Which sampler should be used in rocky soils as a preferred option for undisturbed subsurface sampling?

• A. Veihmeyer Tube Sampler
• B. Push Tube Sampler
• C. Split Spoon Tube Sampler
• D. A Trier Sampler

Answer: (A)

When sampling in rocky soils, the goal is to preserve the natural soil structure while obtaining an undisturbed subsurface sample. The Veihmeyer tube sampler achieves this by using a rigid, thick-walled cylinder to take a relatively undisturbed soil column as it is driven or pushed into the subsurface. This design minimizes disturbance to the soil fabric and moisture content, which is crucial in rocky or hard layers where other methods can smear, fracture, or otherwise alter the in-situ conditions. The result is a representative sample of the soil mass that retains its density and stratification, making it preferable for undisturbed sampling in rocky conditions.

Push-tube samplers are useful but can struggle with very hard layers and may disturb the soil structure more as they advance. Split-spoon samplers are typically used for disturbed samples and soil behavior tests that don’t require intact structure. Trier samplers are robust and used in certain stiff or cohesive soils, but the Veihmeyer tube’s simplicity and ability to yield an undisturbed column in rocky soils make it the better choice in this scenario.