SCOPE:
Determination, in place, of the dry density of natural or compacted fine and medium grained soil.
IS CODE:
IS: 2720(PART XXVIII) ; 1974 In this standard, we had two methods
(A).SMALL POURING CYLINDER METHOD:
This method covers determination, in-place, of the dry density of natural or compacted fine and medium grain soils for which a small sand pouring cylinder is used.
This method is applicable to layers not exceeding 150 mm in thickness.
(B).LODGE POURING CYLINDER METHOD
This method covers the determination, in-place, of dry density of natural or compacted soil containing stones which make the test of section (A) difficult to perform.
This is an alternative method of test to section (A) for fine and medium grained soils and should be used instead of that test for layers exceeding 150 mm but not exceeding 250 mm in thickness.
In this,We going to see about large pouring cylinder method
APPARATUS:
1. Large sand pouring cylinder
2. Tools for excavating holes
3. Cylindrical calibrating container
4. Balance
5. Glass plate
6. Metal containers
7. Metal tray with Central hole
8.Sand.(uniformly graded natural sand passing the 1.18mm IS sieve and retained on the 600-micron IS sieve shall be used.)
PROCEDURE:
Calibration of apparatus:
1.The pouring cylinder shall be filled with the given initial weight of sand(W1)
2. Volume of sand equal to that of the calibrating cantainer should be allowed to run out of the pouring cylinder under gravity.
The shutter on the pouring cylinder Should be closed and the cylinder placed on the plane surface.(on glass plate).
3.The shutter on the pouring cylinder should be opened and sand allowed to run out. When no further movement of sand take place in the cylinder the shutter shall be closed and the cylinder removed carefully.
The sand that has filled the cone of the pouring cylinder shall be collected and weighed to the nearest 0.1 % of its total weight.(W2)
4. The internal volume in ml of the calibrating container shall be determined. (V)
5. The pouring cylinder shall be placed, concentrically on the top of the calibrating container after being filled to the constant weight(W1).
The shutter shall be open and sand allowed to run out, when no for the movement of sand take place in the cylinder the shutter shall be closed.
The pouring cylinder shall be removed and weighted to the nearest gram.(w3).
Measurement Soil density:
At site, The metal tray with a central hole shall be laid on the prepared surface of the soil with the hole over the portion of the soil to be tested.The hole in the soil should be excavate using the hole in the tray as a pattern to the depth of 150 -250mm. The the excavated soil shall be carefully collected and weighed to the nearest gram.(Ww).
The water content of the excavated soil shall be determined as (w).
Then, the pouring cylinder filled with sand to the constant weight(W1).
It should be placed on the hole concentrically.
The shutter on the pouring cylinder shall be opened and sand allowed to run out into the hole.
when no further movement of sand take place the shutter shaWe have to seen large pouring cylinder method.ll be closed.
The cylinder shall be removed and weighed to the nearest gram(W4).
CALCULATION:
The weight of sand required to field calibrating container
(Wa),
Wa = W1 - W3 - W2
Where,
W1 = weight of pouring cylinder and sand before pouring into calibrating container (g).
W3 = weight of cylinder with sand after pouring into calibrating container and cone (g).
W2 = weight of sand in cone (g).
Bulk density of the sand
Where,
V = volume of calibrating container (ml).
The weight of sand required to fill the excavated hole
(Wb),
Wb = W1 - W4 - W3
Where,
W1 = weight of cylinder and sand before pouring into hole (g)
W4 = weight of cylinder and sand after pouring into hole and cone (g).
W2 = weight of sand in cone (g).
Bulk density of soil,
Where,
Ww = weight of soil excavated (g)
Wb = weight of sand required to fill the hole (g)
rb = bulk density of sand (kg/m3)
Dry density of soil
Where,
W = water content of the soil rb = bulk density of soil
Note,
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