Question

Sensitivity of a soil is defined as the ratio of the
1. undisturbed strength to the remoulded strength at same water content
2. undisturbed strength to the remoulded strength at 100% moisture content
3. remoulded strength to the undisturbed strength at same water content
4. remoulded strength to undisturbed strength at 100% moisture content

Answer 1

Correct Answer - Option 1 : undisturbed strength to the remoulded strength at same water content

Explanation:

Sensitivity (S_t):

(i) Consistency of a clay sample is altered even at the same water content on its remoulding. This change in consistency or loss of straight takes place due to the following:

• Due to permanent destruction of soil solids on remoulding.
• Due to change in orientation of the water molecules in the adsorbed layer of soil solids.

(ii) Sensitivity is defined as the ratio of the unconfined compressive strength of an undisturbed specimen of the soil to the unconfined compressive strength of a specimen of the same soil after remoulding at unaltered water content.

\({\rm{Sensitivity}} = \frac{{\left( {{\rm{qu}}} \right){\rm{\;undistrubed}}}}{{\left( {{\rm{qu}}} \right){\rm{\;remoulded}}}}\)

(iii) It represents degree of disturbance achieved on remoulding.