Answer:
the diameter of the stand pipe is 24.456mm
Explanation:
Given that:
Height of the soil sample = 90 mm
Cross section area of the soil sample = 6000 m²
The head fell from 500 mm to 300 mm
i,e
[tex]H_1 = 500 \ mm[/tex]
[tex]H_2 = 300 \ mm[/tex]
Time = 1500 s
The permeability of the soil (K) was 2.4x10⁻³ mm/s.
The objective is to determine the diameter of the stand pipe. (in mm)
Using the formula :
[tex]K = \dfrac{(2.303 )*a*L}{A*t} log(\dfrac{H_1}{H_2})[/tex]
[tex]2.4*10^{-3}= \dfrac{(2.303 )*a*(90)}{(6000 )*(1500 )} log(\dfrac{500}{300 })[/tex]
[tex]2.4*10^{-3}= \dfrac{(207.27 *a)}{9000000} *0.22185[/tex]
[tex]2.4*10^{-3}*9000000= (207.27 *a)}*0.22185[/tex]
21600 = 45.983 a
a = 21600/45.983
a = 469.74 mm
Recall thar:
a = π/4 (d²)
So;
469.74 = 0.7854 ((d²)
d² = 469.74/0.7854
d² = 598.09
d = √598.09
d = 24.456 mm
Hence ; the diameter of the stand pipe is 24.456mm