大口径、长距离水下管道整体一次沉管施工技术

在内陆湖泊取水工程及沿海地区生活污水处理排污管道工程等水下管道施工项目中,如何快速、安全、可靠进行沉管施工是一项技术难题。本文介绍了一种"水上管线一次性沉管技术配合岸边分段组对工艺"快速进行大口径、长距离水下管道施工技术,供类似工程项目借鉴。     

大口径PE管道修复方法探讨

聚乙烯PE埋地管材在国内外已经得到广泛应用,大口径室外PE埋地管线是业界发展潮流,如何快捷更换老化的PE管线、修复局部破裂的PE管线成为值得深入探讨的问题。本文就此问题在实际施工中的几种解决方法进行论述。     

使用21年后主蒸汽管道的性能变化及其安全评估

对某石化热电厂材质为１０ＣｒＭｏ９１０,服役时间超过１０万ｈ的主蒸汽管道进行全面检测与安全评估,对１１７个现场测定的硬度值进行统计分析,介绍了新管材、旧管母材及焊缝的常温和高温拉伸试验结果,－６０～５５０℃影响各温度下冲击功值,以及由试验定的韧脆性转变温度,并评价了长期服役对韧脆性转变温度的影响。     

大型过江沉管水上焊接及预制管段施工技术

大型过江沉管水上焊接及预制管段存在水上作业环境影响大、管道接口与转角弯点多、管材体量大、管道设计工作压力高于施工规范等难点。本文从管道分段焊接预制、管道焊缝接口质量检查与防腐修补要求、管段下水、管段水上成型对接以及管段管道严密性试验等方面研究总结出一套大型过江沉管水上焊接技术。该技术施工效率高、施工作业安全，降低了施工成本，保障了施工质量。     

塔河9区高含H_2S凝析气藏地面集输管道防腐蚀选材与内涂层防腐蚀考察

塔河油田9区生产层为奥陶系,采出介质具有"高H_2O、高H_2S、高CO_2、高Cl~-、低pH值"的"四高一低"强腐蚀特性,集输工况具有高温、高压特点,现有普通碳钢管材质已无法适用现场使用寿命要求。通过分析腐蚀环境,开展了抗腐蚀管材评价试验、内涂层适应性评价试验。基于试验结果进行技术可行性分析与全生命周期经济性对比分析,推荐9区地面单井集输管道采用825内衬双金属复合管,天然气外输管线采用L245NS抗硫管材+缓蚀剂,可为治理"H_2O、H_2S、CO_2、Cl~-"腐蚀环境下的集输管道腐蚀提供借鉴。     

浅析内陆湖泊浅水地区长距离大口径管道水上连接技术

本文结合大理市三库连通洱海应急补水工程——茈碧湖虹吸取水管道工程实例,介绍了一种长距离、大口径管道水上管口连接技术。根据项目的施工可行性及质量控制措施,采用在岸边分为多个作业点将管道快速组对为多段,运输至湖面组对为整根管线后进行沉管的施工工艺,并详细阐述了其中关键的水上管道连接施工技术,即分段管道浮运封堵、分段管道水上连接以及受力分析等。该技术既解决了浅水地区长距离大口径管道水上运输技术难题,又解决了水上管口组装连接难题,为类似工程项目提供实践经验。     

聚乙烯管材耐慢速裂纹增长性能的快速评价的研究现状

聚乙烯(PE)管材的耐慢速裂纹增长性能是评价管材使用寿命的关键指标。文中概述了塑料管材典型的破坏模式,介绍了常规评价聚乙烯管材耐慢速裂纹增长性能的切口管试验(NPT)、全切口拉伸蠕变试验(FNCT)、宾夕法尼亚切口拉伸试验(PENT)、锥体试验(Cone)等试验方法;详细介绍了最新研发的变硬化模量法、缺口圆柱棒-循环载荷法2种新型试验方法,并比较分析了新型试验方法的优势。最后就聚乙烯管材耐慢速裂纹增长性能评价方法的发展方向进行了展望。     

探索管道自动化焊接新技术的研发与应用

在锅炉、石化、建筑安装行业,管道焊接的工作量非常大,而国内外建筑安装行业管道焊接施工基本上还是采用手工焊接。由于目前市场上的焊接高技能人才奇缺,在很大程度上满足不了行业高速发展的需要,影响了工程进度和焊接质量。为了解决这个问题,从保证焊接质量,提高工作效率,缩短安装周期、同时也为了提升公司科技实力和市场竞争力,我们从焊接设备和焊接工艺的研发着手,开发管-管对接与管-法兰焊接一体化自动化焊接设备,研发成功新的GMAW自动焊接设备及工艺,解决这一制约安装工程工艺管线焊接加工的新问题。     

三峡工程枢纽区乐天溪污水管道系统设计

针对工程现状,确定了关键设计参数,对管线进行了布置,并确定了管道管材、接口、基础等,最后提出了工程设计中存在的问题及建议,为工程的实施提供有益参考。     

钢管提升装置

一、简述背景及存在的问题 现代建筑高大空间较多,机电系统齐全,管线复杂,高大空间处机电管线施工是一大难点.传统施工中,高大空间的管道安装工程垂直上料主要依靠人力,施工人员用肩膀扛、绳子拉,人工需求多,操作安全危险性大,工作效率低.现场研发小组针对这一施工难题,结合现场施工实际情况,收集各类提升装置资料并进行研发,并利用现场现有材料及设备,研制了一种便于提升钢管的装置,能安全、快速提升各种管线构件,同时达到省时省力的效果.     

A physical probabilistic model to predict failure rates in buried PVC pipelines

For older water pipeline materials such as cast iron and asbestos cement, future pipe failure rates can be extrapolated from large volumes of existing historical failure data held by water utilities. However, for newer pipeline materials such as polyvinyl chloride (PVC), only limited failure data exists and confident forecasts of future pipe failures cannot be made from historical data alone. To solve this problem, this paper presents a physical probabilistic model, which has been developed to estimate failure rates in buried PVC pipelines as they age. The model assumes that under in-service operating conditions, crack initiation can occur from inherent defects located in the pipe wall. Linear elastic fracture mechanics theory is used to predict the time to brittle fracture for pipes with internal defects subjected to combined internal pressure and soil deflection loading together with through-wall residual stress. To include uncertainty in the failure process, inherent defect size is treated as a stochastic variable, and modelled with an appropriate probability distribution. Microscopic examination of fracture surfaces from field failures in Australian PVC pipes suggests that the 2-parameter Weibull distribution can be applied. Monte Carlo simulation is then used to estimate lifetime probability distributions for pipes with internal defects, subjected to typical operating conditions. As with inherent defect size, the 2-parameter Weibull distribution is shown to be appropriate to model uncertainty in predicted pipe lifetime. The Weibull hazard function for pipe lifetime is then used to estimate the expected failure rate (per pipe length/per year) as a function of pipe age. To validate the model, predicted failure rates are compared to aggregated failure data from 17 UK water utilities obtained from the United Kingdom Water Industry Research (UKWIR) National Mains Failure Database. In the absence of actual operating pressure data in the UKWIR database, typical values from Australian water utilities were assumed to apply. While the physical probabilistic failure model shows good agreement with data recorded by UK water utilities, actual operating pressures from the UK is required to complete the model validation.     

Polarised infrared and differential scanning calorimetry studies on oriented vinyl pipe materials

The molecular orientation in a conventionally extruded PVC pipe, a uniaxially oriented PVC pipe and a biaxially oriented PVC pipe has been studied via Infrared dichroism. The degree of order or crystallinity has also been studied by Differential Scanning Calorimetry and also via Infrared Spectroscopy. The fundamental structural difference between the conventional and oriented pipes was that polymer chains were preferentially aligning in the hoop direction for oriented pipes whereas they were fairly isotropic in the conventional pipe with a slight preferential alignment in the axial direction. Analysis of the C–Cl stretching mode indicated that the uniaxially oriented pipe had much higher alignment of the C–Cl bond in the axial direction than the biaxial pipe, which correlates with higher fracture toughness for circumferential cracking in the biaxial pipe. Both DSC and Infrared spectroscopy detected little change in the crystallinity or order in the oriented pipes compared to the conventionally extruded pipes.     

大口径X70感应加热试制弯管的组织与性能

选用直缝埋弧焊钢管,使用局部淬火和整体回火的工艺,通过严格控制各项工艺参数试制了两根弯曲度分别为25°和36°的大口径X70感应加热弯管,并对试制的弯管进行显微组织检验和力学性能试验。结果表明:试制的两种弯曲度的大口径X70感应加热弯管的显微组织均为贝氏体+铁素体+珠光体,为正常组织;其拉伸性能也均达到了X70级钢管的强度要求,且在-60℃低温时依然表现出优良的冲击性能。     

弯曲输流管道流固耦合动力特性分析

管道中流体和弹性体之间的相互作用是引起管道振动的主要原因,这种流固耦合作用对管道动力特性有直接影响。以流固耦合理论为基础,对脉动压力作用下的弯曲输流管道建立流体动力学模型及固体运动模型,在ANSYS Workbench中分别进行双向流固耦合受力分析、单双向流固耦合对比分析和模态分析,并考虑脉动压力,壁厚和管径等参数的影响。结果表明,弯管最大应力发生在入口和出口附近上下部,最大变形发生在转角及中间处;双向耦合作用下弯管最大等效应力与最大变形量均大于单向耦合;双向耦合作用下弯管固有频率明显降低,且固有频率随壁厚和管径的增大呈非线性增长。     

Factors influencing lead and iron release from some Egyptian drinking water pipes

The major objective of this study is to assess the effect of stagnation time, pipe age, pipes material and water quality parameters such as pH, alkalinity and chloride to sulfate mass ratio on lead and iron release from different types of water pipes used in Egypt namely polyvinyl chloride (PVC), polypropylene (PP) and galvanized iron (GI), by using fill and dump method.Low pH increased lead and iron release from pipes. Lead and iron release decreased as pH and alkalinity increased. Lead and iron release increased with increasing chloride to sulfate mass ratio in all pipes.EDTA was used as an example of natural organic matter which may be influence metals release. It is found that lead and iron release increased then this release decreased with time.In general, GI pipes showed to be the most effected by water quality parameters tested and the highest iron release. PVC pipes are the most lead releasing pipes while PP pipes are the least releasing.     

建筑隔震橡胶柔性管道抗震性能试验研究

橡胶柔性管道在隔震建筑中逐渐得到应用，其震后能否正常工作会直接影响建筑的使用功能。该文选取竖向安装的橡胶柔性管道作为研究对象，变形位移需求为400 mm，考虑2种公称内径和4种管道设计长度影响，进行了抗震性能试验，对比分析了该类管道的地震损伤演化模式、变形和承载能力特征。试验结果表明:设计长度较小的管道均无法满足预期变形目标，经历管道绷直以及单侧断裂破坏两个关键状态，震后必须更换；对于设计长度符合规范建议的管道，则可以满足变形需求；回归分析获得了管道公称内径和设计长度与其水平变形能力之间的量化关系；管道设计长度相同时，管道公称内径与其破坏时的水平极限荷载呈正相关关系，但大公称内径和小公称内径管道的极限水平荷载之比小于公称内径比。     

Effect of toughness on low cycle fatigue behavior of pipeline steels

The effect of toughness on the fatigue behavior of pipeline steels was investigated, including the fatigue crack propagation rate and low cycle fatigue test under the loading condition simulating the actual operation of pipelines. The results indicate that the toughness can strongly influence the fatigue behavior of pipeline steels (i.e., the steels with high toughness possess high resistance to fatigue crack propagation and high tolerance of damage, which are much beneficial to obtaining a long life for line pipe structures).     

基于激光跟踪仪的超声流量计几何参数实测方法

针对需要现场安装的大口径超声流量计的几何参数外部测量问题,建立了基于激光跟踪仪的大口径超声流量计几何参数测量方法。利用跟踪仪在管道外部测量管段壁面和超声探头的三维特征,并通过三维建模工具获得管段和探头的相对位置关系,进而计算得到流量计几何参数。结合现场测量案例,评估了内径、声道长度、声道角、声道高度等参数对流量不确定度的贡献。该方法不仅解决了管道外部几何参数实测问题,而且能将不确定度水平控制在0.2%左右。与跟踪仪实测值相比,几何参数厂家设置值存在一定的差异,建议厂家和用户给予几何参数实测更多的关注。     

Structural integrity analysis of HDPE pipes for water supplying network

A problem of reliability of polymer pipes manufactured with the high‐density polyethylene (HDPE) for drinking water supply was considered. The safety of the pipelines network was analyzed with taking into account two main factors: arising of sudden overpressure (water hammer phenomenon) and presence of defects on pipe surface. Based on elastoplastic fracture mechanics and using of J‐integral approach, the numerical model of cracked pipe was developed and verified by direct experimental test. The formula for calculation of crack initiation pressure, which is the function of pipe size and size of external surface defect, was derived. The validity of this relation was proved for pipes of diameter 450 to 800 mm. It was also shown that the pressure peaks of the water hammer phenomenon are quickly damped because of the high deformability of the polyethylene pipes and the defect depth that is equivalent to 40% of pipe wall thickness can be considered as acceptable. The applicability of developed tools was demonstrated under analysis in the real state of South Tunisian water supply network.