Geophysical investigations of river dikes in Vietnam

摘要

The safety of river dikes in the Red River Delta is affected by a diversity of problems. Sandy formations in the dike foundation cause seepage effects. Buildings on the dike shoulders results in stability problems. Various termite species dig their nests in the dike body. A variety of geophysical methods were used to investigate weak zones in the dikes. We report the results of investigations of three dike sections in the Hanoi region where geoelectrical resistivity profiling and sounding, infrared surface temperature mapping, and geophysical logging were used. Two-dimensional (2D) inversion of a resistivity profile has successfully detected permeable zones in the dike foundation. In the case of a sealed dike surface, infrared measurements can detect fracture zones. Geophysical logging with density and humidity tools provide reliable depth information in anomalous zones.