SAND REPLACEMENT METHOD

Updated: Apr 1, 2020

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.




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