大口径新老排水管道连接技术的探讨

在现代城市市中心复杂的环境下,大口径新老排水管道的连接,已成为市政工程中的一大难题。为确保管井基坑安全和管道质量,结合工程实例叙述了适合原总管结构类型和周边环境实际情况的管井以及围护结构类型以及原总管的加固、接口缝处理等技术措施。     

软土地区大口径埋地塑料排水管道试验研究

上海地方标准中埋地塑料排水管道的适用管径范围小于DN1000,而目前大中型工程中需要大量直径DN1200及以上的管道。大口径埋地塑料排水管道应用越来越广泛,但缺乏相关的试验研究。本文结合试验探讨了大口径埋地塑料排水管道工程运用中的设计问题,利用大型砂箱试验系统模拟管道在土体中的实际受力状况,对管道的变形数据进行系统性的试验研究。试验结果显示管道竖向变形率小于规范公式的计算值。通过分析认为,对于软土地区的大口径埋地塑料排水管道,规范公式计算的变形值可进行修正,并给出了变形修正公式。     

浅谈定向钻牵引技术在市政排水管道工程中的应用

随着近年来人们对于社会问题、交通问题和环境污染问题的日趋关注,非开挖定向钻牵引技术在市政排水管道工程中越来越得到广泛的运用。本文主要介绍定向钻牵引技术在市政排水管道设计、施工中的应用,并结合实例对大口径管道在定向钻施工中的运用做了简要介绍。     

大口径排水管道顶管施工技术

结合武汉五环大道大口径排水管道顶管工程实例,研究和分析了大口径管道顶管施工方案的选择及顶力计算、工作坑支护和顶管施工过程中的技术难点,阐述了顶管施工的方法及技术措施。     

某小学综合楼加固工程优化设计

某小学综合楼原加固设计存在一些不足,导致加固工程无法按时完工.本文对其进行了优化设计.在优化设计中,对结构加固方案的合理选择、合理利用原桩、新桩与原桩沉降差异控制措施及新老承台连接构造处理进行了分析和探讨.所述原桩利用方法与新老承台连接构造措施可以为类似工程提供一定参考.     

大管径排水管线四合一组件施工

四合一组件是一种针对大口径排水管道安装的组件,它截取了管道基础的一部分。其特点是改变了传统的大口径管道施工工艺,克服了基础分两步浇筑费工、误时的弊端,将基础一次浇筑完成,缩短了管道的安装时间,提高了工作效率。     

某住宅项目改造抗震加固设计

在对原有建筑进行多项改造的基础上,对原结构进行了抗震加固设计,设计的主要内容为老构件改造和新构件的增加引起的抗震加固、新老构件的连接及新规范要求下构件节点的加固,通过设计实现了旧建筑新的使用功能,满足了业主的需求。     

新型微型顶管技术在小口径排水管道工程中的应用

顶管技术在国内大口径排水管道工程中有广泛的应用,且施工技术成熟,但在小口径排水管道工程中的实际应用却不多,又无相关的技术规范,而微型顶管技术则填补了小口径顶管技术的空白.因此结合工程实例,介绍了微型顶管技术的施工方法、工艺流程,总结了其适用范围、技术要点、施工注意事项和工艺特点.该应用案例可为小口径管道顶管施工提供参考...     

新型塑料管材的发展和工程应用

近年来，大口径塑料排水管材已越来越多的应用于市政排水工程中。传统的排水管道以混凝土管为主，由于其使用寿命短，化学性质不稳定．连接不严．易泄漏，不但对资源造成浪费．而且对地下水造成了二次污染：铸铁管道有施工不便、材料和施工费用昂贵等诸多缺点。因此，用新型排水管材对市政排水管道更新改造已成为当务之急。相对于传统的混凝土管材，     

塑料管道在工程应用中的质量现状

随着城镇建设速度的加快,塑料管的用量逐年递增15%～20%,但其施工应用技术、检测技术还停留在低水平,基础研究更是空白。对于大口径聚乙烯给水管道、排水管道系统我国还处于起步阶段,有些     

建筑给水塑料管发展前景

重点介绍了建筑给水塑料管中占主导地位的铝塑复合管，无规共聚聚丙烯鉴定的生产工艺、产品特性和应用情况，通过市场分析，提出了给水塑料管的发展优势，指出其具有巨大的市场潜力。     

微/微小型热管研究的现状与展望

微/微小型热管在航天器热控系统、微电子元器件散热等领域中有着广泛的应用。作者从微热管和微小型轴向槽道热管两方面综述了当前国内外关于微/微小型热管研究的现状.总结了当前该领域研究已取得的研究成果并展望了该领域的未来研究方向,希望能引起国内同行的关注。     

Large bending of pipes

The computer model developed has been used successfully for studying the large pipe-bending problem frequently encountered in offshore structural engineering. The pipe-soil interaction is modelled by using the Coulomb friction law. The modified finite element approach coupled with a modified tangent stiffness procedure is used to handle the nonlinearities (geometric and material, etc.) in the problem. The material nonlinearity has been considered both by the plastic-hinge method and by an elastic-plastic method. Before studying the practical problems, sufficient check problems were analysed and a good agreement was found between theoretically exact solutions and the results obtained from the developed computer model.     

新型塑料给排水管材的特点及应用前景

通过国家发布的各类文件及相关数据描述了塑料管材在我国给排水领域中的应用和发展历程,然后通过对常用新型建筑塑料管材的特点的描述、各类管材性能的比较和塑料给水管的应用,为设计、监理、施工等建筑企业在选择和利用塑料管材时提供一定的帮助。     

定向钻非开挖技术在城市建设中的应用

介绍了采用定向钻非开挖技术的基本工作原理与设备组成。详细讲述了施工中管线调查、导向孔钻进、扩孔、回拖管道等施工方法。说明了这一技术有效地解决了旧城改造中基础设施管线的破路敷设问题。     

塑料管设计的欧洲标准和规范

为把塑料管的设计方法统一起来,欧洲的塑料管业开展了大量的调查研究和大规模的试验,其重大成果已经逐步进入欧洲标准和规范。借鉴这些想法,对推动我国相关标准和规范的修编和拓展具有裨益。本文将相关情况作一介绍,仅供参考。     

钢筋混凝土管顶管施工技术

针对过公路段大口径钢筋混凝土管顶管施工难度和特点,结合近年来国内过公路段大口径钢筋混凝土管顶管施工技术,对钢筋混凝土管顶管施工方法和技术进行探讨,以完善钢筋混凝土管顶管施工工艺。     

管道伸出屋面防水构造细部做法的设计与施工

对管道伸出屋面防水处理工程易出现的质量通病进行了分析，结合施工经验，阐述了管道伸出屋面防水构造的施工工艺，提出了该工艺的选用范围及优点。     

Parametric study of frost-induced bending moments in buried cast iron water pipes

While the features of frost susceptible soils have been examined in various studies, the mechanisms by which volume changes due to ground freezing can influence cast iron water pipes buried below the frost line have not been explained, and the hypothesis that frost-induced ground deformations can induce ring fractures due to longitudinal bending of these pipes has not been proven. Therefore, a parametric study employing three dimensional finite element analysis is reported, where the soil–pipe interaction associated with a pipe crossing under an intersection of a major arterial road with a residential street are examined. The arterial road is modeled as having non-frost susceptible sub-base and the local street is represented as having a lower grade pavement with frost susceptible sub-base. One specific frost loading case featuring both isotropic pore water expansion and orthotropic ice lens formation is modeled.The analysis demonstrates how volume changes due to ground freezing in soil strata above the buried pipe can induce bending moments sufficient to cause ring fracture. Changes in the relative axial stiffness of the pipe were found to have only a small effect on pipe moments. Decreases in the relative flexural stiffness of the pipe resulting from reductions in pipe modulus also had only a small effect on pipe deflections and normalized moments. Changes due to soil modulus had a significant effect on deformations, but little influence on moments. Decreases in pavement stiffness decrease pipe deflections and moments. Trench backfill conditions greatly affect deflection and moment. Reduction in burial depth from 2 m to 1.5 m increases deflections, and increases moments beyond the failure capacity of the grey, cast iron pipe considered in the study, and this computational result is directly supported by field evidence.     

Meeting Standards for Lead in Drinking Water

During the last twenty years, the UK has made steady progress in the understanding of the 'lead in drinking water'issue and towards compliance with a lead standard which is more stringent than elsewhere in Europe.
Evaluating the needs for corrective action has not been straightforward because of the difficulties in characterizing the pick-up of lead from lead pipes throughout whole water supply zones. Survey methods have developed over the past twenty years as the behaviour of lead pipes has become better understood, but some ambiguities may still need to be addressed.
Information from Bristol Water suggests that compliance with a new lead standard of 10 μg/1 may be feasible by corrective water treatment in some zones, based on the already accepted practice of dosing with phosphoric acid, depending on how this more stringent standard is implemented. This view is also held by Anglian Water, based on their extensive experience with phosphoric acid dosing (without any significant problems) since the mid-1980s. Therefore total lead pipe replacement, at substantially higher cost, can likely be avoided in many zones.