A barrel sampler is a tool used in environmental and geotechnical field investigations to collect soil or sediment samples from below the ground surface. It typically consists of a hollow tube or barrel that can be pushed or hammered into the soil to extract a cylindrical core sample. Barrel samplers come in various designs, but they are generally characterized by their ability to capture an intact section of soil or sediment for analysis.

The collected samples can be used to assess soil composition, contamination levels, and other geotechnical properties. Barrel samplers are commonly employed in environmental site assessments, construction projects, and geological studies to gather representative samples from specific depths in the subsurface.