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river 2024年第3期3卷 272-283页

作者： Haokun Wei Xichao Gao Jie Feng Zhiyong Yang State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin China Institute of Water Resources and Hydropower ResearchBeijingChina Key Laboratory of River Basin Digital Twinning of Ministry of Water Resources BeijingChina

The escalation of compound extreme events has resulted in noteworthy economic and property *** the intricate interconnections among these events has become *** tackle this challenge,we have formulated a comprehensive framework for the systematic analysis of their *** framework consists of three steps.(1)Deﬁne extreme events using Mahalanobis distance thresholds.(2)Represent dependencies among multiple extreme events through a point process-based method.(3)Verify dependencies with residual tail coefﬁcients,determining theﬁnal dependency *** this framework to assess the extreme dependence of precipitation on wind speed and temperature in China,revealed four distinct dependency *** northern,Jianghuai,and southern China,precipitation heavily relies on wind speed,while tempera-tures maintain relative *** northeastern and northwestern China,precipitation exhibits relative independence,yet a notable dependence exists between temperatures and wind *** southwestern China,precipitation strongly depends on temperature,while wind speed remains relatively *** Qinghai–Tibet Plateau region displays a signiﬁcant dependence relationship among precipitation,wind speed,and temperature,with weaker dependence between extreme wind speed and *** framework is instrumental for analyzing dependencies among extreme values in compound events.

关键词： compound extremes events extremal dependency structure extreme precipitation extreme temperatures extreme value theory extreme wind speed

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Effects of logjams on river hydrodynamics under inundation conditions

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Journal of Hydrodynamics 2024年第4期36卷 757-771页

作者： Huai-jian Bao Ping Wang Wei-jie Wang Yu-yan Liu Tian-jiao Feng School of Soil and Water Conservation Beijing Forestry UniversityBeijing100091China State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin China Institute of Water Resources and Hydropower ResearchBeijing100048China

Large wood in rivers can lead to accumulations in the river channel, affecting local flow structures, aquatic habitats, and the river’s topography. This plays a crucial role in the ecological restoration of the river. This paper presents flow field measurements downstream of six types of logjams at different flow velocities using acoustic Doppler velocimetry (ADV) for artificially designed engineered logjams. The results indicate that the presence of logjams reduces the flow velocity and increases the turbulent kinetic energy in the wake region, and as the distance downstream increases, the flow velocity and turbulence intensity in the wake region gradually return to the upstream level. The minimum values of normalized flow velocity under different conditions are located in the region of the bottommost logs. The differences in normalized flow velocity at various flow rates are not significant. Jets are less likely to be generated in logjams with larger and more concentrated projection areas, but the strength of the jet is influenced by the physical structure of the logjam (projection area, gap ratio). The flow distribution behind the logjam is primarily influenced by the proportion of the projected area in different regions. Changes in the vertical physical structure of the logjam have minimal effect on the lateral flow distribution. Flow velocity in the gap area (b0) at the bottom of different logjams is influenced by their physical structure. The larger the overall blockage area of the logjams, the larger the flow velocity in the bottom gap area will be. The flow velocity in the bottom gap area of a densely placed logjam is mainly influenced by the gap ratio. The velocity of flow in the gap area can impact the initiation and deposition of sediment near the logjam. However, the internal structure complexity of the logjam does not significantly affect river energy dissipation and flow attenuation. This study broadens the applicability of certain theoretical models a

关键词： Open channel flow engineered logjams nonuniform logs flow structure river ecological restoration

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Coupling effect analysis of dam break flood spread and building collapse based on numerical simulation

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Science China(Technological Sciences) 2024年第11期67卷 3571-3584页

作者： SONG TianXu LIU JiaHong MEI Chao ZHANG MengXue WANG Hao NAZLI Sana State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin China Institute of Water Resources and Hydropower ResearchBeijing 100038China Key Laboratory of River Basin Digital Twinning of Ministry of Water Resources Beijing 100038China Engineering and Technology Research Center for Water Resources and Hydrogeology of the Ministry of Water Resources Beijing 100044China

Large-scale floods induced by dam failures could cause significant structural damage to buildings and massive loss of *** coupling effect of large-scale flood spread and building collapse has complex impacts on the entire flow field,affecting flood risk assessment and building vulnerability *** this paper,a dynamic elevation change model designed to seamlessly interface with a structural vulnerability assessment model to investigate the interaction effect between floods and buildings is *** efficiency of the framework was validated by reconstructing the Gleno Dam-Break flood in ***,a hydrodynamic model of the Jinsha-Yalong river that considers dynamic building collapse was *** proposed model was compared with two traditional building treatment approaches and one that ignored the *** results show that the interaction between the flood and buildings decreases the low-velocity area(below 1 m/s)by 7.44%-9.56%while increasing the high velocity area(above 4 m/s)by 10.71%-11.96%.Traditional and neglecting building treatments provide preliminary insights into densely built areas,and the latter could be an alternative for simplification because it can represent the worst-case *** collapse in response to large-scale floods typically occurs in four stages:flood spread,rapid expansion,gradual expansion,and flood *** analysis offers novel perspectives on flood prediction and simulations where the floodplain may contain *** method could be useful for assessing structural vulnerability associated with large building stocks and developing flood mitigation strategies in densely populated areas.

关键词： dam break flood risk structural vulnerability building collapse urban area

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A coordinated drainage and regulation model of urban water systems in China:A case study in Fuzhou city

River

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river 2023年第1期2卷 5-20页

作者： Hao Wang Xiaohui Lei Chao Wang Weihong Liao Aiqing Kang Haocheng Huang Xingchen Ding Yang Chen Xuelian Zhang State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin China Institute of Water Resources and Hydropower ResearchBeijingChina

Extreme climate and urbanization lead to frequent urban floods,and urban water system dispatching is an important means of urban flood control.A coupled model is proposed to simulate urban floods in real‐time and achieve comprehensive water system control for urban ***,the systematical description of coordinated drainage and regulation model of urban water systems in China is introduced,then the practice of Fuzhou city was taken as an example to introduce the prediction and forecast systems,as well as water system regulation for urban flood and waterlogging disaster in *** show that the root‐mean‐square error of river flood prediction is less than 0.3 and that the calculation time of waterlogging simulation is less than 10 min;the optimization regulation reduces the peak river water level by 31 *** study will establish a novel urban water system management model to help urban managers better reduce the loss caused by urban floods.

关键词： coordinated drainage and regulation model urban flood water system regulation

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Three-dimensional characterization of particle morphology in natural gravel and blasted rock fragments using SfM-MVS photogrammetry

River

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river 2025年第1期4卷 70-83页

作者： Hongchen Liu Zitao Zhang Huaizhi Su Xuedong Zhang Jing Hu The National Key Laboratory of Water Disaster Prevention Hohai UniversityNanjingChina State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin China Institute of Water Resources and Hydropower ResearchBeijingChina

This study aims to develop a high-precision and cost-efficient method for the threedimensional reconstruction of large particles in natural gravel and blasted rock fragments,utilizing Structure from Motion(SfM)and Multi-View Stereo(MVS)*** proposed approach was applied to characterize the three-dimensional morphology of rockfill dam materials at a real construction *** shape was quantitatively analyzed using shape indices of sphericity,convexity,and *** predominant morphology of natural gravel is characterized as slightly elongated and slightly flat,while rock fragments are slightly elongated and not *** density distributions of shape indices follow a skewed normal distribution:sphericity and convexity show leftward skewness,whereas angularity is *** parameters of sphericity and angularity are consistent between natural gravel and blasted rock fragments,indicating comparable shape *** skewness is significantly higher in natural gravel compared to rock fragments,by approximately an order of *** relationship between size and particle shape shows that form ratios and associated shape descriptors change linearly with the logarithm of size;larger particles approach spherical or cubic *** innovative measurements contribute to the particle shape data set of rockfill dam materials,providing valuable insights into the three-dimensional and statistical morphological characteristics of relatively large particles in natural gravel and blasted rock *** approach enhances understanding of particle morphology's impact on the mechanical behavior of granular materials.

关键词： 3D reconstruction angularity convexity particle morphology shape form

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Quantification of backwater effect in Jingjiang Reach due to confluence with Dongting Lake using a machine learning model

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water Science and Engineering 2025年第2期18卷 187-199页

作者： Shang, Hai-xin Xia, Jun-qiang Hu, Chun-hong Zhou, Mei-rong Deng, Shan-shan State Key Laboratory of Water Resources Engineering and Management Wuhan University Wuhan430072 China State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin China Institute of Water Resources and Hydropower Research Beijing100048 China

The backwater effect caused by tributary inflow can significantly elevate the water level profile upstream of a confluence point. However, the influence of mainstream and confluence discharges on the backwater effect in a river reach remains unclear. In this study, various hydrological data collected from the Jingjiang Reach of the Yangtze river in China were statistically analyzed to determine the backwater degree and range with three representative mainstream discharges. The results indicated that the backwater degree increased with mainstream discharge, and a positive relationship was observed between the runoff ratio and backwater degree at specific representative mainstream discharges. Following the operation of the Three Gorges Project, the backwater effect in the Jingjiang Reach diminished. For instance, mean backwater degrees for low, moderate, and high mainstream discharges were recorded as 0.83 m, 1.61 m, and 2.41 m during the period from 1990 to 2002, whereas these values decreased to 0.30 m, 0.95 m, and 2.08 m from 2009 to 2020. The backwater range extended upstream as mainstream discharge increased from 7 000 m3/s to 30 000 m3/s. Moreover, a random forest-based machine learning model was used to quantify the backwater effect with varying mainstream and confluence discharges, accounting for the impacts of mainstream discharge, confluence discharge, and channel degradation in the Jingjiang Reach. At the Jianli Hydrological Station, a decrease in mainstream discharge during flood seasons resulted in a 7%–15% increase in monthly mean backwater degree, while an increase in mainstream discharge during dry seasons led to a 1%–15% decrease in monthly mean backwater degree. Furthermore, increasing confluence discharge from Dongting Lake during June to July and September to November resulted in an 11%–42% increase in monthly mean backwater degree. Continuous channel degradation in the Jingjiang Reach contributed to a 6%–19% decrease in monthly mean backwater degr

关键词： Lakes

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Exploring impact of street layout on urban flood risk of people and vehicles under extreme rainfall based on numerical experiments

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Science China(Technological Sciences) 2023年第9期66卷 2561-2574页

作者： MEI Chao LIU JiaHong SHI HongYuan WANG Hao WANG Jia DONG LiRong SONG TianXu ZHANG HaiJia State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin China Institute of Water Resources and Hydropower ResearchBeijing 100038China Key Laboratory of River Basin Digital Twinning of Ministry of Water Resources(Preparation) Beijing 100038China Beijing Key Laboratory of Urban Water Cycle and Sponge City Technology Beijing Normal UniversityBeijing 100875China

Urban street layout is an important factor in the formation process, characteristics, and risk level of urban flooding;therefore, this study numerically investigates the impact of street layout on urban flood risk to people and vehicles. Four typical street-layout scenarios with areas of 3 km × 3 km are established based on a block-scale investigation. The layout types are regular grid,irregular grid, radial, and annular. Urban inundation models are then constructed for these typical street layouts based on the twodimensional(2D) hydrodynamic method. Two historic, extreme rainfall events, which occurred in Beijing on July 21, 2012 and in Zhengzhou on July 20, 2021, are used as rainstorm scenarios for urban inundation modelling. The flood risks to people and vehicles are then calculated. Results show that, for an extreme rainstorm on the block scale, the street layout impacts the spatial and temporal distributions of the inundation variables, which include the water depth, flow velocity, flood volume, and inundated area. Moreover, for the same extreme-rainfall scenario, the greatest differences in the total flood volume, maximum street-water depth, and maximum street-flow velocity caused by street-layout differences are 17.22%, 60.25%, and 61.50%, *** the four street layouts considered in this study, the annular street layout exhibits the lowest degrees of inundation and flood risk. For the same extreme-rainfall scenario, the proportions of high-risk road sections for adults and children in this layout are 58.89% and 62.28% smaller than those for the layout with the largest proportion of high-risk road sections, respectively;the proportions of high-risk road sections for the Honda Accord and Audi Q7 were 55.31% and 53.04% smaller, respectively. The findings of this study may aid scientific understanding and development of “flood-sensitive” block-scale street layouts and urban planning in the context of the changing environment.

关键词： urban inundation street layout urban form flood risk hydrodynamic simulation

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Enhancing deformation characteristics prediction of coarse-grained soils with time-series generative adversarial network-based data augmentation and pre-training

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Frontiers of Structural and Civil Engineering 2025年第3期19卷 396-410页

作者： Ying ZHANG Meng JIA Xuedong ZHANG Liping CAO Ziying AN Hongchao WANG Jinyu WANG School of Control and Computer Engineering North China Electric Power UniversityBeijing 102206China The State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin China Institute of Water Resources and Hydropower ResearchBeijing 100038China

Coarse-grained soils are fundamental to major infrastructures like embankments,roads,and *** their deformation characteristics is essential for ensuring structural *** methods,such as triaxial compression tests and numerical simulations,face challenges like high costs,time consumption,and limited generalizability across different soils and *** address these limitations,this study employs deep learning to predict the volumetric strain of coarse-grained soils as axial strain changes,aiming to obtain the axial strain(ε_(a))-volumetric strain(ε_(v))curve,which helps derive key mechanical parameters like cohesion(c),and elastic modulus(E).However,the limited data from triaxial tests poses challenges for training deep learning *** propose using a Time-series Generative Adversarial Network(TimeGAN)for data ***,we apply feature importance analysis to assess the quality of the numerical augmented data,providing feedback for improving the TimeGAN *** further enhance model performance,we introduce the pre-training strategy to reduce bias between augmented and real *** results demonstrate that our approach effectively predictscurve,with the mean absolute error(MAE)of 0.2219 and the R^(2) of *** analysis aligns with established findings in soil mechanics,underscoring the potential of our method in engineering applications.

关键词： coarse-grained soils deformation characteristics TimeGAN data augmentation pre-training

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Study on the motion characteristics of bedload sediment particles under different sediment transport intensities

River

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river 2024年第2期3卷 140-151页

作者： Chunjing Liu Lingfeng Zhang Yu Zhang Xiaopeng Jiang Fei Liu Leilei Gu Jing Lu State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin BeijingChina Key Laboratory of Sediment Science and Northern River Training of Ministry of Water Resources BeijingChina China Institute of Water Resources and Hydropower Research BeijingChina

Bedload studies at the particle scale may help grasp the essence of the *** studies suffer from short filming durations,limited data volume,and a narrow range of sediment transport intensity *** paper employs the high-speed photography technology and conducts experimental studies on bedload particle motion under 8 different sediment transport *** the latest image processing technology,over 6 million sediment particle coordinate points and nearly 400,000 particle motion trajectory curves were automatically obtained and used to compare the motion characteristics of bedload particles under different sediment transport *** results show that under low sediment transport intensity,both the number of moving particles and particle motion velocity contribute to the bedload sediment transport rate,while under high-intensity conditions,the transport rate mainly depends on the number of moving *** probability density distribution of sediment transport rate is concentrated and varies within a small range under low-intensity conditions,exhibiting a tailing *** contrast,under high-intensity conditions,the range of sediment transport rate values increases,and the probability density curve tends to be symmetric,more closely approximating a normal ***,the paper compares the longitudinal and transverse motion velocities of particles and the coefficient of variation of the bedload sediment transport rate.

关键词： bed load high-speed photography particle motion sediment transport rate

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Features and formulae of sediment incipient motion in vegetated flow environment

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Journal of Hydrodynamics 2024年第2期36卷 331-339页

作者： Yu-xuan Xu Wei-jie Wang Shi-bao Zhang Han-qing Zhao Xue-kai Chen Hai-ping Zhang School of Water Conservancy North China University of Water Resources and Electric PowerZhengzhou450045China State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin China Institute of Water Resources and Hydropower ResearchBeijing100038China China Three Gorges Corporation Wuhan430010China

Aquatic vegetation is a vital component of natural river ecosystems,playing a crucial role in maintaining ecological balance,providing habitat and improving water ***,the presence of vegetation results in increased resistance in vegetated channels compared with non-vegetated channels,rendering traditional sediment movement predictions inadequate for the ***,the concept of a vegetation influence factor,denoted by CDah,has been proposed by previous researchers to represent the effect of vegetation on sediment movement in *** this study,we focus on exploring the vegetation resistance coefficient(CD)among the vegetation influence factors,evaluating two different calculation methods for vegetation resistance coefficient,and presenting two expressions through genetic algorithm analysis to predict the incipient flow velocity of sediment in vegetated *** predicted values from the new formulae show excellent agreement with measured data,highlighting the high accuracy of the proposed methods in predicting the incipient flow velocity of *** results provide a solid theoretical basis for understanding the influence of aquatic vegetation on sediment particle movement.

关键词： Vegetation flow vegetation resistance coefficient genetic algorithm sediment initiation

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