The following data are for a falling-head permeability test:
• Length of the soil sample = 500 mm
• Area of the soil sample = 1600 mm2
• Area of the standpipe = 97 mm2
• At time t = 0, head difference = 410 mm
• At time t = 10 min, head difference γw = 185 mm
If the test was conducted at 20°C at which gw = 9.789 kN/m3 and h = 1.005 × 10-3 N s/m2,
a. Determine the absolute permeability of the soil (cm/sec).
b. What was the head difference at t = 7 min?