Geotechnical Engineering, Civil Engg, Bhimaji Dashrath Kanawade

1. Experiment No. 06 (A) Date:
DETERMINATION OF FIELD DENSITY BY CORE CUTTER METHOD
Object and scope:
To determine field density and dry density of given soil sample by Core cutter method.
Reference:
IS: 2720 (Part-29) - 1975
Theory:
Density of soil: The density of the soil is defined as the mass of the soil per unit volume.
Bulk density (ρ): The bulk density or moist density is total mass ‘M’ of the soil per unit of its volume.
Thus ρ = M/ V
It is expressed in terms of g/ cm3 or kg/cm3
Dry density (ρd): The dry density is the mass of solids per unit of total volume (prior to drying of the
soil mass.
Thus ρd = Ms/ V
Field density and dry unit weight of soil can be determined by the following methods
1) Core cutter method: suitable for cohesive soil
2) Sand replacement method: suitable for cohesive as well as non cohesive soil.
3) Clod method: suitable for cohesive soil.
All above method are useful to find the density of natural soil deposit or man-made deposits like
embankments, earth fill behind retaining wall and to check the compaction parameters of soil during
construction etc.
Equipment:
1) Cylindrical core cutter of steel, 130 cm long and 10 cm internal diameter with a wall thickness of 3
mm, beveled at one end
2) Steel dolly, 2.5 cm high and 10 cm internal diameter with wall thickness 7.5 mm fitted with a lip to
enable it to fit on top of the core cutter.
3) Steel rammer having mass of 9 kg.
4) Palette knife
5) Steel rule
6) Spade or pickaxe or grafting tool
7) Straight edge
8) Balance accurate to 0.1gm
9) Container for water content determination.
Procedure:
1) Measure the inside dimension of the core cutter and calculate its volume. Find the mass of the core
cutter (without dolly).

2. 2) Expose the soil area, about 30 cm2 to be tested and level it. Put the dolly on the top of the core cutter
and drive the assembly into the soil with help of rammer until the top of the dolly protrudes about
1.5cm above the surface.
3) Dig out the container from the surrounding soil and allow some soil to project from the lower end of
the cutter. With the help of the straight edge, trim flat end of the cutter. Take out the dolly and also
trim flat other end of the cutter.
4) Find the mass of the cutter with soil.
5) Keep some representative specimen of soil for water content determination.
6) Repeat the test at two or three locations nearby and get the average dry density.
Observation table:
Sr.
No.
Determination no. Sample-1 Sample-2 Sample-3
(A) Determination of bulk density of soil
1 Mass of core cutter (kg)
2 Mass of core cutter + wet soil (kg)
3 Diameter of core cutter ‘d’ (m)
4 Height of core cutter ‘h’ (m)
5 Volume of core cutter (m3)
6 Bulk density ‘ρ’ (kg/ m3)
Average Bulk density (kg/m3)
(B) Determination of water content
7 Container No.
8 Mass of container m1(gm)
9 Mass of container + wet soil m2(gm)
10 Mass of container + dry soil m3(gm)
11 Water content ω (%)
12 Dry density ρd= ρ / (1+ ω) (kg/ m3)
Average value of dry density (kg/ m3)
Calculation:
Bulk density ρ = M/ V
Dry density ρd = ρ / (1+ ω)
Result:
1. Bulk density of soil, ρ =
2. Dry density of soil, ρd =

3. Fig.1. Core Cutter Apparatus for Field Density Determination