Atterberg limits in soil mechanics — the minimum water content at which a soil still behaves as a liquid yet just develops a small shear resistance to flow is called:

Introduction / Context:
The consistency of fine-grained soils changes with water content. Atterberg limits define key transition points between the liquid, plastic, semi-solid, and solid states. The threshold at which a soil stops flowing like a viscous liquid and just begins to sustain a minute shear resistance is fundamental for classification and for predicting field behavior such as workability and settlement.

Given Data / Assumptions:

• Soil is fine-grained (silt/clay) and responds to changes in water content.
• Standard definitions per Atterberg limits are used (liquid limit LL, plastic limit PL, shrinkage limit SL).
• “Small shearing strength” refers to the barely measurable resistance that differentiates liquid from plastic behavior.

Concept / Approach:

The liquid limit (LL) is the water content at which soil changes from a liquid-like state to a plastic state. In the lab, LL is determined by standardized methods (e.g., Casagrande cup or cone penetrometer) that correspond to a very low shear strength. This boundary is used with the plastic limit to compute plasticity index PI = LL - PL, a key classifier in systems like USCS and BIS/IS codes.

Step-by-Step Solution:

Verification / Alternative check (if short method exists):

In practice, the cone penetrometer LL test targets a specific penetration at which the soil’s undrained shear strength is about 1.7–2.0 kPa, aligning with the “small shear strength” description.

Why Other Options Are Wrong:

Plastic limit — boundary between plastic and semi-solid, not liquid behavior.

Shrinkage limit — boundary below which further drying does not reduce volume.

Permeability limit/consistency limit — not standard Atterberg terms defining this transition.

Common Pitfalls (misconceptions, mistakes):

Confusing LL with PL; assuming LL is a fixed property independent of test method; ignoring sensitivity of LL to sample remolding and salts.

Final Answer:

liquid limit