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21.
以同煤集团塔山洗煤厂为例,探讨了强夯法在湿陷性黄土中的应用,提出了强夯法处理黄土的适用条件、强夯方案的确定原则、地基土含水量对强夯施工效果的影响等论点,尤其是用复合地基理论确定强夯地基承载力的方法。 相似文献
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V. A. Lutskii 《Seismic Instruments》2009,45(1):69-74
The results of determining the relative number of recorded oscillograms for acoustic event intensities of up to 400 1/s in the four-channel Aline32D system for acoustic data reception and processing are presented. Since the internal characteristics of a computer determining the data processing performance are not always available, this problem is solved experimentally. Recommendations concerning the determined working parameters of the Aline32D system are given. This work may be used for the solution of geophysical applied problems. 相似文献
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基于主成分神经网络的台风灾害经济损失评估 总被引:6,自引:0,他引:6
本研究建立了浙江省台风灾害直接经济损失评估模型。把浙江省台风灾害直接经济损失资料换算成直接经济损失指数,运用主成分分析法对表示致灾因子、孕灾环境与承灾体的评估因子进行数据处理,提取主成分作为BP神经网络模型的输入,从而建立评估模型。模型历史拟合结果和实际一致。在2007年和2008年影响浙江省的5个台风的实际评估中,强台风"Vipa"灾后评估值比实际值偏大2.16,其余4个台风灾后评估值比实况偏大0.2~0.7,反映了人们对影响大的台风防灾减灾工作的重视和防灾减灾效果。根据台风开始影响时过程风雨预报值进行预评估,过程风雨预报值较准确的台风,预评估结果和灾后评估值一致;过程风雨预报值误差较大的台风,预评估效果较差。因此,该模型可用于实际台风灾害直接经济损失评估,提高台风影响前风雨预报准确率是提高预评估准确率的关键。 相似文献
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The Ričice reservoir was built in 1987 in the central part of the bare Dinaric karst region in Croatia, on the border with Bosnia and Herzegovina. The reservoir water level rise rapidly after rainfall, but due to high water-loss rates the water remains impounded for a very short time. The reservoir volume at the spillway altitude is 18.4 × 106 m3. Due to water losses, the mean annual water volume in the 1989–1995 period was 6.5 × 106 m3. Interdisciplinary analyses and investigations of geological, hydrological and hydrogeological factors which caused water losses from the Ričice reservoir have been carried out. Water losses from the reservoir are defined using a water budget equation. An assessment of the calculation of hydraulic conductivity, and a definition of the groundwater level below the Ričice reservoir, using Darcy's equation for vertical flow, is carried out. It may be concluded that the water losses from the Ričice reservoir are mainly controlled by the water level in the reservoir. 相似文献
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1949-2015年中国典型自然灾害及粮食灾损特征 总被引:6,自引:0,他引:6
中国是一个自然灾害频发的国家,研究其自然灾害演变特征及粮食灾损规律,对实现中国社会经济可持续发展、解决中国粮食安全问题具有重要意义。本文先基于Python语言编程获取1949-2015年中国31省市自然灾害造成的受灾、成灾、绝收面积,构建灾害强度指数分析不同灾种的时序特征分异,利用趋势分析、ESDA方法分析不同灾种在省域空间的分布特征及冷热区;再获取1949-2015年粮食种植数据,通过粮食灾损估算模型、定义粮食灾损率、地理空间探测器,计算并检验中国粮食损失时空特征及分异性。结果表明:① 相比受灾面积曲线,本文构建的灾害程度指数能够更好揭示自然灾害时序演变特征;② 1949-2015年期间中国两大主力灾害(洪灾、旱灾)交替出现,未来5~10年以洪灾为主;③ 灾种排序旱灾>洪灾>风雹>低温>台风,其中旱灾、洪灾受灾占比过半;④ 省域不同灾种间空间趋势变化特征明显,区域受灾面积东部>西部,北部>南部,且北部灾种单一、南部多灾并发;⑤ 自然灾害受灾总和、旱灾、雹灾、低温空间上全局自相关性不显著,呈随机模式分布,洪涝、台风在空间分布上具有显著的全局自相关性,呈集聚模式;⑥ 1949-2015年灾害、灾损量、灾损率整体时序趋势呈现先升后降,2000年为临界点,空间分布具有异质性,单因子解释力度差异显著,多因子交互均呈非线性增强关系,胡焕庸线两侧冷热点分布呈两极化且其重心向北迁移。建议政府加强除旱减雹(西北)、除旱排内涝(东北)、排涝防冻(中部)、排涝预台(东南沿海)等工程技术措施;同时西北(环境恶劣)、东北(中国粮仓)应作为防灾减灾重点保护区,制定专项保护方案,以保证中国粮食丰产增收。 相似文献
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Alexandre Cunha Costa Saskia Foerster José Carlos de Araújo Axel Bronstert 《水文研究》2013,27(7):1046-1060
Scarcity of hydrological data, especially streamflow discharge and groundwater level series, restricts the understanding of channel transmission losses (TL) in drylands. Furthermore, the lack of information on spatial river dynamics encompasses high uncertainty on TL analysis in large rivers. The objective of this study was to combine the information from streamflow and groundwater level series with multi‐temporal satellite data to derive a hydrological concept of TL for a reach of the Middle Jaguaribe River (MJR) in semi‐arid north‐eastern Brazil. Based on this analysis, we proposed strategies for its modelling and simulation. TL take place in an alluvium, where river and groundwater can be considered to be hydraulically connected. Most losses certainly infiltrated only through streambed and levees and not through the flood plains, as could be shown by satellite image analysis. TL events whose input river flows were smaller than a threshold did not reach the outlet of the MJR. TL events whose input flows were higher than this threshold reached the outlet losing on average 30% of their input. During the dry seasons (DS) and at the beginning of rainy seasons (DS/BRS), no river flow is expected for pre‐events, and events have vertical infiltration into the alluvium. At the middle and the end of the rainy seasons (MRS/ERS), river flow sustained by base flow occurs before/after events, and lateral infiltration into the alluvium plays a major role. Thus, the MJR shifts from being a losing river at DS/BRS to become a losing/gaining (mostly losing) river at MRS/ERS. A model of this system has to include the coupling of river and groundwater flow processes linked by a leakage approach. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献