On the permeability of layered soil system: experimental study

The work presented in this paper aimed at investigating soil stratification and flow movement direction effects on the equivalent normal coefficient of permeability,(k(eq))(n), of a layered soil system following the "falling head" permeability test procedure. A special mold capable of measuring the permeability of layered soil systems was manufactured. Downward flow, horizontal flow and upward flow have been considered. Experimental results showed that the order of soil layers has a significant contribution to the deviation between the experimental and the theoretical values of the equivalent coefficient of permeability. Greater deviations have been observed when the ratio of the inlet layer coefficients of permeability to the exit layer coefficient of permeability exceeds 1.0. A minor effect on the equivalent coefficient of permeability was noticed for the direction of flow movement. Moreover, an empirical formula capable of predicting the experimental coefficient of permeability value was presented herein.