Decision support framework to incorporate river bank stability in pipeline crossing risk assessment

苏格兰水务公司已经确定，在评估管道穿越处的河流侵蚀风险时，有必要制定处理不确定性的方法。特别是，对于被认为受河岸侵蚀或桥台周围冲刷的风险较大的资产，需要开发和试行各种方法，利用初步资产检查的数据，量化风险和不确定性，以决定在更详细的检查中在哪里投入额外资源。这一挑战源于这样一个现实，即在过去10-15年里，管道穿越检查一直是以临时方式进行的。因此，这项建议的目的是建立一个决策支持框架，将河岸稳定性纳入管道穿越风险评估。这将在2016年内立即用于苏格兰水务公司的首个全国性管道桥梁资产检查项目。具体目标是：(1)评估用于筛查风险的现有基于APP的低成本检查数据库中的不确定性；(2)评估河岸稳定性评估最初案头阶段产生的不确定性；(3)制定管道穿越冲刷评估框架，以便在筛选阶段分析河岸稳定性，并为初步评估阶段确定适当的分析；(4)递归测试风险评估框架。为了实现这些目标，将有三个方法阶段，结果将逐步报告。首先，将使用复制检测应用程序重新调查管道穿越的样本。结果将能够在风险管理的筛选阶段评估数据采集中的不确定性及其对河流稳定性决策的影响。其次，将考虑资产检查应用程序、谷歌地球图像、苏格兰水务委托的高分辨率航空图像以及苏格兰政府收购的遗留激光雷达的数据，评估评估银行侵蚀的不确定性。河流不稳定的证据将从图像中绘制出来。将使用适当的技术来量化变化，以表示数字化和地形变化分析中的误差。最后，结果将被用来产生一个框架，以：(1)确定筛查期间的风险特征；(2)为初步风险评估确定最适当的基于案头的分析形式。该框架将包括一个多标准程序，用于在初步评估阶段之后计算风险，以确定是否有必要进行更详细的评估阶段，如果有必要，则采取必要的行动。这一框架将在另外20个地点进行测试。项目产出将付诸实施，并用于改进决策。基于应用程序的数据捕获将得到改进，为资产检查员提供增强的数据字段和培训材料。评估数据和分析中的不确定性的结果将被输入一个多标准评分框架，该框架将改进筛选和初步评估阶段的决策，从而使稀缺资源能够优先用于基于案头的河岸稳定性分析。该框架将用于目前的饮用水管道穿越检查方案，也将对未来的废水管道穿越检查方案具有价值。该项目将持续12个月，这将使对足够大的数据样本、分析方法和地点的不确定性进行评估。工程总造价(80%FEC)为国标89,707。这包括威廉姆斯和霍伊的员工成本、9个月的研究助理时间、计算机硬件和旅行。

Scottish Water has identified the need to develop their approach to dealing with uncertainty when assessing the risk of river erosion at pipeline crossings. In particular, there is a need to develop and pilot methods that can use data from initial asset inspections to quantify risks and uncertainties in making decisions on where to invest additional resources in more detailed inspections, for assets deemed to be at greater risk from river bank erosion or scour around bridge abutments. This challenge arises from the reality that, over the past 10-15 years, pipeline crossing inspections have been undertaken in an ad-hoc manner. The aim of this proposal is, therefore, to develop a decision support framework to incorporate river bank stability in pipeline crossing risk assessment. This will be used immediately during 2016 in Scottish Water's first, national-scale pipeline bridge asset inspection programme. The specific objectives are to: (i) evaluate uncertainty in the existing low-cost app-based inspection database that is used to screening risk; (ii) assess the uncertainty that arises from the initial desk-based phase of river bank stability assessment; (iii) develop a pipeline crossing scour assessment framework for analysing river bank stability at the screening phase and determining appropriate analysis for the initial assessment phase; and (iv) recursively test the risk assessment framework. To address these objectives there will be three methodological phases, results from which will be progressively reported. First, a sample of the pipeline crossings will be re-surveyed using a replicate inspection app. Results will enable evaluation of uncertainties in data capture and their consequences for river stability decision making at the screening stage of risk management. Second, uncertainty in assessing bank erosion will be assessed considering data from the asset inspection app, Google Earth imagery, high-resolution aerial images commissioned by Scottish Water, and legacy LiDAR acquired by the Scottish Government. Evidence of river instability will be mapped from imagery. Change will be quantified using appropriate techniques to represent errors in digitising and topographic change analysis. Finally, results will be used to produce a framework to: (i) characterise risk during screening; and (ii) determine the most appropriate forms of desk based analysis for initial risk assessment. The framework will include a multi-criteria process for calculating risk after the initial assessment phase to determine whether a more detailed assessment phase is necessary and, if so, necessary actions. This framework will be tested at a further set of 20 sites. Project outputs will be operationalised and used to improve decision making. App-based data capture will be improved with enhanced data fields and training material for asset inspectors. Results from evaluating uncertainty in data and analysis will be input to a multi-criteria scoring framework that will improve decision making at the screening and initial assessment stages and will thus enable scarce resources to be prioritised for desk-based river bank stability analyses. The framework will be used in the current drinking water pipeline crossing inspection programme and will also be of value for a future waste water pipeline crossing inspection programme. The project will last 12 months which will enable evaluation of uncertainty in a sufficiently large sample of data, analysis approaches and sites. The total cost (80% FEC) of the project is £89,707. This includes staff costs for Williams and Hoey, 9 months research assistant time, computer hardware, and travel.