6.14 A 5-m-thick clay layer, drained at the top only, has some sand drains. A uniform surcharge is applied at the top of the clay layer. Calculate the average degree of consolidation for combined vertical and radial drainage after 100 days of load application, given C = C = 4 mm/ min, d, = 2 m, and r = 0.2 m. Use the equal-strain solution. The combined vertical and radial drainage (refer to 5th Ed. example 8.21, lecture notes): Uv,r=1-(1-U)(1 U) (a) Vertical drainage (one side drainage on the top) (b) Radial drainage (using equal-strain solution)