Sand Replacement Test (GNDEC) Sawanpreet Singh Anoop Singh

1. SAND REPLACEMENT
TEST
Sawanpreet Singh
Anoop Singh
Engineering Soil
Testing

2. Objectives
 Density of soil.
 Bulk density of soil.
 Dry density of soil.
 Water content.
 Void ratio.
 Degree of saturation.

3. Applications
 Stress in soil - due to overburden pressure.
 Bearing capacity of soil.
 Settlement of footings.
 Earth Pressure behind retaining wall, dam,
embankments.
 Stability of natural slopes, dams, embankments.
 Field Compaction of soil.
 Permeability.
 Relative density.
 Void ratio, porosity, degree of saturation.

4. Basics
 Density is mass per unit volume.
Density : Mass
Volume
For same volume:
Cotton Steel
Less mass, less density More mass, more
density

5. Principle
Density = Mass/Volume
For sand,
Volume : known (calibrating cylinder)
Mass : known (mass of sand in calibrating
cylinder)
Density can be calculated.

6. Principle
Volume = Mass/Density
For Soil,
Mass : known (mass of sand in hole)
Density : known (calculated earlier)
Volume of hole can be calculated.

7. Principle
Density = Mass/Volume
For Soil,
Mass : known (mass of excavated soil)
Volume known (calculated earlier)
Density can be calculated.

8. Principle
Density(soil) = Mass(soil)
Volume(hole)
Volume(hole) = Mass(sand)
Density(sand)
Density(sand) = Mass(sand)
Volume(cylinder)
Density(soil) = Mass(soil)
Volume(hole)
Volume(hole) = Mass(sand)
Density(sand)
Density(sand) = Mass(sand)
Volume(cylinder)

9. Apparatus
 Sand pouring cylinder
 Trowel or bent spoon
 Cylindrical calibrating container
 Metal tray with hole
 Sand – clean oven dried, passing through 600 micron
sieve
 Weighing balance
 Glass plate

10. Sand Pouring Cylinder

11. Cylindrical calibrating cylinder
100 mm diameter, 150 mm height

12. Metal tray with hole
300 mm square,
40 mm deep,
with a hole of
100 mm diameter
in centre

13. Procedure
 Calibration of apparatus
 Measurement of soil density

14. Calibration
 Step 1
Measure internal volume of calibrating
container from volume of water required to fill
the container.

16. Calibration
 Step 2
Fill the pouring cylinder with sand within about
1cm of top and weigh it.
 Step 3
Place the pouring cylinder concentrically on
the top of calibrating cylinder.

18. Calibration
 Step 4
Open the shutter to allow the sand to run out
and fill the container.
 Step 5
When there is no further movement of sand in
the pouring cylinder, close the shutter.
Remove the cylinder and weigh it.

20. Calibration
 Step 6
Place the pouring cylinder on a place surface
such as glass plate.
 Step 7
Open the shutter to allow the sand to run out.
When there is no further movement of sand in the
pouring cylinder, close the shutter.
Remove the cylinder and weigh it.

22. Measurement of Soil Density
 Step 1
Fill the pouring cylinder with sand within about
1cm of top and weigh it.
 Step 2
Clean and level the ground where the field
density is required.

24. Measurement of Soil Density
 Step 3
Place the metal tray with the central hole over
the portion of soil to be tested.
 Step 4
Excavate the soil approximately 10 cm
diameter as of hole in tray and 15 cm deep.
This volume will be approximately same as
that of calibrating container.

26. Measurement of Soil Density
 Step 5
Collect the excavated soil in metal tray and
weigh it.
 Step 6
Water content of excavated soil can be
determined later on by drying the excavated
soil and weighing it.

27. Measurement of Soil Density
 Determination of Water Content :
mass of water = mass of wet soil – mass of dry soil
water content, W = mass of water X 100
mass of dry soil

28. Measurement of Soil Density
 Step 7
Place the pouring cylinder over the hole so that
base of cylinder covers the hole concentrically.
 Step 8
Open the shutter to allow the sand to run out into
the hole.
When there is no further movement of sand, close
the shutter.
Remove the cylinder and weigh it.

30. Precautions
 If for any reason, depth of excavation is
changed, calibrating cylinder of comparative
depth should be used.
 Hole should not be enlarged by levering the
digger against the side of the hole.
 No loose material should be left in the hoe.
 Initial height of sand should be kept same
during calibration and measurement.
 There should be no vibrations during the test.
 Since dry density of soil varies from place to
place, repeat the test at several points and
take average.

31. Observations and Calculations

32. Observations and Calculations

33. Observations and Calculations

34. Observations and Calculations

35. Result