共查询到18条相似文献，搜索用时 406 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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施工期导流动态风险不仅与水文不确定性、水力不确定性有关,而且与坝体施工进度及其完工工期的不确定性有关。以风险分析为核心,将各种不确定性因素耦合起来研究施工导流系统的综合风险,提出施工进度计划风险分析模型和假定坝体施工进度确定条件下的施工导流风险分析模型,在此基础上,建立基于Monte-Carlo方法全面考虑水文水力不确定性以及施工进度不确定性的施工导流系统综合风险分析模型。实例分析说明,该施工导流系统综合风险研究方法和分析模型是可靠的、适用的。 相似文献
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《岩土力学》2017,(2):507-516
高拱坝工程基础地质及地形条件的不对称是威胁拱坝安全的重要问题。以白鹤滩高拱坝作为工程实例,通过地质力学模型试验重点研究基础不对称的高拱坝应力、变形及破坏模式的特点。针对初始方案和改进后方案分别建立三维数值模型,并进行弹塑性有限元超载计算。对比分析两方案坝体变形、坝肩应力分布、局部和整体稳定性等的不同,并结合试验现象,分析和评价针对基础不对称性的改进措施的加固效果及加固机制。结果表明:体形不对称性设计及基础加固的协同作用能有效改善坝体变形对称性、坝肩应力状态和传力效果,并提高拱坝-地基系统的整体稳定性。白鹤滩拱坝不对称性问题的研究对深入高拱坝设计优化和工程加固的认识具有重要意义。 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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感潮河段的水位受上游河道洪水与下游河口潮位共同影响,故其河段整治规划中洪潮遭遇分析尤为重要。以瓯江感潮河段为研究区,提出从实测洪潮遭遇数据的频率结构特性出发,选取对上尾部更敏感的Gumbel Copula函数建立洪水和潮位的联合分布,推求各种洪潮组合的重现期,进而建立风险模型。从治涝风险、同现风险和组合风险多角度评估设计组合值的合理性。结果表明:基于Gumbel Copula函数构建的联合分布能够较好的反映瓯江感潮河段的洪潮组合特性。瓯江感潮河段部分现役工程所采用的20a一遇的设计洪水与较不利潮位(5.8m)这一设计组合型的同现重现期为29a,同现风险率为3.46%、组合风险率为11.52%、治涝风险率为15.94%,其防洪涝能力稍显不足。同时基于Copula函数所建立的风险模型集能够较好地对感潮河段防洪设计标准进行风险评估,为感潮河段整治规划提供决策支持。 相似文献
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现行推求设计潮位过程大多采用高潮位与潮差同频率放大的方法,未考虑到二者遭遇可能性的大小。采用G-H Copula函数建立了年最高潮位和相应潮差的二维联合分布模型,通过组合风险分析法研究了设计高潮位和设计潮差的组合风险率。以天津港多年实测资料计算分析为例,结果表明:较大重现期的高潮位和潮差同时发生的概率较小,50年一遇高潮位与50年一遇潮差组合的风险率仅为0.05%,同频率设计偏安全,可依据组合风险率适当降低潮差设计标准。所采用的联合分布模型及其应用,在定量分析基础上为设计潮位过程的推求提供了一种新方法。 相似文献
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分析洪峰、洪量和历时三变量联合分布与风险概率及其设计分位数,为水利工程规划设计和风险评估提供参考依据。以珠江流域西江高要站52年洪水数据为例,采用非对称阿基米德M6 Copula函数与Kendall分布函数计算三变量洪水联合分布的“或”重现期、“且”重现期和二次重现期及其最可能的设计分位数。结果表明:“或”重现期的风险率偏高,“且”重现期的风险率偏低,二次重现期更准确地反映了特定设计频率情况下三变量洪水要素遭遇的风险率;按三变量“或”重现期或三变量同频率设计值推算的洪水设计值偏高,以最大可能概率推算的三变量洪水要素的二次重现期设计值可为防洪工程安全与风险管理提供新的选择。 相似文献
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桩锚支挡体系在广西寨-任二级公路高边坡治理工程中的应用 总被引：3，自引：0，他引：3
(六)寨-(水)任二级公路施工后,滑坡、坍塌、崩塌现象甚多,边坡治理迫在眉睫。桩锚支挡体系是一项主动性加固边坡技术,具结构轻巧、用材合理、施工简单、工期短、费用低等特点。论文通过其在(六)寨-(水)任二级公路K56段高边坡治理工程中的应用,对桩锚支挡体系的设计及施工要点作了介绍。 相似文献
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Risk assessment and mitigation for the Hongshiyan landslide dam triggered by the 2014 Ludian earthquake in Yunnan,China 总被引：1，自引：0，他引：1
Z. M. Shi X. Xiong Ming Peng L. M. Zhang Y. F. Xiong H. X. Chen Y. Zhu 《Landslides》2017,14(1):269-285
An Ms 6.5 earthquake shocked the Ludian County, Yunnan Province, China, on 3 August 2014 and triggered the Hongshiyan landslide dam. The dam, with a height of 83 m and a lake capacity of 260?×?106 m3, threatened more than 10,000 people. A unique feature of this landslide dam was that it formed between a man-made dam and a hydropower plant. An existing drainage tunnel connecting the lake and the hydropower plant became a natural drainage conduit for the landslide dam, which played an important role in the mitigation of the landslide dam risks. This paper reports a quantitative risk assessment for the Hongshiyan landslide dam considering both engineering and non-engineering risk mitigation measures. The risk assessment is divided into three stages according to the implementation of two engineering measures: construction of a diversion channel and excavation of a branch drainage tunnel. The dam breaching hydrographs, flood zones, population at risk, and likely fatalities in each of the three stages are analysed. The optimum evacuation strategy in each stage is also studied based on the principle of minimum total consequence. It is found that the diversion channel decreases the dam breaching peak discharge and the associated risks significantly. The branch drainage tunnel prevent the landslide dam from overtopping failure in non-flooded period; however, the landslide dam may fail by overtopping in a future flood if the inflow rate is larger than the outflow rate through the drainage tunnels, resulting in serious losses of lives and properties. The dam breaching risks in all the three stages could be largely reduced by the optimal evacuation decision, which shows that timely evacuation is vital to save life and properties. The study provides a scientific basis for decision making in landslide dam risk management. 相似文献
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某水电站某泥石流沟内常年流水,属季节性排洪沟谷,水动力类型为暴雨,沟内松散物源丰富,具有泥石流发生条件。在上游区以拦挡泥石流为主,通过修建拦挡措施,减少形成泥石流的固体物质,在下游区以防水、边坡防护及引流等措施,通过修建溢流坝截断上游水流对沟内堆渣体渗流影响;通过修建排洪渠及排洪洞引流;通过削坡、修坡进行边坡维护加固。确保了导流洞出口及上下行交通洞进出口的施工期安全及运行安全。 相似文献
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Peng Lin Xiaoxu Zhu Qingbin Li Hongyuan Liu Yongjun Yu 《Rock Mechanics and Rock Engineering》2016,49(1):115-142
A grouting model is developed for use during the grouting of the complex foundation of a super high arch dam. The purpose as to determine the optimal grouting timing and appropriate grouting pressure involved in controlling the uplift deformation of the dam. The model determines the optimal grouting time as the height of the arch dam increases with the concrete pouring, by checking the tensile stresses in the dam against standard specifications. The appropriate grouting pressures are given on the basis of the actual grouting pressures monitored during the upstream riverbed foundation grouting. An engineering procedure, applying the model, was then proposed and used during foundation grouting under the toe block of the Xiluodu super high-arch dam in south-western China. The quality of the foundation grouting was evaluated against the results from pressurized water permeability tests, acoustic wave velocity tests, elastic modulus tests and panoramic photographing of the rockmass on completion of the foundation grouting. The results indicated that the proposed grouting model can be applied to effectively reduce the uplift deformation and associated cracking risk for super high arch dams, and it can be concluded that the proposed engineering grouting procedure is a valuable tool for improving foundation grouting under the toe blocks of a super high arch dam. 相似文献
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引水式水电站深埋长引水隧洞对电站下游水温的影响直接关系到下游水生物生境.采用k-ε模型,结合能量传输方程建立了引水隧洞三维水温预测模型,并在利用原型观测资料验证模型的基础上,对拟建的锦屏二级引水隧洞的水温进行了预测.预测结果表明,由于雅砻江上拟建的锦屏二级隧洞洞径与过流量较大,水流在隧洞内滞流时间短,水温升高不明显.由于模型采用隧洞实际空间布置数据,建立包括混凝土衬砌区域在内的三维空间计算域,同时考虑温度场与流场的相互影响,实现了对温度场的精确模拟,从而可为水电站设计和水生物保护提供科学依据. 相似文献
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This paper describes the results of the engineering geological investigations and rock mechanics studies carried out at the proposed Uru
Dam site. Analyses were carried out in terms of rock mass classifications for diversion tunnel, kinematic analysis of excavation slopes, permeability of the dam foundation and determination of rock mass strength parameters.Uru
Dam is a rock-filled dam with upstream concrete slab. The dam will be built on the Suveri River in the central part of Turkey. The foundation rocks are volcanic rocks, which consist of andesite, basalt and tuff of Neogene Age. Studies were carried out both at the field and the laboratory. Field studies include engineering geological mapping, intensive discontinuity surveying, core drilling, pressurized water tests and sampling for laboratory testing.Uniaxial, triaxial and tensile strength tests were performed and deformation parameters, unit weight and porosity were determined on the intact rock specimens in the laboratory. Rock mass strength and modulus of elasticity of rock mass are determined using the Hoek–Brown empirical strength criterion. Rock mass classifications have been performed according to RMR and Q systems for the diversion tunnel.Engineering geological assessment of the proposed dam and reservoir area indicated that there will be no foundation stability problems. Detailed geotechnical investigations are required for the final design of the dam. 相似文献
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Analysis of support requirements for a shallow diversion tunnel at Guledar dam site, Turkey 总被引：2，自引：0，他引：2
Engineering geological properties and support design of a planned diversion tunnel at Guledar dam site, which was located at the North of Ankara, Turkey were studied in this article. The main purpose of the construction of the planned tunnel is to regulate, drainage and to provide water for irrigation purposes. The diversion tunnel runs mainly through formations of limestone, sandstone and diabase. Rock masses at the site were characterized using Rock Mass Rating (RMR), Rock Mass Quality (Q), Rock Mass Index (RMi) and Geological Strength Index (GSI). RMR, Q, RMi and GSI were determined by using field data and mechanical properties of intact rock samples, measured in the laboratory. Support requirements for the planned diversion tunnel were determined accordingly in terms of the rock mass classification systems. Recommended support systems by empirical methods were also analyzed using 2D Finite Element method. Calculated parameters based on empirical methods were used as input parameters in the finite element models. The results from both methods were compared with each other. This comparison suggests that more reliable support design could be achieved by using the finite element method together with the empirical methods. 相似文献