Soil exploration – common tool for obtaining a disturbed sample Which sampler is most commonly used to obtain a disturbed soil sample during in-situ investigations for foundation design?

Introduction:
Distinguishing between disturbed and undisturbed sampling methods is vital for geotechnical design. Disturbed samples are routinely taken for identification, classification, and index testing, while undisturbed samples are needed for strength and compressibility measurements. The Standard Penetration Test (SPT) apparatus and sampler are ubiquitous in practice.

Given Data / Assumptions:

• Routine subsurface exploration for building foundations.
• Typical borehole drilling with wash/rotary methods.
• Need for classification tests (moisture content, Atterberg limits, grain size).

Concept / Approach:

The split spoon sampler, driven during the SPT, retrieves a sample that is disturbed due to dynamic driving and cutting. It is rugged, economical, and yields N-values used for correlations, making it the most commonly used tool for disturbed sampling. Open drive samplers are also disturbed but less universal; piston and Shelby tube samplers aim for relatively undisturbed samples in soft cohesive soils.

Step-by-Step Solution:

Verification / Alternative check:

Project records and standards show widespread SPT usage globally, confirming the prevalence of split spoon sampling for disturbed material retrieval.

Why Other Options Are Wrong:

Open drive (B) is used but less standard than SPT; piston (C) and Shelby (D) target undisturbed samples; core barrels (E) are for rock/cemented materials and aim at relatively intact cores.

Common Pitfalls:

Using SPT samples for strength/compressibility without correction; mislabeling Shelby tube samples as disturbed when handled carefully.

Final Answer:

split spoon sampler