Testing, analysis and performance of new and existing buried pipes installed using conventional and trenchless technologies

安装、维修和更换地埋式下水道、自来水和能源管道涉及巨额支出。例如，2012年加拿大基础设施成绩单规定，“废水基础设施的重置成本为390亿美元，处于”一般“到”非常差“的状态。”渗漏的下水道和水管形成的天坑危及地面的交通和基础设施。生命线故障的风险包括自来水管道受损或洪水泛滥，而油气管道泄漏造成的爆炸或环境污染造成的成本可能非常巨大(2010年密歇根州Enbridge管道破裂后，清理工作花费了7亿美元)。 新埋地管道在覆岩压力作用下的二维强度极限已被申请人等人广泛研究。然而，硬质下水道管道在使用寿命结束时的稳定性受管道结构断裂的控制，这可能是由于管道旁边的土壤通过渗漏的接头侵蚀而引起的，如果这些侵蚀空洞需要在用衬垫修复下水道之前需要修复，以及如何修复，需要提供指导。还需要关于钢筋混凝土下水道中钢筋腐蚀的影响的信息。此外，沿连续和连接的管道的不均匀地面移动导致的荷载可能会导致故障，目前在拥挤的城市地区广泛使用的非开挖更换或安装管道的方法可能会损坏邻近的管道基础设施。这笔探索基金将支持一项研究计划，调查控制“多少管道和/或土壤的恶化是太严重的恶化？”的因素，土壤或管道修复前后土壤-管道相互作用的变化，不同地面运动对水、石油和天然气输送管道的影响，以及与非开挖施工相关的管道损坏问题。其目标是为新管道或替换管道的设计和施工、劣化管道的评估及其维修制定新的和扩展现有的指导方针。 1.对渗漏下水道侵蚀造成的土壤空隙的开创性调查将首次测量空隙对管道强度的影响，以及一旦填充灌浆或聚合物泡沫后空隙的影响。空洞几何形状和管道响应的测试数据将支持使用衬里修复管道之前和之后的土壤空洞的计算机建模。土壤空洞可能会导致最灾难性的市政管道故障(人行道或其他结构下的天坑将公共和其他基础设施置于危险之中)。此外，粘土和混凝土下水道的长期故障可能是由于接缝的这种侵蚀造成的，这些工艺的确认将加强开发具有更长寿命的管道的努力。 2.利用埋地管道试验和分析来研究移动地面上的压力管道响应。在管道穿过不稳定的斜坡或地震断层时，或在非开挖施工方法(如静力爆管和定向钻探)引起变形的情况下，将检查管道弯曲和失效。新的测试、分析和设计程序可以提高管道的安全性和经济性。 这两个主题领域的13个研究生项目将在DG资助的5年内提出。四名硕士研究生和九名博士生将致力于获得开创性测试结果的项目，开发新的计算机分析方法，制定新的或改进的管道和涵洞安装、评估和设计程序，获得岩土和/或结构工程方面的专业知识，以及对行业具有重要价值的尖端分析、测试和设计能力。

The installation, repair and replacement of buried sewer, water and energy pipes involves huge expenditures. For example, the 2012 Canadian Infrastructure Report card states "the replacement cost for the wastewater infrastructure in “fair” to “very poor” condition is $39 billion". Sinkholes from leaking sewers and water pipes endanger traffic and infrastructure at the ground surface. Risks from lifeline failures include loss of water or flooding from damaged water mains, and the costs resulting from explosions or environmental contamination from leaking oil and gas pipelines can be very substantial (>$700M was spent on cleanup after the Enbridge pipeline rupture in Michigan in 2010). The two dimensional strength limits of new buried pipes under overburden pressures have been studied extensively by the applicant and others. However, rigid sewer pipe stability at the end of service life is controlled by fracture of the pipe structure, likely caused by erosion of the soil beside the pipe through leaking joints, and guidance is needed if these erosion voids require repair before the sewer is rehabilitated with a liner, and how to do so. Information is also needed on the impact of corrosion of steel in reinforced concrete sewers. Furthermore, the loading that results from nonuniform ground movements along continuous and jointed pipelines can induce failure, and trenchless methods of pipe replacement or installation now used widely in congested urban areas can damage adjacent pipe infrastructure. This Discovery Grant will support a program of research investigating the factors controlling ‘how much pipe and/or soil deterioration is too much deterioration?’, the changes to soil-pipe interaction that occur with that deterioration, both before and after repair of the soil or pipe, the impact of differential ground movements on water, oil and gas transmission pipelines, and pipeline damage issues associated with trenchless construction. The goal is to develop new and extend existing guidance for design and construction of new or replacement pipes, the assessment of deteriorated pipes, and their repair. 1. A seminal investigation into soil voids due to erosion into leaking sewers will be the first to measure void impacts on pipe strength and the influence of the void once filled with grout or polymer foam. Test data on void geometry and pipe response will support computer modeling of soil voids before and after pipe repair using liners. Soil voids likely produce the most catastrophic municipal pipe failures (sinkholes under pavements or other structures place the public and other infrastructure at risk). Also, the long term failure of clay and concrete sewers likely results from such erosion through joints, and confirmation of these processes will strengthen efforts to develop pipes with improved longevity. 2. Pressure pipe response in moving ground will be examined using buried pipe tests and analyses. Pipeline bending and failure will be examined where pipes pass across unstable slopes or earthquake faults, or where deformations are induced by trenchless construction methods such as static pipe bursting and directional drilling. The new testing, analysis and design procedures can improve both pipeline safety and economy. Thirteen graduate student projects in the two theme areas are being proposed over the 5 years of DG funding. Four MASc and nine PhD students will work on projects obtaining seminal test results, developing new methods of computer analysis, producing new or improved procedures for pipe and culvert installation, assessment, and design, and acquiring specialised expertise in geotechnical and/or structural engineering, and leading-edge analysis, testing and design capabilities of great value to industry.