Why to do Sand Cone test?
Sand cone test is performed to test the field density in highway or road construction.
Actually it is the simplest way to check the compaction of the different layers below the surface of the ground.
Principle of Sand Cone Test
To replace the excavated site soil with the help of the known value of soil to calculate the volume of the dug hole. After that the field density of soil is calculated by dividing mass to the volume of in-situ soil.
- Sand Pouring Cylinder
- The sand of Known density(D1)
- Standard base plate with a hole
- excavating rod
- field soil container
- Weighing Machine
Procedure for Sand Cone Test
Take an empty sand cone and weight it (W1).
Again fill it with known value of sand and reweigh it to get exact weight of test sand(W2).
Now, go to field and place the hole plate where you want to test the density of soil.
After that dig the soil gently deep about 4 to 5 inches with the help of hole base plate.
Take out the dogged soil from hole making the whole inner surface smooth and uniform.
After that, take weight of previously excavated soil from hole(W4).
After that place the sand cone on the hole of plate exactly covering whole around.
Now, let the sand from the cone fill the excavated area by opening the control valve and close the funnel valve once the area filled.
The, again take the weight of the remaining test sand in the funnel.
Let, the remaining weight of sand be (W3).
After calculating the weight of remaining test soil we can calculate the weight of test soil reached to the excavated area (W2-W3).
Now the volume of that excavated portion can be calculated by Volume of Excavation(V) = (Weight of test sand(W2-W3)/density of test sand(D1))
and now you can be able to calculate the field density of soil by formula (Weight of field soil(W4)/ Volume of field Soil(V))
The volume of the hole =Weight of sand in hole(W4)/Density of used sand(D1).
Wet density of Soil in-situ = Mass of wet excavated soil(W4)/Volume of hole(V).
Dry density = Wet density x 100%/ Moisture content of soil + 100.
Degree of compaction = Dry density x 100(370/Maximum dry density. )
Precaution of sand cone test
- The test sand should be dry and fine enough to fill the excavated portion uniformly.
- The inner lateral surface area of the hole should be made uniform before filling the test sand.
- The weight of sand should be taken correctly.
- The base place should be fixed at the testing place with the help rod or nail.
- The control valve should make tight enough after filling the test sand into the hole.