Civil Engineering - UPSC Civil Service Exam Questions - Discussion

Vane shear test is used to determine the cohesion or shear strength of sensitive soft clays because their cylindrical specimen cannot be easily prepared. It is necessary that the soil mass should be saturated completely because the angle of shearing resistance will not be zero for partially saturated soils. This method should be used when;

(i) Clay is deep, normally consolidated and sensitive
(ii) Only the undrained shear is required.

The test cannot be conducted on the fissured clay or the clay containing sand or silt laminations.

It can be also used for determination of liquid limit of soils because of the shear strength at liquid limit about 2.7 kN/m2.

I think C is correct.

Option B should be correct. Vane shear test used to check shear strength of clay soil.

How C is correct? Explain it @Roy.

C is the correct answer.

In vane shear test, we determine a shear parameter (cohesion), shear strength. So, Option B is CORRECT.

C is the correct answer.

I think C is correct.

The Vane shear test is used to determine the cohesion or shear strength of cohesive clay not for sand.

Hence options A and B are incorrect and used to find the liquid limit also, shear strength at the liquid limit is about 2.7kn/m2.