Example 3: For a laboratory consolidation test on a soil specimen that is drained on both sides, the following were obtained:
Thickness of the clay specimen = 25 mm
P1 = 50 kN/m2 ; e1 = 0.92
P2 = 120 kN/m2 ;e2 = 0.78
Time for 50% consolidation = 2.5 min
Determine the soil permeability for the loading range.