Preliminary investigation of earth dam using multiple geophysical imaging techniques

Every dam site must have a complete stability assessment and seismic integrity evaluation under high ground vibration because aging, foundation deterioration, seepage phenomena, internal erosion, cavities, and cracks have resulted in dam damage. Often ERT technique and in-situ measurement in boreholes are used to monitor the state of the dam. In this project, we propose to use variety of seismic techniques both active and passive seismic combined with 3D ERT and spectral GPR measurements on the same profile. In this study, compression and shear wave velocities were integrated to delineate elastic properties of the dam's materials and evaluate the seismic stability subjected to local soil stiffness and site response at the Rybnik dam and Orzepowice embankment, Poland. To asses those values we used seismic travel time tomography for general recognition of spatial differences, MASW technique to assess water infiltration and reflection seismic imaging to recognize the geological structures under the dam. Here we present initial results and gathered data. We used standard standalone 3C seismic stations combined with Distributed Accousting Sensing (DAS). As sources both sledgehammer and industrial S wave source were used. This setup allows comparison of multicomponent data for both source types. We plan to record seismic data on exactly the same lines next year to obtain time laps observation and recognize the different in the medium.   This research was funded by National Science Centre, Poland (NCN) project number 2022/45/B/ST10/00658.