共查询到20条相似文献，搜索用时 62 毫秒
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《地理与地理信息科学》2016,(5)
滑坡体堵江易发性评价是滑坡堵江风险研究中的短板,不利于其防灾减灾工作的开展。该文以物质来源、水力条件和河谷地形为主要影响因素进行滑坡体堵江概率预测分析和应用,提供了基于GIS技术的河谷横剖面形态参数自动提取方法,以定量表征河谷地形特征;以中国喜马拉雅山地区为例,分别提取堵江滑坡和非堵江滑坡事件为样本,基于逻辑回归建立了研究区滑坡体堵江概率预测模型,经验证精度较理想。取得的主要结论有:1)河谷横剖面形态参数自动提取方法,具有面向对象、表征全面、提高计算效率和精度等优点。2)在中国喜马拉雅山地区,堵江滑坡事件与非堵江滑坡事件发生处河谷横剖面的坡高、不同深度宽深比、凹度和河宽指数具有显著差异,其中河宽指数差异最大,3/4坡高宽深比次之。3)基于逻辑回归开展滑坡体堵江易发性评价是可行的,该方法在中国喜马拉雅山地区的应用精度达80%以上,各变量按照与滑坡体堵江形成的相关性从大到小依次是坡高宽深比、滑坡面积、工程地质岩组、河宽指数和凹度。 相似文献
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通过勘查贵定县定东小学滑坡区,查清定东小学滑坡体基本特征,分析其滑体、滑面、滑床及滑坡边界条件。通过岩石力学实际值、经验值等比选出适当的参数,对定东小学滑坡体稳定性进行验算。评价滑坡体在饱和状态和天然状态下的稳定性,最终选取经济合理的防治方案。 相似文献
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汶川地震非规范滑坡体上植被的自然恢复能力研究——以彭州银厂沟谢家店子滑坡体为例 总被引：3，自引：0，他引：3
在野外样方调查的基础上,对汶川地震极重灾区彭州市谢家店子非规范滑坡体上的植物群落组成、物种多样性以及生物量进行详细调查和统计分析.结果表明:(1)植物群落的物种组成已比较丰富,已统计到高等植物20科35属53种.(2)物种的多样性指数较高,Shannon-wiener指数(H′)、Simpson指数(D)、Margalef丰富度指数(Ma)和Pielou均匀度指数(E)的均值分别达1.894、0.787、9.713和2.741.(3)群落的生物量已较大,植物的鲜重和干重均值分别达2.20 kg/m2和0.97 kg/m2.由于该滑坡区气候条件优越,植物群落的自然演替完全能够顺利进行,加之土壤条件较差以及地质灾害风险大,不宜人工恢复植被.研究结果不仅为该区生态环境的自然恢复提供依据,而且为震后形成的山地特殊滑坡体上植被的恢复模式提供参考. 相似文献
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大埔县三叠系粉砂岩分布较为广泛,区内护坡、崩塌等地质灾害较发育。通过对大埔县某滑坡进行工程地质调绘,在实地勘查的基础上,基本查明了滑坡区地形地貌、地层岩性、水文条件等,分析其滑坡体特征和成因,并给出对应的防治建议。 相似文献
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滑坡是一种常见的地质灾害,其危害性极大,科学地划分滑坡危险度是防灾减灾工作中主动预测预警的重要环节.该文结合GIS技术与信息熵理论,充分利用熵值法特别适合于确定同一个指标下不同因素相对权重的特点,开展了滑坡危险度区划模型中证据权法的改进研究,并以台湾地区为实验区,在综合考虑滑坡的形成要素并提取滑坡危险度评价因子后,实现了研究区滑坡危险度区划.通过定性和定量等精度检验和对比分析,证明了结合信息熵改进的证据权法所获得的滑坡危险度区划结果更准确且更符合实际. 相似文献
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滑坡是斜坡体物质变形累积到一定程度而形成并发生的,因此通过滑坡体的变形监测,能揭示和预测坡体的变形趋势,且监测的数据精度越高,对滑坡的预测和趋势分析准确度越高.目前对滑坡体的地表变形监测手段很多,但大多数监测数据的精度都不尽如人意,因此监测仪器以及手段的选择至关重要.GPS对静止物体的空间相对定位精度已非常高,本研究正是基于GPS观测数据高精度的特点,借助其对滑坡进行监测,从而分析滑坡的变形特征以及可能发展趋势. 相似文献
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Women,Politics, Elections,and Citizenship 总被引：1，自引：1，他引：0
《The Journal of geography》2012,111(1):1-10
Abstract Significantly more women than men are registered voters in the United States, and a higher proportion of women voters actually cast ballots on election day. Yet the 106th Congress (1999-2001) includes only 56 women members, 12% of the total membership of the House and Senate. Likewise, women hold only 22% of the total seats in state legislatures. The purpose of this article is to examine this paradox. It first examines the history of the women's movement in the United States. It then turns to an evaluation of women's progress in gaining elected office. Finally it considers three primary obstacles to women gaining equitable representation: solidarity among women, political culture, and the single-member district system now employed in the United States. 相似文献
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Robert G. Darmody & Colin E. Thorn 《Geografiska Annaler: Series A, Physical Geography》1997,79(4):215-222
Chemical weathering and associated soil development trends on glacial forelands are commonly assumed to exhibit increases with time elapsed since glaciation. However, this gross trend is complicated by several other factors including elevation, aspect, and microtopography. This paper demonstrates that on the glacial foreland at Storbreen, Jotunheimen, Norway, chemical weathering and associated soil development trends show significant elevational influences. We sampled soils at shallow depths (0–1, 1–5, and 15–20 cm) at two sites on a moraine dated to 1750 at its elevational extremes of 1155 m (site L) and 1385 m (site H). The two moraine sites also differed developmentally from an adjacent 9000-year-old surface (site T) at an intermediate elevation, 1205 m. Analyses were conducted on the fine-earth fractions. Extractable elemental composition exhibited detectable differences between the same-age soils at different elevations with the lower site L tending to have measured parameters intermediate between the high site H and the older site T. Weathering, as indicated by mineralogy, was more pronounced at the 9000-year-old site T and least evident at the high elevation site H. In addition, elevation under the conditions of the field research may inhibit pedogenesis as indicated by the chemical data. Site H, for example, showed little variation with depth and had in general, less organic matter accumulation, smaller C:N ratio, greater pH, and lesser amounts of the measured extractable elements than the soil at site L. Site T generally had smaller pH and larger levels of the measured elements than the other sites. It was concluded that elevation has a significant control on weathering and pedogenesis that may mask the effects of age in this cold and wet environment. 相似文献
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Rolf Sternberg 《Geographical review》1998,88(3):327-348
ABSTRACT. Wilhelm Richard Wagner fused fantasy based on epic and lore with seamless scores, using landscapes and urban images to forge spatial order on stage. As a footloose composer-conductor, Wagner was considered a globetrotter for his time, and from trans-European tours he drew inspiration for numerous stagings. Nine of his operas have rustic pastoral settings, with actors silhouetted against geological formations, forests, vistas of undulating terrain for pilgrimages, or raging seas, all visually believable scenery. Rienzi and Die Meistersinger von Nürnberg are urban in setting, whereas Die Feen and Das Liebesverbot are set in a castle-like format. 相似文献
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