An embankment is constructed at the top of a 3-layer soil system as shown in the figure. If the magnitude of the external load is 200 kPa, compute the total vertical effective stress at point A due to both the external load and the geostatic stresses. Use the Boussinesq method for your calculations. The material properties are indicated in the table below. 3 m 3 m 4 m Material properties e Gs q = 200 kPa +-3.5 m- == =//=//=//=//=//=//=/ A Soil layer SP CH SW 0.80 0.65 0.70 2.68 2.65 2.70 SP CH SW