Answer Happy

(3 marks) The soil profile at a site is shown below and consists of 2 m of silty sand underlain by 5 m of soft, normally consolidated sandy clay, then a layer of sandy gravel. The water table lies 1.5 m below the ground surface level. A 3 m-high compacted fill is constructed at the ground. Soil properties are as follows: Silty Sand: bulk unit weight = 17 kN/m', saturated unit weight = 18 kN/m'; Soft Sandy Clay: fully saturated (S=100%), initial water content = 27.5%, specific gravity = 2.71, Compression Index (C) = 0.58, Coefficient of Volume Compressibility (m) = 0.00135 kPa coefficient of consolidation of clay (c) = 2 m /yr; Compacted fill: bulk weight = 19.5 kN/m! = If the final or ultimate consolidation settle is 23.9cm (a) estimate the time for 50 mm consolidation settlement, in years and days. (b) Estimate the consolidation settlement in 15 months. (c) How long will it take the clay layer to reach 90% consolidation, in years. 1.5m Silty Sand SM 2m Soft Sandy Clay CH Sm Sandy Gravel GP