Determination Of Field Density By Core Cutter Method 6j6hn

Geotechnical Engineering – I

Experiment No. 2(A)

Experiment no.2 (A) Title:- Determination of field density by Core Cutter method Object and Scope :The object of the test is to determine the dry density of soil in place by the core cutter

Material and Equipment :1) Cylindrical core cutter of steel 127.4 mm 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 mm internal diameter, with wall thickness 7.5 mm filled with a lip to enable it to be fitted on top of the core cutter. 3) Steel Rammer 4) Palette Knife 5) Steel Rule 6) Spade or pickaxe or grafting rod 7) Straight Edge 8) Balance to 1gm 9) Container for water content determination

Test Procedure :1) Measure the inside dimension of the core cutter and calculate its volume. Weigh the core cutter accurate to 1 gm. 2) Expose the small area, about 30 cm square to be tested and level it. Put the dolly on the top of the core cutter and drive the assembly into the soil with the help of the rammer until the top of the dolly protrude about 1½ cm above the surface.

FIELD DENSITY BY CORE CUTTER

7

Geotechnical Engineering – I

Experiment No. 2(A)

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 the end of the cutter. Take out the dolly and also trim flat the other end of the cutter. 4) Weigh the cutter full of 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.

Reference To Indian Standard:IS 2720-1975/88 (Part XXIX) Determination of dry density of soil in place by the core cutter method

Discussion :The Core cutter method is suitable for soft cohesiveness soils, where can be pushed without disturbing the soil. It cannot be used in soil containing boulders and cobbles. It can be used in moist soils.

Observation Table:1) Diameter of core cutter = d = 2) Height of core cutter = h = 3) Volume of core cutter = v =

FIELD DENSITY BY CORE CUTTER

10

12.8 = 1005.3 cm³

8

Geotechnical Engineering – I Sr no.

Description

1

Mass of empty core cutter (M1) gm

2

Mass of cutter + wet soil (M2) gm

3

Mass of wet soil (M2 – M1) gm

4

Volume of core cutter (Vc) cm³

5

Bulk Density =

6

Bulk unit weight = bulk density X 9.81 KN/m³

7

Average bulk unit weight KN/m³

Sr no. 1 2 3 4 5 6 7

Experiment No. 2(A)

=

1

2

gm/cm³

Description

1

2

3

1

2

3

Mass of container (M3) gm Mass of container + moist soil (M4) gm Mass of container + dry soil (M5) gm Water content

w

%

Average water content w% Dry unit weight = ρ

!"#$ "%&' ()&*+' ,-(

Average dry unit weight KN/m³

Result:Average dry unit weight =

FIELD DENSITY BY CORE CUTTER

9