SOLVE

Objective:

To determine coefficient of permeability of given soil sample by constant head permeability test.

Apparatus used:

Permeameter, Filter paper, Porous stones, Water tank, Timer, Beakers, Graduated measuring cylinder, Connecting water pipes.

STEP 1

Measure the inner diameter and height of the mould, then calculate the volume of the mould.

Area of mould, A	= π × ^d²⁄₄ =		cm²
Volume of mould, V	= A × L =		cm³

STEP 2

Place the sealing gasket and the porous stone inside the groove of the baseplate.

Setup stand stand Setup

STEP 3

Fix the mould on the base plate. Using the nut and bolt mechanism completely fasten the bolts to make the permeameter completely leak proof and then place a filter paper inside the mould.

Setup stand

STEP 4

Pour the soil sample into the mould in 3 layers with 5 blows to each layer.

Setup Mould

STEP 5

Place a filter paper on top of the soil and then place a porous stone on top of it.

Setup Mould

STEP 6

Insert the sealing gasket into the top plate and place it above the mould. Then using the nut and screw mechanism completely fasten the bolts to make the permeameter completely leak proof.

nut Setup Mould stand stand stand stand stand Mould nut nut nut nut nut nut nut nut

STEP 7

Now connect the water pipe from the overhead tank to the bottom outlet pipe of the permeameter and also open the air release valve.

STEP 8

Allow the water to fill inside the permeameter and all the air voids also will get escaped through the air release valve. Once water starts to flow through the air release valve, stop the water supply and close the air release valve.

STEP 9

Now connect the water pipe to the inlet pipe of the permeameter and allow the flow of water maintaining a constant head of water in the overhead tank.

STEP 10

Collect the water with a measuring jar for a fixed time interval and note down the value. Repeat the same process for different time intervals.

Trial No.	Time, t (sec)	Volume of water, Q (cm³)

Observations:

Trial No.	Time, t (sec)	Volume of water (cm³)

Calculations:

Average of volume of water, Q =		cm³
Coefficient of permeability of given soil sample, (K_t) = ^{Q × L}⁄_{A × t × h} =		× 10^-4cm/s

Inference:

As the value of coefficient of permeability lies between 10^-3 to 10^-4 the soil can be classified as silty sand.

Constant Head Permeability test

Objective:

Apparatus used:

Observations:

Calculations:

Inference: