IN-SITU DRY DENSITY BY CORE CUTTER METHOD

AIM
To determine the in-situ dry density of soil by core cutter method as per IS: 2720 (Part XXIX) - 1975.

APPARATUS

i) Cylindrical core cutter
ii) Steel dolley
iii) Steel rammer
iv) Balance, with an accuracy of 1g
v) Straightedge
vi) Square metal tray - 300mm x 300mm x 40mm
vii) Trowel

PROCEDURE
i) The internal volume (V) of the core cutter in cc should be  calculated from its dimensions which should be measured to  the nearest 0.25mm.
ii) The core cutter should be weighed to the nearest gram (W₁).
iii) A small area, approximately 30cm square of the soil layer to  be tested should be exposed and levelled. The steel dolly  should be placed on top of the cutter and the latter should be rammed down vertically into the soil layer until only about 15mm of the dolly protrudes above the surface, care being  taken not to rock the cutter. The cutter should then be dug  out of the surrounding soil, care being taken to allow some soil to project from the lower end of the cutter. The ends of  the soil core should then be trimmed flat in level with the  ends of the cutter by means of the straightedge.
iv) The cutter containing the soil core should be weighed to the  nearest gram (W₂).
v) The soil core should be removed from the cutter and a  representative sample should be placed in an air-tight container and its water content (w) determined as in Para 

REPORTING OF RESULTS

Bulk density of the soil  γ =(W₂ -W₁)/V g/cc

Dry density of the soil γ_d = 100γ/(100+w) g/cc

Average of at least three determinations should be reported to the second place of decimal in g/cc.
A sample proforma for the record of the test results is given below..