Village Protection during Flooding by Wrap Faced Embankment at Netrokona, Bangladesh

Abstract

In this paper, a case study is presented for a wrap face embankment. This type of embankment is found to be more efficient than a traditional embankment in case of stability, dynamic wave action under flooding. In the deltaic region, where soft soil exists below an embankment, it may suffer relatively more damage. Under this situation, a wrap-faced embankment may be a relatively better solution. The example presented here is based on a real-life wrap-faced embankment on a soft soil area located at Nowagoan Alga Hati village under Mohanganj upazila, Netrokona, Bangladesh. This study also discusses the application of soil improvement for soft soils via jet grouting in some parts of the site. Jet grouting has improved soil stability and soil settling after being applied to the soil. Soil strength before and after jet grouting were 0.005 MPa and 0.94 MPa respectively. The soil gains 186.8 times the strength of soil before applying jet grouting which was very impressive. Jet grouting also improved the settlement of soil to a great extent. The areas without soil improvement by jet grouting showed more settlement than the areas with jet grouting. After flooding, settlement of wrap face embankment without jet grouting area was found to be 112mm. On the other hand, settlement of wrap face (after flooding) in the jet grouting area was only 19mm. This research output is significant for design and implement of the future flood resilient embankment in the Deltaic region.