Performance assessment of buried pipes: service life and pipe-soil stability over time

埋地管道的性能评估：使用寿命和管土稳定性随时间的变化

• 批准号: 105634-2006
• 负责人: Moore, Ian
• 金额: $ 4.92万
• 依托单位: Queen's University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2008
• 资助国家: 加拿大
• 起止时间: 2008-01-01 至 2009-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=390935
• 关键词: Performance; assessment; buried; pipes; service

Many of our buried pipes are more than 50 years old, and Canada invests $B's each year on sewer, culvert and water pipe repair. This has prompted the development of decision support systems to minimize life cycle cost. Unfortunately, most research has considered the pipe in its initial burial configuration over its service life, setting that service life by considering how the pipe alone degrades. Actual failure often involves changes in soil and pipe components and their interaction: rigid pipe (clay, concrete) generally fails when backfill erodes as water flows in through joints; thermoplastic pipe design uses 'constant stress' testing to establish material limits which ignores varying stresses, and also neglects soil deterioration; cast iron water pipes mostly experience ring fractures, not a result of internal pressure but of longitudinal bending due to frost. Better pipe service lives are needed, considering changes in the pipe and soil system and the actual mechanisms of pipe failure. The goal is to incorporate improved models of pipe failure into decision support systems being developed with collaborators for transportation and municipal engineers. Theme A (Gravity flow pipes) will study the stability of rigid pipes in eroded backfill, how different components in joint systems interact and the implications for long term performance of flexible and rigid pipes (including a study of the loads and capacity of joints supporting vertical service connections, i.e. risers), how water inflow at joints induces backfill erosion, the long term strength of thermoplastic pipes under complex stress conditions, and the long term performance of metal and concrete culverts considering construction and other effects. Theme B (Pressure pipes) will investigate water supply pipes under frost loads and the strength of deteriorated cast iron pipes. The work will involve training of six MSc and six PhD students over the five year funding period.

我们的许多埋地管道已有 50 多年的历史，加拿大每年投资 B 美元用于下水道、涵洞和水管修复。这促使决策支持系统的开发，以最大限度地降低生命周期成本。不幸的是，大多数研究都考虑了管道在其使用寿命期间的初始埋藏配置，通过考虑管道本身如何降解来设定使用寿命。实际失效通常涉及土壤和管道成分的变化及其相互作用：刚性管道（粘土、混凝土）通常在水流经接缝时回填土受到侵蚀时失效；热塑性管道设计使用“恒定应力”测试来建立材料限制，忽略变化的应力，也忽略土壤恶化；铸铁水管大多会出现环形断裂，这不是由于内压造成的，而是由于霜冻造成的纵向弯曲。考虑到管道和土壤系统的变化以及管道失效的实际机制，需要更长的管道使用寿命。目标是将改进的管道故障模型纳入与交通和市政工程师合作者开发的决策支持系统中。主题 A（重力流管道）将研究侵蚀回填中刚性管道的稳定性、接头系统中不同组件如何相互作用以及对柔性和刚性管道的长期性能的影响（包括研究支撑垂直方向的接头的载荷和能力）服务连接，即立管），接头处的水流入如何引起回填侵蚀，热塑性管道在复杂应力条件下的长期强度，以及考虑施工和其他影响的金属和混凝土涵洞的长期性能。主题 B（压力管道）将研究霜冻载荷下的供水管道以及劣化铸铁管道的强度。这项工作将涉及在五年资助期内培训六名硕士生和六名博士生。