Damage Case Analysis of Predicting Degree of Damage in Embankment by Earthquakes

Abstract

River embankments are verified based on the amount of embankment settlement after an earthquake. Earthquakeverification is carried out using numerical analysis to predict the amount of river embankment settlement after earthquake. However, during earthquakes, not only settlement but also bank cracks may occur. The cracks are damaging to the inside of the river embankment and are thought to have an impact on osmosis and erosion during flood season, but this is not a verification item in the current design approach. Against this background, this study focuses on bank cracks that occur during earthquakes the analysis of damage cases caused by past earthquakes. From damage case analysis, the higher the embankment height, the more likely deep cracks are to occur, and that the smaller the embankment height, the more likely shallow cracks are to occur. Also, from an analysis focus on damage mechanisms, in cases of liquefaction of the embankment, the settlement tended to be large and the cracks shallow. On the other hand, in cases of liquefaction of the foundation ground, the settlement tended to be smaller and the cracks deeper. In some damage cases, embankment opening surveys were carried out after the earthquake. This has revealed not only information on cracks and settlement from outside the embankment, but also damage inside the embankment. The study analysis the results of the embankment opening survey, which confirmed that damage within the embankment tended to be more significant the fine fraction content was smaller.