Question

Types of soil simples in soil exploration

Answer 1

There are two main types of soil samples

1) Disturbed samples ,and

2) Undisturbed samples.

Disturbed samples:- These are the samples in which the structure of soil is disturbed to the specific degree by the action of drilling or boring tools. This disturbance can be due to:

1) disturbance of soil structure

2) change in void ratio and water content

3) variations in stress conditions

4) methods of boring

5) type of samplers used

6) change in chemical configuration

On disturbed samples we can perform only certain laboratory test such as : water content test , specific gravity test ,unconfined compression tests, consistancy tests etc.

UNDISTURBED SAMPLES :- these are the samples in which the structure of soil is not Disturbed. For taking such samples ,special samplers are used such as split spoon samplers. There are some special requirements which should be kept in mind to take UNDISTURBED samples these are:

1) there should be no any change in the structure of soil.

2) there should be no change in void ratio and water content.

3) variations in stresses should not be ignored.

4) there should be no change in chemical configuration.

Special set of laboratory tests are performed on such type of samples like Shear tests (Direct shear test and triaxial shear tests) ,test for identification of clay minerals (scanning electron microscope) and also other special tests.