Question

For an anisotropic soil, permeability in x and y direction are $k_{x}and{k}_y$ respectively in a two dimensional flow. The effective permeability $k_{eff}$ for the soil is given by

• A. $k_x+k_y$
• B. $\frac{k_x}{k_y}$
• C. $(k_x^2+k_y^2{)}^{1/2}$
• D. $(k_x\times k_y{)}^{1/2}$

Answer 1

The correct option is D $(k_x\times k_y{)}^{1/2}$

Effective permeability $k_{eff}$ for the anisotropic soil,

$k_{eff}=\sqrt{K_x{K}_y}$


Note : Discharge through flow net for the anisotropic soil

$q=k_{eff}{H}_L\frac{N_f}{N_d}$

where,

$k_{eff}=\sqrt{K_x{K}_y}$

$H_L=Totalheadlossthroughflownet$

$N_f=No.offlowchannelsinaflownet$

$N_d=No.ofequipotentialdrops$