This standard specifies the laboratory methods for determining the specific gravity of soil solids. It covers procedures for both fine-grained soils (using a pycnometer or density bottle) and coarse-grained soils (using a gas jar). This fundamental soil property is essential for calculating phase relationships like void ratio and degree of saturation.
Describes the method for determining the in-situ undrained shear strength of soft cohesive soils using the field vane shear test.
Quick Reference Values
Standard reporting temperature27 °C
Accuracy of weighing balance0.001 g for fine-grained soils
Pycnometer/Density Bottle capacity50 ml for fine-grained soils
Typical G for sand (inorganic)2.65 - 2.68
Typical G for clay (inorganic)2.70 - 2.80
Minimum mass of soil for fine-grained soil test25 to 50 g
Key Formulas
G = (M2 - M1) / [ (M4 - M1) - (M3 - M2) ] — Specific Gravity at test temperature T°C
G_27°C = Kt * G_T°C — Specific Gravity corrected to standard temperature 27°C
Practical Notes
Complete removal of entrapped air by vacuum is the most critical step; insufficient de-airing leads to erroneously low specific gravity values.
Applying the temperature correction factor (Kt from Table 1) to normalize the result to the standard 27°C is mandatory for reporting.
The code is split into two sections within Part 3: Section 1 for fine-grained soils and Section 2 for coarse-grained soils, which require different apparatus sizes and sample quantities.