ANALYSIS OF EMBANKMENT ON SOFT SOIL

Abstract

Embankments are the structural barrier used especially to hold the water back. The ground should be enough stable to bear the load of embankment. In the present study, the soil at the base is soft clayey soil. So it is necessary to improve the ground conditions. There are number of methods available to improve the ground conditions such as sand drains, jet grouting, compaction grouting, preloading, sand drains, etc. Even though the mentioned processes are costly and time consuming, they must be done in order to mitigate the undesirable consequences. Sand Drains are considered under the scope of the study for improving the ground conditions. The main objective of the study is to determine the behaviour of embankment on soft soil by studying maximum displacement and excess pore pressure for varying properties under „No Sand Drain Condition‟ and thus comparing the results with the varying properties under „With Sand Drain Condition‟. A numerical model is developed in PLAXIS-2D for both conditions. In the detailed parametric study, effect of key parameters like slope of embankment, surcharge and soil modulus is investigated. Also, influence of sand drain with respect to its diameter and spacing is examined. The results showed that the maximum displacement for „No Sand Drain Condition‟ is always more than the maximum displacement under „With Sand Drain Condition‟ for all values of different key parameters. The maximum displacement increases with the time. Furthermore, the extreme excess pore pressure under „No Sand Drain Condition‟ is always more than the extreme excess pore pressure under „With Sand Drain Condition‟ for all values of different key parameters. This is because of the higher dissipation of pore pressure due to the presence of sand drains. The excess pore pressure dissipates with the time and thus becomes less after significant amount of time.