基于神经网络的降雨径流预报

本文将人工神经网络应用于二滩水电站以上支流鱼河的降雨径流预报，通过建模、计算、比较和分析可知，其非线性映射能力、自学习能力和灵活性，均能较好地反映降雨径流之间的非线性的、复杂的转换关系，结合流域水文特性并合理处理建模数据，值得进一步深入研究。     

全球气候变暖对水资源的影响

全球气候变暖加剧了干旱、洪涝、台风等自然灾害的发生，是目前各国政府和社会公众普遍关注的热点问题。根据有关资料对气候变暖研究进展情况作相关介绍，可供参考。     

80年代黄河中游来沙减少的原因分析

80年代黄河中游来沙量减少,主要原因是降雨量减少和降雨强度减小,流域综合治理也起到了减沙作用。据分析,降雨因素减沙约占总减沙量的70％,流域综合治理减沙约占30％。     

Ermüdungsverhalten und Dauerfestigkeit von Graphit und Aluminium – infiltriertem Graphit

Fatigue behaviour and endurance limit of graphite and of aluminium‐infiltrated graphite Fatigue properties of polycrystalline, isotropic graphite FU2590 and of FU2590 infiltrated with AlSi7Mg (FU2590/AlSi7Mg) were investigated in reversed bending tests at 25 Hz at numbers of cycles below 10⁷ and in tension‐compression tests at 20 kHz below 10⁹ cycles. The open porosity of Graphite (10‐11 Vol.‐%) was infiltrated with the aluminium alloy using the squeeze casting infiltration method, which led to an increase of the bending strength by 50 %, increase of tensile strength by 30 % and increase of stiffness by 15 %. Fully reversed tension‐compression loading of FU2590 delivers a mean endurance limit at 10⁹ cycles at the normalized maximum stresses (i.e. maximum tension stress of a cycle divided by the static strength) of 0,65±0,03. Mean numbers of cycles to failure of 10⁴ were found in fully reversed bending tests at the normalized maximum stress of 0,78. The infiltrated material shows approximately 30 % higher cyclic strength in reversed bending tests, and the mean endurance limit under tension compression loading increases by 15 %. The increased endurance limit of the infiltrated material is caused by the increased stiffness. The increased toughness of graphite due to the infiltration with aluminium is of additional beneficial influence at the higher cyclic stresses investigated in reversed bending tests and in static tests.     

山前平原地下水侧向补给潜力空间变异模拟

SWAT模型利用分辨率较高的DEM数据,可以估算山前地下水侧向补给的空间变异,并可以计算不同降水年型下补给量的差别。模拟需要对研究区进行填洼、流向确定、汇流和河网水系的提取四步运算,并对河道临界支撑面积的取值进行分析。分别模拟了平水年和丰水年两种降雨年型下研究区13个出水口的地下水侧向补给潜力。在研究区,由于地形的变化,导致山与平原交接断面上出水口的集水面积变异非常大,因此山前平原所接受的地下水侧向补给量的空间变异也非常大。不同的降雨年型下,降雨量转化为地下水侧向补给量的比例也不同。平水年的转化比例较小,丰水年的转化比例较大。应用SWAT模型时,与ArcView的拓展模块有机结合,可以更方便提取完整的大流域,划分出合理的子流域。     

露采边坡渗流的有限元分析及其实例

介绍了应用有限元法求解渗流问题的原理及其实例。     

Evaluation of rainfall networks using entropy: II. Application

This paper, the second in the series, applies the entropy approach to space and time evaluation of rainfall networks in Louisiana. The evaluation is made for five sampling intervals: daily, 2-day, weekly, monthly, and yearly, and for two separate seasons. In each case, the best combination of raingages is suggested and the lines of equal information (isoinformation contours) are constructed showing the areas of greater or less information transfer. The isoinformation lines are especially suitable in decisions concerning the expansion of the existing network or deleting the unnecessary raingages.     

水利工程排涝减灾效益分析与计算

在分析涝灾成因特点基础上对涝灾进行了重新定义，在研究涝灾损失及 排涝效益时引入了临界降雨量的概念，从而奠定了水利工程排涝减灾效益分析与计算的理论基础，并给了效益计算的一般计算模型。     

Impacts of green roofs and rain water use on the water balance and groundwater levels in urban areas

Ohne Zusammenfassung

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Impacts of green roofs and rain water use on the water balance and groundwater levels in urban areas

     

堆积体内部裂隙对降雨入渗的影响

降雨条件下滑坡体稳定性与裂隙诱发入渗密切相关。为了探究裂隙发育对堆积体降雨入渗的影响,以澜沧江某巨型堆积体坡表发育的裂隙现象为出发点,设计了均质堆积体和主-次裂隙堆积体2种模型。通过室内物理模拟试验及数值分析,并结合土体中的含水率、基质吸力、湿润锋迁移速度及深度的变化趋势可得出以下结论:裂隙型堆积体在降雨1 h和观测23 h的整个时间段内,其湿润锋迁移变化趋势可归纳为入渗加速→峰值→入渗减速→趋向于0;裂隙的存在为雨水入渗提供了有利的通道,雨水可到达土体深部,形成暂态饱和区,随降雨结束又逐渐消散;降雨在裂隙型发育的堆积体中的入渗过程可分为4个阶段,即前期完全入渗、裂隙下方强烈入渗、补偿加速入渗及水平侧渗。研究结果可为后续滑坡复活机理和稳定性评价提供参考。