深圳市断裂构造的活动性及其对地质环境的影响   总被引：11，自引：0，他引：11  

陈伟光  赵红梅  李富光  刘特培  常郁 《热带地理》2001,21(1):45-50,60

从地质、地貌、地球化学、地壳形变、地震活动等多学科研究分析深圳市断裂第四纪以来的活动，指出晚更新世以前北东向与北西向两组断裂有多期活动，并以后者切截，错移前者为特征。但晚更新世以来至今活动已明显减弱，现今活动微弱。断裂活动对该地区地壳稳定性及其他地质地貌环境没有构成较严重的自然灾害隐患。  相似文献   

Water quality in Sepetiba Bay,Brazil     

Copeland G  Monteiro T  Couch S  Borthwick A 《Marine environmental research》2003,55(5):385-408

Sepetiba Bay is located at 23 degrees S, 44 degrees W in Rio de Janeiro State, Brazil. Water samples were taken at eight locations adjacent to the north shore of the Bay, near to villages and towns without sewage treatment provision. The samples were analysed and total and faecal coliform concentrations determined. A hydrodynamic model of the Bay was used together with a species dispersion model based on an adaptive quadtree mesh to predict faecal concentrations in the Bay. Effluent sources used in the model were defined using population data from census returns with flow and concentration values estimated using standard values recommended by the World Bank (WB) and the World Health Organisation (WHO). Sufficient agreement was obtained between the measured and predicted concentrations to support the use of WB and WHO summary statistics to estimate sources of sewage.  相似文献   

广东省电白县大放鸡岛滨珊瑚的重金属含量及其意义   总被引：2，自引：1，他引：2  

彭子成  刘军华  刘桂建  贺剑峰  聂宝符  陈特固  温孝胜 《海洋地质前沿》2003,19(11):5-12

采用等离子体质谱(ICP-MS)技术，测定了1982-2001年广东省电白县大放鸡岛(111^* 11’E、21^*21’N)滨珊瑚中的Pb、Cd、Cu、Co、Cr、Mn、Ni、Zn重金属元素的含量。结果表明，珊瑚中有高的Ni和Zn含量的平均值，且在1990和2001年Zn的含量高出平均值1．8和2．3倍；1997和1998年，Pb的含量高出平均值3．5和2．3倍；1987年Cu的含量高出平均值1．5倍。这表明珊瑚样品在上述的年段内受到了Zn、Ni、Pb和Cu较显著的污染。其他重金属元素未构成明显的影响。此外，还用多元统计分析的方法，探讨了重金属含量的年际变化率与气候环境和经济环境指标的相关性，以及重金属元素之间的相似性和差异性。  相似文献   

基于航空影像的盘锦湿地监测空间数据采集方法研究     

马婉婷  桑特  王峰 《测绘通报》2015,(10):94-98

随着航空摄影的日益常态化,高分辨率的航空影像将成为湿地监测的重要数据源之一。本文以地理国情普查数据为基础,结合盘锦双台河口湿地的具体情况,建立了湿地监测的数据分类基本框架。利用2013年、2008年、2003年3期航空影像数据选取代表性区域,与地理国情普查地表覆盖数据相叠加进行了分析,形成了双台河口湿地的地表覆盖分类空间数据的采集方法。  相似文献   

Green-Ampt模型渗透系数取值方法研究     

吕特  张洁  薛建峰  黄宏伟  于永堂 《岩土力学》2015,36(Z1):341-345

格林-安姆普特（Green-Ampt）模型原理简单、使用方便,在浅层滑坡的降雨入渗分析中有很大的应用潜力。渗透系数是Green-Ampt模型中的一个主要参数,该渗透系数并不一定等于土体的饱和渗透系数。通过与理查茲（Richards）方程求解进行比较,研究了Green-Ampt模型中渗透系数的取值方法。研究发现,为获得与Richards方程相同的入渗量计算结果,需对饱和渗透系数进行修正,该修正系数的大小与入渗深度和土体类型有关。对于文中研究的土体,当Green-Ampt模型中渗透系数取为0.7倍饱和渗透系数时,由Green-Ampt模型计算的孔隙水压力分布与Richards方程计算结果最为接近,建议Green-Ampt模型中渗透系数修正系数取0.7。  相似文献   

适用于斜坡降雨入渗分析的修正Green-Ampt模型     

张洁  吕特  薛建锋  郑文棠 《岩土力学》2016,37(9):2451-2457

降雨入渗分析是预测降雨诱发滑坡的关键因素之一。Green-Ampt模型原理简单、使用方便,在浅层滑坡的降雨入渗分析中有很大的应用潜力,但该方法主要适用于初始含水率为均匀分布的情况。基于这一不足,推导了初始含水率为非均匀分布条件下降雨入渗深度和时间的关系,并给出了基于Runge-Kutta原理的数值解法。当初始含水率为均匀分布时,提出的方法可简化为文献中已有的Green-Ampt模型。当初始含水率为非均匀分布时, Richards方程预测所得的孔隙水压力分布图中土体饱和区和未受降雨影响的非饱和区之间存在一个较窄的过渡段,由新模型计算所得的湿润锋穿过这一过渡段,且靠近饱和部区的底部。总体而言,新方法计算所得的孔隙水压力分布与Richards方程求解结果类似。  相似文献   

Cyclic test of a coupled steel plate shear wall substructure     

Chao‐Hsien Li  Keh‐Chyuan Tsai  Jing‐Tang Chang  Chih‐Han Lin  Jia‐Chian Chen  Te‐Hung Lin  Pei‐Ching Chen 《地震工程与结构动力学》2012,41(9):1277-1299

Coupled steel plate shear wall (C‐SPSW) consists of two or more steel plate shear walls interconnected by coupling beams at the floor levels. In this study, a six‐story C‐SPSW prototype building was designed. A 40% scale C‐SPSW specimen, which is representative of the bottom two‐and‐half‐story substructure of the prototype, was cyclically tested using Multi‐Axial Testing System at the National Center for Research on Earthquake Engineering in 2009. In addition to a constant vertical force representing the gravity load effects, cyclic increasing displacements and the corresponding overturning moments transmitted from the upper stories were computed online and simultaneously applied on the substructural specimen. This paper firstly introduces the designs of the prototype C‐SPSW and the test specimen. Then, the test results and the numerical simulation are discussed in detail. Test results confirm the effectiveness of the proposed column capacity design method, which aims at limiting the plastic hinge formation within the bottom quarter height of the bottom column. Test and analytical results suggest that the coupling beam rotational demands can be estimated as the design story drifts when the formation of desirable plastic mechanism of the C‐SPSW is expected. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

陕西省凤县九子沟铜矿矿床地质特征及成因研究     

宁传奇  李成博  李降印  牛特 《吉林地质》2019,38(3):35-41

本文通过对九子沟铜矿床成矿地质背景,矿区地质特征,矿体特征,矿石特征,流体包裹体特征,硫同位素特征等几个方面的综合研究,九子沟铜矿床矿体主要赋存于星红铺组地层中的九子沟-太山庙灰岩单斜层北接触面及其附近,以层状、似层状产出。九子沟铜矿床分为三个成矿期:早期沉积-变质期、中期热液改造期和晚期表生期,中期热液改造期为主要成矿期。流体包裹体特征显示成矿温度主要集中于180~240℃,盐度集中于2.0%~6.0%NaCl,密度为0.68%~0.95%,成矿深度为0.9~3.2km,成矿流体属于低盐度低密度体系。九子沟铜矿δ18OH2O平均为-4.098‰;δDH2O平均为-80.625‰,说明成矿流体主要为大气降水或地下热卤水。δ34S值变化范围为6.21‰~9.37‰,平均7.44‰,说明硫主要来源于地壳,且有少量海水硫酸盐中硫的加入。认为该区矿床属沉积-热液叠加改造型铜矿床。  相似文献   

Water publications of State Agencies - A bibliography of publications on Water Resources and Their Management published by the States of the United States: G.J. Giefer and D.K. Todd (Editors), 1972. Water Information Center,Port Washington,N.Y., 319 pp., U.S. $39.50     

Ven Te Chow 《Earth》1973,9(4):375-376

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Risk analysis of fractured rock mass underground structures     

Gian Franco Napa-García  André Teófilo Beck  Tarcisio B. Celestino 《Georisk: Assessment and Management of Risk for Engineered Systems and Geohazards》2018,12(2):123-134

Recent accidents in underground structures have raised the risk awareness of the geotechnical engineering community. Geotechnical design is subject to significant uncertainties in load and strength parameters as well as in engineering models. However, engineering models which objectively address such uncertainties in design are still scarce. This paper presents an objective framework for the quantification of the risks involved in underground structures excavated in fractured rock masses, where structural failures may occur due to block falls. The framework considers the structure as a distributed system, where falling block probabilities are integrated over the main structural dimension. Random block size and geometry, arising from random joint orientation, are taken into account, as well as uncertainties in joint strength and geometrical parameters. A cost function is used to quantify failure consequences in terms of the block size. The framework is demonstrated in an application to a case study involving a real structure: the Paulo Afonso IV power station cavern. Results of the case study show that the studied cavern presents high reliability and very low risk. The framework proposed herein is shown to be a practical tool for the risk evaluation of underground structures constructed in rock masses, such as caverns and tunnels.  相似文献