Venice channel side-wall assessment with GPR technique - A case study

A Ground Penetrating Radar survey was recently conducted in the Murano Island in the Venice Lagoon, to assist an ongoing channel and bank refurbishment activity. The major survey targets were detected and resolved down to the depth of the salty water table. The brine saturated environment limited effective propagation of electromagnetic waves. The results of some test records, conducted in a drained bank, have been obtained after a crucial trial phase of the optimum transducers and data processing choices. Radar penetration capability was suddenly increased after concrete reinforcement injection into bank's brine filled fractures and cavities. This occurrence has suggested the use of the radar system as a sort of reflectometer to map temporal changes in the dielectric properties of the investigated structure. Some field procedures have been developed with non-invasive and cost- effective radar imaging techniques to assess the quality and the amount of the grout injection. GPR results, confirmed by drilling cores, have been useful to calibrate the best concrete mixture. The detail of the radar images and its capability to provide comprehensive information proved to be an essential complement to direct investigations in engineering quality test of wall assessment. © 2004 Elsevier B.V. All rights reserved.