A permeability test was run on a compacted sample of dirty sandy gravel. The sample was 175 mm long and the diameter of the mold 175 mm. In 90 s the discharge under a constant head of 38 em was 405 cm3 The sample had a dry mass of 4950 g and its Ps was 2710 kg!m3 Calculate (a) the coefficient of permeability, (b) the seepage velocity, and (c) the discharge velocity during the test.

(a). The coefficient of permeability is .

(b). The seepage velocity is 0.0330 cm/s.

(c). The discharge velocity during the test is 0.0187 cm/s.

Explanation:

Given that,

Length = 175 mm

Diameter = 175 mm

Time = 90 sec

Volume= 405 cm³

We need to calculate the discharge

Using formula of discharge

Put the value into the formula

(a). We need to calculate the coefficient of permeability

Using formula of coefficient of permeability

Where, Q=discharge

l = length

A = cross section area

h=constant head causing flow

Put the value into the formula

The coefficient of permeability is .

(c). We need to calculate the discharge velocity during the test

Using formula of discharge velocity

Put the value into the formula

The discharge velocity during the test is 0.0187 cm/s.

(b). We need to calculate the volume of solid in the ample

Using formula of volume

Put the value into the formula

We need to calculate the volume of the soil specimen

Using formula of volume

Put the value into the formula

We need to calculate the volume of the voids

Put the value into the formula

We need to calculate the seepage velocity

Using formula of velocity

Put the value into the formula

The seepage velocity is 0.0330 cm/s.

Hence, (a). The coefficient of permeability is .

(b). The seepage velocity is 0.0330 cm/s.

(c). The discharge velocity during the test is 0.0187 cm/s.