AIM
To determine the in-situ dry density of soil by sand replacement
method as per IS: 2720 (Part XXVIII) – 1974.
APPARATUS
SAND-POURING CYLINDER
i) Sand-pouring cylinder conforming to IS: 2720 (Part XXVIII) -
1974
ii) Cylindrical calibrating container conforming to IS: 2720 (Part
XXVIII) - 1974
iii) Soil cutting and excavating tools such as a scraper tool,
bent spoon
iv) Glass plate - 450mm square and 9mm thick or larger
v) Metal containers to collect excavated soil
vi) Metal tray - 300mm square and 40mm deep with a 100mm
hole in the centre
vii) Balance, with an accuracy of 1g
PROCEDURE
A. Calibration of apparatus
a) The method given below should be followed for the
determination of the weight of sand in the cone of the
pouring cylinder:
i) The pouring cylinder should be filled so that the level of the
sand in the cylinder is within about 10mm of the top. Its
total initial weight (W1) should be maintained constant
throughout the tests for which the calibration is used. A
volume of sand equivalent to that of the excavated hole in
the soil (or equal to that of the calibrating container) should
be allowed to runout of the cylinder under gravity. The
shutter of the pouring cylinder should then be closed and
the cylinder placed on a plain surface, such as a glass
plate.
ii) The shutter of the pouring cylinder should be opened and
sand allowed to runout. When no further movement of sand
takes place in the cylinder, the shutter should be closed
and the cylinder removed carefully.
iii) The sand that had filled the cone of the pouring cylinder
(that is, the sand that is left on the plain surface) should be
collected and weighed to the nearest gram.
iv) These measurements should be repeated at least thrice and
the mean weight (W2) taken.
b) The method described below should be followed for the
determination of the bulk density of the sand ( γs ):
i) The internal volume (V) in ml of the calibrating container
should be determined from the weight of water contained in
the container when filled to the brim. The volume may also
be calculated from the measured internal dimensions of the
container.
ii) The pouring cylinder should be placed concentrically on the
top of the calibrating container after being filled to the
constant weight (W1) as in Para a) i), above. The shutter of
the pouring cylinder should be closed during the operation.
The shutter should be opened and sand allowed to runout.
When no further movement of sand takes place in the
cylinder, the shutter should be closed. The pouring cylinder
should be removed and weighed to the nearest gram.
iii) These measurements should be repeated at least thrice and
the mean weight (W3) taken.
B. Measurement of soil density
The following method should be followed for the measurement of
soil density:
i) A flat area, approximately 450sq.mm of the soil to be
tested should be exposed and trimmed down to a level
surface, preferably with the aid of the scraper tool.
ii) The metal tray with a central hole should 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 then be
excavated using the hole in the tray as a pattern, to the
depth of the layer to be tested upto a maximum of 150mm.
The excavated soil should be carefully collected, leaving no
loose material in the hole and weighed to the nearest gram
(Ww). The metal tray should be removed before the pouring
cylinder is placed in position over the excavated hole.
iii) The water content (w) of the excavated soil should be determined by the method specified in Para 5.1. Alternatively, the
whole of the excavated soil should be dried and weighed
(Wd).
iv) The pouring cylinder, filled to the constant weight (W1) as in
Para A.a) i) above, should be so placed that the base of the
cylinder covers the hole concentrically. The shutter should
then be opened and sand allowed to runout into the hole.
The pouring cylinder and the surrounding area should not be
vibrated during this period. When no further movement of
sand takes place, the shutter should be closed. The
cylinder should be removed and weighed to the nearest
gram (W4).
CALCULATIONS
REPORTING OF RESULTS
The following values should be reported:
i) dry density of soil in kg/m3 to the nearest whole number;
also to be calculated and reported in g/cc correct to the
second place of decimal
ii) water content of the soil in percent reported to two
significant figures.
