Damage Survey of Water Supply Systems and Fragility Curve of PVC Water Pipelines in the Chi–Chi Taiwan Earthquake     

Ban-Jwu Shih  Che-Hao Chang 《Natural Hazards》2006,37(1-2):71-85

Substantial damage to water supply systems, including water delivery pipelines, water treatment plants, reservoirs, and water storage tanks, was reported after the 1999 Chi–Chi Taiwan Earthquake. This paper first summarizes the damage survey and then presents the results of seismic fragility analysis for underground pipelines. Construction blueprints of the water delivery pipelines and repair work orders of 11 townships and cities in the disastrous area were digitized into a Geographical Information System (GIS) for analysis and assessment. With the aid of the GIS system, we found that PVC pipes made up 86% of water delivery pipelines while steel, cast iron, ductile iron, PE and others took the rest. Therefore, this paper focuses on the fragility analysis of PVC pipes. Three different methods were applied to derive the fragility relations between the PVC water pipes having nominal diameters (approximately inner diameters) greater than or equal to 65 mm and earthquake intensity parameters such as peak ground acceleration and peak ground velocity. The results were then examined with those of other countries. The discrepancy between our results and the empirical equation used by HAZUS, an earthquake loss estimation software developed by the Federal Emergency Management Agency was not significant.  相似文献   

Hydrogeology of thermal waters in Viterbo area, central Italy     

V. Piscopo  M. Barbieri  V. Monetti  G. Pagano  S. Pistoni  E. Ruggi  D. Stanzione 《Hydrogeology Journal》2006,14(8):1508-1521

A conceptual hydrogeological model of the Viterbo thermal area (central Italy) has been developed. Though numerous studies have been conducted on its geological, geochemical and geothermal features, there is no generalized picture defining the origin and yield of the hydrothermal system. These latter aspects have therefore become the objectives of this research, which is based on new hydrogeological and geochemical investigations. The geological setting results in the coexistence of overlapped interacting aquifers. The shallow volcanic aquifer, characterized by fresh waters, is fed from the area around the Cimini Mountains and is limited at its base by the semiconfining marly-calcareous-arenaceous complex and low-permeability clays. To the west of Viterbo, vertical upflows of thermal waters of the sulphate-chloride-alkaline-earth type with higher gas contents, are due to the locally uplifted carbonate reservoir, the reduced thickness of the semiconfining layer and the high local geothermal gradient. The hot waters (30–60°C) are the result of deep circulation within the carbonate rocks (0.5–1.8 km) and have the same recharge area as the volcanic aquifer. The upward flow in the Viterbo thermal area is at least 0.1 m³/s. This flow feeds springs and deep wells, also recharging the volcanic aquifer from below.  相似文献   

Temperature dependence of large-scale water-retention curves: a case study     

Hui-Hai Liu  G. S. Bodvarsson  J. H. Dane 《Hydrogeology Journal》2006,14(8):1403-1408

A local-scale model for temperature-dependence of water-retention curves may be applicable to large scales. Consideration of this temperature dependence is important for modeling unsaturated flow and transport in the subsurface in numerous cases. Although significant progress has been made in understanding and modeling this temperature effect, almost all the previous studies have been limited to small scales (on the order of several centimeters). Numerical experiments were used to investigate the possibility of extending a local-scale model for the temperature-dependence of water retention curves to large scales (on the order of meters). Temperature effects on large-scale hydraulic properties are of interest in many practical applications. Numerical experiment results indicate that the local-scale model can indeed be applicable to large-scale problems for special porous media with high air entry values. A typical porous medium of this kind is the porous tuff matrix in the unsaturated zone of Yucca Mountain, Nevada, the proposed geologic disposal site for national high-level nuclear wastes. Whether this finding can approximately hold for general cases needs to be investigated in future studies.  相似文献   

The effective elastic thickness of the India Plate from receiver function imaging, gravity anomalies and thermomechanical modelling   总被引：2，自引：0，他引：2  

György Hetényi  Rodolphe Cattin  Jérôme Vergne  John L. Náb&#;lek 《Geophysical Journal International》2006,167(3):1106-1118

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Control of dust emissions by geomorphic conditions, wind environments and land use in northern China: An examination based on dust storm frequency from 1960 to 2003   总被引：9，自引：1，他引：9  

Xunming Wang  Zijiang Zhou  Zhibao Dong 《Geomorphology》2006,81(3-4):292-308

The degree to which dust emissions are controlled by geomorphic conditions, wind environments and land use was investigated using the dust storm frequency (DSF) and data from more than 300 meteorological stations throughout northern China. Our analysis showed that most dust emissions originated in gobi deserts that developed in piedmont alluvial fans of the Kunlun, Qilian and Helan mountains. Dust emissions are low from other gobi desert regions, such as the northern Gurbantunggut and eastern Taklimakan, where high vegetation coverage restrained dust emissions or where dust-size particles are not abundant after a long period of strong wind erosion. Sandy deserts with relatively high vegetation coverage or an extensive cover by mobile sands are not a major dust source. Although the highest dust emissions did not appear in regions with the highest wind energy, DSF trends in each region from 1960 to 2003 were closely related to local wind activity. DSF was low in regions with high levels of human activity, where the mean DSF from 1960 to 2003 did not exceed 4 days/year; even from the 1960s to the early 1970s, the period with the greatest DSF, frequency did not exceed 8 days/year, which indicates that extensive land use did not contribute to DSF. The low DSF in these areas might result from the fact that although land use could produce abundant fine soil fractions, vegetation coverage and soil moisture remained higher than in the gobi deserts of arid China, thereby decreasing dust-storm occurrence.  相似文献   

四川省康定县滑坡灾害发育特征与形成条件   总被引：3，自引：0，他引：3  

刘岁海  刘爱平 《中国地质灾害与防治学报》2006,17(3):27-31

康定县地处四川盆地西缘山地及青藏高原过渡地带。县域内地势险峻,地形切割强烈,地层与地质构造复杂,新构造运动强烈,地震活动频繁。加之降水充沛,致使山地灾害十分发育,其中滑坡灾害占山地灾害的38.32%。通过搜集资料及现场调查,概述了该县县域内滑坡灾害的分布;从行政区划、自然地理及灾害规模等3方面统计分析了滑坡灾害的发育现状;从地形地貌、地层岩性、地质构造、降雨、地震活动、人类工程活动等方面总结了滑坡灾害的形成条件,并提出防治对策与措施,力求有效地预防与减少滑坡灾害的发生。  相似文献   

Phase Equilibria of the Lyngdal Granodiorite (Norway): Implications for the Origin of Metaluminous Ferroan Granitoids   总被引：2，自引：0，他引：2  

BOGAERTS  MICHEL; SCAILLET  BRUNO; AUWERA  JACQUELINE VANDER 《Journal of Petrology》2006,47(12):2405-2431

The Proterozoic (950 Ma) Lyngdal granodiorite of southern Norwaybelongs to a series of hornblende–biotite metaluminousferroan granitoids (HBG suite) coeval with the post-collisionalRogaland Anorthosite–Mangerite–Charnockite (AMC)suite. This granitoid massif shares many geochemical characteristicswith rapakivi granitoids, yet granodiorites dominate over granites.To constrain both crystallization (P, T, fO₂, H₂O in melt) andmagma generation conditions, we performed crystallization experimentson two samples of the Lyngdal granodiorite (with 60 and 65 wt% SiO₂) at 4–2 kbar, mainly at fO₂ of NNO (nickel–nickeloxide) to NNO + 1, and under fluid-saturated conditions withvarious H₂O–CO₂ ratios for each temperature. Comparisonbetween experimental phase equilibria and the mineral assemblagein the Lyngdal granodiorite indicates that it crystallized between4 and 2 kbar, from a magma with 5–6 wt % H₂O at an fO₂of NNO to NNO + 1. These oxidized and wet conditions sharplycontrast with the dry and reduced conditions inferred for thepetrogenesis of the AMC suite and many other rapakivi granitesworldwide. The high liquidus temperature and H₂O content ofthe Lyngdal granodiorite imply that it is not a primary magmaproduced by the partial melting of the crust but is derivedby the fractionation of a mafic magma. Lyngdal-type magmas appearto have volcanic equivalents in the geological record. In particular,our results show that oxidized high-silica rhyolites, such asthe Bishop Tuff, could be derived via fractionation of oxidizedintermediate magmas and do not necessarily represent primarycrustal melts. This study underlines the great variability ofcrystallization conditions (from anhydrous to hydrous and reducedto oxidized) and petrogenetic processes among the metaluminousferroan magmas of intermediate compositions (granodiorites,quartz mangerites, quartz latites), suggesting that there isnot a single model to explain these rocks. KEY WORDS: ferroan granitoids; crystallization conditions; experiments; Norway; Sveconorwegian; Bishop Tuff  相似文献   

盛源盆地南部铀成矿水文地球化学条件分析     

石平 《铀矿地质》2005,21(1):38-44,51

本文阐述了盛源盆地南部铀成矿的地质、水文地质和水文地球化学条件 ,分析了区内放射性水异常的产出、分布特征和控制因素 ,认为坝口等地段水的循环深度大 ,深部氧化 还原过渡带发育 ,大面积、交互叠加的放射性水异常是寻找大型隐伏铀矿床的重要标志。  相似文献   

镉的地球化学研究现状及展望   总被引：13，自引：0，他引：13  

叶霖潘自平  李朝阳刘铁庚 夏斌 《岩石矿物学杂志》2005,24(4):339-348

镉是重金属有毒元素,其环境污染一直是众多学者研究的焦点。近年来研究发现,镉等分散元素并不“分散”,它在特定的条件下会富集,甚至形成独立矿床或矿体,因此有必要对镉等分散元素的地球化学行为进行重新认识和再研究。本文介绍了有关镉的分布和赋存状态的一些研究进展,总结了我国镉矿资源的分布及特点和地球化学研究现状,提出应加强镉的超常富集机制、铅锌矿床表生地球化学过程中镉的释放及其对环境的影响方面的研究。  相似文献   

地下圆形衬砌隧道对沿线地震动的影响(II):数值结果   总被引：5，自引：3，他引：5  

梁建文  纪晓东  Vincent W Lee 《岩土力学》2005,26(5):687-692

利用地下圆形衬砌隧道对入射平面P波和SV波散射级数解答，定量分析了入射波长、入射角度、隧道直径、衬砌刚度等因素对沿线地表位移放大作用的影响。计算结果表明，当入射频率较低时，地下隧道的存在对地表位移幅值影响不大；而当入射频率较高时，地表位移幅值可以达到无隧道情况的4．5倍以上；衬砌情况下地表位移幅值可以高出非衬砌情况的87．8％。建议在地铁的规划设计中考虑地下隧道的建设对隧道沿线设计地震动的影响。  相似文献