For a laboratory consolidation test on a 25-mm-thick clay specimen (drained on both ends), the following data were obtained: e ' (kN/m2) 0.85..................125 0.71..................250 If

For a laboratory consolidation test on a 25-mm-thick clay specimen (drained on both ends), the following data were obtained:
e σ' (kN/m2)
0.85..................125
0.71..................250
If the time for 70% consolidation is 4.8 min, determine the hydraulic conductivity of the clay for the loading range.