Dam Seepage Sensing and Modelling

大坝渗流传感和建模

• 批准号: 543918-2019
• 负责人: Butler, Karl
• 金额: $ 3.4万
• 依托单位: University of New Brunswick
• 依托单位国家: 加拿大
• 项目类别: Collaborative Research and Development Grants
• 财政年份: 2021
• 资助国家: 加拿大
• 起止时间: 2021-01-01 至 2022-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=720828
• 关键词: Dam; Seepage; Sensing; Modelling

Earthen embankment dams are widely used to contain hydroelectric reservoirs, water supplies and wastes such as those produced by mining and oil sands operations. Concentrated water seepage through such dams must be avoided to prevent internal erosion of fine-grained materials and the development of piping - a major cause of dam failure. Although standards for dams in Canada are amongst the strongest in the world, best practices have progressed over time, and the need for improved seepage monitoring methods that can be applied to aging structures is recognized internationally. UNB and NB Power will design and evaluate, through field trials and modelling, three minimally invasive geophysical approaches for the early detection and quantification of concentrated water seepage. The project will be based at NB Power's Mactaquac Generating Station on the Saint John River near Fredericton, NB, which includes a 500 m long zoned embankment dam, completed in 1968, that rises 32 m above its toe. The methods will rely largely on monitoring of seasonal temperature variations within the dam, as measured directly using distributed temperature sensing (DTS), and indirectly by electrical resistivity imaging (ERI). Regions of higher seepage are expected to exhibit greater seasonal variations in temperature and hence resistivity as water from the dam reservoir moves through it. Zones of particular interest include the dam's clay till core and the left abutment where the dam adjoins a concrete diversion spillway structure that is undergoing differential expansion as a consequence of Alkali Aggregate Reactivity in the concrete. The former will be investigated using time-lapse 2D resistivity monitoring along the dam crest which has yielded encouraging results on similar dams in Sweden. The abutment region will be investigated in more detail using borehole DTS complemented by time-lapse 3D resistivity monitoring with electrodes on the back of the dam. The research will build on valuable insights obtained from prior monitoring research in the abutment region using DTS and self-potential (SP) methods. It will be applicable worldwide but particularly in regions such as Canada where seasonal temperature variations are large.

土堤坝广泛用于容纳水电站、供水和废物，例如采矿和油砂作业产生的废物。必须避免集中水渗过此类大坝，以防止细粒材料的内部侵蚀和管道的发展——这是大坝溃坝的主要原因。尽管加拿大的大坝标准是世界上最严格的标准之一，但随着时间的推移，最佳实践已经取得了进步，并且国际上认识到需要改进可应用于老化结构的渗流监测方法。 UNB 和 NB Power 将通过现场试验和建模来设计和评估三种微创地球物理方法，用于早期检测和量化集中渗水。该项目将设在新斯科舍省弗雷德里克顿附近圣约翰河上的 NB Power Mactaquac 发电站，其中包括一座 500 m 长的分区堤坝，于 1968 年竣工，坝趾高出 32 m。这些方法将在很大程度上依赖于对大坝内季节性温度变化的监测，使用分布式温度传感（DTS）直接测量，并通过电阻率成像（ERI）间接测量。当大坝水库的水流过渗透率较高的区域时，预计温度和电阻率的季节性变化较大。特别令人感兴趣的区域包括大坝的粘土心墙和左坝肩，其中大坝毗邻混凝土导流溢洪道结构，该结构由于混凝土中的碱骨料反应性而发生差异膨胀。前者将利用沿坝顶的延时二维电阻率监测进行调查，这在瑞典的类似水坝上取得了令人鼓舞的结果。将使用钻孔 DTS 并通过大坝背面的电极进行延时 3D 电阻率监测来更详细地研究桥台区域。该研究将建立在之前使用 DTS 和自电位 (SP) 方法对基台区域进行监测研究中获得的宝贵见解的基础上。它将适用于全世界，特别是在加拿大等季节性温度变化较大的地区。