What type of soil sampler would you use to obtain an undisturbed sample of very stiff clay?

What type of soil sampler would you use to obtain an undisturbed sample of very stiff clay?

• A. Split-spoon sampler
• B. Shelby Tube
• C. Piezometer
• D. Pitcher Barrel Sampler

Answer: (D)

To obtain an undisturbed sample from very stiff clay, you want a tool that minimizes disturbance to the soil fabric during insertion and retrieval, so the natural structure and water content are preserved. The pitcher barrel sampler is designed to capture a soil column in a sealed, smooth-walled barrel, reducing shear and disturbance as it is advanced and then withdrawn. This helps keep the stiff clay’s structure intact, yielding an undisturbed sample suitable for testing. In contrast, a split-spoon sampler is driven in and tends to disturb the soil, producing a disturbed sample; a piezometer is used to measure pore pressure rather than to collect a soil sample; and while a Shelby tube is another undisturbed option, the pitcher barrel approach is specifically effective for maintaining column integrity in very stiff clays under field conditions.

To obtain an undisturbed sample from very stiff clay, you want a tool that minimizes disturbance to the soil fabric during insertion and retrieval, so the natural structure and water content are preserved.

The pitcher barrel sampler is designed to capture a soil column in a sealed, smooth-walled barrel, reducing shear and disturbance as it is advanced and then withdrawn. This helps keep the stiff clay’s structure intact, yielding an undisturbed sample suitable for testing. In contrast, a split-spoon sampler is driven in and tends to disturb the soil, producing a disturbed sample; a piezometer is used to measure pore pressure rather than to collect a soil sample; and while a Shelby tube is another undisturbed option, the pitcher barrel approach is specifically effective for maintaining column integrity in very stiff clays under field conditions.