砚瓦河渡槽和支渡槽工程槽身现浇施工可行性分析

砚瓦河渡槽和支渡槽工程渡槽槽身自重大,受地形、起吊高度、吊车分解拖运到场荷载及拖运设备长度等影响,如果进行渡槽槽身预制吊装则需要对现有进场道路升级改造,待吊车进场后再进行现场吊装场地改造,但道路升级改造所需时间长、资金量大,涉及协调工作量大,工期和安全性得不到保障,故而将渡槽槽身设计吊装方案变更为现浇施工方案。通过对渡槽槽身现浇施工的可行性进行深入探讨,在现浇施工通过可行性论证的基础上,对下行式移动模架现浇施工方案和钢管满堂架现浇施工方案进行比选。分析结果表明,砚瓦河渡槽和支渡槽工程渡槽槽身推荐采取下行式移动模架现浇施工方案。     

升钟水库右总干渠及武都引水工程渡槽现浇法施工技术

升钟水利工程右总干渠、武都引水工程总干渠系目前省内已建成的两大灌区骨干工程 ,渠线上已建成不同结构型式的大型渡槽 17座。着重介绍的渡槽现浇法施工技术 ,可供同类工程借鉴。     

浅议渡槽现浇法施工技术

钢筋混凝土渡槽是灌区常用的输水水工建筑物。槽身的支承结构有拱肋、排架、砌石边墩等形式。槽壳断面有矩形、U形,施工方法根据渡槽的形式、尺寸、构件重量、吊装设备、地形和自然条件等因素而定。一般多采用预制吊装、预制吊装与现浇法结合及整体现浇法施工。本文着重介绍石头河灌区东干渠东滑峪支线渡槽整体现浇法施工技术。     

大型渡槽现浇法施工技术

升钟水利右总干渠，武都引水工程总干渠是四川省内已建成的两大灌区骨干工程，渠线上已建成不同结构形式的大型渡槽１７座。本文着重介绍渡槽现浇法的施工技术，可供同类工程借鉴。     

满堂支架法现浇U型薄壁渡槽施工技术

U型现浇渡槽槽身预应力钢筋混凝土薄壁结构的施工是槽渠建筑物施工的难点。本文重点介绍了普沙渡槽U型薄壁槽身现浇混凝土的施工,以及预应力施工技术,较系统地反映了普沙渡槽满堂支架法现浇混凝土施工技术的实际应用情况,为今后同类工程施工提供了参考借鉴。     

下行式移动模架在砚瓦河渡槽工程的应用

下行式移动模架造桥机自带模板,能进行渡槽工程原位整孔双线箱梁及连续梁施工,且对于低墩现浇梁施工十分适用,过孔速度较快。小浪底北岸(济源)灌区工程施工二标砚瓦河渡槽工程选用QJMXD300型下行式移动模架造桥机用于渡槽20m梁现浇施工,为保证施工质量和进度,必须加强造桥机关键性技术参数的选定、渡槽型式选择、移动模架造桥机失稳控制、槽身混凝土浇筑过程的控制。     

钢筋混凝土U型薄壁渡槽槽身施工技术

U型现浇渡槽槽身钢筋混凝土薄壁结构的施工是渠系建筑物施工的难点,通过对禹门口灌区干渠渡槽槽身U型现浇钢筋混凝土施工关键工序的介绍,提出了施工过程中存在的问题及有关注意事项,并阐述了施工质量控制中必须注意的几个要点。     

槽身模板支架及成套运输系统在高渡槽施工中的应用

结合毗河供水一期工程书永分干渠高石梯渡槽特点以及现场实际条件,对高渡槽的槽身现浇支架搭设及垂直运输方案进行了优化。介绍了高渡槽现浇支架的设计、施工及其成套运输系统,可供类似工程施工时借鉴。     

泵送混凝土在30m跨渡槽槽身施工中的应用

以漕河渡槽槽身三向预应力混凝土施工为例,介绍泵送混凝土施工在渡槽工程的具体实施情况。高架现浇三向预应力渡槽采用泵送混凝土在国内经实践检验,效果良好,保证了混凝土入仓强度,为大型渡槽混凝土施工积累了一定的经验.     

大流量大跨度预应力渡槽支架法现浇施工技术

南水北调中线干线工程贾河渡槽设计流量大、结构跨度大,单体槽身自重约3600t,其结构复杂程度与施工技术难度国内罕见。本文重点介绍了贾河渡槽槽身模板及模板支架的设计与施工,以及槽身混凝土与预应力施工技术,较系统地反映了贾河渡槽支架法现浇施工技术的实际应用情况,供同行在同类工程施工中参考。     

龟石水库灌区仁岩渡槽渗漏加固处理

贺州市龟石水库灌区仁岩渡槽经过30多年的运行，槽身渗漏造成钢筋锈蚀、槽壳外侧钢筋保护层混凝土脱落，伸缩缝防渗材料老化失效。介绍了防渗漏处理过程中，浆液及其配合比，对槽身伸缩缝等不同部位采取的各种施工工艺。     

杜拉纤维混凝土在渡槽工程上的应用探讨

纤维混凝土技术应用于渡槽的防渗抗裂,其性能明显优于普通混凝土。为此,以某水库灌区应用实例,探讨杜拉纤维混凝土的功能及作用机理,实际应用效果表明：该技术成熟,投资省,质量有保证,可显著提高渡槽混凝土的变形能力和耐久性,防护效果好。     

Hydraulic effects of aquatic weeds in U.K. rivers

The effects of large aquatic plants (aquatic macrophytes) have been given limited attention in literature dealing with open channel flow. This is despite a large number of river channels in the U.K. being affected by profuse growths of these plants. This paper contributes to three major areas in relation to aquatic macrophytes and river channels. First, a literature review examines four areas of vegetated channel research. Early work on vegetated channels concentrated upon grass-lined farm drainage channels in the U.S.A. This was complemented by flume studies of predominantly artificial vegetative roughness elements. The review discusses research into large aquatic plants in stream channels, and the discussion draws together a number of disparate areas of research into vegetated channels including theoretical considerations. Secondly, the paper discusses results obtained from laboratory flume experiments, using real plants, and field monitoring on the River Ebble, Wiltshire, U.K. The relationship between discharge and Manning's roughness coefficient (n) is examined. Field monitoring results are presented as generalizations in the relationship between Manning's n when the monitoring sites were vegetated and unvegetated. The relationship between plant cover in the channel and Manning's n is also examined. Two measurements of plant cover are employed: the percentage cross-sectional area of channel vegetated, and biomass per unit area. The field data for Manning's n and discharge are then discussed in detail in a case study of one site on the River Ebble. Finally, the results obtained from field monitoring are compared to previous research. In the light of these comparisons and detailed examination of the field and flume data, a conceptual model of the effects of aquatic plant growth on channel roughness, mean flow depth, and flow stage is represented. Using this model, an estimate can be made of the likely effect of changing plant cover and discharge on flow stage in an open channel.     

凉水河水环境治理生物填料对河道阻力的影响

结合北京市凉水河水环境治理工程,利用水槽试验,研究河道布设生物填料后,其阻力特性的变化规律.分析了水槽中布设单排、双排生物填料,在不同生物填料高度、流量等运行条件下,水槽综合糙率系数的变化规律;定量提出生物填料相对高度与综合糙率系数的相关关系.并根据凉水河河道水力参数及布设的生物填料数量、高度等参数,提出凉水河布设生物填料后的综合糙率系数值,为论证凉水河水环境治理工程是否影响河道行洪安全提供技术依据.     

U型薄壁渡槽槽身施工技术

介绍了U型薄壁渡槽槽身大跨度的结构施工技术,即：模板支撑桁架的型式,模板支撑调节器的选用,按刚度、强度及稳定性的要求确定的模板,以及混凝土浇筑关键控制工序和拆模后的养护.此外,还介绍了槽身止水的施工.     

塑料模型沙起动流速试验研究

通过水槽试验进行了塑料沙的起动流速试验,以5组泥沙为例,推导出沙粒在不同运动状态下塑料沙的起动流速公式,并与3种常用模型沙起动流速公式计算值比较,建议对轻质模型沙起动流速估算时,采用塑料沙起动流速计算公式.     

大型预应力混凝土箱形渡槽结构三维有限元分析

结合南水北调中线工程中大型预应力混凝土箱形渡槽的结构设计,采用三维有限元技术对其受力性能进行了分析探讨。依此,证明所采用的渡槽结构型式及尺寸,预应力筋的布置方案是合理的。渡槽结构应力、变形满足规范要求。     

氨太克3599聚胺酯防水密封涂料在渡槽伸缩止水缝中的应用

本文针对汾西灌区新建三座钢筋混凝土渡槽伸缩缝处理所采用的氨太克3599（聚胺酯）材料性能、配比、施工工艺、需注意事项、运用效果等方面进行了介绍。     

Scour around submarine pipes due to high-amplitude transient waves

Estimation of scour dimensions below submarine pipelines is a vital step in designing offshore infrastructure. Extreme events like tsunami waves produce strong erosive forces below the underwater pipes, apt to create scour holes, jeopardizing the safety of the structure. Despite the importance of this issue, previous studies have mainly focused on steady flow cases, and the scour pattern below submarine pipes induced by high-amplitude transient waves has rarely been investigated. This paper reports the results of 40 experimental runs on transient wave-induced scour below a model pipe in a laboratory flume under a variety of initial conditions. The variables included the bed particle size and gradation,initial water depth, wave height, and slope of the bed layer. Waves were generated by a sudden release of water from a sluice gate, installed in the middle of the flume. A pressure transducer data acquisition system was used to record the wave heights at different time steps. The results indicate that, with a shallower initial depth of flow, the scour depth is relatively large. It was also found that there exists a direct correlation between the induced wave height and the size of the scour hole. It was observed that, in clear water conditions, the size of the scour hole in coarse sediments is smaller, while in live-bed conditions, larger scour holes are created in coarser sediments. It was also observed that at high wave amplitudes, the live-bed conditions are dominant, and consequently the bed elevation is altered.     

圆弧直墙平底量水槽试验研究与示范推广

灌区量水是灌区实现＂总量控制＂和＂定额管理＂的基础性工作.通过圆弧直墙平底量水槽试验研究和示范推广,为我省灌区防洪度汛、抗旱、供水调度、计量收费提供科学依据,改善管理人员测流工作环境,减轻工作人员劳动强度,提高测流精度和测流工作效率,节约管理费用开支,提高灌区的现代化管理水平.