Question

While computing the values of limits of consistency and consistency indices, it is found that liquidity index has negative value. Consider the following comment on this value.
1. Liquidity index cannot have a negative value and should be taken as zero.
2. Liquidity index can have a negative value.
3. The soil tested is in semisolid state and stiff.
4. The soil tested is in medium soft state.
Which of these statements are correct?

• A. 1 and 4
• B. 1 and 3
• C. 2 and 3
• D. 2 and 4

Hint:

If the Liquidity Index (LI) is negative, the soil is in the semisolid state and is stiff.

Answer 1

The Correct Option is C

Step 1: Understanding Liquidity Index (LI). - Liquidity Index (LI) is given by: \[ LI = \frac{W - PL}{LL - PL} \] where W is natural moisture content, PL is plastic limit, and LL is liquid limit. Step 2: Can Liquidity Index be negative? - Yes, LI can be negative when natural moisture content (W) is below the plastic limit (PL). - This happens when soil is in the semisolid state and is stiff. Step 3: Evaluating the statements. - Statement 1 is incorrect because LI can be negative. - Statement 2 is correct because LI can have negative values. - Statement 3 is correct because negative LI means soil is in the semisolid state. - Statement 4 is incorrect because medium soft soil has positive LI. Thus, the correct answer is (C) 2 and 3.