The influence of rainstorm pattern on shallow landslide

In this study, the influence of the rainstorm pattern on shallow landslide is examined. The physically-based shallow landslide model is used to conduct this examination with considering four representative rainstorm patterns including uniform, advanced, central, and delayed rainstorms. The results show that in spite of the rainfall duration and the rainfall pattern, the rainstorm with less than the minimum landslide-triggering rainfall amount will not trigger landslide. However, for the rainstorm with greater than the minimum landslide-triggering rainfall amount, the occurrence of landslide significantly depends not only on the rainfall duration but also on the rainfall pattern. Among the four representative rainstorm patterns, the delayed rainstorm has the greatest rainfall duration threshold for landslide occurrence, followed by the central rainstorm, and then the uniform rainstorm. In addition, for each rainstorm pattern, the corresponding rainfall duration threshold for landslide occurrence decreases with the increase of rainfall amount, and seems to be constant for large rainfall amount.     

Real-time identification of urban rainstorm waterlogging disasters based on Weibo big data

With the acceleration of urbanisation in China, preventing and reducing the economic losses and casualties caused by urban rainstorm waterlogging disasters have become a critical and difficult issue that the government is concerned about. As urban storms are sudden, clustered, continuous, and cause huge economic losses, it is difficult to conduct emergency management. Developing a more scientific method for real-time disaster identification will help prevent losses over time. Examining social media big data is a feasible method for obtaining on-site disaster data and carrying out disaster risk assessments. This paper presents a real-time identification method for urban-storm disasters using Weibo data. Taking the June 2016 heavy rainstorm in Nanjing as an example, the obtained Weibo data are divided into eight parts for the training data set and two parts for the testing data set. It then performs text pre-processing using the Jieba segmentation module for word segmentation. Then, the term frequency–inverse document frequency method is used to calculate the feature items weights and extract the features. Hashing algorithms are introduced for processing high-dimensional sparse vector matrices. Finally, the naive Bayes, support vector machine, and random forest text classification algorithms are used to train the model, and a test set sample is introduced for testing the model to select the optimal classification algorithm. The experiments showed that the naive Bayes algorithm had the highest macro-average accuracy.     

基于暴雨衰减特性的上海市长历时综合暴雨公式

编制适用于不同历时的综合暴雨公式是协调城市管网排水与区域防洪治涝的重要基础。选用上海市代表雨量站徐家汇站65 a实测雨量资料,建立不同重现期暴雨强度与历时关系,解析暴雨衰减规律,编制单一重现期暴雨公式,结合雨力公式推求适用不同重现期的长历时综合暴雨公式,并推导出暴雨重现期公式。结果表明:不同重现期1~24 h历时暴雨强度均以0.74的衰减指数衰减,据此推求的长历时综合暴雨公式可计算1~24 h任意历时、2~100 a任意重现期的设计暴雨,且平均相对和平均绝对均方根误差分别为1.9%和0.009 mm/min,符合规范要求;暴雨重现期公式可估算1~24 h历时内任意场次暴雨的重现期,高效地服务于城市洪涝防治决策。成果已纳入上海市治涝地方标准,对其他城市具有参考价值。     

基于WCA2D与SWMM模型的城市暴雨洪涝快速模拟

为探讨计算高效的元胞自动机模型(WCA2D)与传统一维管网模型耦合的机制以及计算效果,尝试将WCA2D与SWMM模型耦合(SWMM/WCA2D),以广州市长湴片区为例探究一种暴雨洪涝快速二维模拟技术,对比实测积水数据以及SWMM/LISFLOOD-FP模拟,结果表明:SWMM/WCA2D模拟结果与"20180607"实测积水数据相近,表明模型精度良好;根据多指标评估结果,综合考虑主干渠道淤积以及建筑物阻挡情景的R_TPR、R_PPV、F₁值分别达到0.8、0.6、0.7,模拟精度最高,最能反映区域实际情况;通过与SWMM耦合,WCA2D和LISFLOOD-FP的模拟结果差异小(最大水深差值基本低于0.1 m)、相关性强(相关系数基本超过0.7),但前者计算效率是后者的3～5倍,表明WCA2D能够耦合SWMM且计算效率更高,为复杂城市化地区暴雨洪涝快速模拟提供了一种新方法。     

Up-to-date urban rainstorm intensity formulas considering spatial diversity in China

With accelerating urbanization in China, urban waterlogging has had a serious impact on urban sustainable development and citizen welfare. Simple urban rainstorm intensity formulas with a monotonous frequency distribution type cannot meet the practical needs of urban drainage planning and design. This study focuses on the development of urban rainstorm intensity formulas based on spatial diversity in China. Using the annual maximum sampling method, rainstorm data of 607 cities throughout China were collected into a database, with a total of 24,933 rainfall samples (annual observations) under various specified precipitation durations. The database was used to verify that integrating the Pearson III and Gumbel distributions would constitute an optimal theoretical distribution type, owing to its small error and increased fitting precision. Modification and coordination of four important parameters in the rainstorm intensity formula were done using a digital elevation model, which improved the accuracy of the formula. In addition, precipitation distributions in China were treated from the perspective of topographic features to validate the calculations from up-to-date formulas. Accuracy assessment was accomplished using a national code (GB-50014-2006), GIS-based isograms, and authoritative results from the Hydrological Bureau of the Ministry of Water Resources. This work provides a comprehensive foundation for the establishment of an up-to-date rainstorm intensity formula for China, which can be used widely in different cities.     

城市暴雨内涝数学模型的研究与应用

以城市地表与明渠、河道水流运动为主要模拟对象,研制了模拟城市暴雨内涝积水的数学模型。模型以平面二维非恒定流的基本方程和无结构不规则网格划分技术为骨架,同时,针对小于离散网格尺度的河道或明渠,应用了一维非恒定流方程的算法。采用分类简化处理的方法,将通道分为河道型、路面型、特殊通道型(城市内的二级河道),根据不同类型简化动量方程,求任意网格各个通道上的单宽流量。采用一维非恒定流方程模拟地下排水管网内的水流,并给出泵站、闸门、淹没出流管道等排水系统的处理方法。根据无结构不规则网格的设计思路,按照天津、南京、南昌三市的地形地貌特征分别设计多边形的计算网格。介绍了城市面雨量的计算方法以及数学模型在天津市、南京市、南昌市的应用情况和误差分析。     

设计暴雨雨型对城市内涝影响数值模拟

为分析设计暴雨雨型对城市内涝的影响,应用耦合了水文和水动力过程的数值模型,以陕西省西咸新区为研究区域,对不同重现期及峰值比例设计暴雨条件下的内涝过程进行模拟,并对内涝积水总量、不同积水深度内涝面积等量值进行对比分析。结果表明:设计暴雨重现期短于20年时,峰值比例较小的设计暴雨内涝积水总量较大,而重现期长于20年时,规律相反;除2年一遇设计暴雨外,峰值比例较大的设计暴雨致涝总面积较大,但其中影响严重的Ⅳ级致涝面积较小;设计暴雨峰值比例越小,重现期越长,积水总量峰值时刻相对于暴雨峰值时刻的迟滞时间越长。揭示了暴雨雨型与内涝积水程度的量化规律,对更合理地开展城市雨洪管理工作具有指导意义。     

城市公园污水生态化处理方法和模式研究

分析城市公园污水特点,从有利于保护生态环境、地下水资源和节约成本的角度,分析了适合我国城市公园污水生态化处理的方法以及处理模式,最后对我国今后城市公园污水处理系统建设提出建议.     

Food consumption expenditure pattern of urban households in Bangladesh

Summary The technically recoverable hydrocarbon reserves of the North Sea are currently estimated at 23 × 10⁹ bbls of oil, condensate and NGL and 90 × 10¹² scf of gas.The North Sea underwent a complex geological evolution. The oil and gas occurrences in the central and northern North Sea are tied to Mesozoic and Tertiary sediments; the gas fields of the southern North Sea are mainly contained in Permian series.The proven hydrocarbon provinces cover at best one third of the total area of the North Sea.It is estimated that in the early 1980's the oil production from the North Sea will meet 22% of the oil demand of Western Europe.

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Zusammenfassung Die technisch ausbeutbaren Kohlenwasserstoffreserven der Nordsee werden gegenwärtig auf 23 × 10⁹ bbls Öl, Kondensat und NGL 90 × 10¹² scf Gas geschätzt.Das Nordseegebiet durchlief eine komplexe geologische Entwicklungsgeschichte. Die Öl- und Gasfelder der zentralen und nördlichen Nordsee sind hauptsächlich and mesozoische und tertiäre Sedimente gebunden. Die Gasfelder der südlichen Nordsee sind hauptsächlich in permischen Serien enthalten.Die nachgewiesenen Kohlenwasserstoffprovinzen bedecken höchstens ein Drittel der Gesamtoberfläche der Nordsee.Es wird angenommen, da die Ölproduktion der Nordsee während der ersten Hälfte der 1980er Jahre 22 % des Ölbedarfs von West-Europa decken wird.

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Résumé Les réserves exploitables de la mer du Nord sont actuellement estimées 23 × 10⁹ bbl de pétrole, condensat et NGL et 90 × 10¹² scf de gaz.L'évolution géologique du bassin de la mer du Nord est très complèxe. Les champs de pétrole et de gaz des parties centrales et septentrionales de la mer du Nord se trouvent surtout dans des séries mésozoiques et tertiaires, tandis que la majorité des champs de gaz des régions méridionales sont situés dans des réservoirs permiens.Les provincespetrolfières connues couvrent moins d'un tiers de la surface totale de la mer du Nord.La production de pétrole de la mer du Nord est estimée correspondre pour les premirès années de 1980 à 22 % de la demande en pétrole de l'Europe occidentale.

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Abbreviations scf standard cubic feet (atmospheric conditions at 15° C) - TCF 10¹² scf - bbls barrels - NGL Natural Gas Liquids     

城市下垫面空间格局对社区尺度内涝过程的影响模拟

为研究城市下垫面空间格局对社区尺度内涝过程的影响, 构建社区尺度下的8种不同城市下垫面空间格局, 并建立相应的城市内涝数值模型, 模拟6种不同重现期(2 a, 5 a, 10 a, 20 a, 50 a, 100 a)设计降雨条件下内涝过程; 基于不同下垫面和降雨情景下的内涝数值模拟结果, 分别从内涝淹没特征值、时空变化过程、水动力特性等方面开展分析。结果表明: ①城市下垫面空间格局对社区尺度内涝淹没特征值、淹没时空变化过程和内涝积水流速分布均有一定影响; ②设计降雨重现期为2 a、5 a、50 a和100 a时, 不同城市下垫面空间格局间的积水总量峰值、积水面积峰值、区域最大积水深差别显著, 重现期为10 a和20 a时, 无明显差别; ③内涝积水较大流速分布主要集中在道路交汇处, 在本研究构建的情景中, 最大流速的差值占比为31.9%;④在8种不同城市下垫面空间格局中, 环形放射型格局在应对内涝方面更具弹性。本研究可为城市下垫面空间管控和城市内涝形成机理研究提供科学参考。     

福建雨季暴雨及台风暴雨诱发地质灾害的研究

以1990～2006年发生地质灾害为例,运用实证研究法,通过天气、气候学的分析和数理统计处理,揭示了福建重度地质灾害和严重地质灾害的时空分布规律;给出了不同天气系统暴雨所致地质灾害的基础雨量与触发雨量;对比分析了雨季暴雨、台风暴雨诱发严重地质灾害的实例。研究表明,福建地质灾害以滑坡为主(80.5%),崩塌为次(15.5%),泥石流较少(4%)。时空分布特点6月份为高峰期,内陆的南平和三明是频发区,对应天气系统是雨季的梅雨锋;8月份为次峰期,沿海的漳州和泉州是频发区,对应天气系统是台风。地质灾害对暴雨的滞后期,雨季期长,台风期短,其基础雨量台风雨小于锋面雨,而临近触发雨量则相反,台风雨大于锋面雨。     

城市水环境承载能力研究

针对人类高强度活动区——城市水资源系统特点和存在的水环境问题,探讨城市水环境承载能力和水资源承载能力的概念及内涵;提出了计算城市水环境承载能力的"控制目标反推模型"(COIM模型),该模型主要包括:城市污染物排放量计算、控制断面径流量计算、控制断面水质指标计算、控制目标方程和城市水环境承载能力计算;以郑州市为应用范例,介绍城市水环境承载能力计算模型应用及水环境调控对策制定.     

Derivation of short-duration design rainfalls using daily rainfall statistics

Design rainfall intensity–frequency–duration data are a basic input to many water-related development projects. To derive design rainfalls, one needs long period of recorded rainfall data. Although daily rainfall data are generally widely available, short-duration rainfall data are scarce. For many urban applications, design rainfalls for much shorter durations are needed, which cannot be obtained directly from daily read rainfall data. This paper presents a simple approach that can be adopted to derive design rainfalls of short durations using daily rainfall data and other physio-climatic characteristics using a novel ‘index frequency combined with parameter regression technique’. This uses L moments to reduce the impacts of sampling variability in the analysis. Furthermore, this adopts generalised least squares regression to account for the inter-station correlation of the rainfall data in the analysis. The proposed method is applied to a pilot data set consisting of 203 rainfall stations across Australia. An independent Monte Carlo cross-validation test shows that the proposed method is capable of generating consistent and accurate design rainfall estimates from 6-min to 12-h duration. The developed technique can be adapted to other countries where there is a scarcity of short-duration rainfall data, but daily rainfall data are abundant.     

北京市区域成矿规律初步研究

根据成矿理论和我国成矿规律研究的最新成果,对北京市区域成矿规律进行了初步研究,划分出2个Ⅳ级成矿区和5个Ⅴ级成矿带(或矿集区),并对其成矿特征进行了总结,编制了区域成矿规律图,这项研究对提高本地区地质工作研究程度、确定已知矿区深部及外围的找矿方向提供了依据.     

An ensemble risk assessment model for urban rainstorm disasters based on random forest and deep belief nets: a case study of Nanjing,China

Natural Hazards - Effective management of rainstorm risk is essential for reducing regional rainstorm disaster risks and losses. In this paper, we discussed the influencing factors of urban...     

地铁隧道施工引起地层位移规律的探讨

目前对城市隧道开挖所引起的地表以下地层的位移规律的认识还很不充分，长期以来只有定性地认识。英国学者Mair等人（1993年）根据在黏土中的有限实测资料，基于预测地表位移的Peck公式，考虑了沉降槽宽度随深度变化，从而提出了地表以下的位移计算公式。他们的研究成果被广泛引用，但是由于其仅适用于黏性土，且假定地表处沉降槽宽度参数为0.5，因此在应用上受到很大的限制。在Mair公式的基础上，着重讨论了沉降槽宽度参数随地层深度的变化趋势，并提出了修正计算公式，不仅可以考虑地表沉降槽宽度参数与0.5相差较大的情况，还适用于砂类土地层，因此比Mair公式具有更广泛的适用性。     

植被对台风暴雨型滑坡发育的促进作用

植被在世界各地被广泛用于防止滑坡,但在我国东南沿海的台风季节,植被覆盖较好的地区受台风暴雨诱发常有大量滑坡发生。为了研究台风暴雨条件下植被对滑坡发育的促进作用,通过风洞物理模拟实验研究了风荷载和植被摇曳对滑坡稳定性的影响。结果表明: 台风通过植被对边坡施加的荷载不容忽视,在超强台风条件下(风速≥17 m/s),风荷载可使潜在滑坡体的下滑力增加10%以上; 由于台风的风荷载,植被会通过根部对土壤施加强大的扭矩,导致土壤出现裂缝,这些裂缝为雨水渗透提供了快速通道,土壤的渗透系数会增加10倍以上。因此在东南沿海地区的台风季节,应注意植被、特别是高大乔木对滑坡稳定性的不利影响。     

岳城水库控制流域暴雨洪水的时程分布规律及分期划分研究

从两个方面全面分析了岳城水库控制流域的暴雨洪水时程分布及分期规律:一是根据实测水文资料,通过统计暴雨日数,典型历时年最大降水量、年最大洪峰流量和5日洪量在各旬出现的频率,对流域暴雨洪水时程分布特性进行了多方面的综合分析;二是通过对流域所处地区暴雨形成的天气成因分析,为前述的统计分析结果提供必要的成因基础.还利用旬平均降雨量的相对系数来确定汛期的起止时间.分析结果表明,岳城水库控制流域的暴雨洪水时程分布具有比较明显的变化规律,其中有一个时期暴雨洪水出现的次数多、量级大,主汛期特征显著,汛期可以划分为3个分期,即前汛期、主汛期和后汛期.