共查询到17条相似文献，搜索用时 140 毫秒
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进行流域梯级水电站开发,对相邻两座同期建设的水电工程组成的梯级施工导流系统进行整体风险分析意义重大。基于风险分析理论,考虑梯级施工导流系统水文和水力的不确定性,建立了系统整体风险数学模型。在此基础上构建了不同洪水组合情况下的风险计算模型,并利用Monte-Carlo方法耦合主要风险因素进行模型求解。同时,针对洪水过程遭遇情况下的风险模型,通过引入起始时间差随机因素来计算下游导流系统施工洪水过程。工程实例分析证明,风险分析模型和方法是可靠、有效的,为流域梯级开发条件下施工导流标准选取及导流方案优选提供重要依据。 相似文献
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面向工程设计阶段,采用高拱坝施工动态仿真技术获取施工初-中期挡水度汛面貌数据,综合考虑水文、水力随机性因素,构建高拱坝施工初-中期导流风险模型,提出采用Monte Carlo方法耦合挡水度汛面貌数据和主要随机因素进行风险模型求解的方法。基于风险分析原理提出了导流洞设计的风险判别方法,给出导流洞尺寸设计优化的数学模型和具体步骤。通过金沙江上游某高拱坝工程案例分析的结果表明:所提风险模型及求解方法是适用的、有效的,该模型能够得到整个施工初-中期导流风险率,较为客观地反映高拱坝施工中期度汛可能存在的两种挡水情况,克服了初期导流风险模型的局限性;施工中期导流风险率随导流洞尺寸增大而减小,导流洞尺寸设计的可行方案集存在界限,即优化方案。研究成果可为高拱坝施工导流的风险决策和设计优化提供理论支撑。 相似文献
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岩土工程风险分析及应用综述 总被引：2，自引：0，他引：2
系统分析了岩土工程不确定性的根源及其分析方法,总结了降低不确定性的途径。系统评述了岩土参数随机场估计、随机变量描述方法以及模型不确定性研究。对几类典型岩土工程问题的风险分析方法、研究现状及其工程应用进行了总结。对目前岩土工程风险理论及其应用的前沿问题进行了研究和展望。研究指出岩土工程风险分析待研问题主要有：系统的风险源辨识方法包括风险源辨识的可视化研究,不确定性因子的合理描述研究,极限状态包括失效模式的仿真研究,不确定性计算包括应用信息融合技术数据挖掘技术研究,目标可靠度研究,风险转嫁风险交换的量化及风险跟踪的实施研究,风险的反分析研究等。展望岩土工程风险分析与应用：风险分析反映了对工程设计的综合性要求,表现了安全与经济的统一;定量风险分析作为决策工具或传统设计的补充,可给决策者提供更多的辅助评价信息,提高了结果的置信程度;但现在能描述的还只是“随机性的确定性模式”,工程师们只有使用“保守的”选择,以适应和弥补不完全的认识与有限的资料的条件。 相似文献
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针对复杂洪水灾害系统中随机、模糊、灰色等各种不确定性,结合洪水灾害风险管理广义熵智能分析的理论框架,以最大熵原理和属性区间识别理论为基础,建立了基于最大熵原理的洪水灾害风险属性区间识别模型(AIRM-POME),利用梯形模糊数和层次分析法相结合的方法确定评价指标权重,采用均化系数综合AIRM-POME计算得到的属性测度区间,由置信度准则和特征值公式对各评价单元进行危险、易损等级的评定和排序,并根据联合国对自然灾害风险的定义及其定量表达式给出风险等级。将模型应用到荆江分洪区洪水灾害风险分析中,实例研究表明,模型合理可靠,深层次地刻画了各种不确定性,是一种风险分析新方法,可推广应用到其他自然灾害的风险分析中。 相似文献
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分析梳理了防洪减灾风险、风险及其分析、风险管理和治理等概念,指出防洪减灾理念从20世纪早期的"控制洪水"到20世纪后期的"减小洪灾损失"再到21世纪初的"降低洪灾风险"的演变,与防洪减灾形势、社会公共管理水平等密切相关;防洪减灾风险源于洪水时空变化的不确定性、承灾体的不确定性和防灾减灾措施实际效果的不确定性等,需要根据具体问题做具体分析;防洪减灾风险管理指采取多方参与方式,在洪灾发展周期的不同阶段,针对多种不确定性,综合分析各种风险,力求做出相对科学的决策。在防洪减灾风险管理的研究和实践中,应重视有关人文因素及其不确定性、构建风险分析文化的重要性。 相似文献
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Risk analysis for flood-control structure under consideration of uncertainties in design flood 总被引：1，自引：0，他引：1
This study presents a risk analysis model to evaluate the failure risk for the flood-control structures in the Keelung River
due to the uncertainties in the hydrological and hydraulic analysis, including hydrologic, hydraulic, and geomorphologic uncertainty
factors. This study defines failure risk as the overtopping probability of the maximum water level exceeding the levee crown,
and the proposed risk analysis model integrates with the advanced first-order and second-moment (AFOSM) method to calculate the overtopping probability of levee system. The proposed model is used to evaluate the effects of the
freeboard and flood-diversion channel on the flood-control ability of the levees in the Keelung River, which were designed
based on the 3-day, 200-year design rainfall event. The numerical experiments indicate that the hydrologic uncertainty factors
have more effect on the estimated maximum water level than hydraulic and geomorphologic uncertainty factors. In addition,
the freeboard and the flood-diversion channel can effectively reduce the overtopping probability so as to significantly enhance
the flood-control capacity of the levee system in the Keelung River. Eventually, the proposed risk analysis successfully quantifies
the overtopping risk of the levee system under a scenario, the increase in the average 200-year rainfall amount due to climate
change, and the results could be useful when planning to upgrade the existing levee system. 相似文献
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Midstream of the Keelung River Basin in Northern Taiwan has become highly urbanized and densely populated area. Flood inundation
along riversides frequently occurred during typhoons or rainstorms. Three protection measures, including constructions of
high-level protection levees, a diversion channel, and a detention reservoir, were proposed for flood mitigation. The main
purpose of this study is to evaluate the flood mitigation performance of the three proposed structural measures by using combined
hydrologic analyses and hydraulic routings. A semi-distributed parallel-type linear reservoirs rainfall-runoff model was used
for estimating the surface runoff. Furthermore, a 1-D dynamic channel routing model was coupled with a two-dimensional inundation
model to simulate the hydraulic characteristics of river flooding and overland flow. Simulation results of flood stages, runoff
peak discharges, and inundation extent under design rainfall scenarios were chosen as the criteria for evaluation. The results
showed a diversion channel is superior to the other two measures for flood mitigation of the study area. After the process
of environmental impact assessment, a revised diversion channel approach has been approved for construction as the major structural
measure. 相似文献
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Steven B. Meyerhoff Reed M. Maxwell Wendy D. Graham John L. Williams III 《Hydrogeology Journal》2014,22(6):1329-1343
Subsurface heterogeneity is one of the largest sources of uncertainty associated with saturated hydraulic conductivity. Recent work has demonstrated that uncertainty in hydraulic conductivity can impart significant uncertainty in runoff generation processes and surface-water flow. Here, the role of site characterization in reducing hydrograph prediction bias and uncertainty is demonstrated. A fully integrated hydrologic model is used to conduct two sets of stochastic, transient simulation experiments comprising different overland flow mechanisms: Dunne and Hortonian. Conditioning hydraulic conductivity fields using values drawn from a simulated synthetic control case are shown to reduce both mean bias and variance in an ensemble of conditional hydrograph predictions when compared with the control case. The ensemble simulations show a greater reduction in uncertainty in the hydrographs for Hortonian flow. The conditional simulations predict surface ponding and surface pressure distributions with reduced mean error and reduced root mean square error compared with unconditional simulations. Uncertainty reduction in Hortonian and Dunne flow cases demonstrates different temporal signals, with more substantial reduction achieved for Hortonian flow. 相似文献
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Abderraouf El Ouazzani Taibi Amro Elfeki Guoping Zhang 《Arabian Journal of Geosciences》2011,4(5-6):1005-1018
The research presented in this paper focuses on the application of a newly developed physically based watershed modeling approach, which is called representative elementary watershed approach. The study stressed the effects of uncertainty of input parameters on the watershed responses (i.e., simulated discharges). The approach was applied to the Zwalm catchment, which is an agriculture-dominated watershed with a drainage area of 114 km2 located in East Flanders, Belgium. Uncertainty analysis of the model parameters is limited to the saturated hydraulic conductivity because of its high influence on the watershed hydrologic behavior and availability of the data. The assessment of output uncertainty is performed using the Monte Carlo method. The ensemble statistical watershed responses and their uncertainties are calculated and compared with measurements. The results show that the measured discharges fall within the 95% confidence interval of the modeled discharge. This provides the uncertainty bounds of the discharges that account for the uncertainty in saturated hydraulic conductivity. The methodology can be extended to address other uncertain parameters as far as the probability density function of the parameter is defined. 相似文献
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三峡工程大江截流水文泥沙监测规划 总被引：1，自引：0，他引：1
鉴于三峡工程大江截流是一项复杂的系统工程,具有水深大,流量大,抛投量大和截流期不断航等显著特点。水文泥沙监测作为其重要的组成部分,监测导流与截流过程中水流泥沙和水下地形的变化,为截流设计优化,调整施工方案与措施等提供科学的决策依据,同时也为导流明渠分流与通航,围堰度汛,截流水力学试验研究及水文预报,水文分析计算等提供水文原型观测资料。本文介绍了水文泥沙监测的目的、任务和水文数据采集,传输,处理与信 相似文献
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The role of heterogeneity and uncertainty in hydraulic conductivity on hillslope runoff production was evaluated using the fully integrated hydrologic model ParFlow. Simulations were generated using idealized high-resolution hillslopes configured both with a deep water table and a water table equal to the outlet to isolate surface and subsurface flow, respectively. Heterogeneous, correlated random fields were used to create spatial variability in the hydraulic conductivity. Ensembles, generated by multiple realizations of hydraulic conductivity, were used to evaluate how this uncertainty propagates to runoff. Ensemble averages were used to determine the effective runoff for a given hillslope as a function of rainfall rate and degree of subsurface heterogeneity. Cases where the water table is initialized at the outlet show runoff behavior with little sensitivity to variance in hydraulic conductivity. A technique is presented that explicitly interrogates individual realizations at every simulation timestep to partition overland and subsurface flow contributions. This hydrograph separation technique shows that the degree of heterogeneity can play a role in determining proportions of surface and subsurface flow, even when effective hillslope outflow is seen. This method is also used to evaluate current hydrograph separation techniques and demonstrates that recursive filters can accurately proportion overland and base-flow for certain cases. 相似文献
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降雨型浅层滑坡危险性预测模型 总被引：5，自引：0，他引：5
通过分析SHALSTAB和TRIGRS等浅层滑坡物理确定性模型存在的问题,提出了基于降雨入渗动态守恒的瞬态降雨入渗模型,该模型考虑了初期降雨过程、降雨历程以及饱和非饱和入渗过程,证明了SHALSTAB模型是该模型的特殊形式,并克服了TRIGRS模型参数繁多及一维入渗路径的问题.将无限边坡模型、瞬态降雨入渗模型和GIS进行耦合,研发了可用于大范围降雨型浅层滑坡危险性预测的集成系统,根据边坡的地质条件、地形参数和降雨特征即可对降雨条件下浅层滑坡的危险性进行评估. 相似文献