Have tested rocks in the laboratory and in the field
In collaboration with SINTEF Energi and NTNU, Lena Selen has through her work looked at the effect swelling mechanisms and the weathering of rock material have on already weathered or weak rock.
This has been done by looking at the different methods that are often used to assess different rock materials' composition, strength, swelling properties (how they react with water), as well as how the properties change when the rock material gets wet and dried in several cycles, as they often do in the hydropower tunnels.
In addition, she has worked to improve laboratory assessments of swelling or weak rock in order to predict potential challenges with stability and the need for protection in water tunnels. She has also tested measurements of in-situ swelling potential and weathering during full-scale operation of the hydropower plant.
Through the research carried out in the project, several critical limitations of current test methods for swelling and weak rock material have been highlighted, these can in turn lead to too little securing of weak areas or an unnecessary reinforcement in parts of the tunnel that do not need it.