Monitoring the water content evolution of dikes [Elektronische Ressource] = Überwachung der Wassergehaltsentwicklung in Deichen / von Jörg Rings

Monitoring the water content evolution ofdikes¨Uberwachung der Wassergehaltsentwicklung inDeichenZur Erlangung des akademischen Grades einesDOKTORS DER NATURWISSENSCHAFTENder Fakulta¨t fu¨r Physik der Universita¨t (TH)KarlsruhegenehmigteDISSERTATIONvonDiplom-Physiker Jo¨rg Ringsaus Pru¨mTag der mu¨ndlichen Pru¨fung 01.02.2008Referent Prof. Dr. Christoph KottmeierKorreferent Prof. Dr. Kurt RothAbstractA new combination of methods is applied to monitor the water content evolu-tion of soils which is of interest in a broad range of applications, including theenergy balance over land surfaces and the stability of flood-protection dikes.The water content in model dikes is quantified using electrical resistivity to-mography (ERT), and numerical simulations of water flow are used to predictits evolution.The viability of ERT to quantify water content change is shown in experimentson three model dikes. In conjunction with an initial water content estimate, ERTis shown to be applicable for monitoring soil water content. During a floodingexperiment on a full-scale dike model, ERT successfully quantifies the watercontent of 34%. The inversion process that transfers measured data into modelsof subsurface resistivity can be disturbed by inversion artifacts if spatial con-trasts in resistivity are present. Modeling of synthetic data can help identifyartifacts and the modification of inversion regularization can diminish artifacts.