In-Situ Dry Density by Sand Replacement Method


Aim: Determination of in-situ dry density by sand replacement method

Theory

A hole of stated measurements is dug in the ground. The weight of the dug soil is ascertained.

The size of the hole is ascertained by filling it up with clean, unvarying sand whose dry density ( clip_image002 ) is computed distinctly by standardization. The size of the hole is equivalent to the weight of the sand packed in the hole divided by its dry density.

The dry density of the dug soil is ascertained as:

clip_image004

Where,

M= mass of the excavated soil,

V= volume of the hole,

w= water content.

Tool and Equipment

1. Sand – pouring cylinder

2. Calibrating container, 100mm diameter and 150mm stature

3. Soil cutting and excavating tools, such as scrapper tool, curved spoon

4. Glass plate, 450mm square, 9mm dense

5. Metal vessel to gather excavated soil

6. Metal tray, 300mm square and 40mm deep with a hole of 100mm in width at the middle

7. Weighing balance

8. Humidity content cans

9. Oven

10. Desiccator

Clean, unvarying sand passing 1mm IS sieve and recollected on 600micron IS sieve in adequate amount.

Procedure

Part I: Calibration

1. Ascertain the interior volume of the standardizing container by filling it with water and shaping the mass of water essential. The mass of water in grams is roughly equivalent to the volume in milliliters. The volume might also be ascertained from the taken dimensions of the vessel.

2. Fill the sand-pouring barrel with sand, inside around 10mm of its top. Decide the mass of the barrel (M1) to the closest gram.

3. Put the sand-pouring barrel vertically on the adjusting holder. Open the shade to permit the sand run out from the barrel. At the point when there is no further development of the sand in the barrel, close the shade.

4. Raise the pouring barrel from the aligning compartment and measure it to the closest gram (M3).

5. Once again fill the pouring barrel with sand, inside 10mm of its top.

6. Open the screen and permit the sand to come up short on the barrel. At the point when the volume of the sand let out is equivalent to the volume of the adjusting holder, close the shade.

7. Put the barrel over a plane surface, for example, a glass plate. Open the screen. The sand fills the cone of the chamber. Close the shade when no further development of sand happens.

8. Detach the cylinder. Gather the sand left on the glass plate. Decide the mass of sand (M2) that had filled the cone by measuring the gathered sand.

9. Decide the dry thickness of sand, as appeared in the information sheet, part-I

Part II: Dry Density

1. Uncover a zone of around 450mm square on the outward of the soil mass. Trim the surface down to a ground surface utilizing a scrapper instrument.

2. Put the metal plate on the leveled surface.

3. Dig the soil with the help of the focal gap of the plate, utilizing the gap in the plate as an example. The deepness of the exhumed opening ought to be around 150mm.

4. Gather all the uncovered soil in a metal compartment, and then ascertain the mass of the dirt (M).

5. Expel the metal plate from the uncovered gap.

6. Fill the sand pouring barrel inside 10mm of its top. Compute its mass (M1).

7. Put the chamber specifically over the exposed gap. Permit the sand to run out the barrel by opening the screen. Close the shade when the gap is totally filled and no further expansion of sand is witnessed

8. Expel the barrel from the filled gap. Compute the mass of the barrel (M4).

9. Take a representative specimen of the unearthed soil. Ascertain its water content.

Ascertain the dry density of soil as appeared in the information sheet, Part-II.

Data Sheet for Sand Replacement Method

Part-I: Calibration for Dry Density of Sand

Sl. No. Observations an Calculations Determination No.
1 2 3

Observation

1 Volume of calibrating cone VC      
2 Mass of pouring cylinder (M1), filled with sand      
3 Mass of pouring cylinder after pouring sand into the calibrating container and cone (M3)      
4 Mass of sand in the cone (M3)      

Calculations

5 Mass of sand in the calibrating container

MC=(2) – (3) – (4)

     
6 Dry density of sand

clip_image002 =MC/VC

Part II: Dry Density of Soil

Sl. No.                  Observations an Calculations Determination No.
1 2 3

Observation

1 Mass of excavated soil (M)      
2 Mass of pouring cylinder (M1), filled with sand      
3 Mass of pouring cylinder after pouring into the hole and cone (M4)

Calculations

4 Mass of sand in the hole

MS=M1 – M4– M2

     
5 Volume of sand in the hole

V=Ms/ clip_image002

     
6 Bulk density  clip_image003 =M/V      
7 Water content      
8 Dry density using formula

Dry density=_______g/ml.

Result: