Gesteinsfeuchtemessung an natürlichen Felswänden und an Bauwerken und ihr Einfluss auf die Verwitterung

Rock moisture is one of the most important determining factors for the intensity and distribution of weathering processes. However, quantitative measurements are scarce, which is partly due to the lack of reliable measurement techniques. In our studies we apply 2D-resistivity profiling adapted to the requirements of small-scale rock / stonework investigation. We use a GeoTom 2D system with individually manufactured shielded cables for 50 electrodes, connected with crocodile clips to an array of screws drilled in rockwalls or, respectively, medical ECG electrodes stuck to built walls to avoid damage. The spacing between electrodes is 4-8 cm depending on the individual wall geometry, leading to total profile length of 2-4 m. Medical ECG electrodes have been found to provide good electrical contact with the wall surface, without causing any damage and to be robust over several days or even weeks. The overall aim of the sampling campaigns is to investigate the variability of moisture contents over space and time and their relation to weathering features observed.