 2D modeling assumption is overstretched for practical purposes in a variety of settings, the purpose of this study is to critically evaluate the use of 2D modeling for the prediction of the seismic demands on these systems. Using a rigorous soil–structure interaction approach, the difference between the two and three‐dimensional response for gravity dams was investigated first in the frequency domain for a range of canyon widths and foundation to dam moduli ratios. Then, the time domain differences between the crest displacements and the maximum principal stress were obtained using 70 different ground motions in order to show the possible bias introduced into the analysis results due to the modeling approach. The results of the study show that even for relatively wide canyons, the 2D analysis can lead to misleading predictions. Copyright © 2017 John Wiley & Sons, Ltd.  相似文献   

基于Hilbert-Huang变换的地震瞬时属性提取方法及应用(英文)     

黄亚平  耿建华  钟广法  郭彤楼  蒲勇  丁孔芸  麻纪强 《应用地球物理》2011,8(2):125-133

希尔伯特—黄变换(Hilbert-Huang transform,HHT)是一种新的适合非平稳和非线性信号的分析方法,由于地震信号一般呈现出非平稳与非线性特性,因此HHT非常适合地震信号的分析。本文首先介绍了HHT中关于经验模态分解(Empirical Mode Decomposition,EMD)的实现过程,在此基础上分析了几种基于EMD获得本征模态函数(Intrinsic Mode Functions,IMF)来计算瞬时频率的算法,其中利用了两个采样间隔瞬时频率的平均来计算瞬时频率,较好地反映了地震信号频率成分随时间变化的特征。将该方法应用于四川东北部某地区海相碳酸盐岩地层三维地震叠后偏移数据处理,提取"三瞬"地震属性,与传统的希尔伯特变换提取的"三瞬"地震属性进行对比,结果表明基于HHT的"三瞬"地震属性结果具有更高的分辨率,IMF2的瞬时相位能够较好地刻画台地边缘生物礁相,IMF2的瞬时频率亦具有较好的分带性。将IMF2的"三瞬"地震属性与钻井等资料结合分析,能够更好地识别沉积相的分布。  相似文献   

高频大地电磁测深（EH-4）在热储构造勘查中的试验研究-以抚州地热区为例     

叶益信 《地质与勘探》2011,47(4):649-653

EH-4电磁成像系统是目前国内外较为先进的电磁法勘探仪器,它具有勘探深度大、成果反应直观、轻便高效等优点。本文首先介绍了该方法的工作原理,然后以抚州地热区的勘查为例,说明它在热储构造勘查中的应用。本文通过高频大地电磁测深（EH4）在抚州地热区的应用,结合快速松弛反演（RRI）技术,揭露了该地区的深部地电剖面特征,反演结...  相似文献   

双频激电法在河南某钼矿带进行快速找矿评价中的应用          下载免费PDF全文

尚建阁李 冰  丁云河  冯亮 《中国地质》2011,38(2):473-478

文章主要介绍了运用双频道激发极化法在河南省豫西山区进行快速找矿工作中发现矿体的过程及在野外施工过程中应注意的几个问题。通过双频激电中梯测量,在工作区圈定了3处激电异常,通过该区地质资料,岩(矿)石物性特征以及化探次生晕资料对激电异常进行了综合研究分析,经过钻探验证,此异常与隐伏钼矿体和钼矿化有关。证明了双频激电法完全能适应在豫西山区进行快速找矿评价,并取得良好的效果。  相似文献   

《地球科学与环境学报》2004—2010年载文信息及被引频次统计分析     

马文军  孙守增  刘洪涛 《西安地质学院学报》2011,(3):326-330

运用文献计量学方法,对《地球科学与环境学报》（以下简称《学报》）2004—2010年载文的第一作者学历、职称和服务单位、论文资助项目来源、研究领域、出版时滞、被引频次、下载次数、影响因子等论文信息指标进行了统计分析。结果表明《学报》呈现以下特征：高学历作者比例稳步提升;副高职称和中级职称作者是《学报》作者的骨干力量;作者来源呈多元化发展,主办单位论文呈下降趋势;大多数论文有各类基金项目资助;基础地质及矿产地质是《学报》载文的主要内容;出版时滞需要进一步优化;被引频次计量指标反映《学报》呈现良好的发展态势。  相似文献   

内蒙古乌尼克吐铅锌矿电法异常特征及试验     

张威  王文国  张强  黄力军 《物探与化探》2011,35(3):333-336

以时间域中梯装置激发极化、偶极—偶极装置相位激电测深和可控源音频大地电磁测深在内蒙古乌尼克吐铅锌矿试验结果为例,验证综合电法在寻找矽卡岩型铅锌矿床中的作用及找矿效果。试验结果表明,在激发极化普查测量中应注意供电电极与异常体之间相互关系,否则会产生虚假异常;在勘查区岩矿石电性条件较好的情况下,激发极化面积测量基本能够反映出异常源平面分布情况。在矿(体)与围岩之间的电阻率差异不明显的条件下,较相位激电测深,可控源音频大地电磁测深基本能够推断出矿体的空间赋存位置。所以,时间域中梯装置激发极化与可控源音频大地电磁测深的电法组合在有色金属矿产勘查中可以发挥更大作用。  相似文献   

物探在豫西隐伏金矿找矿中的应用   总被引：1，自引：0，他引：1  

杨守渠  乔刚  李萍  袁文婷  张炳顺  郭建勇 《物探与化探》2011,35(4):455-460

结合成矿地质条件,简要介绍了磁法、甚低频电磁法、瞬变电磁法、激电测深在金矿找矿工作中的不同特点和作用;给出了在豫西几个金矿区多金属成矿带上寻找隐伏金矿体的成功实例,说明在具备地球物理前提的条件下,用磁法、甚低频电磁(或瞬变电磁)法快速扫面测量可圈定找矿靶区。在找矿靶区做一定量对称四极激电测深工作,可预测矿体埋藏深度等;这是经济、快速地探测浅—深部隐伏、半隐伏盲矿体的有效方法,值得推广应用。  相似文献   

Cretaceous Sandbody Characters at Shallow‐Water Lake Delta Front and the Sedimentary Dynamic Process Analysis in Songliao Basin,China     

CAI Xiyuan  ZHU Rong 《《地质学报》英文版》2011,85(6):1478-1494

Based on the abundant information from drilling, cores, and logging, the influence of topography, size of rivers and lakes, climate changes and the lake level’s fluctuation on the sandbodies at shallow-water delta front are systematically summarized and the sedimentary dynamic processes are analyzed. The interwell communication among the sandbodies and their planar distribution revealed from the hydrodynamic features of the development wells are integrated during the analysis. The fundamental requirements for the development of the shallow-water delta included flat topography and uniform subsiding rate. The delta plain was connected smoothly with the wide delta front and predelta, without the three-fold structure of topset, foreset, and bottomset as defined in the Gilbert Delta Model. Because of the weak fluvial effect and the lake energy is strong, the small and scattered shallow-water delta is destroyed by the scouring-backwashing, coastal current, and lake wave, resulting in the coastal sheet deposition. As the fluvial effect became stronger and the lake energy became weaker, the shape of the shallow-water deltas transferred from sheets to lumps and then branches.  相似文献   

双频激电法在浙江省苦麻岭地区找矿勘查中的应用     

刘达龙  刘鸿福  张新军  张和生 《中国煤炭地质》2011,(2):59-63

浙江省常山县苦麻岭地区位于钱塘台褶皱带华埠-新登陷褶带上,具备了与成矿密切相关的条件,但地形起伏大、构造复杂、植被发育茂盛等因素严重制约着探矿效果。为此采用双频激电法,通过对称四极测深对该勘查区进行勘探。针对视电阻率测深曲线出现的跳跃、波动等异常形态,结合地层岩性、构造裂隙发育情况及视幅频率反映,对干扰因素进行排除,并依据视电阻率曲线拐点异常及增大趋势确定区内花岗岩岩体埋深及边界变化规律,指出该花岗岩顶部界面较平缓或下凹处,其围岩接触带为富集、成矿的有利部位。由视电阻率ρs和视幅频率Fs断面图推断,矿化异常等值线未封闭,异常中心位于测线以东,该结论对勘查区及类似地区扩大找矿规模具有一定指导意义。  相似文献   

镉和汞胁迫对四角蛤蜊（Mactra veneriformis）血细胞的毒性损伤研究     

王晓宇  杨红生  邢坤  王清 《海洋与湖沼》2011,42(6):850-856

采用透射电镜观察、溶酶体膜稳定性衡量和微核生成率检测的方法,系统研究了室内模拟Cd和Hg污染胁迫对四角蛤蜊血细胞的毒性损伤。结果表明,Cd对四角蛤蜊血细胞超微结构的损伤表现出明显的浓度依赖效应,125μg/L Cd胁迫下血细胞结构损伤程度高于25μg/L Cd胁迫;不同浓度Cd和Hg暴露14天后,各处理组（2μg/L ...  相似文献