Covers the field procedure for determining the in-situ bulk and dry density of natural or compacted soils using the sand replacement method. It is a critical quality control test used widely to verify the degree of compaction achieved in earthworks, road subgrades, and embankments.
Specifies the sand replacement method for determining the in-situ density of natural or compacted soils.
Quick Reference Values
Small pouring cylinder diameter100 mm
Large pouring cylinder diameter200 mm
Standard sand passing sieve1.00 mm IS Sieve
Standard sand retained sieve600 micron IS Sieve
Calibrating container internal depth (Small)150 mm
Calibrating container internal depth (Large)250 mm
Key Formulas
Volume of hole (V) = (W1 - W4 - W2) / γ_s — where W1=initial sand wt, W4=final sand wt, W2=sand in cone, γ_s=bulk density of sand
Bulk Density (γ_b) = Ww / V — where Ww is weight of wet soil from hole
Dry Density (γ_d) = 100 * γ_b / (100 + w) — where w is moisture content in %
Practical Notes
Vibrations from nearby equipment must be strictly avoided during the sand pouring process, as they will prematurely consolidate the sand and alter its bulk density.
The 200 mm (large) cylinder must be used when the soil contains a significant proportion of coarse gravel or stones. The 100 mm (small) cylinder is only for fine to medium-grained soils.
The bulk density of the standard sand should be calibrated frequently (ideally daily), as variations in atmospheric humidity can change its flow characteristics.