Presentation on theme: "Flow through Soils (ch7). Energies Kinetic E (velocity) Strain E (fluid pressure) Potential E (elevation) Head: convert each form of energy into the equivalent."— Presentation transcript:
Energies Kinetic E (velocity) Strain E (fluid pressure) Potential E (elevation) Head: convert each form of energy into the equivalent potential energy and express it as the corresponding height. units of LENGTH
Heads h v = velocity head (KE) h p = pressure head (SE) h e = elevation head (PE) h = total head = h v + h p + h e (Bernoulli) units of LENGTH
k pore size Hazen’s Correlation ~ (pore diameter) 2 (pore diameter) ~ D 10 For loose clean sands with 0.1mm < D 10 < 3mm and C u < 5 k = [cm/sec] C = Hazen’s coefficient = 0.8 – 1.2 (typical = 1) D 10 = [mm] USE THESE UNITS!
Example Given:k sand = 4x10 -2 cm/sec reservoir length (into board) = 1000 m clay 3.2 m sand seam 256 m el. = 167.3m el. = 165m Compute seepage loss (Q) through the sand seam
Solution Q = kiA k = 4x10 -2 cm/sec i = h/L = (167.3m – 165m) / 256m = 0.009 A = (3.2 m) (1000 m) = 3200 m 2 Q = kiA = 0.0115 m 3 /sec = 41.5 m 3 /hr