Evaluation of levee stability considering foundation soil conditions using centrifuge and numerical modeling

Abstract

Embankment and levee are important structures which are closely related to human life. Failures of river embankment and levee have been recently growing due to climate change over the world. Therefore, extensive embankment reinforcement has been widely performed along the major rivers as a part of Four-River-Refurbishment-Project by Korean government. Therefore, evaluation of levee stability becomes an important issue. In this study, geotechnical perspective for evaluating the levee stability is focused. Especially, the seepage and deformation characteristics of levee according to the foundation soil conditions were deeply analyzed because the role of foundation layers on entire embankment system has been ignored in practice. Total three conditions of levee were categorized in accordance with the geotechnical perspective. Centrifuge tests were performed on critical conditions and numerical analyses were performed for validating the centrifuge test and proposing the design method. Two types of levee were selected in order to understand the seepage characteristics. One is the Gimpo-levee which has high possibility of piping because of unexpected high permeable layer in foundation. On the contrary, the other is Nam-myeun-levee which has the low permeable foundation on the gravel layer with ground water level. As the results, piping failure was successfully reproduced through centrifuge test and it was investigated whether piping occur or not according to the conditions of permeable layer, which are location, length, and hydraulic conductivity of permeable layer. In the case of Nam-myeun-levee, the low permeable foundation shows the high degree of saturation even the foundation is on the ground water level and it can affect to the seepage characteristics in the embankment. Buyeo-levee, which has enlargement embankment on soft foundation, was analyzed for understanding the deformation characteristics. Centrifuge model was modeled considering the staged-constructio...