Instrumentation and Monitoring Systems for Evaluation of Plug Responses in Geological Disposal Demonstration

Three of the five demonstration plugs within the DOPAS project had extensive monitoring systems installed to evaluate material and structural performance. The massive full-scale tunnel end plugs were placed in-situ and their performance was evaluated for both the early- and late-ages. The evaluated properties included aspects of concrete hydration, such as temperature rise, as well as any potential responses of the structure and materials to accelerated pressurization to simulate the design-life. Concrete structural monitoring includes properties such as strain and displacement, while the total and water pressure are evaluated behind and around the plug, and in some cases within a bentonite clay layer. The selection of monitoring systems, including both sensors and data collection, has provided insight which can be utilized in various other applications for material performance in challenging environments.