Strain Based Design for Buried Steel Pipelines

埋地钢质管道基于应变的设计

• 批准号: RGPIN-2017-06606
• 负责人: Cheng, JungJune
• 金额: $ 1.53万
• 依托单位: University of Alberta
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=712271
• 关键词: Strain; Based; Design; Buried; Steel

Pipelines are one of the most economical modes of transportation for oil and gas from the location of the resources to the market. They are a key factor influencing the Canadian energy industry and overall economy. Energy pipelines are designed to transport pressurized highly flammable substances over a long distance, therefore, safety of the pipelines is paramount throughout the life of the infrastructure. To minimize the environmental and temperature effects, most of pipelines in Canada are buried underground. During the operation, pipelines are normally sustained a combination of circumferential stresses due to the internal pressure and longitudinal stresses induced by external loads/deformations. These external loads/deformations are primarily the result of soil movement and temperature effects. The stress design method is normally used to design these complex combined loading conditions. However, due to the complex nature of each ultimate limit state of a buried pipeline under internal and external loads/deformations, the stress design method is unable to address the needs of pipeline design, maintenance and operation. The strain based design method is proposed here, in recognizing various ultimate limit states of a buried pipe under combined loading conditions. Both the critical buckling compressive strain and tensile fracture strain capability will be included. The post-buckling behaviour of a buried pipe, based on the past research, has shown significant reserve capacity and unique behaviour after buckling. The inclusion of post-buckling strength into the strain based design will yield a more economical, rational and safe design. The various parameters will be investigated in this program, including different grades of steel, diameter to thickness (D/t) ratios, internal pressures, external loads, girth welds, corrosion, defects (or dents), and cold-bend. The limit states of a buried pipe under various combined loading conditions will be identified and corresponding strain limits will be proposed. Due to the harsh environmental and unpredictable operational conditions of a buried pipeline, a probability based risk assessment is proposed for a safe operation of a pipeline. Structure health monitoring methodology will be used in conjunction with the strain based design methods in developing the assessment tool. The signature patterns of each limit state will be studied and developed using the finite element method. The feasibility of using fibre optic sensing (FOS) technology in measuring distributed strains of a buried pipe will be investigated. Finally, structural health monitoring programs using various innovative sensing technologies will be proposed for each limit state of a buried pipe and its unique responding signature patterns.

管道是将石油和天然气从资源位置运输到市场的最经济的方式之一。它们是影响加拿大能源工业和整体经济的关键因素。能源管道的设计目的是长距离输送加压的高度易燃物质，因此，管道的安全性在基础设施的整个生命周期中至关重要。为了尽量减少环境和温度的影响，加拿大的大部分管道都埋在地下。在运行过程中，管道通常承受由内部压力引起的周向应力和由外部载荷/变形引起的纵向应力的组合。这些外部载荷/变形主要是土壤移动和温度效应的结果。 应力设计方法通常用于设计这些复杂的组合载荷条件。然而，由于埋地管道在内部和外部载荷/变形下的每个极限状态的复杂性，应力设计方法无法满足管道设计、维护和运行的需要。 本文提出了基于应变的设计方法，以识别埋地管道在复合荷载作用下的各种极限状态。将包括临界屈曲压缩应变和拉伸断裂应变能力。基于过去的研究，埋地管道的屈曲后行为已经显示出显著的储备能力和屈曲后的独特行为。将屈曲后强度纳入基于应变的设计中，将使设计更加经济、合理和安全。在本程序中将研究各种参数，包括不同等级的钢、直径与厚度（D/t）比、内部压力、外部载荷、环焊缝、腐蚀、缺陷（或凹痕）和冷弯。对埋地管道在各种组合荷载作用下的极限状态进行了识别，并提出了相应的应变限值。 针对埋地管道的恶劣环境和不可预测的运行条件，提出了基于概率的风险评估方法，以保证管道的安全运行。在开发评估工具时，结构健康监测方法将与基于应变的设计方法结合使用。每个极限状态的签名模式将使用有限元法进行研究和开发。研究了光纤传感技术在地下管道应变测量中的可行性。最后，结构健康监测计划，使用各种创新的传感技术将提出每一个极限状态的埋管和其独特的响应签名模式。