Given below, the following soil layering system: a. Calculate the total stress, pore water pressure and the effective stress at each of the following levels (i.e., levels 1,2,3 and 4)? b. Draw the variation plot for total stress, pore water pressure and effective stress in the box to the right of each level. SAND, V=18 kN/m 2 q=40 kN/m CLAY, V=19 kN/m 3 CLAY, V=20 kN/m 4 h1=4m h2=3m h3=3m Variation plot for total stress, pore water pressure and effective stress