某水库大坝渗漏勘察实例分析

某重点工程的供水水库发生严重渗漏,经多种手段的勘察论证和分析,查明了渗漏部位、渗漏模式和渗漏强度,为工程堵漏提供了准确的地质依据,试验段的堵漏效果明显,为一次成功的水库渗漏勘察。     

杨房沟水电站拱坝坝肩抗力体稳定性分析

杨房沟水电站拱坝两岸Ⅳ、Ⅴ级结构面发育,特别是平行拱轴力的侧向结构面连通性较好,对坝肩抗滑稳定不利。本文分析两岸坝肩抗力体内可能组合块体,研究块体结构面的力学参数,查明其连通率,评价对坝肩抗力体的稳定影响。     

Applicability of Sediment Transport Capacity Formulas to Dam-Break Flows over Movable Beds

In this paper, we investigate the extent to which well-known sediment transport capacity formulas can be used in one-dimensional (1D) numerical modeling of dam-break waves over movable beds. The 1D model considered here is a one-layer model based on the shallow-water equations, a bed update (Exner) equation, a space-lag equation for the nonequilibrium sediment transport and an empirical formula calculating the sediment transport capacity of the flow. The model incorporates a variety of sediment transport capacity formulas proposed by Meyer-Peter and Müller, Bagnold, Engelund and Hansen, Ackers and White, Smart and Jaeggi, van Rijn, Rickenmann, Cheng, Abrahams and Camenen, and Larson. We examine the performance of each formula by simulating four idealized laboratory cases on dam-break waves over sandy beds. Comparisons between numerical results and measurements show that for each case better predictions are obtained using a particular formula, but overall, formulas proposed by Meyer-Peter and Müller (with the factor 8 being replaced by 12), Smart and J?ggi, Cheng, Abrahams and Camenen, and Larson rank as the best predictors for the entire range of conditions studied here. Moreover, results show that in the cases where a bed step exists, implementing a mass failure mechanism in the numerical modeling plays an important role in reproducing the bed and water profiles.     

Efficient Implicit Finite-Element Hydrodynamic Model for Dam and Levee Breach

This technical paper presents the development and application of a pseudo-transient continuation (PTC)– inspired flow model for the simulation of dam and levee failure. The unstructured, implicit, Petrov-Galerkin finite-element model relies on computed residuals to automatically adjust the time-step size. The implicit time integration, together with the automatic time-step size selection through PTC, makes the model computationally efficient. The model is verified and applied to several analytic and real-world test cases that exercise model behavior and accuracy for several critical, transcritical, and subcritical flows. The result is an efficient and accurate prediction of both the speed and depth of shock waves as the dam-break flow passes over initially dry and wet land.     

Seasonal Variations in Fatty Acid Composition of Different Tissues of Mirror Carp,Cyprinus Carpio,in Orenler Dam Lake,Afyonkarahisar, Turkey

The seasonal variations of fatty acids compositions in the muscle, liver, and ovarian tissues of mirror carp (Cyprinus carpio) living in Örenler Dam Lake were determined by using gas chromatography. The results obtained were subjected to statistical analyses by employing SPSS software and p < 0.05 was accepted as significant value. In the statistical analyses, multiple comparisons tests were performed. The results showed that monounsaturated fatty acids levels were found to be higher than that of polyunsaturated fatty acids and saturated fatty acids in all seasons. Palmitic and stearic acid levels were the highest in ovaries (19.95% in winter and 7.79% in summer, respectively). Oleic and palmitoleic levels were at the highest levels in liver tissues (34.53% in summer and 18.37% in winter, respectively). Docosahexaenoic (C22:6ω3, DHA), eicosapentaenoic (C20:5ω3, EPA), eicosatrienoic acid, and arachidonic (C20:4ω6, AA) levels were at the highest level as 17.27, 2.54, and 8.41% in ovaries in the winter and 6.37% in muscle tissues in the spring, respectively. ω3/ω6 ratios were 0.62–0.98 in muscle, 1.54–2.82 in the liver, and 2.82–3.89 in the ovaries. From the point of total fatty acid variations, the highest variations were observed as follows: muscle in spring (26.73%), liver in winter (33.85%), and ovaries in winter 36.38%.     

A Pressure Dam Bearing Analysis with Adiabatic Thermal Effects©

To improve the stability of fixed geometry journal bearings in high-speed rotating machinery, pressure dam or stepped bearings have often been used in place of plain or other bearings. Despite their long history and wide range of applications in industry, only isoviscous analyses have been reported in the literature. Since stability problems usually occur at relatively high speeds where considerable heating occurs, it is desirable to include the thermal effects in pressure dam bearing analysis. This study presents a full adiabatic thermohydrodynamic analysis for pressure dam bearings. The theoretical results show that the pressure and temperature distributions on a stepped pad are quite different from those on a smooth pad. The thermal effects have significant influence on the predicted bearing performance, such as journal eccentricity, dynamic coefficients, and rotor stability. The example of a flexible rotor indicates improved stability prediction with the thermal effects included.     

鸽子沱水库大坝除险加固

鸽子沱水库为均质土坝,建于上世纪六七十年代,是典型的"三边"工程,对于我国当时建成的水库存在的问题具有一定的代表性.本文针对鸽子沱水库大坝病险原因及大坝的稳定状况进行分析,并提出工程加固方案.整治加固后,水库运行良好,因此该整治加固方法对类似水库除险加固具有一定的参考价值.     

东北某水库坝基岩体质量分级研究

应用单因素和多因素分类方法,对东北某水库坝基岩体质量进行了分级研究.研究结果表明,除新鲜岩体和微风化岩体外,该区弱风化岩体为良质岩体,经适当处理后,可以考虑作为该水库坝基岩体;而对小部分的弱风化镶嵌结构的岩体,性质较差,需要挖除.     

基于PLC的分布式大坝安全监测数据采集系统

针对大坝现场自然条件恶劣的特点,设计了基于PLC的分布式数据采集系统,相对于单片机系统,具有可扩展性好,可靠性高,抗干扰能力强等优点,使用VC＋＋6．0实现PLC和上位机的通讯,对于现场PLC供电的特殊要求,设计了后备电源解决方案,并进行了实际应用。     

小浪底工程粉煤灰质量波动对砼性能影响的试验论证

结合小浪底水利枢纽工程的施工,对用于小浪底工程粉煤灰的质量波动是否影响砼性能,进行了试验,结果分析表明：在细度为15～25％、烧失量4～12％之间变化,其它指标满足Ⅱ级粉煤灰要求的情况下,砼力学性能、变形和耐久性没有明显变化。该成果的采用,为保证工程进度、节约费用、确保工程质量产生了巨大的综合效益。