双沟水电站厂房布置设计

文中介绍了双沟水电站发电厂房的厂区布置、总体设备布置、厂房分缝及厂内止水排水布置、厂房基础处理,以及厂房主要结构布置设计。厂房设备布置简洁、紧凑,布置合理,主要结构布置设计通过多种理论和方法分析并采取了多项优化措施,取得了显著的经济效益,可为其它相关工程设计提供参考和借鉴。     

白山抽水蓄能电站地下厂房设计

1 地下厂房位置的确定 白山抽水蓄能电站为地下厂房,布置在左岸山体内.在确定地下厂房布置时,主要考虑地质构造和初始应力场及输水系统的布置等因素,整体布置同主变洞、交通洞等主要附属洞室相协调,尽可能使厂房纵轴线与地质构造成较大交角.     

仙居县抽水蓄能电站地下厂房监测布置及成果分析

地下厂房布置监测仪器对抽水蓄能电站的地下厂房性能监测尤为重要。以仙居县抽水蓄能电站地下厂房监测布置为例,介绍蓄能电站地下厂房的布置方法、测试仪器、数据整理和成果分析。     

冲乎尔水电站厂房屋顶出线架结构设计

1 工程概况 冲乎尔水电站位于新疆阿勒泰地区某县境内,厂房布置为坝后式,纵轴线与河流方向近正交,电站装机4× 27.5 MW.主厂房包括主机间和安装间两部分,安装间布置在主机间的左侧;副厂房布置于主厂房上游侧,与主厂房等长;主变压器布置于一次副厂房内,开关设备为户内GIS方式布置,也布置于副厂房内. 2 出线架布置 电站厂房采用户内式升压输电,考虑厂房整体布置,出线场选择布置在一次副厂房屋顶.为架空高压线需设计出线杆塔及出线横梁,出线杆塔与横梁均采用钢结构.     

喀斯特地区大变幅尾水发电厂房新型结构应用

贵州省夹岩工程位于喀斯特地区,其坝后发电厂房受地下暗河顶托影响,厂房尾水水头达到44.92 m,挡水高度相当于一个中等高度重力坝,给厂房布置及结构设计带来较大困难。通过创新发电厂房结构型式,采用主副厂房立体层叠结构,成功解决夹岩工程高尾水发电厂房结构设计、进场交通、防洪安全等布置难题。该新型发电厂房结构型式采用外部井筒及内部板梁结构抵御高尾水压力,利用井筒内部空间布置主副厂房,节约工程占地,节省工程量及工程投资,较好地适应了喀斯特高尾水地区发电厂房布置条件,可供其他类似工程参考借鉴。     

敞开式组合电器在云口水电站屋顶开关站中的应用

鉴于云口水电站厂房距河口开阔地带有一定距离,处于峡谷之中,开关站在厂房附近就地布置困难较大,采用敞开式组合电器,布置在电气副厂房屋顶上,成功地解决了开关站布置困难的问题.     

戈兰滩水电站厂房布置设计

根据坝址区的地形地质条件,对厂房布置方案进行了优化比选,较好地解决了高边坡、窄河谷、高尾水地区的厂房布置问题,同时针对厂房布置中的特殊问题,提出了有效的解决方案.     

大石门水利枢纽电站厂房布置设计

文章依据大石门发电厂房布置于狭窄河谷,受制于地形限制,布置上充分利用地形条件,对主、副厂房及安装间进行布置优化,既满足了厂区各类建筑物布置的要求,又改善了厂房的施工、交通及运行管理等条件,且节约了工程投资。     

益地水电站地下厂房布置

益地水电站地下厂房所处地层岩性以中薄层变质石英砂岩为主,结合厂区建筑物布置、岩层走向、地质构造、地应力等对厂房纵轴线及洞室布置方式进行比较,最终确定厂房纵轴线及主要洞室布置方式。     

皂市水利枢纽电站厂房设计

皂市水电站厂房的布置,经研究分析和方案比较后,采用右岸坝后式厂房布置型式.设计中根据本工程具体特点,对建筑物布置方案进行比选,对建筑物结构进行优化,并引进新的设计思路和方法,提出技术可行、经济合理、施工方便、便于运行管理的工程方案.根据坝址区地形地质条件及枢纽布置特点,电站厂房设计中面临的主要技术难点为厂房边坡稳定处理,主要采用选择合理厂房位置和型式、优化厂房布置、减小边坡高度和加强边坡处理措施等加以解决.     

地下厂房施工过程的三维非线性数值模拟分析

根据冗各电站地下厂房开挖支护的施工顺序,以隐式杆单元模拟锚杆,以壳单元模拟混凝土喷层,采用三维非线性有限元技术,对洞室群的开挖支护动态过程进行了模拟计算。通过三维非线性有限元计算分析得到:洞室群动态开挖过程中围岩应力变形的分布规律,围岩塑性区的发展规律,锚杆受力变化情况。计算结果表明:整个开挖过程中,洞周围岩位移变化规律正常,量值较小,塑性区主要分布在洞室周边,围岩稳定性较好;但在洞室交叉口处围岩的变形较大,出现较大范围的塑性区,在此基础上提出了支护措施优化方案,并对优化方案的效果进行了评价。     

老化钢筋混凝土结构的分形性质分析

混凝土结构中的超声声速测值或回弹测值被描绘成一立体图形时，图形上表面的起伏程度反映了结构混凝土的均匀程度。计算分析发现，超声声速值和回弹值的功率谱与圆频率有负幂率关系，表明立体图的上表面即混凝土均匀性具有分形性质。由于代表混凝土不均匀程度的超声声速和回弹分维数，与构件混凝土强度和混凝土碳化深度有着良好的相关关系，混凝土的均匀性就与结构的老化进程相关，是进行结构耐久性分析时需要考虑的一个因素。另外，实例计算表明，混凝土裂缝的分布也具有分形的统计自相似性，其分布的分维数能较好地表征裂缝的发育程度，且与结构老化的其它指标相互印证。因此，裂缝分布的分维数也可以作为衡量结构老化程度的一个有效指标。     

NUMERICAL STUDY OF WAVE EFFECTS ON SURFACE WIND STRESS AND SURFACE MIXING LENGTH BY THREE-DIMENSIONAL CIRCULATION MODELING

1. INTRODUCTION Coastal and continental shelf regions are characterized by intensive interaction between wave and current. These regions are of great economic significance to mankind. Therefore, the modeling of wave and current as well as their mutual int…     

EXPERIMENTAL STUDY HYDRAULIC ROUGHNESS FOR KAN TIN MAIN DRAINAGE CHANNEI IN HONG KONG

The Kam Tin Main Drainage Channel (KTMDC) is an important river for the city drainage in Hong Kong. The roughness and its variations have an obvious effect on the flood control capacity and the flow capacity. So physical model tests are designed to study the KTMDC. Due to its complex channel structure, the tests are completed in two steps. In Step 1, the energy loss is measured along the main channel without inflows, with all inflows and outflows being sealed. In Step 2, all the inflow and outflow structures are measured, with the sealed inflows and outflows being opened on the basis of Step 1. In each step, two schemes are employed. One of the key issues is the choice of suitable materials to make the model’s roughness similar to that of the prototype. According to the gravity similarity criterion, the 1:25 scale model is built, with the main channel made of Perspex. The facing slopes of the grasscrete and the stone masonry need to be roughened. A kind of the nylon net is selected to simulate the roughness of the stone masonry and the plastic lawn for the grasscrete facing slope. For the different structure reaches, the roughness coefficients are estimated based on the hydraulic theory. The rationality of the test results is verified in this study. The results of testing can provide a reliable basis for the renovation, the expansion, the optimization of this channel.     

Comparison of the interannual and interdecadal variability of heavy flood characteristics upstream and downstream from dams in inversed hydrologic regime: Case study of Matawin River (Québec,Canada)

Erected in 1930, the Matawin Dam caused an inversion of the hydrologic regime of the Matawin River: snow‐melt water in spring (April to June) is stored in the reservoir and then released in winter (January to March) to feed the hydroelectric generating stations built downstream on the Saint‐Maurice River. Thus, heavy floods occur upstream from the dam in spring but downstream in winter. We compared the interannual and interdecadal variability of the heavy flood characteristics (magnitude, duration, frequency and variability) both upstream (spring floods) and downstream (winter floods) from the dam during the 1934–1994 period. This comparison revealed that the principal change observed downstream from the dam translates into a strong increase in the duration (in days) of heavy floods. The average duration of these floods quintupled. This change in duration occurred around the mid‐1960s and thus led to a significant decrease in the magnitude, frequency and variability of heavy floods. It also altered the relationship between the climate indices and these fundamental characteristics (magnitude, frequency and duration). Downstream from the dam, the magnitude and frequency are positively correlated to the Atlantic multidecadal oscillation (AMO), whereas upstream they are negatively correlated to the same index. However, the AMO index is negatively correlated to the duration downstream from the dam, whereas upstream this characteristic is no longer significantly correlated to any climatic index. Two factors have been invoked to explain this change observed downstream from the dam.

• The cooling observed since the 1960s at the station located at the dam. However, this cooling was not observed on the scale of the entire watershed. This reduces its plausibility.
• The increase in hydroelectric power production in the watershed after nationalization of hydroelectric power in 1962. This increase would be explained by the expansion of the market for hydroelectric power (national and international markets). Before nationalization, the hydroelectric power produced in the watershed was intended only for regional industries.

Copyright © 2010 John Wiley & Sons, Ltd.     

基于BP神经网络-马尔科夫链模型的隧道围岩位移预测

在隧道工程施工中,围岩位移预测起着很重要的作用。将BP神经网络-马尔科夫链模型引入到隧道围岩位移预测中来,通过对训练样本的学习,利用BP神经网络实现了对位移时间序列的滚动预测,同时得到了实测值与预测值的相对误差;在此基础上利用马尔科夫链对相对误差进行修正,有效地提高了预测结果的精度。并将该模型应用于某公路隧道拱顶下沉位移时序预测中,结果表明该模型具有精度高、科学可靠的特点,为隧道围岩变形的预测提供了新的途径。     

试论工程建设项目施工无标底招标

简述我国工程建设项目施工近20年的招标投标活动,形成了以标底为核心的投标报价体系,它对于降低工程造价,缩短建设周期,保证工程质量,维护社会、政治稳定,促进国民经济健康发展起到了重大的作用.但随着市场经济的不断深化和完善,其作用日渐衰弱,弊端却不断显露出来.无标底招标是市场经济发展的必然,也是国际惯例,采用无标底招标具有十分重要的意义,也具备了实行的条件.     

The past,present, and future Aral Sea

The Aral Sea, a once vast brackish terminal lake in the heart of Central Asia, has been rapidly drying since the 1960s. It had separated into four separate waterbodies by September 2009. The maximum water level decline was more than 26 m, whereas the lake surface area decreased 88% and the water volume 92%. The lake salinity increased by more than 20‐fold. Prior to the modern recession, the Aral Sea experienced a number of water level declines and subsequent recoveries over the last 10 millennia. The main causative factor until the 1960s was the periodic westward diversion of the Amu Dar’ya, the main influent river, towards the Caspian Sea by both natural and human forces. The post‐1960 recession, however, was overwhelmingly the result of unsustainable irrigation development. The lake’s modern recession has caused a broad range of severe negative ecological, economic and human welfare problems. To restore the Aral Sea to its 1960s’ size and ecological condition would be very difficult, if not impossible, in the foreseeable future. The plight of the Aral Sea, however, is far from hopeless. Partial restoration of portions of the lake is still feasible. A project to raise the Small (northern) Sea was completed in Fall 2005, raising its water level by 2 m, and lowering its salinity to a level not much higher than the early 1960 levels. Its ecological recovery has been dramatic, and a new project to improve further the Small Aral was recently announced. Improving the Large (southern) lake would be much more difficult and expensive. A project to save the deep Western Basin partially is technically feasible, however, and should be given careful evaluation. It is important to repair and preserve what is left of the deltas of the two tributary rivers, Syr Dar’ya and Amu Dar’ya, as these two rivers are of great ecological and economic value, and act as biological refugia for endemic species of the Aral Sea.     

新疆北疆某供水渠道冻胀融沉变形性状分析

针对冻土区季节性输水渠道冻融破坏问题,选取新疆北疆某长距离供水渠道作为研究对象,开展冬季冻胀、春季融沉、通水期及停水后等四种工作状态下阴面渠坡的原位监测试验,研究分析一个完整运行周期内地层岩性为膨胀型沙质泥岩阴面渠坡法向及顺坡向变形性态,并对冻胀变形进行了数值模拟。结果表明:在冻胀期,渠坡顺坡向收缩变形0.3～6.0 mm,坡脚法向隆起变形97.9～115.6 mm;在融沉期,渠坡沿坡面向下滑移约10.0～30.0 mm,顺坡向变形较大的渠段其坡脚法向隆起变形呈增大趋势,最大隆起量为144.0 mm,顺坡向变形较小部位其坡脚法向变形呈沉陷状态,变形量约186.0 mm。通水前后,渠坡顺坡向变形增加约4.0 mm,坡脚法向已隆起部位变形量有所减少,坡脚法向沉陷部位变形增加68.4～80.8 mm。停水后,渠坡法向隆起或沉陷部位的变形不大,已发生衬砌板开裂或错台的部位的顺坡向变形进一步增加约8 mm。研究成果对该渠道工程维修提供了可靠的技术支持,具有一定参考价值。