Volume change upon drying: As water content decreases, the volume of a cohesive soil reduces in which consistency states?

Introduction / Context:
Atterberg limits classify the consistency of fine-grained soils as liquid, plastic, semi-solid, and solid states with decreasing water content. Understanding where volume change occurs is vital for predicting shrinkage, cracking, and settlement in earthworks and foundations.

Given Data / Assumptions:

• Cohesive soil transitions from liquid limit (LL) → plastic limit (PL) → shrinkage limit (SL).
• Below the shrinkage limit, further drying does not reduce volume significantly.
• Typical laboratory definitions apply.

Concept / Approach:

Volume reduction begins above the plastic limit as water drains and adsorbed-water layers thin, continues through the plastic range, and persists in the semi-solid range until the shrinkage limit is reached. Past SL, the soil becomes rigid enough that additional moisture loss produces negligible volume change, only increase in negative pore-water pressure and microcracking.

Step-by-Step Solution:

Verification / Alternative check:

Shrinkage-limit tests quantify the moisture at which further drying causes negligible volume change; measured shrinkage ratio confirms this behavior.

Why Other Options Are Wrong:

Each of (a), (b), (c) alone is incomplete—contraction occurs across all three ranges until SL; “none” is incorrect.

Common Pitfalls:

Assuming shrinkage occurs only in the plastic range; ignoring semi-solid contraction up to SL.

Final Answer:

All of these