A Study on the Performance of a Reinforced Dike Section With Geogrid During the Tottori-Ken Seibu Earthquake

A dike section reinforced with geogrid against soil liquefaction was hit by a damaging earthquake in 2000. As the site condition of this dike section was anticipated to be liquefied by an earthquake, so it was decided to take remedial measures against possible damage. However, since the hinterland of this newly constructed dike section was a rural area, primary objective of the treatment design was set to avoid the stretching effect caused by the liquefaction. For this purpose, three sheets of geogrid were laid at the bottom of the embankment. It was detected that 85% length of the dike section survived successfully without apparent damage after the earthquake. As this type of remedial treatment was a first attempt, this section was instrumented to monitor strong ground motion, change of groundwater level, and the subsidence of the dike since the completion of the embankment construction in 1996. Thus the effectiveness of the geogrid was shown together with the instrumented records on the behavior of the dike section during the earthquake