Two meters of compacted fill (y = 20 kN/m) is placed over a large area (Figure 4). A rectangular foundation of size 4 m x 5 m is constructed at the site with its base located at the existing ground surface. GWT is found at a depth of 3 m below the existing ground surface. a). Calculate and plot the in-situ vertical effective stress profile to a depth of 16 m below the existing ground surface prior to fill and footing placement. Use points with z = +2, +1, 0, -1, -2, -3, -5, -10, -13, -16 m (with z measured from the existing ground surface). b). Calculate and plot the additional effective stress due to the fill to a depth of 16 m. Use the same points as in part a). c). If the load applied on the foundation is 4 MN, calculate and plot the effective stress increase due to the footing to a depth of 16 m. Use the 2:1 approximate method and the same points as in part a). Summarize your calculations in an Excel spreadsheet and present sample calculations for z = 0, -3, -10 and -16 m (with z measured from the existing ground surface). All three vertical effective stress profiles should be shown on the same plot. Hint: the additional stress due to the fill will be constant with depth as the fill is placed over a large area. -Z Ali ! Bedrock Q = 4 MN 4 mx 5 m 3.0 m Fill y= 20 kN/m Sand = 18 kN/m Year 19 kN/m Clay 7sat = 16 kN/m 20m 10.0 m A 6.0 m Figure 4. Stress increase due to the combined effect of backfill and footing