The flow of ground water in a buried permeable paleo‐channel can be observed at the ground surface through its self‐potential signature. We apply this method to delineate the Saint‐Ferréol paleo‐channel of the Rhone River located in Camargue, in the South East of France. Negative potentials, ∼−30 mV (reference taken outside the paleo‐channel), are associated with ground water flow in this major sand‐filled channel (500 m wide). Electrical resistivity is primarily controls by the salinity of the pore water. Electrical resistivity tomography and in situ sampling show the salinity of the water inside the paleo‐channel is ten times smaller by comparison with the pore water of the surrounding sediments. Combining electrical resistivity surveys, self‐potential data, and a minimum of drilling information, a 3‐D reconstruction of the architecture of the paleo‐channel is obtained showing the usefulness of this methodology for geomorphological reconstructions in this type of coastal environment.
This paper investigates the feasibility of a real-time tunnel location-based services (LBS) system to provide workers’ safety protection and various services in concrete dam site. In this study, received signal strength- (RSS-) based location using fingerprinting algorithm and artificial neural network (ANN) risk assessment is employed for position analysis. This tunnel LBS system achieves an online, real-time, intelligent tracking identification feature, and the on-site running system has many functions such as worker emergency call, track history, and location query. Based on ANN with a strong nonlinear mapping, and large-scale parallel processing capabilities, proposed LBS system is effective to evaluate the risk management on worker safety. The field implementation shows that the proposed location algorithm is reliable and accurate (3 to 5 meters) enough for providing real-time positioning service. The proposed LBS system is demonstrated and firstly applied to the second largest hydropower project in the world, to track workers on tunnel site and assure their safety. The results show that the system is simple and easily deployed.
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