Investigation of pull-out behaviour of small diameter medium density polyethylene pipes

小直径中密度聚乙烯管材拔出性能研究

• 批准号: 514564-2017
• 负责人: Dhar, Ashutosh
• 金额: $ 5.03万
• 依托单位: Memorial University of Newfoundland
• 依托单位国家: 加拿大
• 项目类别: Collaborative Research and Development Grants
• 财政年份: 2017
• 资助国家: 加拿大
• 起止时间: 2017-01-01 至 2018-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=618049
• 关键词: Investigation; pull; out; behaviour; small

Pipelines play an important role in modern society through transporting liquids and gases from the source to theusers. According to Natural Resources Canada, about 825,000 kilometers of oil and gas transmission, gatheringand distribution pipelines traverse Canada. Many of these pipelines pass through the areas prone to landslides.Soil movement due to landslides may cause longitudinal, transverse or combined loads on the pipelines,depending upon the orientation of the pipeline with respect to the moving ground. The existing designguidelines for structural integrity assessment of pipelines in landslide areas were developed based on theobservations for rigid pipes, which may not be applicable to flexible pipes, such as Medium DensityPolyethylene (MDPE) pipes. However, flexible polyethylene pipes including MDPE pipes have been widelyused over the last few decades due to their various advantages. The design method for the assessment of theperformance of MDPE pipelines subjected to landslide loading is not well-developed. Full-scale tests and finiteelement (FE) modelling of MDPE are also very limited. In the proposed research, a set of full-scale tests ofsmall diameter MDPE pipe will be conducted using the facility at Memorial University of Newfoundland(MUN) to develop a database and an improved understanding on the behaviour of pipes under the loads fromground movements. The test program will consists of following: i) axial pullout testing of plane pipes; ii) axialpullout testing of pipes with Tee-junctions (branched pipes); and iii) lateral pullout testing for pipes, buried inloose and dense sand. Laboratory element testing will be conducted to find geotechnical parameters anddevelopment of constitutive models for sand and the strain rate dependent behavior of MDPE pipe materials.FE modelling techniques will be developed using Abaqus FE software to simulate the observed response fromthe full-scale pipe tests. The findings from this research will be useful to the Canadian pipeline industry,enabling them to assess pipeline conditions in unstable ground and thus to make more effective managementdecisions to ensure structural integrity of the pipeline and minimize the risk of pipeline failure.

管道在现代社会中扮演着重要的角色，它将液体和气体从源头输送到用户。根据加拿大自然资源部的数据，大约有82.5万公里的石油和天然气输送、储存和分配管道横穿加拿大。这些管道中有许多都经过易发生滑坡的地区。滑坡引起的土壤移动可能会对管道造成纵向、横向或组合载荷，具体取决于管道相对于移动地面的方向。滑坡区管道结构完整性评估的现有设计指南是根据刚性管道的观察结果制定的，这可能不适用于柔性管道，如中密度聚乙烯（MDPE）管道。然而，包括MDPE管在内的柔性聚乙烯管由于其各种优点在过去几十年中得到了广泛的应用。滑坡荷载作用下MDPE管道的设计方法还不成熟。MDPE的全尺寸试验和有限元（FE）建模也非常有限。在拟议的研究中，将使用纽芬兰纪念大学（MUN）的设施进行一系列小直径MDPE管道的全尺寸试验，以开发数据库并提高对管道在地面运动载荷下的行为的理解。试验程序将包括以下内容：i）平面管道的轴向拉拔试验; ii）带三通接头的管道（分支管道）的轴向拉拔试验; iii）埋在松散和密实砂中的管道的横向拉拔试验。将进行实验室元件测试，以确定岩土参数，并开发砂的本构模型和MDPE管道材料的应变率相关行为。将使用Abaqus有限元软件开发有限元建模技术，以模拟全尺寸管道测试中观察到的响应。这项研究的结果将是有用的加拿大管道行业，使他们能够评估管道条件不稳定的地面，从而作出更有效的管理决策，以确保管道的结构完整性，并尽量减少管道故障的风险。