注浆在水库病险处理中的应用

大坝渗漏是水库病险中的主要现象,对水库的安全运行构成了严重威胁.分析了水库大坝渗漏的主要原因,决定采用注浆对大坝进行除险加固,注浆后压水试验表明,渗透系数最大为1.89×10-5cm/s,最小为1.86×10-7cm/s.实践证明注浆是一种有效处理大坝渗漏的方法.     

Assessing the Potential of Internal Instability and Suffusion in Embankment Dams and Their Foundations

Suffusion is the process by which finer soil particles are moved through constrictions between larger soil particles by seepage forces. Soils susceptible to suffusion are described as internally unstable. This technical note describes a method for assessing the potential of internal instability of silt-sand-gravel or clay-silt-sand-gravel soils based on their particle size distribution based on laboratory tests carried out by the writers and results published by others. It is shown that some commonly used methods are conservative for these soils.     

THE RELATIONSHIP BETWEEN THERMAL REGIME ALTERATION AND SPAWNING DELAY OF THE FOUR MAJOR CHINESE CARPS IN THE YANGTZE RIVER BELOW THE THREE GORGES DAM

Large dams often alter flow and thermal regimes downstream, resulting in fish spawning delays and larval abundance declines. Accurate prediction of the delayed spawning period under changed thermal regime is critical for selecting a correct timing to modify dam operation and to release the environmental flow needed to enhance fish spawning. We used correlation analysis to investigate the relationship between thermal regime alteration and spawning delay of the four major Chinese carps (FMCC) below the Three Gorges Dam in the Yangtze River, China, using a 13‐year ecological data series (1997–2009). Eighteen variables were defined to quantify thermal regime and related to two variables representing spawning timing. Our results demonstrate that the start of FMCC spawning has been delayed from early May to middle June since the Three Gorges Dam initiated operation in 2003. Water temperature declines of 2 °C–4 °C in March, April and May (a critical period for gonad development) were the principal reason for the observed spawning delay. The variable most associated with spawning timing was the arrival date of the cumulative temperature needed for gonad development from stages IV to V (D_DegDayIV–V), which describes the long‐term impacts of the timing, magnitude and duration of thermal regime upon gonad development. Only the cumulative temperature for gonad development and the minimum temperature for FMCC spawning (18 °C) are both satisfied, the occurrence of suitable flow conditions, that is, flow increase or flash flood, would produce a successful spawning event. Consequently, we suggest that the experimental flow increase process of the Three Gorges Reservoir aimed at enhancing FMCC spawning should initiate after 15 June when the requisite thermal regime can be met. Copyright © 2013 John Wiley & Sons, Ltd.     

高安市水库常见病险原因与整治方法探讨

对江西省高安市水库常见病险的成因进行了分析,并结合工程实际对各类病险的整治技术和方法作了全面阐述.     

Phosphate exchange characteristics of wet and dried sediment samples from a hypertrophic reservoir: Implications for the measurements of sediment phosphorus status

This paper examines changes in the phosphate exchange characteristics induced in sediment samples by drying during preparation for analysis. Comparison of selected sediment parameters measured in wet and dried subsamples of a range of sediments from hypertrophic Hartbeespoort Dam showed that air drying resulted in major changes in their physical and chemical composition. Particle size distribution in the dried sediments showed a shift towards larger particles, particularly in samples in which smaller particles were abundant, indicative of irreversible aggregation of finer particles. Drying decreased the bioavailable phosphorus (NTA-extractable) content of sediments but reduced the phosphate buffering capacity and increased the phosphate equilibrium concentrations by a factor of 3, thereby increasing the phosphate release potential of dried sediments. Since sediment phosphorus status is often studied with a view to assessing the role of sediments in phosphorus cycling and eutrophication control, it is concluded that inappropriate decisions could result from the use of dried samples for analysis. The implications of these results in the marginal zones of lakes, which experience natural dehydration during periods of draw-down, are discussed.     

电脑三维渲染技术在水利工程设计中的应用

以往的水利水电枢纽概貌表现图多采用手工描绘，缺乏精确的比例、真实的场景和视角可变性，而在图形工作站完成，则价格昂贵。采用电脑三维渲染技术可以准确地表达设计者的设计构思和工程建成后的形象，这里，作者通过电脑三维表现图的制作思路、过程的分析，将电脑三维表现图的基本制作过程分为建模、渲染及实景合成，明确了各步骤的目的和原则。并以皂市水利枢纽工程表现图的制作过程为例，较为详尽地介绍和解释了各操作步骤及基本技法，为电脑三维渲染技术在水利工程设计中的应用提供了较好的示例。     

温泉堡水库碾压混凝土拱坝试验研究

温泉堡水库碾压混凝土拱坝是当今世界上建设在寒冷地区坝体最薄，厚高比最小的全断面碾压混凝土拱坝，被列为水利部“八五”科技重点项目。     

观音阁水库选坝过程中岩溶勘察与研究

观音阁水库位于太子河沉降带,广泛发育有寒武系、奥陶系灰岩,岩溶十分发育,在选坝过程中先后选择了六条对比坝线,可研阶段对三、四、六三条坝线进行了对比,通过区域及坝址的岩溶研究,论证了库首及坝下渗漏问题,并对三条坝线的岩溶发育特点及帷幕处理进行了评价,最后选出六坝线作可研阶段的推荐坝线,利用张夏灰岩作持力层,凤山组页岩作隔水层。水库建成后,没有发现坝下及绕坝渗漏问题。     

用一维简化动力法计算灰坝地震液化的研究

根据太原第一热电厂石庄头灰场沉积粉煤灰的物理力学性质和地震引起变形的特性试验,通过尾矿坝抗震设计中的一维简化动力法,试图解决一般高灰坝在抗震设计中的地震液化分析问题,并为抗震稳定分析提供依据     

Dams and Floods

The possible mitigation of floods by dams and the risk to dams from floods are key problems. The People’s Republic of China is now leading world dam construction with great success and efficiency. This paper is devoted to relevant experiences from other countries, with a particular focus on lessons from accidents over the past two centuries and on new solutions. Accidents from floods are analyzed according to the dam’s height, storage, dam material, and spillway data. Most of the huge accidents that have been reported occurred for embankments storing over 10 hm³. New solutions appear promising for both dam safety and flood mitigation.