Numerical Analysis of Stability of a Road Embankment Subjected to Floods

Abstract

In the floodplains of the river Indus several road embankments have been failed due to the action of floods. The main motivation for this study is to analyse how much high floods a typical road embankment could sustain and to suggest remedies to prevent failure if the flood is exceptionally high. For this purpose, an 8 m high road embankment located in flood region of the Indus river was analysed for stability when subjected to 4 m and 7 m high floods. Numerical analysis was performed with finite element program PLAXIS 2D. The results showed that the road embankment was stable prior to occurrence of the flood. The road embankment became instable when it was subjected to flood water of 4 m. This implies that the road embankment might not withstand pressure of the flood water higher than 4 m. The analysis suggested that the road embankment could fail if the flood water is 7 m high. To stabilize the road embankment when subjected to 7 m high flood, rockfill berm was utilized on the downstream side. Optimization analysis was conducted to use minimum volume of rockfill in order to reduce costs. The findings of this study could be beneficial to practicing engineers involved in maintenance of road embankments in floodplains