Toughness index (It) is determined by ratio of plasticity index to flow index: It=IP/If.

The quantity of dry soil and dispersing agent is taken as double of pipette which is 500 ml.

In sedimentation analysis hydrometer method differs from pipette method in method of taking observation.

Concept:

Core cutter test:

• This method is used to find in-situ unit weight in case of fine-grained cohesive soils without stones.
• This method cannot be used in case of hard and gravelly soils.

Equipment used:

1. Cylindrical core cutter, 100 mm internal diameter and 130 mm long.
2. Steel rammer of mass 9 kg and overall length 900 mm
3. Steel Dolley, 25 mm high and 100 mm diameter
4. Weighing balance of accuracy up to 1 gm

Cone penetration apparatus is used for finding WL value, according to IS: 2720 (part 5) -1965.

The right side particle size distribution curve shows coarse-grained while left shows relatively fine-grained soil.

Alternatively, shrinking limit can be found out if specific gravity G of soil grains is known.

Since collapsible soil exhibit loose, weakly cemented sands y are usually present in arid and semi- arid regions.

In liquid limit apparatus, handle is rotated at a rate of about 2 revolutions per second.

Clay containing will have relatively low activity, while montorillonite have high activity.