Consolidation history terminology: A clay deposit that has previously been subjected to an effective overburden pressure greater than its present effective overburden is termed as what?

Introduction / Context:
Clays remember their stress history. When a deposit has experienced higher past effective stress than the current value, it behaves stiffer and stronger at small strains compared to normally consolidated soils. Several terms are used for this condition across literature and practice.

Given Data / Assumptions:

• Present effective overburden is lower than the historical maximum.
• No cementation is implied; purely stress history.
• Terminology differences exist among authors.

Concept / Approach:
“Overconsolidated” describes soils that have been unloaded (erosion, drawdown, desiccation). “Preconsolidated” and “pre-compressed” are often used synonymously to mean the same condition. The key quantitative measure is the overconsolidation ratio OCR = sigma′max / sigma′present > 1.

Step-by-Step Solution:

Verification / Alternative check:
Oedometer e–log sigma′ plots show a preconsolidation pressure where the curve breaks, confirming overconsolidation.

Why Other Options Are Wrong:

• Choosing only one term ignores accepted synonymous usage across geotechnical texts and specifications.

Common Pitfalls:
Confusing overconsolidation with cementation or aging; misreading preconsolidation pressure from lab data.

Final Answer:
All of the above (synonymous usage in practice)