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Research on unmanned swarm scheduling strategies for mountain obstacle-breaching missions 认领 引用
1
作者 WANG Kaisheng HUANG Yanyan +1 位作者 TAN Jinxi ZHAI Wenjie 《Journal of Systems Engineering and Electronics》 SCIE CSCD 2026年第1期26-35,共10页
In response to the challenges faced by unmanned swarms in mountain obstacle-breaching missions within complex terrains,such as poor task-resource coupling,lengthy solution generation times,and poor inter-platform coll... In response to the challenges faced by unmanned swarms in mountain obstacle-breaching missions within complex terrains,such as poor task-resource coupling,lengthy solution generation times,and poor inter-platform collaboration,an unmanned swarm scheduling strategy tailored is proposed for mountain obstacle-breaching missions.Initially,by formalizing the descriptions of obstacle breaching operations,the swarm,and obstacle targets,an optimization model is constructed with the objectives of expected global benefit,timeliness,and task completion degree.A meta-task decomposition and reassembly strategy is then introduced to more precisely match the capabilities of unmanned platforms with task requirements.Additionally,a meta-task decomposition optimization model and a meta-task allocation operator are incorporated to achieve efficient allocation of swarm resources and collaborative scheduling.Simulation results demonstrate that the model can accurately generate reasonable and feasible obstacle breaching execution plans for unmanned swarms based on specific task requirements and environmental conditions.Moreover,compared to conventional strategies,the proposed strategy enhances task completion degree and expected returns while reducing the execution time of the plans. 展开更多
关键词 mountain obstacle breaching unmanned swarm task scheduling meta-task
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Impact of seepage on the breaching of non-cohesive landslide dams with different grain size distributions 认领 引用
2
作者 QIN Tao YANG Xingguo +2 位作者 ZHOU Jiawen XIANG Shenghao LIAO Haimei 《Journal of Mountain Science》 SCIE CSCD 2026年第2期706-722,共17页
Landslide dams often undergo seepage due to poor particle gradation and loose structure,yet most existing studies focus solely on overtopping-induced breaching mechanisms,neglecting the potential influence of pre-brea... Landslide dams often undergo seepage due to poor particle gradation and loose structure,yet most existing studies focus solely on overtopping-induced breaching mechanisms,neglecting the potential influence of pre-breaching seepage.Seepage may alter the dam's erodibility,structural stability,and material composition,thereby affecting the overtopping breaching process.Through flume experiments,this study investigates the breaching mechanisms of cohesionless landslide dams with different gradations within the same particle size range under coupled seepage-overtopping conditions.The results demonstrate that pre-breaching seepage significantly impacts breaching dynamics.Within a specific particle size range,compared to pure overtopping,seepage reduces downstream slope stability,increases material erodibility,shortens breaching duration,amplifies peak discharge,and advances the timing of peak flow.As the median particle size(D50)increases,the amplification effect of seepage on peak discharge initially increases then decreases,the advancement of peak flow timing diminishes,and the breach erosion rate declines.When D50is sufficiently large,seepage has negligible effects on breach development.For smaller D50,seepage markedly accelerates breach widening and deepening.Furthermore,coupled seepage-overtopping extends the downstream deposition area and exacerbates channel erosion due to differences in sediment sorting.These findings highlight the critical role of seepage in landslide dam breaching,providing a scientific basis for hazard prevention and mitigation. 展开更多
关键词 Seepage Non-cohesive landslide dams Particle size distribution Breaching mechanisms Dam failure
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Modeling of breaching parameters for debris flow dams 认领 引用
3
作者 RUAN He-chun CHEN Hua-yong +8 位作者 CHEN Xiao-qing ZHAO Wan-yu CHEN Jian-gang WANG Tao JIANG Yao Wang Xi-an Li Xiang-ning LI Xiao YU Yun-han 《Journal of Mountain Science》 SCIE CSCD 2023年第10期2835-2851,共17页
The debris flow dam is a common type of barrier dams,which shows significant differences from other types of barrier dam such as landslide dam,moraine dam in their formation processes,dam body shapes,and internal comp... The debris flow dam is a common type of barrier dams,which shows significant differences from other types of barrier dam such as landslide dam,moraine dam in their formation processes,dam body shapes,and internal compositions.The basic breaching parameters such as flood peak discharge are vital indicators of risk assessment.In this study,we elucidated the failure process of the debris flow dam through the flume experiment,and built the calculation equation of the breaching parameters by selecting critical factors.The result shows that the overtopping failure process of the debris flow dam is capable of forming significantly retrogressive scarps,and the failure process experiences three stages,the formation of the retrogressive scarp,the erosion of the retrogressive scarp,and the decline of the retrogressive scarp.Five factors used for establishing the calculation equations for peak discharge(Qp),final width(Wb)of the breach,and duration(T)of the debris flow dam failure are dam height(h),reservoir capacity(V),the fine grain content(P0.075)of the soil,the nonuniformity coefficient(Cu)of the soil,and the upper limit grain size(D90)of the soil,respectively.In the three equations,the correlation coefficients between Qp,Wb,T and the five factors were 0.86,0.70,0.63,respectively.The equations still need to be modified and verified in actual cases. 展开更多
关键词 Debris flow dams Overtopping failure Breaching g parameters Peak discharge Flume experiment
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Empirical Research on Farmer's Breaching Behavior in Order Contract 认领 引用 被引量：1
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作者 Guifang CHAO Mojing CHEN Xinxin DING 《Asian Agricultural Research》 2016年第12期43-47,共5页
In " leading enterprise + farmer" cooperation model,farmer's behavior of breaching contract exists generally. In this paper,from the angle of incomplete contract,the influencial factors of farmer breakin... In " leading enterprise + farmer" cooperation model,farmer's behavior of breaching contract exists generally. In this paper,from the angle of incomplete contract,the influencial factors of farmer breaking contract are analyzed. It is found that farmer sex,age,culture degree and farming period have obvious effects on the behavior of breaching contract. Under regulating effect of relationship quality,farmer assest specificity,exogenous uncertainty and endogenous uncertainty affect farmer's breaking behavior. That is,the higher the farmer assest specificity,the lower the farmer breaching tendency; higher exogenous uncertainty causes that farmer is easy to generate breaching behavior; higher endogenous uncertainty causes that farmer is also easy to take breaching behavior. 展开更多
关键词 Farmer breaching Relationship quality Assest specificity Uncertainty
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Experimental investigation on breaching of embankments 认领 引用 被引量：19
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作者 ZHU YongHui VISSER P J +1 位作者 VRIJLING J K WANG GuangQian 《Science China(Technological Sciences)》 SCIE EI CAS 2011年第1期148-155,共8页
Breaching of embankments has recently drawn more and more attention due to its importance in the development of early warning systems for embankment failures,in the evacuation plans of people at risk,in the design met... Breaching of embankments has recently drawn more and more attention due to its importance in the development of early warning systems for embankment failures,in the evacuation plans of people at risk,in the design method of embankments based on a risk-approach,etc. The erosion process observed during embankment breaching tests in the laboratory and the analysis of the results are described in this paper. Five embankments,one constructed with pure sand,four with different sand-silt-clay mixtures were tested. The height of the embankments was 75 cm and the width at the crest was 60 cm. Examination of the data from these tests indicated that headcut erosion played an important role in the process of breach growth in the embankments made of cohesive soil mixtures. Flow shear erosion,fluidization of the headcut slope surface,undermining of the headcut due to impinging jet scour and discrete soil mechanical slope mass failure from the headcut were all observed during these tests. For the embankment constructed with pure sand,the breach erosion process was dominated by shear erosion,which led to a gradual and relatively uniform retreat of the downstream slope. The cohesive proportion in the sand-silt-clay mixtures strongly slowed down the erosion process. 展开更多
关键词 embankments breaching experiments headcut erosion
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Failure mechanisms of landslide dams with different materials:laboratory experiment and physical analysis 认领 引用
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作者 Shenggong Guan Ruile Lin +4 位作者 Zhenming Shi Ming Peng Qi Liang Hongchao Zheng Zhen Wang 《Earthquake Research Advances》 CAS CSCD 2026年第2期28-42,共15页
China's southwestern region is characterised by active geological structures and frequent seismic activities.These conditions frequently trigger landslides that obstruct rivers and form landslide dams.The failure ... China's southwestern region is characterised by active geological structures and frequent seismic activities.These conditions frequently trigger landslides that obstruct rivers and form landslide dams.The failure of these dams represents a significant threat to downstream populations,as exemplified by the breach of the Tangjiashan landslide dam during the Wenchuan earthquake.This study focuses on the overtopping breach type of landslide dams.It conducts large-scale experiments to investigate the impacts of various grading materials on the breach process.Furthermore,the DABA(Dam Breach Analysis)numerical simulation model is employed to conduct an in-depth analysis of the breach process in landslide dams.Based on the experimental and simulated results,the following characteristics of landslide dam breaches were analyzed.Under identical inflowing conditions,the peak discharge of the fine-grained dam is 1.6 times that of the widely-graded dam,which has a significantly higher susceptibility to breaching.Although both dams failed due to overtopping,their erosion mechanisms differed substantially.For the widely graded dam,coarse particles led to scouring and retrogressive erosion,significantly prolonging the breaching process.In contrast,the fine-grained dam primarily failed through layered scouring.The results show a high degree of consistency between the DABA numerical simulation outcomes and the large-scale experiment data,thus validating the model's reliability.The parameter sensitivity analysis revealed that breach development duration and peak discharge were significantly influenced by dam height,dam crest width,and initial water level.Scientific simulation models can more precisely predict the breach time and impact range of landslide dams,aiding in the development of more effective prevention methods. 展开更多
关键词 Landslide dams Failure mode Grading materials Breach mechanism Physical simulation
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Influence of material characteristics on the failure mode and process of landslide dam 认领 引用
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作者 HU Liang ZHONG Qiming +3 位作者 CHEN Liang YANG Meng ZHANG Lucheng WU Hao 《Journal of Mountain Science》 SCIE CSCD 2025年第1期89-109,共21页
Landslide dams,as frequent natural hazards,pose significant risks to human lives,property,and ecological environments.The grading characteristics and density of dam materials play a crucial role in determining the sta... Landslide dams,as frequent natural hazards,pose significant risks to human lives,property,and ecological environments.The grading characteristics and density of dam materials play a crucial role in determining the stability of landslide dams and the potential for dam breaches.To explore the failure mechanisms and evolutionary processes of landslide dams with varying soil properties,this study conducted a series of flume experiments,considering different grain compositions and material densities.The results demonstrated that grading characteristics significantly influence landslide dam stability,affecting failure patterns,breach processes,and final breach morphologies.Fine-graded materials exhibited a sequence of surface erosion,head-cut erosion,and subsequent surface erosion during the breach process,while well-graded materials typically experienced head-cut erosion followed by surface erosion.In coarse-graded dams,the high permeability of coarse particles allowed the dam to remain stable,as inflows matched outflows.The dam breach model experiments also showed that increasing material density effectively delayed the breach and reduced peak breach flow discharge.Furthermore,higher fine particle content led to a reduction in the residual dam height and the base slope of the final breach profile,although the relationship between peak breach discharge and the content of fine and coarse particles was nonlinear.To better understand breach morphology evolution under different soil characteristics and hydraulic conditions,three key points were identified—erosion point,control point,and scouring point.This study,by examining the evolution of failure patterns,breach processes,and breach flow discharges under various grading and density conditions,offers valuable insights into the mechanisms behind landslide dam failures. 展开更多
关键词 Landslide dams Overtopping Grain size distribution Breaching process Outflow discharge
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Overtopping breaching of cohesive homogeneous earth dam with different cohesive strength 认领 引用 被引量：37
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作者 ZHANG JianYun LI Yun +2 位作者 XUAN GuoXiang WANG XiaoGang LI Jun 《Science China(Technological Sciences)》 EI CAS 2009年第10期3024-3029,共6页
In consideration of the range of clay content of Chinese earth dams, the world's highest prototype tests have been made to research on the effects of cohesive strength of filling of cohesive homogeneous earth dam ... In consideration of the range of clay content of Chinese earth dams, the world's highest prototype tests have been made to research on the effects of cohesive strength of filling of cohesive homogeneous earth dam on breach formation. Three breach mechanisms were presented, they were the source-tracing erosion of dam body with the form of "multilevel headcut", "two-helix flow" erosion of dam crest and collapse of breach sidewalls due to instability. It can be concluded that the cohesive strength of filling of earth dam has great effect on breach formation. When the cohesive strength is bigger, the breach process becomes slower, and the peak outflow and the final width and depth of breach become smaller. The main character of the breach formation is head cutting and dumping collapse. When the cohesive strength is smaller, the breach process becomes faster, and the peak outflow, the final width and depth of breach become bigger. The main character of the breach formation is single level head cutting and shearing collapse. 展开更多
关键词 earth dam breach mechanism headcut two-helix flow
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基于DL Breach模型的堰塞湖溃决洪水分析 认领 引用
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作者 周兴波 王双敬 +1 位作者 杨子儒 杨晟 《水利水电科技进展》 CSCD 北大核心 2025年第1期68-72,78,共5页
为了高效精准地分析预测堰塞湖溃决洪水,回顾了DL Breach模型的基本原理,反演分析了唐家山堰塞湖溃决洪水流量过程,并与实测流量过程作对比。结果表明DL Breach模型具有可靠性和稳定性,利用该模型计算得出的唐家山堰塞湖溃口流量过程与... 为了高效精准地分析预测堰塞湖溃决洪水,回顾了DL Breach模型的基本原理,反演分析了唐家山堰塞湖溃决洪水流量过程,并与实测流量过程作对比。结果表明DL Breach模型具有可靠性和稳定性,利用该模型计算得出的唐家山堰塞湖溃口流量过程与实测流量过程较为接近,溃口峰值流量计算值为7 323 m3/s,较实测值6 500 m3/s误差约为11.2%,峰值出现时间计算值较实测值提前近1 h,主要是由于唐家山堰塞湖溃口的小石梁提升了堰塞体的抗冲刷能力。此外,坝体材料粒径增大会降低峰值流量;而黏聚力、上游坡比及初始溃口深度增大会降低溃口底高程,对峰值流量的影响较小。 展开更多
关键词 防洪工程 堰塞湖 溃决洪水 洪峰流量 DL Breach模型
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Influence of breach parameter models on hazard classification of off-stream reservoirs 认领 引用
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作者 Nathalia Silva-Cancino Fernando Salazar +1 位作者 Ernest Bladé Marcos Sanz-Ramos 《Water Science and Engineering》 EI CAS CSCD 2025年第1期102-114,共13页
The classification of dams or off-stream reservoirs concerning potential hazards in the event of failure often involves the use of two-dimensional hydraulic models for computing floodwave effects.These models necessit... The classification of dams or off-stream reservoirs concerning potential hazards in the event of failure often involves the use of two-dimensional hydraulic models for computing floodwave effects.These models necessitate defining breach geometry and formation time,for which various parametric models have been proposed.These models yield different values for average breach width,time of failure,and consequently,peak flows,as demonstrated by several researchers.This study analyzed the effect of selecting a breach parametric model on the hydraulic variables,potential damages,and hazard classification of structures.Three common parametric models were compared using a set of synthetic cases and a real off-stream reservoir.Results indicated significant effects of model choice.Material erodibility exerted a significant impact,surpassing that of failure mode.Other factors,such as the Manning coefficient,significantly affected the results.Utilizing an inadequate model or lacking information on dike material can lead to overly conservative or underestimated outcomes,thereby affecting hazard classification. 展开更多
关键词 Dam breach Off-stream reservoir Hazard classification Flooding Potential damages
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Assembly and comparative analysis of the complete mitochondrial genome of Yulania liliiflora:an ornamental plant with high medicinal value 认领 引用
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作者 Yunhan Chen Wei Liu +1 位作者 Jing Qiu Changwei Bi 《Ornamental Plant Research》 2025年第1期267-277,共11页
Yulania liliiflora is a highly exploitable plant with medicinal value from its flower buds,leaves,and bark.The species,as an ornamental plant,has significant implications for the phylogeny of land plants and offers pr... Yulania liliiflora is a highly exploitable plant with medicinal value from its flower buds,leaves,and bark.The species,as an ornamental plant,has significant implications for the phylogeny of land plants and offers promising prospects for scientific research.In this study,the Y.liliiflora mitochondrial genome(mitogenome)was assembled into a breach linear chromosome using PacBio HiFi sequencing,with a length of 865,191 bp and a GC content of 46.95%.A total of 69 genes were identified in the Y.liliiflora mitogenome.The Y.liliiflora mitogenome contains 65 unique genes,including 41 protein-coding genes,21 tRNA genes,and three rRNA genes.Numerous repetitive sequences have been discovered,revealing the recombination events and the reason for the bigger mitogenome of Y.liliiflora.Many mitochondrial plastid sequences were found,with 12 complete chloroplast genes encompassed in these homologous fragments.Mitogenome from other Magnoliids were also used for collinearity comparison,which suggests a high recombination rate between Y.liliiflora and Magnoliids.Analysis of phylogeny has demonstrated that Y.liliiflora had the strongest genetic relation to Magnolia biondii of the Magnoliaceae,and Magnoliids emerged as a sister group to the clade encompassing monocots and eudicots.The results presented in this paper improve the understanding of the existing genetic knowledge of the genus Yulania.Simultaneously,they offer a promising avenue for conducting more comprehensive genomic investigations of Y.liliiflora. 展开更多
关键词 mitochondrial genome mitogenome scientific researchin breach linear chromosome mitochondrial genome phylogeny land plants pacbio hifi sequencingwith yulania liliiflora phylogeny
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Monopolar Transurethral Resection of the Prostate: Evaluation of the Results in the Urology Department of the Sino-Guinean Friendship Hospital in Conakry (Guinea) 认领 引用
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作者 Thierno Amadou Oury Sow Mohamed Habiboullah Ova +5 位作者 Lahoumbo Ricardo Gnammi Mamadou Diawo Bah Thierno Mamadou Oury Diallo Ibrahima Bah Abdoulaye Bobo Diallo Oumar Raphiou Bah 《Open Journal of Urology》 2025年第2期27-33,共7页
Introduction: The therapeutic approach to benign prostatic hyperplasia (BPH) has evolved profoundly. Surgical treatment is reserved for complicated cases and the reference surgical technique is transurethral resection... Introduction: The therapeutic approach to benign prostatic hyperplasia (BPH) has evolved profoundly. Surgical treatment is reserved for complicated cases and the reference surgical technique is transurethral resection of the prostate (TURP). This work aims to study the epidemiological, clinical and therapeutic aspects of monopolar transurethral resection of the prostate in our department. Materials and Methods: We conducted a descriptive study with retrospective data collection over a 12-month period from November 1, 2023 to December 31, 2024. The urology unit, an integral part of the surgery department, of the Sino-Guinean Friendship Hospital in Conakry served as the setting for this study. It included 27 patients with benign prostatic hypertrophy treated surgically by monopolar transurethral resection and having a usable medical record. The parameters studied were epidemiological, clinics and therapeutic. Results: The mean age of the patients was 68.57 ± 5.7 years with extremes from 50 to 79 years. The peak frequency was observed between 70 and 79 years (48.15%). All our patients had lower urinary tract disorders, i.e. 100% of cases. On digital rectal examination, an increase in the volume of the prostate of benign appearance was observed in all cases. The mean prostate volume was 43.7 cc on ultrasound with extremes from 34 cc to 58 cc. The total PSA level was less than 4 ng/ml in the majority of cases. The postoperative course was generally uncomplicated (n = 26) with removal of the urinary catheter on the second postoperative day (D2). However, one peroperative complication was observed in one patient;it was a bladder breach, leading to the passage of glycine into the peritoneum. Conclusion: Transurethral resection of the prostate has reduced the length of hospital stay of our patients, as well as the comorbidities associated with the treatment. The complications associated with it are rare but potentially serious. Its performance requires in-depth mastery of the endoscopic anatomy of the lower urinary tract as well as technical operative expertise. 展开更多
关键词 RTUP Monopolar BPH Bladder Breach Conakry
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A framework of numerical simulation on moraine-dammed glacial lake outburst floods 认领 引用
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作者 ZHANG Xiujuan LIU Shiyin 《Journal of Arid Land》 SCIE CSCD 2015年第6期728-740,共13页
Glacial outburst floods（GLOFs） in alpine regions tend to be relatively complicated, multi-stage catastrophes, capable of causing significant geomorphologic changes in channel surroundings and posing severe threats t... Glacial outburst floods（GLOFs） in alpine regions tend to be relatively complicated, multi-stage catastrophes, capable of causing significant geomorphologic changes in channel surroundings and posing severe threats to infrastructure and the safety and livelihoods of human communities. GLOF disasters have been observed and potential hazards can be foreseen due to the newly formed glacial lakes or the expansion of existing ones in the Poiqu River Basin in Tibet, China. Here we presented a synthesis of GLOF-related studies including triggering mechanism（s）, dam breach modeling, and flood routing simulation that have been employed to reconstruct or forecast GLOF hydrographs. We provided a framework for probability-based GLOFs simulation and hazard mapping in the Poiqu River Basin according to available knowledge. We also discussed the uncertainties and challenges in the model chains, which may form the basis for further research. 展开更多
关键词 moraine-dammed glacial lakes glacial outburst floods dam breaching mechanisms dam-breach models flood routing models
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Addressing Soil Degradation and Flood Risk Decision Making in Levee Protected Agricultural Lands under Increasingly Variable Climate Conditions 认领 引用 被引量：3
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作者 Lois Wright Morton Kenneth R. Olson 《Journal of Environmental Protection》 2014年第12期1220-1234,共15页
Public and private levee systems may not be robust enough to address flooding risk to agriculture under changing climate conditions. Of concern are levee protected riverine bottomlands with intensive agricultural uses... Public and private levee systems may not be robust enough to address flooding risk to agriculture under changing climate conditions. Of concern are levee protected riverine bottomlands with intensive agricultural uses and diminished wetland systems that give resilience to floodplain hydrologic functions. In the United States natural and induced levee breaching has caused soil damage, loss of agricultural productivity, and public tension among agricultural landowners, urban residents, and environmental interests. Risk management and adaptive capacity of this humannatural system could be improved by assessments of 1) soil damage and 2) stakeholder values, fears, and knowledge about the riverine bottomland agroecosystem. 展开更多
关键词 Levee Breaching Soil Damage Climate Change Agriculture Stakeholder Values Agroecosystem Flooding
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Experimental investigation of p-section concrete beams under contact explosion and close-in explosion conditions 认领 引用 被引量：8
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作者 Zhen Li Yan Liu +2 位作者 Jun-bo Yan Wen-li Yu Feng-lei Huang 《Defence Technology（防务技术）》 SCIE EI CAS CSCD 2018年第5期540-549,共10页
This paper presents the results of an experimental investigation on explosive breaching of p-section concrete beams. Twenty three p-section concrete beams with a 100 cm length were tested. TNT charges were placed at t... This paper presents the results of an experimental investigation on explosive breaching of p-section concrete beams. Twenty three p-section concrete beams with a 100 cm length were tested. TNT charges were placed at three positions: contact detonation in the center, contact detonation above the web and close-in detonation in the center. The external and internal breach parameters of the panels were evaluated by measuring the diameter of the ejection crater, spalling crater and breach hole created by the charge detonation. The experimental results were compared to predict values obtained by the analytical models proposed by McVay, Morishita and Remennikov. A modified breach with crater limit line and breach without crater limit line were put forward based on the experimental results. The maximum cross-sectional destruction area ratio(MCDAR) values were used to evaluate the damage degree. The maximum value of MCDAR reached 0.331 corresponding to the C5 experimental condition, of which explosion occurred above the web. 展开更多
关键词 P-section concrete beam Contact explosion Close-in explosion Explosive breach
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BREACH模型与MIKE21模型在溃坝风险中的耦合分析 认领 引用 被引量：17
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作者 杨德玮 盛金保 +1 位作者 彭雪辉 何佳卓 《水利水运工程学报》 CSCD 北大核心 2016年第6期23-28,共6页
BREACH模型常用来模拟水库大坝漫顶及管涌溃坝模式并获取溃口流量与时间关系,MIKE21模型常用来模拟湖泊、河口、海湾等二维水动力学并获取洪泛区内洪水风险信息要素,两大模型耦合分析在保障水库大坝安全运行及风险管理方面发挥了积极作... BREACH模型常用来模拟水库大坝漫顶及管涌溃坝模式并获取溃口流量与时间关系,MIKE21模型常用来模拟湖泊、河口、海湾等二维水动力学并获取洪泛区内洪水风险信息要素,两大模型耦合分析在保障水库大坝安全运行及风险管理方面发挥了积极作用。以BREACH模型模拟溃口流量动态数据过程与溃口演变尺寸为基础,通过Arc GIS预处理地形文件、工程建筑物参数与水文数据,构建MIKE21二维水动力学模型并计算网格差值空间,利用Flow Model模块生成溃坝洪水模拟文件,采用判别溃口流量差值是否满足精度要求的迭代法来耦合两大模型,最终结合所要分析水库大坝的工程概况,计算不同风险情况下的水库大坝溃坝洪水淹没水深与范围,进而模拟溃坝洪水演进过程。该方法已成功应用于郑州常庄水库风险分析,结果表明,该方法能客观反映溃坝洪水行洪情况,使用方便,为水库大坝运行管理与应急处置提供了一定的技术支持。 展开更多
关键词 BREACH模型 MIKE21模型 溃坝风险 耦合分析
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Numerical modeling of earthen dam breach due to piping failure 认领 引用 被引量：8
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作者 Sheng-shui Chen Qi-ming Zhong Guang-ze Shen 《Water Science and Engineering》 EI CAS CSCD 2019年第3期169-178,共10页
Based on model tests of earthen dam breach due to piping failure, a numerical model was developed.A key difference from previous research is the assumption that the cross-section of the pipe channel is an arch, with a... Based on model tests of earthen dam breach due to piping failure, a numerical model was developed.A key difference from previous research is the assumption that the cross-section of the pipe channel is an arch, with a rectangle at the bottom and a semicircle at the top before the collapse of the pipe roof, rather than a rectangular or circular cross-section.A shear stress-based erosion rate formula was utilized, and the arched pipe tunnel was assumed to enlarge along its length and width until the overlying soil could no longer maintain stability.Orifice flow and open channel flow were adopted to calculate the breach flow discharge for pressure and free surface flows, respectively.The collapse of the pipe roof was determined by comparing the weight of the overlying soil and the cohesion of the soil on the two sidewalls of the pipe.After the collapse, overtopping failure dominated, and the limit equilibrium method was adopted to estimate the stability of the breach slope when the water flow overtopped.In addition, incomplete and base erosion, as well as one-and two-sided breaches were taken into account.The USDAARS-HERU model test P1, with detailed measured data, was used as a case study, and two artificially filled earthen dam failure cases were studied to verify the model.Feedback analysis demonstrates that the proposed model can provide satisfactory results for modeling the breach flow discharge and breach development process.Sensitivity analysis shows that the soil erodibility and initial piping position significantly affect the prediction of the breach flow discharge.Furthermore, a comparison with a well-known numerical model shows that the proposed model performs better than the NWS BREACH model. 展开更多
关键词 Earthen dam Piping failure Overtopping failure Breach flow Numerical modeling Sensitivity analysis
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A simplified physically-based breach model for a high concrete-faced rockfill dam:A case study 认领 引用 被引量：6
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作者 Qi-ming Zhong Sheng-shui Chen Zhao Deng 《Water Science and Engineering》 EI CAS CSCD 2018年第1期46-52,共7页
A simplified physically-based model was developed to simulate the breaching process of the Gouhou concrete-faced rockfill dam （CFRD）, which is the only breach case of a high CFRD in the world. Considering the dam he... A simplified physically-based model was developed to simulate the breaching process of the Gouhou concrete-faced rockfill dam （CFRD）, which is the only breach case of a high CFRD in the world. Considering the dam height, a hydraulic method was chosen to simulate the initial scour position on the downstream slope, with the steepening of the downstream slope taken into account; a headcut erosion formula was adopted to simulate the backward erosion as well. The moment equilibrium method was utilized to calculate the ultimate length of a concrete slab under its self-weight and water loads. The calculated results of the Gouhou CFRD breach case show that the proposed model provides reasonable peak breach flow, final breach width, and failure time, with relative errors less than 15% as compared with the measured data. Sensitivity studies show that the outputs of the proposed model are more or less sensitive to different parameters. Three typical parametric models were compared with the proposed model, and the comparison demonstrates that the proposed physically-based breach model performs better and provides more detailed results than the parametric models. 展开更多
关键词 Concrete-faced rockfill dam Physically-based breach model Parametric breach model Sensitivity analysis Gouhou CFRD
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两种溃坝模型在唐家山堰塞湖溃决模拟中的对比 认领 引用 被引量：22
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作者 李相南 陈祖煜 《水利水电科技进展》 CSCD 北大核心 2017年第2期20-26,共7页
基于唐家山堰塞坝溃决的实测数据,使用BREACH模型及中国水科院DB-IWHR模型,对唐家山堰塞坝溃决过程进行了反演分析,并对两种模型进行参数敏感性分析。研究结果表明:使用针对唐家山的参数,两种模型均可较好地反演唐家山溃决洪水的过程,BR... 基于唐家山堰塞坝溃决的实测数据,使用BREACH模型及中国水科院DB-IWHR模型,对唐家山堰塞坝溃决过程进行了反演分析,并对两种模型进行参数敏感性分析。研究结果表明:使用针对唐家山的参数,两种模型均可较好地反演唐家山溃决洪水的过程,BREACH模型的下游坡比和孔隙率是对结果影响比较敏感的输入参数;DB-IWHR模型在冲刷参数和下游水深计算两方面做了改善,较好地解决了这一问题;DB-IWHR提供了一个Excel格式的计算软件,数值分析稳定性好,使用简洁客观,可供类似堰塞湖应急处置时参考。 展开更多
关键词 堰塞湖 BREACH模型 DB-IWHR模型 溃坝洪水分析 唐家山
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The role of time preferences in contract breach:Evidence from Chinese poultry farmers participating in contract farming 认领 引用 被引量：2
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作者 HOU Jing ZHOU Li +1 位作者 Jennifer IFFT YING Rui-yao 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2023年第2期623-641,共19页
Farmers’contract breach behavior is cited as one of the major stumbling blocks in the sustainable expansion of contract farming in many developing countries.This paper examines farmers’contract breach decisions from... Farmers’contract breach behavior is cited as one of the major stumbling blocks in the sustainable expansion of contract farming in many developing countries.This paper examines farmers’contract breach decisions from the perspective of time preferences.The empirical analysis is based on a household survey and economic field experiments of poultry households participating in contract farming conducted in Jiangsu Province,China.A discounted utility model and a maximum likelihood technique are applied to estimate farmers’time preferences and the effect of time preferences on contract breach in the production and sales phases are explored with a bivariate probit model.The results show that,on average,the poultry farmers in the sample are generally present biased and impatient regarding future utility.The regression results show that farmers with a higher preference for the present and a higher discount rate are more likely to breach contracts,and time preferences play a greater role in the production phase than in the sales phase.When considering heterogeneity,specific investments and transaction costs promote contract stability only for farmers with a low degree of impatience.Moreover,compared with large-scale farmers,small-scale farmers’contract breach decisions are more significantly affected by their time preferences.These results have implications for contract stability policies and other issues that are impacted by the linking of behavioral preferences to agricultural decisions. 展开更多
关键词 time preferences contract breach contract farming economic field experiments China
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