Soil Behavior Terms – Thixotropy, Sensitivity, Remoulding Loss, and Dilatancy Choose the correct statement(s) regarding common soil behavior terms used in geotechnical engineering.

Introduction / Context:
Precise terminology helps geotechnical engineers interpret lab and field results. Four frequently encountered concepts—thixotropy, sensitivity, remoulding loss, and dilatancy—capture time-dependent strength recovery, structure sensitivity, and volumetric response under shear.

Given Data / Assumptions:

• Fine-grained soils may exhibit structure re-formation with time at rest.
• Undrained strengths are compared for sensitivity and remoulding loss.
• Dense sands show characteristic volume change on shearing.

Concept / Approach:

Thixotropy: disturbed clay regains strength with time at constant water content. Sensitivity: S_t = su(undisturbed)/su(remoulded) under undrained conditions. Remoulding loss: strength drop due to remoulding, i.e., su(undisturbed) − su(remoulded). Dilatancy: dense granular soils increase volume when sheared at low confining stress, explaining peak strength and strain-softening behavior.

Step-by-Step Solution:

Verification / Alternative check:

Classical soil mechanics texts and lab standards define these terms consistently. Field observations (e.g., sand heave around footings) illustrate dilatancy; time-restored strength in sensitive clays illustrates thixotropy.

Why Other Options Are Wrong:

Since all listed statements are correct, any single choice omits other valid definitions.

Common Pitfalls:

Confusing thixotropy with consolidation (they are distinct); using sensitivity with drained strengths; ignoring confining pressure effect on dilatancy.

Final Answer:

All of the above