To determine the field density by Water Replacement/Oil Replacement Method.

OBJECT : To determine the field density by Water Replacement/Oil Replacement Method.

OBJECTIVE AND SCOPE

This method covers the determination of the in-situ density of compacted soils by using a core cutter. The in-situ density of natural soil is needed for the determination of the bearing capacity of soils for the purpose of stability and analysis of slopes, for the determination of pressures on underlying strata for the calculation of settlement, and for the design of underground structures. It is a very quality control test, where compaction is required, in the cases like embankment and pavement construction.

STANDARDS

AASHTO T191-86

ASTM D1556-82

BIS1377:part 4

EQUIPMENT

Shoveling tool, Plastic or balloon, Water, Graduated cylinder, Plastic bag for soil, containers sensitive weight balance.

THEORY

The in-situ density is defined as the bulk density of soil measured at its actual depth. By conducting this test, it is possible to determine the field density of the soil. The moisture content is likely to vary from time and hence the field density also. So it is required to report the test result in terms of dry density.

PROCEDURE

1. Dig out the soil sample required for the test and store it in a plastic bag.
   
2. Now place the plastic bag inside the pit.
   
3. Pour water into the pit from the graduated cylinder and note the volume of water till it fills the pit.
   
4. Now take the weight of the soil sample and find its Bulk density.
   
5. Now find its Dry density.
   

OBSERVATION

Moisture Content:

Wt. of container + Wet Soil (W)= ___________ (gm)

Wt. of Container (W_c)=____________ (gm)

Wt. of Container + dry soil (W_d) =____________ (gm)

Wt. of Moisture (W-W_d) =____________ (gm)

Wt. of dry soil (W_d-W_c)=____________ (gm)

Moisture Content w = ((W-W_d)/ (W_d-W_c))x100=____________ (%)

Dry Density:

Wt. of wet soil (W_s)=____________ (gm)

Volume of soil (V_s)=____________ (c.c)

Bulk density of soil (Y = (W_s/V_s))=____________ (g/c.c)

Dry density of soil (Y_{d =} (Y/1+w))=____________ (g/c.c)

Result

The field dry density of the soil comes out to be(g/cm³)

Review Questions

1. Can we use any other liquid, instead of water in this test?
   
2. What is the density of water in g /cm³?
   
3. Which method is more accurate between sand cone and water displacement, to determine field density of soil and why?