Question

List eleven tests conducted on soils from a soils investigation.
a- Indicate whether each test requires a disturbed or undisturbed sample.

b- Indicate whether each test is used from granular or clay soils.

Answer 1

Test on Disturbed sample:

Disturbed sample is a sample in which soil structure is significantly or completely disturbed and the moisture content may also differ from in-situ value.

Test

1. Sieve Analysis : for classification of soil conducted on granular soil

2. Atterberg limit test : test conducted on clays or fine soils to determine plastic limit , liquid limit and shrinkage limit of soil.

3. Dry density and moisture content : In laboratory these test conducted on Disturbed soil samples for all type of soils.

4. Specific gravity : Test conducted by density bottle and pychnometer. Generally density bottle used for fine grained soils and pychnometer used for granular soils.

5. Differential Free Swell Test
In order to determine the swelling characteristics of the soil, differential free swell test is carried out on soil passing from 425 micron sieve.

6. Direct shear test is carried out using shear box with the Disturbed soil specimen's. This test generally used for granular soils.

7. Permeability tests

There are several tests available to determine a soil's hydraulic conductivity. They include the constant head, falling head, and constant flow methods. Constant head test used for granular soils and falling head test used for clays.

8)The Californian Bearing Ratio

This test is a penetration test used to evaluate the subgrade strength of roads and pavements. Conducted on all type of soils.

9. The Proctor compaction test

This is a laboratory method of experimentally determining the optimal moisture content at which a given soil type will become most dense and achieve its maximum dry density. Used for all type of soils.

(ii) Undisturbed sample:

Undisturbed sample is a sample which retains as closely as practicable, the true in-situ structure and moisture content of soil.

1. Consolidation Test
The consolidation tests were carried out on undisturbed soil specimen in order to determine the settlement characteristics of soil at different depths. Conducted on highly compressible soil.

2. Tri-axial (undrained) tests

Triaxial shear tests are carried out on saturated clay or fine grained soil samples. For unconsolidated undrained tri-axial compression test, the undisturbed soil specimen having diameter 38 mm and height to diameter ration 2 is prepared and placed on the pedestal of the tri-axial cell.

3. Standard Penetration Test:

This test was conducted during the course of investigation work. This test used for granular soil because in fine grained soil pore water pressure affect results significantly. This test also gives idea about soil stratification along with depth.