Permeability Of Soil🔥 | Darcy's Law | Seepage velocity | Soil Mechanics
12.3 PERMEABILITYOFSOIL * Permeability of soil is the property that permits the seepage of water through its interconnected voids. The gravels are highly permeable while clay is least permeable. * Darcy’s Law: Darcy (1856) experimentally demonstrated that for laminar flow conditions the rate of flow (i.e., discharge) per unit time, through a saturated soil, is proportional to the hydraulic gradient. Thus, q = k i A where A = Total cross-sectional area of soil mass normal to the direction of flow. i = Hydraulic gradient k = Darcy’s coefficient of permeability. The above equation may be written as where v is the velocity of flow or discharge velocity. From this relation the coefficient of permeability may be defined as the velocity of flow which occurs through the total cross-sectional area of soil under a unit hydraulic gradient. Seepage velocity Flow can occur through voids only, i.e., it cannot occur through solids. Hence, the velocity inside the soil pores is different form velocity