Theory

Unit weight is the weight of soil per unit volume is called unit weight or density. It includes the whole soil mass, the solid particles plus all voids with or without moisture. It depends upon saturation ‘S’. since the dry unit weight of solids per unit of total volume of a soil mass is called dry unit weight.

Volume = Ws/v    gm/c.c.

Application

Therefore density of soil deflects most of the properties of soil. Density of soil in place is compacted soil and used as quality control measured of earth work in embankment in place soil density of natural soil helps to determine bearing capacity, calculation of settlement as well as for stability analysis of natural slops.

Item required

1.     Cylindrical core cutter of steel 127.4 mm long and 100 mm in width a metal thickness of 3 mm at one end.

2.    Steel trolley 2.5 cm high and 10 cm internal diameter with wall thickness 7.5 mm.

3.    Steel hammer.

4.    Steel rule.

5.     Straight edge.

6.    Balance.

7.     Container.



Diagram


Core cutter


Procedure

1.    The inside dimension of core cutter was measured accurately to 0.25 mm and calculated its volume.

2.  The mass of the core cutter without trolley was measured accurately.

3.   Exposed the small area about 30 sq.cm for test levelled that surface put the trolley on the top of the core cutter and drived the assembly into the soil with the help of hammer with the top of the dolly about 1 ½ cm above surface.

4.  Dry weight the container from the surrounding soil and allowed some soil to project from the lower and of the cutter with the help of straight edge.

5.     The mass of cutter face of soil was measured.

6.   Kept some sample of soil for water content determination in the oven.

7.  Repeat the test of the three location neat by end get the average density.



OBS. NO.
DETERMINATION NO.
DETERMINATION
1ST READING
2ND READING
01
Mass of core cutter wet soil (gm)
2645 gm
2580 gm
02
Mass of core cutter (gm)
930 gm
970 gm
03
Mass of wet soil
1715 gm
1670 gm
04
Volume of core cutter (MR)
1021.0 cm3
1021.0 cm3
05
Bulk density P = ¾ g/cm3
1.68 kg/m3
1.58 g/cm2
06
Bulk unit weight Y = 9.81 P
16.48 kg/m3
15.5 kg/m3
07
Container no.
A
B
08
Mass of contain + wet soil
66 gm
37.3 gm
09
Mass of contain + dry soil
58 gm
34.5 gm
10
Mass of container
23 gm
23 gm
11
Mass of dry soil
35 gm
11.5 gm
12
Mass of water
2.89 gm
2.89 gm
13
Water contain
22.66 %
24.35 %
14
Dry density Pd =p/1+w  gm/cm3
1.37 gm/m3
1.28 gm/m3
15
Dry unit wt. Yd = Y/1+w kg/m3
13.41 kg/m3
12.46 kg/m3



RESULTS

1.     Percentage of water content = 24.35 %
2.     Dry density of soil sample = 1.28 gm/cm3
3.     Dry weight of soil sample = 12.46 kg/m3