Self potential and temperature monitoring for seepage detection in embankment dams

土质堤坝被广泛用于容纳供水和水电站水库，以及采矿和油砂作业产生的废物。在所有情况下，都有必要确保通过大坝的任何渗漏都得到控制，以防止细粒材料的内部侵蚀和管道的发展，这可能会导致坍塌和灾难性的洪水或环境污染。UNB和NB Power建议设计、实施和评估一种新的被动监测系统，用于检测土石坝中的集中渗水。该项目将设在北卡罗来纳州弗雷德里克顿附近圣约翰河上的Mactaquac发电站，NB Power希望在那里监测土石坝的碾压混凝土核心与毗邻的混凝土导流结构之间的界面。尽管目前没有证据表明存在渗漏问题，但鉴于Mactaquac的混凝土结构因碱集料活性而退化，NB Power希望加强其监测能力，以进行尽职调查。将安装仪器以监测受水流影响的两个参数的变化：温度和自电电位(SP)。邻近界面的两个相邻钻孔将配备自主光纤分布式温度传感(DTS)和SP监测系统。在大坝下游面的表面上将安装额外的SP电极。SP监测系统的设计和测试，以及预期温度和SP对各种渗漏情况的响应的数值和实验室模拟，将是将在未来3.5年内完成的一个博士论文项目的重点。研究地点和时间范围将允许改进监测仪器和技术，以适用于在寒冷的冬季和炎热的夏季运行的大型堤坝。

Earthen embankment dams are widely used to contain water supplies and hydroelectric reservoirs, as well as wastes such as those produced by mining and oil sands operations. In all cases, there is a need to ensure that any seepage through the dam remains controlled, so as to prevent internal erosion of fine-grained materials and the development of piping, which can lead to collapse and catastrophic flooding or contamination of the environment. UNB and NB Power propose to design, implement and evaluate a novel passive monitoring system for the detection of concentrated water seepage through earthen embankment dams. The project will be based at the Mactaquac Generating Station on the Saint John River near Fredericton, NB, where NB Power would like to monitor the interface between the compacted till core of the embankment dam and the adjoining concrete diversion structure. Although there is no evidence of problematic seepage now, NB Power wishes to enhance its monitoring capabilities in the interest of due diligence, given that the concrete stuctures at Mactaquac suffer from degradation due to Alkali Aggregate Reactivity. Instrumentation will be installed to monitor variations in two parameters influenced by water flow: temperature and electrical self-potentials (SP). Two adjacent boreholes, drilled adjacent to the interface, will be equipped with autonomous fibre optic distributed temperature sensing (DTS) and SP monitoring systems. Additional SP electrodes will be installed on surface on the downstream face of the dam. Design and testing of the SP monitoring system, together with numerical and laboratory modelling of expected temperature and SP responses to various seepage scenarios, will be the focus of a PhD thesis project to be completed over the next 3.5 years. The study site and time frame will allow for improvements to monitoring instrumentation and techniques that are appropriate for large embankment dams operating through cold winters and hot summers.