Unconfined Compression Test of Soils Procedure

Unconfined Compression Test is similar to a compression test performed on concrete cylinders and is made by applying an axial load to cylindrical or prismatic soil samples and measuring the deformation corresponding to the stress as the load is increased. When the stress reaches the ultimate strength, the sample may fail either by a gradual bulging or by a sudden rupture. The ultimate strength of a test specimen prepared from an undisturbed sample (at unaltered moisture content), is a relative measure of the ultimate bearing capacity of a soil. A comparison of the stress-strain characteristics of a soil tested in the undisturbed state, and then in the remoulded state at unchanged moisture content, is indicative of the structural damage caused by remoulding. A simple apparatus intended for field use has been developed. Unconfined Compression Test is generally the most convenient for immediate tests on saturated or nearly saturated clays.