A wide sand embankment is constructed on a 14m thick clay layer that rests on a impervious hard stratum. The height of the sand embankment is 4m and the clay layer is normally consolidated. The ground water table is at the clay surface level. The unit weight of water is 9.81. The technical data of the clay layer are the compression index =0.6, and the initial void ratio =1.30, and the saturated unit weight =17. The coefficient of the vertical flow is 4.1m2/year. Determine the time taken to achieve the 50% of the primary consolidation settlement of the original embankment and the final corresponding average excess pore water pressure for the entire depth of the clay layer. In addition to the sand embankment, a wide surcharge of 60kpa is also applied to preloading the clay layer. Determine the time taken for the application of surcharge to achieve 50% of the primary consolidation settlement in part (a) above after the completion of the construction of the embankment. Comment on the result. In a different setting with part (a), prefabricated band drains (PVD) of 4mm by 100mm in size are installed before the construction of the embankment through the entire depth of