What is the main capability of the Unconfined Compression Test?

The main capability of the Unconfined Compression Test is to determine unconfined compressive strength. This test is commonly used to assess the strength characteristics of cohesive soils, particularly clay. During the test, a cylindrical sample of soil is subjected to axial loading until failure occurs. The maximum axial load carried by the sample, divided by the cross-sectional area, provides the unconfined compressive strength value. This parameter is critical in geotechnical engineering as it helps engineers understand how the soil will behave under load, which is essential for foundation design and stability analysis.

The test is particularly valuable because it does not require drainage, making it suitable for undrained conditions often encountered in saturated soils. Therefore, while the Unconfined Compression Test can provide insights that may relate to shear strength and soil behavior, its primary and most straightforward measure is the unconfined compressive strength.