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1.
选择沂沭泗流域沂河临沂站以上区间、中运河运河站以上区间和沭河大官庄站以上区间3个流域,采用0-1整数规划对现行雨量站进行了优化规划,选出了满足精度要求的雨量站数量,以作为今后水文预报控制雨量站  相似文献   

2.
岩体结构研究日益得到工程地质界的重视,而岩体结构面现场测量数据是获得岩体结构特征的必需资料。在目前常用的 2种结构面测量方法中对如何选择合理的统计区间长度缺乏充分的论证。利用我国西南某大型水电工程丰富的结构面测量资料,研究统计区间长度对岩体结构类型的影响,取得了一定的成果。即最小有效测线长度与结构面间距大小及概率密度分布形式有关,研究岩体结构特征时,必须根据工程实际情况选择满足要求的统计区间长度.  相似文献   

3.
雷鹏  苏怀智  张贵金 《岩土力学》2011,32(2):547-552
针对混凝土大坝坝体和岩基参数的区间不确定性,构造具有区间分析功能的RNN(粗糙神经网络)模型,并运用该模型反演坝体和岩基区间参数值。应用区间有限元对结构进行正分析,根据区间参数反演的需要选取相应的区间学习样本,利用RNN模型对样本进行模式学习直至网络收敛,最后通过网络回想和反归一法得到坝体和岩基力学参数的区间值。研究结果表明,该方法可用于反演混凝土坝坝体和岩基区间力学参数,反演得到的区间参数值是合理的。此外,基于RNN模型的区间参数反演方法经过一定的拓展和改进,理论上可应用于反演其他类型的区间参数。  相似文献   

4.
黄晓虎  易武  黄海峰  邓永煌 《岩土力学》2020,41(4):1396-1403
部分降雨型滑坡的地表裂缝会随着变形的不断增加逐渐形成完整配套的裂缝体系,针对此类滑坡的降雨入渗过程,指出沿地表裂缝形成的优势通道而形成的优势流入渗主导着滑坡稳定性的恶化过程,促进变形的持续发展。系统分析了优势流入渗与地下水位升降、坡体变形之间的相互关系。在此基础上,以王家坡滑坡为典型案例,分析了优势流入渗通道形成的时空规律及对应的变形特征,发现滑坡累积位移曲线上的变形加速区间呈不规则阶跃状,并将加速区间的起点与终点定义为加速拐点和减速拐点。然后以W3监测点的实际监测资料对滑坡变形过程中的地下水升降特征进行反演并获取对应的稳定性演化规律,发现变形加速区间上的加速拐点和减速拐点与稳定性出现变化的起点和终点相吻合,依此可建立确定变形加速区间的方法,进而获取位移速率阈值。  相似文献   

5.
一种改进的灰关联分析方法及其在水环境质量评价中的应用   总被引:32,自引:1,他引:32  
沈珍瑶  谢彤劳 《水文》1997,(3):13-15
对在环境质量评中应用的灰关联分析方法进行了探讨,认为实际上评价标准是区间概念而非 的概念,因而传统灰联分析处理曲线间几何形状接的方法存在一定缺陷。为了改进这种缺陷,提出了一种基于点到区间距离的关联系数公式,并把它用到水环境质量评价虽,发现这种改进的灰关联分析方法具有更大的适应性。  相似文献   

6.
在青藏铁路冻土路基现场实测资料的基础上,用改进的BP神经网络建立起了路基变形与地温、路基高度和上限之间的非线性映射。对某一典型路基第30年的变形进行了预测,结果显示路基的累计融沉量在冻胀量的两倍以上。从绘制的路基变形过程曲线可以很清晰地看出路基一年中的变形趋势和冻胀融沉区间。在4月份以后,路基的变形由冻胀向融沉转变,变形与地温有很好的正比关系,但是当地温升高到一定值时,路基的融沉量便不再随着地温的升高而增大。路基的冻胀与地温的关系也有相似的规律,说明地温对路基变形的影响存在一个比较明显的区间,在这个区间范围内的温度对路基变形的影响较大,这为控制路基的病害提供了一个比较有价值的信息。  相似文献   

7.
黄河中游府谷-吴堡区间水文特性分析   总被引:2,自引:0,他引:2  
马文进  李鹏  任小凤  齐斌  曹嫦娥 《水文》2002,22(5):59-61,24
府谷-吴堡区间是黄河泥沙和暴雨洪水的主要来源区之一,该区间洪水对黄河下游防洪及河床演变有很大影响。应用最新资料,分析了区间降水、径流、泥沙、洪水等水文要素的特性,以期对区间各水文站的洪水测报及黄河下游的防汛和水资源利用等有所帮助。  相似文献   

8.
影响边坡稳定性的岩土参数大多具有随机性、模糊性和可变性等不确定性的特点,因此,需要引入不确定性分析模型进行分析。本文在综合分析岩土参数区间性的基础上,将区间分析模型应用于边坡的稳定性分析。通过引用区间数学的思想,运用区间极限平衡法推导出边坡最小安全系数区间,并在此基础上对边坡进行非概率可靠度分析。  相似文献   

9.
祖厉河流域水沙时空分布及变化分析   总被引:2,自引:0,他引:2  
邓居礼 《水文》2001,21(2):47-50
应用水文站实测水沙资料序列,分区间分阶段统计分析了祖厉河流域的水沙时空分布特性及雨~水~沙关系,并对水沙量变化的影响因素进行了初步探讨,计算了各区间不同阶段的水沙变化量以及由于降雨影响和人类活动影响的水沙变化量所占的比重,对比分析了各区间水沙变化状况。结果表明,70年代后祖厉河流域年径流量、年输沙量明显衰减,主要是人类活动(水土保持和水利工程措施)影响造成的。  相似文献   

10.
不同温度条件下乙酸对长石溶蚀过程的实验研究   总被引:25,自引:3,他引:25  
本文报道了不同埋藏温压条件下乙酸对条纹长石溶蚀过程的实验研究。结果证明:1)在条纹长石溶蚀过程中,K、Na、Al优先释放,Si是最后释放的元素。2)在相对低温的条件下,长石溶出主要元素的比例远远偏离其化学组成,在相对高温的条件下,则接近其化学组成。3)在条纹长石中.钠长石比钾长石更容易分解。4)温度升高对条纹长石中Si的影响最大,其温度效应分别是K、Al、Na的9.2,8.6和5.4倍。5)不同温度区间Si,Al的温度效应存在显著的差别,Al主要在小于95℃区间释放,而Si主要在大于95℃区间释放,此时将有约2/3的Si不能加入到高岭石中。因而在埋藏成岩过程中,自生SiO矿物沉淀造成的孔隙封堵作用主要发生在地温大于95℃的埋深中。6)相对高温高压的实验中获得了蛋白石等自生SiO矿物的沉淀,进一步证明Si主要是在高温区间释放的。  相似文献   

11.
谢群 《铀矿地质》2006,22(2):125-128
本文总结了粤北喀斯特地区某桩基础工程的施工过程,论述了喀斯特地区的溶洞特征及所采取的处理措施。  相似文献   

12.
文章从矿床产出的构造背景、矿床地质及地球化学特征等方面,对勐兴铅锌矿床进行了详细研究,并与Sedex型矿床进行系统的对比,提出勐兴铅锌矿床为Sedex型矿床,在传统找矿思路的基础上,提出了新的找矿关注点。  相似文献   

13.
Hong Jiang 《Geoforum》2005,36(5):641-653
This paper surveys grassland management in China during the socialist period that began in 1949, examining state policies and local practices as well as views of nature underlying both. The case study is set in Uxin Ju, a Mongol-dominated community in western Inner Mongolia that enjoyed a national reputation in the 1960s for its enthusiasm in the campaign to transform its sandy land. This paper adopts a historical-cultural perspective. The grassland is a historical category whose formulation by the state has changed with the political-economic ideologies of the regime. At the same time, local views of the grassland have also changed, which facilitated the adoption of aggressive grassland practices. By examining grassland management and local change as a cultural process, this paper seeks to understand a dimension of grassland change that has not attracted much study in China. In several ways this paper contributes to the study of environmental history in socialist China. First, it adds to a complex appraisal of regional environmental change during the Mao era by demonstrating both grassland improvement and degradation in Uxin Ju. Second, this paper locates the agency of the local people in both predictable and surprising ways, both in resistance to and appropriation of state policies. Third, by covering the entire socialist period from 1949, this paper lends insights into the understanding of continuities and breaks in grassland management between the Mao (1949-1976) and post-Mao (1976-present) eras.  相似文献   

14.
Michael Pryke 《Geoforum》2007,38(3):576-588
The paper adopts a cultural economy approach to explore the emergence of a market in so-called weather derivatives, referred to in the paper as a form of ‘geomoney’. These are specially designed financial products that allow firms to protect their profits against the impact of changing weather conditions. The paper approaches the emergence of this market, and the issues its growth raises, in three interlinked stages. Weather derivatives are located amongst the hybrid collective that is contemporary finance and are analysed through the conceptual apparatus afforded by a cultural economy approach to finance. The paper employs this analytical line to examine the assumptions and models that enable the weather to be turned into a risk and then be transported and traded within capital markets. Through specific examples of weather products together with a discussion of the International Finance Corporation’s recent involvement in this market, the paper suggests something of the ‘world making’ capabilities of finance theory and the politics of finance often hidden beneath the mathematical models. The paper concludes by highlighting not only the usefulness of a cultural economy of finance to geographers but, in light of the examples discussed, the need for cultural economy to recognise and to engage critically in its analysis the politics that such a conceptual approach to the making of financial markets exposes.  相似文献   

15.
Work reported in this paper suggests that there are cases of contamination of soil and water samples by polychlorinated biphenyls (PCB) from paper and plastic packaging. Soil samples, which have been stored in paper bags for more than 20 years, share a similar congener distribution as the bags. Analyses showed a predominance of light congeners. PCB-analyses of water also indicate that water samples could be contaminated by plastic packaging. All analytical results of solid material packaging, as well as soil stored in the packaging, show a high relative amount of light weight PCB congeners. The paper bags that were analysed are made of strong paper and very popular among geochemists because of their watertight quality. These paper bags were manufactured more than 20 years ago. The plastic packaging that was analysed was produced in 1997 and 2008. The analyses of plastic and paper show that the raw material that has been used in the production at different times contains a wide concentration range of PCB. Re-sealable plastic bags, which contained the highest levels of PCB of the plastic material, are used by researchers world-wide as sampling bags for soils and sediments. This paper raises an important issue that packaging may potentially contaminate the samples that they hold.  相似文献   

16.
Efficient waste paper recycling has a significant role in the sustainable environment. Recyclable waste paper as a fundamental ingredient of municipal solid wastes (MSWs) is indeed an “urban ore”. Waste papers are considered as the solid recovered fuel which is recovered from MSW. Recyclable waste papers are segregated into various grades to produce high-quality products. Moreover, sorted paper streams save energy, chemicals, and water, as well as reduce sludge and rejects. Information technology is widely integrated with the waste management industry into its operations such as recycling, reuse, segregating based on categories and so on. This review article focuses on the life cycle of waste paper and existing waste paper sorting techniques. In the paper industry, many types of sensors are used in different mechanical and optical waste paper sorting systems. Such sensors include lignin, gloss, stiffness, mid-infrared, infrared, and color sensors. In this review, also described the effectiveness of different waste paper sorting systems, and finally, recommended appropriate waste paper sorting techniques based on effectiveness and low-cost implementation.  相似文献   

17.
针对深圳市梧桐山地区某住宅区一34m高的深厚人工填土高边坡,通过对其形成历史及地质环境条件分析,采用了抗滑桩为主的分段加固治理设计方案.根据给出的监测和后期使用检验资料,证明了本文所采用的设计方案安全合理.  相似文献   

18.
滑坡是一种重大的地质灾害,本文结合杭州市郊来龙山的滑坡工程,具体分析了滑坡的成因、稳定计算和最终采取的治理措施,通过监测的具体内容和结果进行分析,表明治理效果比较好,为以后该地区的滑坡治理与加固提供相关参照。  相似文献   

19.
国际及中国地球科学发展态势文献计量分析   总被引:7,自引:0,他引:7  
以SCI、ESI(基本科学指标数据库)、GEOREF等数据库为统计分析源,对1993—2003年国际及中国地球科学的发展现状和发展态势从文献计量学的角度进行统计分析,分析了国际地球科学论文产出的主要领域、国家、机构、科学家和期刊,对中国地球科学论文产出的主要领域进行比较分析,并通过论文产出、被引频次、篇均被引频次和国际1%顶尖论文数量对比反映中国的科学影响力。结果表明,国际环境科学和生态学研究论文增长很快,占地球科学相关主题领域论文的比例也比较大,但中国生态学研究论文无论从占国内22个学科论文产出的比例,还是从占全球该领域的比例来说都有较大差距;中国地质科学领域研究重点在地球化学、金属矿产和能源的经济地质学,但在环境地质学领域研究相对较少,而国际上环境地质学研究论文的发展已经大大高于传统的地质学论文。  相似文献   

20.
共转换点道集的迭代算法及应用   总被引:3,自引:0,他引:3  
崔秀  韩立国 《世界地质》1998,17(4):53-57
对转换波共转换点道集选取进行了详细的研究,对水平层状和倾斜情况下共转换点的选取建立了统一的迭代公式,分析了影响共转换点选取的因素,给出了共转换面元的一般原则,最后给出了实际处理结果。  相似文献   

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