大口径高性能聚氯乙烯管道研发与工程安全保障技术

该文围绕大口径高性能聚氯乙烯管道的混配料配方设计、制造设备研发、生产工艺优化、管材质量评定、管线工程安全评价、运行监测与病害修复等关键技术,通过产学研用相结合,持续10余年攻关取得一系列突破性创新成果：研发了新型聚氯乙烯管材复合改性增韧混配料,优化了管材材料配比,创新了大口径高性能聚氯乙烯管材模具与工艺,首创了国内唯一直径1800 mm大口径聚氯乙烯管生产线;研发了具有高强、高韧、高抗冲的聚氯乙烯管道新产品：ABR管(给水用丙烯酸酯共混聚氯乙烯管),建立了ABR管质量评价方法,开展了ABR管管材拉伸、热膨胀和ABR管内、外压结构承载性能试验;创建了复杂运营环境下大口径管线工程安全评价方法,系统开展了落石冲击、土体塌陷、滑坡和和地质断层等自然灾害作用下的埋地聚氯乙烯管线工程安全性能原型试验与数值模拟;开展了基于光纤传感技术的管道变形健康监测试验,研发了新型管道内检测设备—“谛听”机器人,结合“谛听”机器人与目标检测人工智能算法进行了管道缺陷定位识别与病害诊断,提出了Spetec注浆堵漏加固、不锈钢快速锁修复技术、树脂固化局部修复工艺、紫外光固化内衬的整体不开挖修复技术,实现了对聚氯乙烯管...     

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.     

供热管道地震易损性分析

为了研究供热管道的地震易损性,采用有限元分析方法,建立了典型供热管道分析模型,选取典型地震波作为输入,通过数值模拟手段,对供热管道在地震作用下的应力反应进行了计算分析。基于三态破坏准则对单体管道地震破坏概率进行了分析,给出了供热管道不同地震烈度下的破坏概率。根据管道破坏服从泊松分布的基本假定,对不同烈度下一定长度供热管道地震破坏处数进行了估计,同时与历史地震中管道震害经验统计结果进行了对比分析,初步评述了供热管道的抗震性能。     

X65管线钢焊接接头在模拟浅表海水环境中的应力腐蚀试验研究

在海水环境中,由于海水从海底管道外管焊缝浸入,导致外管焊接接头断裂。为了研究可能导致X65外管焊接接头断裂的因素,应用慢应变速率拉伸试验(SSRT),通过应力-应变曲线、扫描电镜(SEM)等手段分析了3个X65管线钢焊接接头在空气及模拟浅表海水环境中的应力腐蚀性能。结果表明:在空气中X65钢焊接接头试样的延长量最大,达5.6 mm,在模拟海水中试样的延长量均减小,其中2号试样延长量最小,仅3.6 mm,表明试样在浅表海水中塑性变形能力降低;模拟海水中3个试样的应力腐蚀敏感性指数均处于有应力腐蚀倾向的范围;在空气中试样的断裂为韧性断裂;在浅表海水环境中试样的断裂为韧性断裂与脆性断裂的混合断裂,有应力腐蚀开裂的趋势;海水中含有的大量Cl~-导致焊接接头的应力腐蚀敏感性升高,失效风险增加。     

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。     

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.     

管道承插式接口轴向力学性能试验研究与数值模拟

通过球墨铸铁供水管线承插式接口抗拉静载力学性能试验,分析管道接口轴向的拉伸力学性能和破坏模式,并建立相应管道接口受力分析的有限元数值模型。在外部无覆土、加压注水条件下,对球墨铸铁输水管道承插式接口进行拟静力拉拔试验,模拟其在地震作用等往复荷载下的轴向受力与变形特征。试验结果表明,加载方式以及管道内部水压等对接口的轴向抗拉力学性能和破坏方式的影响不大,抗拉极限位移达到60 cm。基于OpenSees计算平台建立管道接口有限元模型,并对试验结果进行了模拟,结果表明建立的管道接口有限元模型能够较好地模拟管道接口在轴向往复荷载作用下的刚度退化和耗能等力学特征,为埋地管道在复杂轴向荷载作用下的受力分析和性能评估提供了必要的试验数据和计算模型。     

An application of experimental design‐an improvement of a golden mill

Abstract

The seismic behavior of lifeline systems is predominately controlled by the ground displacement/strain characteristics. This study investigates the wave propagation effect and the ground displacements and ground strains from the latest strong‐motion array data recorded at the Public Work Research Institute (PWRI) of Japan by using finite element method. Usually, the buried pipeline almost moves with the surrounding soil during seismic shaking. In this respect, the investigation of ground displacement characteristics can be used for further application to seismic design of buried pipelines.     

穿越非均匀土体埋地管道地震离心实验研究

穿越非均匀土体经历不同地震作用的埋地管线的变形和残余强度严重影响着管道的安全。该文采用离心振动台分别平行于埋地管道长度方向输入0.6 g和0.3 g峰值地面加速度地震波,研究了埋地管道在一系列地震作用和不均匀土体变形共同作用下的响应,得到了PVC和铝合金两种埋地管道穿越软土/硬土土体的地震响应规律。地震引起不均匀土体的瞬时变形,导致埋地管道最大应变发生在土体分界面和软土中,管道拉伸应变幅值软土要大于硬土,而压缩应变幅值正好相反,硬土中管道拉伸应变幅值小于压缩应变幅值,硬土中管道压缩应变幅值受地震烈度影响比软土大。地震引起的土体永久变形对埋地管道残余变形影响很大,硬土中的管道残余应变为压应变,软土中管道的残余应变为拉压应变交替分布。     

新安江水力发电厂▽38坝前引水管改造

部分早期建造的水电站的技术供水管道用的是铸铁管,对于无法更换的部分一旦出现裂纹很难处理.新安江水电厂坝前引水管改造中,在铸铁管外面增设一层按密封承压设计的新钢管,并在新、旧钢管之间灌注填料,这为老电站铸铁管的改造提供了一种有效方法.     

Failure resistance of drilling rig casing pipes with an axial crack

Working conditions of casing pipes in drilling rigs can significantly influence the initiation and development of damage in the material, and therefore also the safe service of the entire system. In this work, an integrity assessment of a pipe with initial defect (machined surface crack) is presented. The position of this defect is on the external surface; unlike transport pipes, where internal surface is often endangered due to the contact with the fluid, casing pipes are also often exposed to damages at the external surface. A pipe segment exposed to internal pressure is examined experimentally and numerically, using the finite element method. Experimental setup included tracking of crack mouth opening displacement (CMOD) values, as well as J integral. Criteria for pipe failure are determined on the finite element (FE) models of the pipe; fracture initiation and plastic collapse are considered as failure mechanisms. Several 3D models with different crack sizes are evaluated. 2D plane strain models are also examined, to determine the applicability limits of this simplified approach. Integrity assessment criteria for the analysed geometries are discussed. Assessment of fracture resistance of the pipeline material is also considered in this work. Besides the standard SENB specimens, Ring specimens cut from the pipe are tested, and the results are compared. Both specimen geometries are modelled using local approach to fracture, by application of the micromechanical Complete Gurson model (CGM), developed by Z.L. Zhang. It is shown that the Ring specimens have similar fracture conditions under bending load as SENB specimens. Since they are much simpler to fabricate from the pipe than standard specimens, it is concluded that they can be used for assessment of fracture of the pipes with axial cracks.     

考虑近断层脉冲型地震动影响的埋地管道地震易损性分析

近断层脉冲型地震动具有短时高能量的脉冲特性,会对埋地管道等长周期结构造成较为严重的破坏。为研究近断层脉冲型地震动影响的埋地管道抗震性能,该文基于简化速度脉冲模型,结合脉冲周期、脉冲峰值的经验统计公式,模拟了不同地震动的方向性脉冲分量和滑冲脉冲分量,通过与ATC-63报告推荐的远场地震动中的高频成份进行叠加,合成了具有多种频率成分的近断层脉冲型地震动;在此基础上,进一步考虑空间变异性,生成了的空间相关多点非平稳地震动。利用ANSYS软件进行有限元建模,输入人工合成的地震动进行增量动力时程分析,建立了PGV与埋地管道最大应变之间关系的概率地震需求模型,结合管道极限破坏状态的划分,进而建立了考虑不确定性的不同管材、管径、壁厚及填覆土的埋地管道地震易损性模型。该模型为跨断层埋地管道地震风险评估中的地震易损性分析提供了理论基础。     

Plastic damage analysis of oil and gas pipelines with unconstrained and constrained dents

Indentation resulting from mechanical damage is one of the main causes of pipeline rupture failure. The primary objective of this case study is to analyze the plastic damage of the pipelines with unconstrained and constrained dents using the existing plastic damage model, namely, the ductile failure damage indicator (DFDI) model. As part of this study, an attempt is made to clarify the influence of the constraint on the behavior of the pipeline. The investigation indicates that the plastic damage of the pipeline interior walls outweighs that of the pipeline exterior walls and cracks start frequently from the pipe interior walls. The position of the maximal circumferential plastic damage deviates from the deepest position of the dent when the critical displacement loading arriving due to the circumferential deformation of the pipeline. The total plastic damage of the unconstrained dented pipeline only depends on the initial displacement loading because the working pressure has very little influence on its behavior under the unconstrained condition. However, the total plastic damage of the constrained dented pipeline depends on the initial displacement loading and the working pressure because the working pressure has a significant effect on its behavior under the constrained condition. Under the same condition, the constrained dented pipeline is easier to crack compared to the unconstrained dented pipeline. In this paper, the model, results and the findings are summarized and discussed.     

不同CMR的RC框架结构地震损失分析

为研究结构抗倒塌储备能力对减小结构地震损失的作用,提出基于结构抗倒塌能力储备系数(CMR)的钢筋混凝土框架结构地震损失分析方法。利用IDA方法,确定结构在连续地震强度下的易损性,根据结构的破坏概率及易损性曲线计算地震经济损失。将结构抗倒塌能力指标CMR与结构在给定地震强度下的经济损失相结合,建立基于CMR的地震损失模型。对脆性及延性结构的倒塌特性和地震损失进行了系统地对比分析。通过四个RC框架结构分析,结果表明:地震损失评估与结构的CMR具有密切关系。在给定地震强度作用下,结构地震损失随CMR的增大而减小;CMR较小的结构随地震强度的增大损失增加较快,而CMR较大的结构则随地震强度的增大损失增加相对较平缓。所提出基于结构CMR地震损失评估思想可以作为量化地震损失评估较有前景的改进方法。     

输液管线中的地震动水压力及其影响因素

强烈地震作用可使地上输液管线中的液体产生较大的动水压力。基于模态叠加原理及地震反应谱理论，考虑流体可压缩性及管弹性，建立了输液管线地震动水压力的计算模型。根据流体所处边界条件的不同，给出两种典型工况下，管流地震动水压力的计算公式，并与依据附加质量模型计算所得的结果进行了比较。比较结果表明：管线长度对管流地震动水压力有显著的影响，对长管道而言，以附加质量模型求得的的地震动水压力高于考虑流体可压缩性时求得的地震动水压力，而对于短管道，情况刚好相反。另外，场地类型及管流所处工况对管流地震动水压力也有显著的影响，软土场地上的管理道。其内部流体地震动水压力明显高于硬土场地上的动水压力。     

Use of a Ring DWTT Specimen for Determination of Steel NDT from Pipe of Diameter Less than DN500

It has become recognized that the drop weight tearing test (DWTT) energy better represents the ductile fracture resistance of pipe steels since it utilizes a specimen that has the full thickness of the pipe and has a fracture path long enough to reach steady-state fracture resistance. However, the API 5L code does not require it for pipe sizes less than DN500. The aim of this paper is to propose a DWTT specific to small diameter pipes based on a new specimen, the ring drop weight tearing test (RDWTT) specimen; to evaluate the transition temperature T _{t, DWTT} and nil ductility temperature of the pipe steel API 5L X65; to introduce the transition temperature T _{t, DWTT} in the transition temperature material master curve of the API 5L X65 steel; and to compare the prediction of the crack ductile extension in a pipe based on the RDWTT’s energy and crack tip opening angle in the case of the steel API 5L X65.     

Effect of electric contact surface treatment on microstructure and wear behaviour of ductile iron

Abstract

A study of electric contact surface treatment to ductile iron has been carried out. This technology was based on the application of the contact resistance heating between the electrode and workpiece. For comparison, the experiments of induction hardening to ductile iron were studied. The microstructure, microhardness, surface residual stress and wear properties were investigated using optical microscope, scanning electron microscope, X-ray diffraction, Vickers microhardness and rolling contact wear tests. Electric contact surface treatment resulted in the formation of fine ledeburite (white bright layer) and martensite in the ductile iron surface, in which the hardness in these areas was higher than that of induction hardened surface. The wear test results showed that the ductile iron surface after electric contact surface treatment had better wear resistance owing to the fine microstructure, high hardness and residual compressive stress.     

大口径埋地钢管在地震断层作用下破坏模式的研究

利用壳有限元模型模拟了在土耳其地震和集集地震中埋地供水钢管在地震断层错动作用下的实际震害。从理论上得到一等效边界,引入到壳有限元模型的两端,因此只需对在断层附近发生大变形的管段进行壳分析。与梁有限元模型分析结果的比较,壳有限元模型能够更好地揭示断层作用下埋地钢管的各种屈曲破坏模式。通过区分断层两侧场地条件相同和相异这两种情况,很好地模拟了1999年土耳其地震中一根2.2m口径供水钢管在断层附近的三处破坏和集集地震中一根2.0m口径供水钢管在断层附近的二处破坏,探讨了断层两侧场地条件的分布形式对埋地管道破坏模式的影响。还详细地解释了土耳其地震供水钢管第三处破坏产生的原因。     

Weibull analysis, extrapolations and implications for condition assessment of cast iron water mains

The applicability of Weibull statistics to the condition assessment of cast iron water distribution pipes has been considered. The effect of Weibull modulus, characteristic strength, sample size and mode of loading (tension or flexure) on the strength of cast iron water distribution pipes is investigated. The strength distribution of cast iron samples cut from sections of five different water distribution pipes recovered from the ground have been characterized. Strengths have been measured in flexure, at two different temperatures (ambient and 0 °C), and in tension at ambient temperature using two different sample sizes. It is shown that characteristic strength values in flexure decrease with increasing size of graphite flake and that there is no significant difference between the results at the two temperatures investigated. For samples of the same volume tested in tension and flexure, the reduced strength measured in tension is consistent with Weibull predictions. However, the strength of large samples tested in tension was not significantly different from the small samples, perhaps because the samples were of the same thickness and conventional Weibull scaling is not applicable. Finally, using a method which treats a large pipe as an assembly of small samples, the strength distributions from the small samples tested in tension are used to make a prediction of the strengths of 1 m span sections of pipe loaded in three‐point bending, which were reported in previous work. The predicted pipe strengths are close to the lower end of the measured pipe strength distribution. Overall, this work suggests that Weibull analysis is a useful tool to examine the strength distribution of removed from cast iron water pipes and so has the potential to contribute in the assessment of asset condition.     

Full-scale impact tests on pipelines

There was a possibility that a new submarine pipeline under construction might accidentally fall on an existing pipeline in operation. Full-scale tests were carried out to study what would happen, and to reassure the operator that the existing line would not be ruptured. The tests dropped one length of a concrete-coated 508 mm (20-in) pipe onto another, and the largest kinetic energy of the falling pipe was 154 kJ. The tests measured the dents of the pipes, the damage to the concrete, and its reinforcement. Analysis sets out to account for the division of the impact energy between different absorption mechanisms.